Dose delivery mechanism

The invention relates to a dose delivery mechanism such as an injection pen.

Injection pens can be used for self-injection of a certain amount of a drug, i.e. a certain dose. In order to self-inject the drug, the patient usually has to set a desired dose and then push an actuation member at a distal end of the injection pen in a proximal direction. Most pens use a gearing mechanism with a gearing ratio between 2 and 4 to reduce the force needed to push that actuation member. Such pens are limited regarding the amount of drug that can be self-injected during one actuation of the pen because there is a maximum distance the actuation member can be comfortably pushed with the thumb while holding the pen in one hand.

There is a need for a dose delivery mechanism that allows self-injecting a larger amount of drug in a comfortable manner.

The object is satisfied by a dose delivery mechanism comprising a piston rod and a nut, wherein the piston rod forms an outer thread meshing with an inner thread of the nut, wherein during dose setting, the nut is configured to be rotated relative to the piston rod to advance the nut with respect to the piston rod by a first distance into a distal direction, an actuation member that is movable by a user to effect delivery of a set dose, and a housing, wherein a second threaded connection is provided, wherein the second threaded connection is configured to cause the actuation member to travel a second distance into the distal direction during dose setting, wherein the actuation member is coupled via the nut to the piston rod during dose delivery to advance the piston rod by the first distance into a proximal direction upon proximal movement of the actuation member by the second distance, wherein the second distance is less than 1 .5 times the first distance.

The general idea behind the invention is a dose delivery mechanism that has a relatively small gear ratio to allow delivery of a relatively high amount of drug with a relatively small axial movement of the actuation member.

The second threaded connection may have a constant pitch. The second threaded connection may act between the housing and the actuation member. The actuation member may be configured to follow a path defined by the second threaded connection during dose setting. Alternatively, the actuation member may also be configured to linearly travel the second distance during dose setting while a separate member of the dose delivery mechanism follows the path defined by the second threaded connection.

For example, the second threaded connection may act between a dosing member of the dose setting mechanism and the housing. Thereby, the dosing member may be configured to follow the path defined by the second threaded connection during dose setting. For example, the dosing member may be directly engaged with the housing via the second threaded connection so that the dosing member and the housing form the second threaded connection. The dosing member and/or the housing may also be connected to the second threaded connection via one or more respective intermediate members, such as via an intermediate member that is axially and/or rotationally fixed with respect to the dosing member and/or via an intermediate member that is axially and/or rotationally fixed with respect to the housing.

The actuation member may be configured to both rotationally and linearly travel together with the dosing member in the distal direction during dose setting. Alternatively, the actuation member may also be configured to only linearly but not rotationally travel together with the dosing member at the distal direction during dose setting.

The dose delivery mechanism may comprise a dose setting member that is configured to be gripped and actuated, for example rotated, by a user to set the dose to be injected. For example, rotation of the dose setting member may cause relative rotation of two members that are engaged with each other via the second threaded connection during dose setting, such as the housing and the dosing member. The dose setting member may be configured integral with or rigidly connected to the actuation member, for example as a member that is rotated for setting a dose to be injected and that is pushed in the proximal direction to effect delivery of the set dose. The dose setting member may also be configured separate from the actuation member, for example as a dose setting ring provided around the housing of the dose delivery mechanism.

The first distance is defined by the pitch of the first threaded connection between the piston rod and the nut and the second distance is defined by the pitch of the second threaded connection. The first distance has to match to the desired expelled dose. When using a typical commercial cartridge with nominal fill volume of 3ml, that distance would be about 14mm to expel 1 .0ml. The limit for the second distance is given by a usability assessment and could for example be 20mm. So, if the maximum dose to be expelled from the pen injector would be 1 ml, the pitch of the second threaded connection would be less than 1 .4 times the pitch of the first connection. Additionally or alternatively, a minimum tolerable value of the second pitch may be larger than a maximum tolerable value of the first pitch, whereas the minimum tolerable value of the second pitch is the mimimimum value that the second pitch may assume within its manufacturing tolerances and the maximum tolerable value of the first pitch is the maximum value that the first pitch may assume within its manufacturing tolerances.

The piston rod may be rotationally fixed with respect to the housing during dose setting and/or delivery.

Embodiments of the dose delivery mechanism are defined by the dependent claims and described in the following disclosure. According to an embodiment, the first distance essentially equals the second distance. This allows to self-inject an even larger amount of drug while making sure that the distance the actuation member needs to be pushed in order to inject that amount of drug is small enough so that the actuation member can be pushed in a comfortable manner.

The first and second distances may be essentially equal if the second distance and/or the pitch of the second threaded connection is at most 1 .01 times, in particular at most 1 .005 times the first distance and/or the pitch of the first threaded connection.

The actuation member may be configured to push the piston rod in the proximal direction during dose delivery, either directly or via one or more intermediate members. For example, the actuation member may be configured to push a threaded member, such as the dosing member, that is connected via the second threaded connection with the housing in the proximal direction during dose delivery and therefore effect rotation of this threaded member along the second threaded connection. This threaded member may then be configured to push the piston rod in the proximal direction, for example via an intermediate member, such as the nut. During dose delivery, the nut may be rotationally fixed with respect to the piston rod so that proximal movement of the nut results in proximal movement of the piston rod due to their mutual threaded connection.

The dose delivery mechanism may be configured to advance the piston rod in the proximal direction during dose delivery at the same speed as the actuation member is moved in the distal direction during dose delivery.

During dose delivery, only a single threaded connection, such as the second threaded connection, may effect a guided axial and rotational relative movement between members of the dose delivery device.

According to a further embodiment, all parts that are configured to rotate relative to the housing during dose delivery, are connected to the housing via exactly one thread. “Connected to the housing via exactly one thread” means that all parts that are configured to rotate relative to the housing during dose delivery form a subassembly, and wherein said subassembly is connected via a single threaded connection to the housing. That means that there is no second threaded connection that acts between, i.e. that connects, the housing and the subassembly. The pitch of the single threaded connection defines an axial distance travelled by all rotating parts that rotate during dose delivery for a given angular rotation. All parts that are configured to rotate with respect to the housing during dose delivery may be axially and rotationally fixed with respect to each other during dose delivery. During dose setting, one or more of these parts may be rotationally and/or axially movable with respect to one or more other ones of these parts. With other embodiments, the parts that rotate with respect to the housing during dose delivery may also be rotationally and axially fixed with respect to each other during dose setting. Parts that are configured to rotate relative to the housing during dose delivery can include a driver, a dose sleeve, the dosing member and/or a snap element.

The exactly one thread may be, for example, the second threaded connection.

The dose delivery mechanism may have a dose setting unit comprising the dosing member and the dosing member may be rotationally fixed to the dose setting member and/or the actuation member during dose setting. The dosing member and the dose setting member and the actuation member may be rotatable, for example in unison, to set a desired dose. The dosing member may be connected to the housing via the second threaded connection.

The dosing member may be rotationally decoupled from the dose setting member and/or the actuation member during dose delivery. The dosing member may be configured to rotate with respect to the housing during dose delivery. Additionally or alternatively, the dose setting member and/or the actuation member may be configured to be rotationally fixed with respect to the housing during dose delivery.

The dosing member may be configured to rotate with respect to the housing during dose delivery. The dosing member may be connected to the housing of the device via the second threaded connection during dose delivery. Proximal movement of the actuation member during dose delivery may cause the dosing member to follow a path defined by the second threaded connection in the proximal direction.

The dosing member may be configured to exert a force, such as a linear force in the proximal direction, on the piston rod during dose delivery. For example, the dosing member may exert the force via the nut to the piston rod. The dosing member may be configured to advance in the proximal direction during dose delivery and to thereby abut the nut. The nut and the piston rod may then be drawn into the proximal direction together with the dosing member.

According to an embodiment, the dose delivery mechanism further comprises a dose setting unit with a dose sleeve indicating a set dose being rotationally coupled to the actuation member during dose setting. The actuation member and the dose sleeve can be rotatable to set a desired dose. Preferably, the actuation member and the dose sleeve are rotatable in unison to set a desired dose. The dose sleeve may be connected to the housing via the second threaded connection.

The dose sleeve may constitute the dosing member or it may be a part of the dosing member that is axially and/or rotationally fixed to other parts of the dosing member.

According to an embodiment, the dose sleeve and the actuation member are rotationally decoupled during dose delivery, so that the actuation member does not rotate during dose delivery. This allows the actuation member to be comfortably pushed without causing friction between the thumb and the actuation member. According to an embodiment, the dose delivery mechanism further comprises a driver, wherein the driver exerts a force onto the nut to drive the piston rod during dose delivery. The dose sleeve and the driver can form one piece or can be rotationally and axially rigidly connected to each other. The dose sleeve and the driver may be part of the dosing member.

According to a further embodiment, the driver directly abuts the nut to drive the piston rod during dose delivery. This allows direct transmission of the force exerted onto the driver to the nut.

According to an embodiment, the driver is forced to rotate relative to the housing during dose delivery. This rotational movement is preferably caused by the second threaded connection.

According to a further embodiment, the dose delivery mechanism comprises a spring that acts between the housing and the actuation member during dose setting. The spring can be provided between the housing and the dose sleeve or between the housing and the driver.

Additionally or alternatively, the spring may act between the housing and the dosing member.

Preferably, the spring is configured to support moving the actuation member by a user to effect delivery of a set dose. This makes sure that the patient needs less force for injecting the set dose. In order to make sure that the spring supports moving the actuation member until the end of injection, the spring can be preloaded in an as-delivered state, i.e. a state in which the pen is delivered to the user.

The spring can be a torsion spring. A large supporting force can be reached if the torsion spring is a spiral torsion spring. Preferably, the spring is configured to be tensioned during dose setting. In other words, the spring is preferably arranged in the dose delivery mechanism so that a rotational movement of a dose setting knob, e.g. the actuation member, causes the spring to be tensioned or further tensioned.

According to an embodiment, the spring is coupled to a piston rod guide guiding a linear movement of the piston rod and a driver. The piston rod guide can be part of or fixedly coupled to the housing.

Preferably, the spring is arranged in a proximal part, in particular in a proximal end section, of the dose delivery mechanism. The dose delivery mechanism, e.g. the unit for setting a dose and delivering the set dose, can be coupled to a drug preparation unit such as a unit intended to mix a lyophilized drug with a solvent before use, i.e., a reconstitution unit. It can also be coupled to a unit comprising a cartridge which already contains the ready to use drug.

According to an embodiment, the actuation member is rotationally fixed to the nut during dose setting and dose delivery. The actuation member can comprise longitudinally extending torque transmission means such as a longitudinally extending rib that mesh with longitudinally extending torque transmission means, e.g. a longitudinally extending groove, of the nut.

According to another embodiment, the driver and a part of the housing, in particular the piston rod guide, form the second threaded connection. Preferably, the driver and an inner housing portion, in particular an inner housing portion arranged radially inside of a dose sleeve, form the second threaded connection. Generally, a part rotatable during dose delivery, in particular a part rotatable during dose setting and dose delivery, such as the dose sleeve or the driver, and any part that is non-rotatable relative to the housing during dose delivery can form the second threaded connection.

According to an embodiment, the piston rod is linearly guided in the housing. Alternatively or additionally, the piston rod can be non-rotatably mounted to the housing, i.e. non-rotatably supported by the housing. In order to support the piston rod in a manner that the piston rod is linearly, but non- rotatably, guided in the housing, the housing, in particular the piston rod guide, can have a longitudinal through opening with an out of round inside circumference corresponding to an out of round outer circumference of the piston rod.

A ball bearing may be provided to reduce friction during dose delivery. The bearing can be arranged between the driver and the nut to reduce friction between the driver and the nut. Alternatively or additionally, a washer can be arranged between the driver and the nut, which washer is made of a low-friction material like for example PTFE. It was assumed prior to the development of this dose delivery mechanism that a gearing ration of more than 2 is needed to allow the user to inject the set dose comfortably. However, the improvements described above and below have made it possible to provide a dose delivery mechanism that has a gearing ratio below 2 and even below 1 .5 but still allows the user to inject the set dose comfortably.

According to an embodiment, a speed v _am of the actuation member and a speed v _pr of the piston rod during dose delivery are the same. In other words, preferably the actuation member and the piston rod move simultaneously with the same speed in the proximal direction during dose delivery.

According to an embodiment, the nut is configured not to rotate relative to the housing and/or the piston rod during dose delivery.

These and other features, aspects and advantages are described below with reference to the drawings. Like reference characters denote corresponding features consistently throughout the drawings. The embodiments shown in the drawings may be altered in many ways without departing from the invention.

Figure 1 shows an exploded view of an injection pen according to the invention,

Figure 2A shows a perspective view of a knob cover of the injection pen of Fig. 1 .

Figure 2B shows a side view of the knob cover of Fig. 2A. Figure 2C shows a section view of the knob cover of Fig. 2B along the line A-A of Fig.

2B.

Figure 3A shows a perspective view of an injection button of the injection pen of Fig.

1.

Figure 3B shows a side view of the injection button of Fig. 3A.

Figure 3C shows a section view of the injection button of Fig. 3B along the line A-A of

Fig. 3B.

Figure 3D shows a section view of the injection button of Fig. 3B along the line B-B of

Fig. 3B.

Figure 3E shows a section view of the injection button of Fig. 3B along the line C-C of

Fig. 3B.

Figure 4A shows a perspective view of a snap ring of the injection pen of Fig. 1 .

Figure 4B shows a top view of the snap ring of Fig. 4A.

Figure 4C shows a side view of the snap ring of Fig. 4A.

Figure 4D shows a bottom view of the snap ring of Fig. 4A.

Figure 5A shows a first perspective view of a dose setting knob of the injection pen of

Fig. 1.

Figure 5B shows a second perspective view of the dose setting knob of Fig. 5A.

Figure 5C shows a side view of the dose setting knob of Fig. 5A.

Figure 5D shows a section view of the dose setting knob of Fig. 5A along line A-A of

Fig. 5C.

Figure 6A shows a perspective view of a snap element of the injection pen of Fig. 1 .

Figure 6B shows a side view of the snap element of Fig. 6A.

Figure 6C shows a section view of the snap element of Fig. 6A along the line A-A of

Fig. 6B.

Figure 7A shows a perspective view of a connector of the injection pen of Fig. 1 .

Figure 7B shows a bottom view of the connector of Fig. 7A.

Figure 7C shows a side view of the connector of Fig. 7A.

Figure 7D shows a top view of the connector of Fig. 7A.

Figure 8A shows a first perspective view of a dose selector of the injection pen of Fig.

1.

Figure 8B shows a bottom view of the dose selector of Fig. 8A.

Figure 8C shows a side view of the dose selector of Fig. 8A.

Figure 8D shows a section view of the dose selector of Fig. 8A along the line A-A of

Fig. 8C.

Figure 8E shows a section view of the dose selector of Fig. 8A along the line B-B of

Fig. 8C.

Figure 9 shows a second perspective view of the dose selector of Fig. 8A.

Figure 10A shows a perspective view of a knob key of the injection pen of Fig. 1 .

Figure 10B shows a side view of the knob key of Fig. 10A.

Figure 11 A shows a perspective view of a housing of the injection pen of Fig. 1 .

Figure 11 B shows a side view of the housing of Fig. 11 A. Figure 11 C shows a section view of the housing of Fig. 11 A along the line A-A of Fig.

11 B.

Figure 12A shows a first side view of a dose setting sleeve of the injection pen of Fig.

1.

Figure 12B shows a second side view of the dose setting sleeve of Fig. 12A.

Figure 12C shows a third side view of the dose setting sleeve of Fig. 12A.

Figure 12D shows a fourth side view of the dose setting sleeve of Fig. 12A.

Figure 12E shows a front view of the dose setting sleeve of Fig. 12A.

Figure 12F shows a first perspective view of the dose setting sleeve of Fig. 12A.

Figure 12G shows a second perspective view of the dose setting sleeve of Fig. 12A.

Figure 13A shows a perspective view of a driver of the injection pen of Fig. 1 .

Figure 13B shows a first side view of the driver of Fig. 13A.

Figure 13C shows a second side view of the driver of Fig. 13A.

Figure 13D shows a section view of the driver of Fig. 13A along the line A-A of Fig.

13C.

Figure 14A shows a first perspective view of a nut of the injection pen of Fig. 1 .

Figure 14B shows a second perspective view of the nut of Fig. 14A.

Figure 14C shows a side view of the nut of Fig. 14A.

Figure 14D shows a first section view of the nut of Fig. 14A along the line A-A of Fig.

14C.

Figure 14E shows a second section view of the nut of Fig. 14A along the line B-B of

Fig. 14C.

Figure 15A shows a first side view of a piston rod guide of the injection pen of Fig. 1 .

Figure 15B shows a second side view of the piston rod guide of Fig. 15A.

Figure 15C shows a section view of the piston rod guide of Fig. 15A along the line A-A of Fig. 15A.

Figure 15D shows a perspective view of the piston rod guide of Fig. 15A.

Figure 16A shows a first longitudinal section view of the piston rod guide of Fig. 15A.

Figure 16B shows a second longitudinal section view of the piston rod guide of Fig.

15A.

Figure 16C shows a perspective view of the piston rod guide of Fig. 15A.

Figure 17A shows a side view of a piston rod of the injection pen of Fig. 1 .

Figure 17B shows a section view of the piston rod of Fig. 17A along the line A-A of Fig.

17A.

Figure 17C shows a first perspective view of the piston rod of Fig. 17A.

Figure 17D shows a second perspective view of the piston rod of Fig. 17A.

Figure 18A shows a perspective view of a piston disc of the injection pen of Fig. 1 .

Figure 18B shows a top view of the piston disc of Fig. 18A.

Figure 18C shows a section view of the piston disc of Fig. 18A along the line A-A of

Fig. 18B.

Figure 19A shows a perspective view of a dual chamber cartridge of the injection pen of Fig. 1 . Figure 19B shows a side view of the dual chamber cartridge of Fig. 19A.

Figure 19C shows a section view of the dual chamber cartridge of Fig. 19A along the line A-A of Fig. 19B.

Figure 20A shows a perspective view of a cartridge container of the injection pen of

Fig. 1 .

Figure 20B shows a first side view of the cartridge container of Fig. 20A.

Figure 20C shows a second side view of the cartridge container of Fig. 20A.

Figure 20D shows a section view of the cartridge container of Fig. 20A along the line

A-A of Fig. 20C.

Figure 21 A shows a first perspective view of a cartridge key of the injection pen of Fig.

1 .

Figure 21 B shows a second perspective view of the cartridge key of Fig. 21 A.

Figure 21 C shows a first side view of the cartridge key of Fig. 21 A.

Figure 21 D shows a second side view of the cartridge key of Fig. 21 A.

Figure 22A shows a third side view of the cartridge key of Fig. 21 A.

Figure 22B shows a section view of the cartridge key of Fig. 21 A along the line A-A of

Fig. 22A.

Figure 23A shows a side view of the injection pen of Fig. 1 in an as-delivered state.

Figure 23B shows a section view of the injection pen of Fig. 23A along the line A-A of

Fig. 23A.

Figure 24 shows a perspective view of the injection pen of Fig. 23A without the knob cover and with some parts displayed transparently.

Figure 25A shows a second side view of the injection pen of Fig. 23A.

Figure 25B shows a section view of the injection pen of Fig. 23A along the line A-A of

Fig. 25A.

Figure 26A shows a side view of the injection pen of Fig. 1 in a reconstitution state.

Figure 26B shows a section view of the injection pen of Fig. 26A along the line A-A of

Fig. 26A.

Figure 27A shows a second side view of the injection pen of Fig. 26A.

Figure 27B shows a third side view of the injection pen of Fig. 26A.

Figure 27C shows a section view of the injection pen of Fig. 26A along the line A-A of

Fig. 27B.

Figure 28A shows a side view of the injection pen of Fig. 1 in a knob cover unfastening state.

Figure 28B shows a section view of the injection pen of Fig. 28A along the line A-A of

Fig. 28A.

Figure 29A shows a side view of the injection pen of Fig. 1 in an end of reconstitution state.

Figure 29B shows a section view of the injection pen of Fig. 29A along the line A-A of

Fig. 29A.

Figure 30A shows a side view of the injection pen of Fig. 1 in a set dose state. Figure 30B shows a section view of the injection pen of Fig. 30A along the line A-A of

Fig. 30A.

Figure 31 A shows a side view of the injection pen of Fig. 1 in a start of injection state.

Figure 31 B shows a section view of the injection pen of Fig. 31 A along the line A-A of

Fig. 31A.

Figure 32A shows a further side view of the injection pen of Fig. 1 in a start of injection state.

Figure 32B shows an enlarged section view of the injection pen of Fig. 32A along the line A-A of Fig. 32A.

Figure 33A shows a side view of the injection pen of Fig. 1 in an end of injection state.

Figure 33B shows a section view of the injection pen of Fig. 33A along the line A-A of

Fig. 33A.

Figure 34 shows a second injection pen according to the present disclosure in a preassembled state.

Figure 35 shows another view of the second injection pen in the preassembled state.

Figure 36 shows an exploded view of the second injection pen.

Figure 37 shows a longitudinal cut through the second injection pen in the preassembled state.

Figure 38 shows a detailed view of a distal portion of the second injection pen in the preassembled state.

Figure 39 shows a detailed view of the distal end of the second injection pen in an assembled state during dose setting.

Figure 40 shows another view of the distal end of the second injection pen in the assembled state during dose setting.

Figure 41 shows a detailed view of the distal end of the second injection pen in an assembled state during dose delivery.

Figure 42 shows another view of the distal end of the second injection pen and the assembled state during dose delivery.

Figure 43 shows a longitudinal cut through the dose setting element of the first and second injection pen.

Figure 44 shows a perspective view of the longitudinal cut through the dose setting element.

Figure 45 shows a perspective distal view of the dose setting element.

Figure 46 shows a prospective proximal view of the dose setting element.

Figure 47 shows a perspective view of a third injection pen according to the present disclosure.

Figure 48 shows an exploded view of the third injection pen.

Figure 49 shows a longitudinal cut through a dose delivery mechanism of the third injection pen.

Figure 50 shows a perspective distal view of a dosing member of the third injection pen. Figure 51 shows a perspective longitudinal cut through the dosing member of the third injection pen.

Figure 52 shows a perspective view of a piston rod of the third injection pen.

Figure 53 shows a perspective distal view of an extension of the third injection pen.

Figure 54 shows a distal view of the extension shown in Figure 53.

Figure 55 shows a proximal view of the extension shown in Figure 53.

Figure 56 shows a perspective view of a coupling element of the third injection pen.

Figure 57 shows a perspective view of a bearing, the piston rod, the extension, the coupling element, and an adjusting element of the third injection pen

Figure 58 shows a proximal perspective view of the adjusting element of the third injection pen.

Figure 59 shows a side view of the adjusting element of the third injection pen.

Figure 60 shows a radial cut through the adjusting element of the third injection along the line A-A in Figure 59.

Figure 61 shows a radial cut through the adjusting element of the third injection along the line B-B in Figure 59.

Figure 62 shows a perspective view of a coupling member of the third injection pen.

Figure 63 shows a perspective distal view of a sleeve of the third injection pen.

Figure 64 shows a longitudinal cut through the sleeve of the third injection pen.

Figure 65 shows a perspective view of a housing insert of the third injection pen.

Figure 66 shows a perspective view of a connector of the third injection pen.

Figure 67 shows a perspective view of a longitudinal cut through the connector of the third injection pen.

Figure 68 shows a side view of the third injection pen in an assembled state during dose setting.

Figure 69 shows a side view of the third injection pen in a preassembled state.

Figure 70 shows a detailed view of a longitudinal cut through the distal end of the third injection pen in an assembled state during dose setting.

Figure 71 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen in the assembled state during dose setting.

Figure 72 shows a detailed view of a longitudinal cut through the distal end of the third injection pen in the assembled state during dose delivery.

Figure 73 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen in the assembled state during dose delivery.

Figure 74 shows a detailed view of a longitudinal cut through the distal end of the third injection pen in the preassembled state.

Figure 75 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen in the preassembled state.

Figure 76 shows a perspective view of a fourth injection pen according to the present disclosure.

Figure 77 shows a side view of the fourth injection pen in an assembled state during dose setting. Figure 78 shows a side view of the fourth injection pen in a preassembled state with an adjusting element in a preassembled position.

Figure 79 shows a side view of the fourth injection pen in the preassembled state with the adjusting element in an adjusting position.

Figure 80 shows an exploded view of the fourth injection pen.

Figure 81 shows a longitudinal cut through a dose delivery mechanism of the fourth injection pen in the assembled state during dose setting.

Figure 82 shows a perspective view of a coupling element of the fourth injection pen.

Figure 83 shows a radial cut through the coupling element shown in Figure 82 along the line A-A.

Figure 84 shows a perspective view of a piston rod of the fourth injection pen.

Figure 85 shows a perspective proximal view of an adjusting element of the fourth injection pen.

Figure 86 shows a side view of the adjusting element of the fourth injection pen.

Figure 87 shows a first longitudinal cut through the adjusting element along the line

A-A in Figure 86.

Figure 88 shows a further side view of the adjusting element of the fourth injection pen in a direction perpendicular to the direction of Figure 86.

Figure 89 shows a second longitudinal cut through the adjusting element along the line B-B in Figure 88.

Figure 90 shows a perspective distal view of a sleeve of the fourth injection pen.

Figure 91 shows a perspective distal view of an insert of the sleeve.

Figure 92 shows a perspective proximal view of the insert of the sleeve.

Figure 93 shows a perspective distal view of an outer part of the sleeve.

Figure 94 shows a side view of a coupling member of the fourth injection pen.

Figure 95 a longitudinal cut through the coupling member along the line A-A in Figure

90.

Figure 96 shows a radial cut through the coupling member along the line B-B in Figure 90.

Figure 97 shows a perspective distal view of a dosing member of the fourth injection pen.

Figure 98 shows a perspective view of a longitudinal cut through the dosing member.

Figure 99 shows a longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose setting.

Figure 100 shows a further longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose setting.

Figure 101 shows a longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose delivery. Figure 102 shows a further longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose delivery.

Figure 103 shows a longitudinal cut through a distal end of a dose delivery mechanism of the fourth injection pen in a preassembled state with the adjusting element in an preassembled position.

Figure 104 shows a further longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the preassembled state with the adjusting element in the preassembled position.

Figure 105 shows a longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the preassembled state with the adjusting element in an adjusting position.

Figure 106 shows a further longitudinal cut through the distal end of the dose delivery mechanism of the fourth injection pen in the preassembled state with the adjusting element in the adjusting position.

With reference to figures 1 to 22B, parts of an injection pen 10 according to the invention are described. Afterwards, with reference to figures 23A to 33B it is described how the pen is meant to be used.

Fig. 1 shows an exploded view of a medicament delivery device in form of an injection pen 10. The injection pen 10 comprises - in an order from a distal end 12 to a proximal end 14 - a knob cover 16 that can also be called knob lock, cover or holding element, an injection button 18 that can be part of an actuation member, a snap ring 20, a dose setting knob 22 that can also be called dose setting element, dose adjusting member or knob and can be part of an actuation member, a snap element 24 that can also be called dose setting device, a connector 26, a dose selector 28, a knob key 30 that can also be called a clip, a housing 32 that can also be called body, a dose setting sleeve 34 that can also be called dose sleeve or dose indication member, a driver 36, a nut 38, a spring 40, a piston rod guide 42 that can also be called piston guide, a piston rod 44, a piston disc 46 that can also be called a bearing, a dual chamber cartridge 48 that can also be called a medicament container, a fluid compartment or a cartridge, a cartridge container 50, and a cartridge holder or cartridge key 52. The assembly of the cartridge container 50 and the cartridge holder 52 may also be called medicament container holder. Thereby, the cartridge container 50 provides an outer container holder and the cartridge key 52 provides an inner container holder of the container holder.

While the above mentioned parts of the injection pen 10 can each be formed as separate parts to simplify production of the separate parts, it would be generally possible to form one or more of the parts integrally with each other. For example, the injection button 18, the snap ring 20, and/or the dose setting knob 22 could be formed integrally with each other. Furthermore, the dose setting sleeve 34 and the driver 36 could be formed integrally with each other. Generally, even the housing 32 and the piston rod guide 42 could be formed integrally with each other. The different parts can be grouped together to define different functional units. E.g. the section between the injection button 18 and the piston rod guide 42 can be called a dose setting mechanism 54, a dose setting unit, a dose delivery mechanism and/or a dose delivery activation mechanism. On the other hand, the section between the piston rod guide 42 and the cartridge key 52 can be called drug reconstitution unit 56 or reconstitution means. The cartridge container 50 and the cartridge holder 52 can be called a cartridge holding unit. The cartridge container 50, the cartridge holder 52, and the cartridge 48 can be called a cartridge unit. For example, the cartridge unit may be sold - in a preassembled state or as separate parts - separately from the rest of the injection pen 10.

Next, the above-mentioned parts of the injection pen 10 are described in the order starting from the distal end 12 and ending at the proximal end 14, the distal end 12 and the proximal end 14 being opposite ends of the injection pen 10 and the proximal end 14 comprising a dispensing outlet:

Figs. 2A to 2C depict the knob cover 16. The knob cover 16 covers the dose setting knob 22 during delivery, i.e. shipping, of the injection pen 10 to a costumer, e.g. the patient. The knob cover 16 is fully detachable from the rest of the injection pen 10. The knob cover 16 is attachable to the housing 32 and/or detachable from the housing 32 via two deformable wings 58 that can be deflected outwardly, i.e. in a radial direction, to detach the knob cover 16 from the housing 32. The wings 58 form a proximal end section of the knob cover 16. On an inner surface of each of the wings 58, form-fitting engagement means in the form of a lug 60 are provided, that are configured to engage with the housing 32, in particular with a radially extending coupling surface 228 (cf. Fig. 15C) formed on the piston guide 42, to axially fixate the knob cover 16 relative to the housing 32 in a distal direction. Next to each of the lugs 60, one window 62, i.e. a radially extending opening, is formed in the wings 58. When the knob cover 16 is attached to the housing 32, the windows 62 are positioned at an axial position where the housing 32 forms a circumferentially extending elevation 64 (cf. Fig. 25A). On the distal side of each window 62, i.e. away from the lugs 60, on the inner side surface of the respective wing 58, an abutment 66 is formed. The abutment 66 has a width that is adapted to a width of a recess or cut-out 68 (cf. Fig. 1 1 A) on an outer surface of the housing 32, more precisely in a chamfered portion 69 formed on the outer surface of the housing 32. Furthermore, the abutment 66 forms a front surface 66a that axially abuts a radially extending surface 32a (cf. Fig 1 1 B) defining a proximal end of the cut-out 68 when the knob cover 16 is attached to the housing 32. The radially extending surface 32a defines a stop surface that stops proximal movement of the knob cover 16 relatively to the housing 32, e.g. if the injection pen 10 is dropped onto a floor with the distal end 12 first. In order to further ensure that the knob cover 16 does not move past its attached position in the proximal direction 1 , axial abutment elevations 70 (cf. Fig. 1 1 A) can be formed on the outer surface of the housing 32. The elevations 70 are configured to engage with clearances 72 (cf. Fig. 2C) formed between the wings 58 so that proximal front surfaces of the knob cover 16 abut distal front faces of the axial abutment elevations 70. A form-fitting engagement between the abutments 66 and the cut-outs 68 and/or a form-fitting engagement between the elevations 70 and the clearances 72 make sure that the knob cover 16 is rotationally constrained relative to the housing 32 when the knob cover 16 is attached to the housing 32.

As can be seen from Fig. 2A, the knob cover 16 is only detachable from the rest of the injection pen 10 by moving the knob cover 16 linearly in a distal direction. In order to do so, a linear recess 74 is formed on the inner circumferential surface of the knob cover 16 that corresponds to an antirolling means 76 (cf. Fig. 5B) of the dose setting knob 22 in the form of an axially extending rib. Therefore, the dose setting knob 22 is blocked from rotating inside the knob cover 16 by the formfitting engagement of the linear recess 74 and the anti-rolling means 76. The knob cover 16, as can be seen in Fig. 2A, also forms anti-rolling means 78 in form of an axially extending rib on the outer surface of the knob cover 16. The anti-rolling means 76 and 78 make sure that the injection pen 10 and the knob cover 16 do not roll away when placed on a flat surface. As can be also seen from Fig. 2A, the knob cover 16 has a closed circumference 16a and a closed face 16b at its distal end. Therefore, the knob cover 16 forms a closed sleeve around the distal section of the injection pen 10.

Figures 3A to 3E depict the injection button 18. The injection button 18 forms a distal front surface 80 to apply a force to the injection button 18 to inject a set dose. The injection button 18 comprises axial fixation means 82 to axially attach the injection button 18 to the snap ring 20 (cf. Fig. 4A-4D) which is axially connected to the dose setting knob 22 (cf. Fig. 5A to 5D). The axial fixation means 82 comprise two elastically deformable hooks 82 which engage with a circumferentially extending rib 84 on the snap ring 20. The snap ring 20 also comprises axial fixation means 86 in the form of elastically deformable bendable hooks that engage with an undercut 88 formed in the dose setting knob 22. The injection button 18, the snap ring 20 and the dose setting knob 22 are permanently axially fixed to each other in an assembled state of the dose delivery mechanism 54.

The injection button 18 also forms rotation fixation means 90 in the form of radially extending ribs. The ribs 90 are form-fittingly engaged with rotation fixation means 92 (cf. Fig. 4A) in the form of teeth arranged in an inner circumferential surface of the snap ring 20 to rotationally connect the injection button 18 to the snap ring 20. The rotation fixation means 92 form a toothed part 93 of the snap ring 20 and the ribs 90 form an engaging part of the injection button 18. The snap ring 20 comprises rotation fixation means 94 in the form of axially extending recesses that define side surfaces of the elastically deformable bendable hooks 86 and that engage with rotation fixation means 96 in the form of axially extending ribs (cf. Fig. 5A) on the inner circumferential surface of the dose setting knob 22.

After assembly and in an assembled state of the dose delivery mechanism 54, the injection button 18, the snap ring 20 and the dose setting knob 22 are rigidly connected with each other and form both a dose setting member and an actuation member of the dose delivery mechanism 54. The injection button 18 forms a cylindrical portion 18a. On the cylindrical portion 18a, assembling means 98 in the form of elevations are formed to axially preassemble the injection button 18 with the snap element 24. More precisely, the lower, i.e. proximal, assembling means 98b (cf. Fig. 3C) restricts distal movement of the injection button 18 relative to the snap element 24 by interfering with coupling means 102 on the snap element 24. The upper, i.e. distal, assembling means 98a restricts proximal movement of the injection button 18 relative to the snap element 24 by interfering with coupling means 102 on the snap element 24 after pre-assembly and distal movement of the injection button 18 after final assembly. When the snap element 24 and the injection button 18 are preassembled, i.e. in a preassembled state, the coupling means 102 is arranged between the proximal assembling means 98b and the distal assembling means 98a. In said preassembled state, the injection button 18 is not yet rigidly connected to the snap ring 20 and the dose setting knob 22. However, when the coupling means 102 is arranged distally from the distal assembling means 98a, i.e. in the assembled state, the injection button 18 is rigidly connected to the snap ring 20 and the dose setting knob 22. The injection button 18 also forms coupling means 100 in the form of protrusions being arranged on an outer circumferential surface of the injection button 18 on elastically inwardly bendable portions. The inwardly bendable portions extend in an axial direction and are sectionally surrounded by cut-outs 101 .

The coupling means 100 are configured to permanently axially lock the injection button 18 and therefore also the snap ring 20 and the dose setting knob 22 to the snap element 24 after the injection has been completed to render the injection pen 10 inoperable. Namely, when the injection button 18 is moved axially to initiate the dose delivery, the coupling means 100 pass the radially inwardly extending coupling means in the form of a circumferentially extending ledge 102 (cf. Fig. 6A) on the snap element 24. The radially inwardly extending ledge 102 causes the protrusions being arranged on elastically inwardly bendable portions 100 to bend inwardly until the protrusions have passed the ledge 102. In order to reduce the force needed to push the protrusions 100 past the ledge 102, the protrusions 100 form chamfered outer surfaces 100a. Alternatively or additionally, the ledge 102 could form a chamfered inner surface. When the protrusions 100 have passed the ledge 102, they snap back into their neutral position which causes the injection button 18 to be permanently axially locked relative to the snap element 24. This feature makes sure that the injection pen 10 can only be used one single time to inject exactly one dose.

As can be best seen in Fig. 3C and 3E, the injection button 18 comprises an axially extending rib 104 on its inner circumferential surface. The axially extending rib 104 engages in an axially extending groove 106 of the nut 38 (cf. Fig. 14C) to form rotation fixation means. Due to the axially extending rib 104 and the corresponding axially extending groove 106, the injection button 18 and the nut 38 can move axially relative to each other but are rotationally fixed to each other.

As can be best seen on Fig. 5B and 5D, a set of teeth 108 are formed in an axial section on an inner circumferential side of the dose setting knob 22. These teeth 108 are configured to mesh with a set of teeth 1 10 arranged in a distal section on an outer circumferential surface of the snap element 24 (cf. Fig. 6A-6C) during dose setting. Therefore, when the dose setting knob 22 is rotated during dose setting, the snap element 24 is rotated too. As can be seen in Fig. 6A, the teeth 110 are arranged only in two opposite sections of the snap element 24 while sections between the two opposite sections do not form any teeth. This has advantages regarding production of the injection pen 10. Alternatively, the teeth 110 could be formed along the whole circumference of the snap element 24.

The snap element 24 forms an axial section with a reduced cross section forming a coupling surface 112 for the connector 26. The connector 26 shown in the figures is formed as an integral part. However, the connector 26 could also be formed from multiple, e.g. two, parts connected to each other, e.g. via a form-fitting connection. The connector 26 has an open cross section (cf. Fig. 7D) so it is clippable onto the snap element 24 at the reduced cross section. The connector 26 is axially fixedly connected to the snap element 24 in both directions due to the connector 26 having a length L1 in the axial direction that corresponds to a length L2 in the axial direction of the axial section with the reduced cross section. However, the connector 26 is rotatable relative to the snap element 24. When the dose setting knob 22 is pushed in the proximal direction 1 to initiate dose delivery, the teeth 108 of the dose setting knob 22 engage with a set of teeth 114 formed on an outer circumferential surface of the connector 26 instead of the teeth 110 of the snap element 24 so that the snap element 24 can rotate relative to the dose setting knob 22 during dose delivery. The engagement between the teeth 108 of the dose setting knob 22 and the teeth 114 of the connector 26 makes sure that the dose setting knob 22 does not rotate during dose delivery with respect to the housing 32 due to connector 26 being rotationally fixed to the housing 32 via the dose selector 28.

The snap element 24 further comprises an engagement feature 116 in the form of an axially extending radial projection. The engagement feature 116 is an axially extending rib. The engagement feature 116 can have a symmetrical cross section in a radial plane perpendicular to a longitudinal axis of the injection pen 10 or an asymmetrical cross section. The engagement feature 116 is configured to engage with dose stops 118a, 118b, 118c, and 118d (cf. Fig. 8B) formed on an inner circumferential surface of the dose selector 28 to set a desired dose. Therefore, the engagement feature 116 is used as a dose definition element and the engagement feature 116 together with the dose stops 118a, 118b, 118c, 118d form a dose definition mechanism 115 of the injection pen 10. The dose definition element 116 is located on an elastically deformable section 120, i.e. an axially extending arm partially surrounded by a cut-out 121 . The elastically deformable section 120 bends inwardly when the dose definition element 116 passes one of the dose stops 118a, 118b, 118c, and 118d. In order to reduce the force needed to rotate the dose setting knob 22 and the snap element 24 relative to the dose selector 28 to enlarge or decrease the set dose, the dose stops 118 have chamfered side surfaces 122a-d and 123a-d. According to the embodiment shown in Fig. 8B, the dose stops 118a-d have a symmetrical cross section in the radial plane perpendicular to the longitudinal axis of the injection pen 10. In other words, the chamfered side surfaces 122 and 123 have pitches that are equal to each other regarding their amount. According to another embodiment shown in Fig. 9, chamfered side surfaces 122a’-d’ that get in contact with the projection 116 to deform the elastically deformable section 120 when the dose is set to a higher dose have a smaller pitch than chamfered side surfaces 123a’-d’ that get in contact with the projection 116 when the dose is set to a lower dose. The side surfaces 123a-d define rotational positions corresponding to settable doses. The spring 40 is configured to rotate the snap element 24 relative to the dose selector 28 so that the dose definition element 116 abuts one of the side surfaces 123a-d.

The snap element 24 further comprises a hard stop 124 in the form of an axially extending rib that abuts a hard stop 126 formed on the dose selector 28 when the injection pen 10 is delivered to a costumer. The hard stop 126, contrary to known pens, does not correspond to a zero-dose stop but instead corresponds to a pre-set dose stop. A further discussion regarding this feature follows. The hard stop 124 is axially distanced from the dose definition element 116 but axially aligned with the dose definition element 116. The hard stop 124 is configured to abut an end of dose setting hard stop 128.

The snap element 24 further comprises axial and rotational fixation means in the form of a radially extending opening 130 and an axially extending slot 132 to axially and rotationally fix the snap element 24 to the driver 36. As can be seen in Fig. 13A, the driver 36 has an axially extending rib 134 that is configured to engage with the slot 132 of the snap element 24. Furthermore, the driver 36 has a protrusion 136 with a chamfered surface 136a that engages with the opening 130 of the snap element 24. While the opening 130 and the protrusion 136 form the axial fixation means, the slot 132 and the rib 134 form the rotational fixation means. Due to the axial and rotational fixation means, the snap element 24 and the driver 36 can be connected to each other in one defined relative rotational position. In order to strengthen the rotational fixation between the snap element 24 and the driver 36, an axially extending rib 138 is formed on an inner circumferential surface of the snap element 24 (cf. Fig. 6C) that engages with an axially extending groove 140 (cf. Fig. 13D) on an outer circumferential surface of the driver 36.

Figures 8A to 8E depict the dose selector 28. The dose selector 28 comprises axial fixation means 142 in the form of circumferentially extending projections on an inner circumferential surface of a distal section of the dose selector 28. The dose selector 28 is axially fixed to the dose setting knob 22 by inserting the distal section with the axial fixation means 142 into a circumferentially extending intake 144 (cf. Fig. 5B). In the intake 144, the dose setting knob 22 forms axial fixation means 146 in the form of circumferentially extending protrusions on an outer circumferential surface which get engaged with the axial fixation means 142 of the dose selector 28 to form an axial connection that allows relative rotational movement between the dose selector 28 and the dose setting knob 22.

As can be seen best on Fig. 8E, rotation fixation means 148 in the form of axially extending grooves are formed on an inner circumferential surface of the dose selector 28. The rotation fixation means 148 are engaged with rotation fixation means 150 in the form of axially extending ribs formed on the outer circumferential surface of the connector 26 (cf. Fig. 7B). The rotation fixation means 148, 150 allow axial movement between the dose selector 28 and the connector 26. The dose selector 28 further comprises rotation fixation means 152 in the form of axially extending ribs formed on an outer circumferential surface of the dose selector 26. The rotation fixation means 152 engage with rotation fixation means 154 in the form of axially extending grooves formed on the inner circumferential surface of the housing 32 (cf. Fig. 1 1 C). The rotation fixation means 152, 154 are configured to define one single possible rotational alignment that allows insertion of the dose selector 28 into the housing 32. The rotation fixation means 150, 152 allow axial movement between dose selector 28 and the housing 32.

In order to define deliverable doses, the dose selector 28 (cf. Fig. 8B) forms a circumferentially extending rib 156 with cut-outs 158a, 158b, 158c, and 158d. The cut-outs 158a, 158b, 158c, and 158d are assigned to the respective dose stops 1 18a, 1 18b, 1 18c, and 1 18d. The rib 156 with its cut-outs 158a, 158b, 158c, and 158d makes sure, that injection is only possible if the dose definition element 1 16 of the snap element 24 is at an angular position relating to one of the cut-outs 158a, 158b, 158c, and 158d, i.e. relating to one of the settable doses. If the dose definition element 1 16 is not at an angular position relating to one of the cut-outs 158a-d, axial movement of the dose definition element 1 16, and therefore the snap element 24, relative to the dose selector 28 is blocked by the circumferentially extending rib 156. As can be seen from Fig. 8B, there is no cut-out assigned to the pre-set dose hard stop 126. Therefore, starting an injection is inhibited when the injection pen 10 is set to the pre-set dose.

According to an alternative embodiment, the circumferentially extending rib 156 could be arranged to interact with the hard stop 124 instead of the dose definition element 1 16. Therefore, injection would only be possible if the hard stop 124 of the snap element 24 would be at an angular position relating to one of the cut-outs 158a, 158b, 158c, and 158d, i.e. relating to one of the settable doses.

Figs. 10A and 10B depict the knob key 30. The knob key 30 is configured to be attached to the outer circumferential surface of the dose selector 28 to keep the dose setting knob 24 from unintentionally moving in the proximal direction 1 relative to the housing 32 if the injection pen 10 in an as- delivered state drops onto its proximal end. The clip element 30 has a width W1 that corresponds to a width W2 (cf. Fig. 29A) between a proximal edge 160 of the dose setting knob 22 and a distal edge 162 of the housing 32. The knob key 30 is C-shaped and has holding protrusions 164 that interact with the rotation fixation means 152 on the outer circumferential surface of the dose selector 28 to attach the knob key 30 to the dose selector 28. The knob key 30 can be taken off the dose selector 28 by slightly bending the C-shaped knob key 30. In the as-delivered state, the knob cover 16 extends around the knob key 30 to hold the knob key 30 in place. The knob key 30 can only be taken off the dose selector 28 after the knob cover 16 has be removed.

The housing 32 is shown in Figs. 1 1 A to 1 1 C. The housing 32 forms a viewing window 166 for displaying a state of the injection pen 10, in particular a set dose, indicated by the dose sleeve 34 through the window 166. The dose sleeve 34 rotates relative to the housing during dose setting and dose delivery which causes a change of what is displayed through the window 166. In different circumferential positions along the outer circumferential surface of the dose sleeve 34, labels 168a- 168d (cf. Figs. 12C and 12D) for different settable doses are located. Furthermore, a preset-dose label 168e (cf. Fig. 12B) is located on the dose sleeve 34 that corresponds to a pre-set dose, i.e. an amount of medicament that would be injected if the injection could be started from the pre-set dose. As can be seen from comparing Figs. 12A and 12B, the pre-set dose label 168e differs from a zero-dose label 168f, i.e. the label that shows that no medicament would be injected if the injection would be started in that state. This zero-dose label 168f is shown through the window 166 when the injection has been completed. The labels 168a, 168b, 168c, and 168d correspond to the settable doses defined by the dose stops 1 18a, 1 18b, 1 18c, and 1 18d.

The dose sleeve 34 is rotationally and axially rigidly coupled to the driver 36 (cf. Fig 13A-13D). In order to rotationally couple the dose sleeve 34 to the driver 36 corresponding out-of-round outer and inner circumferential surfaces 169a and 169b are formed on the driver 36 and the dose sleeve 34, respectively. Furthermore, the dose sleeve 34 forms a fixing section 171 that is pinched between a proximal end of the snap element 24 and a face surface 173 (cf. Fig. 13A) of the driver 36 to axially fix the dose sleeve 34 to the driver 36 and the snap element 24. The driver 36 forms an outer thread 170 that engages with an inner thread 172 (cf. Figs. 16A-16B) of the piston guide 42. The threaded connection 170, 172 causes the driver 36 to rotate when the driver 36 is moved axially relative to the piston guide 42 and causes the driver 36 to move axially relative to the piston guide 42 when the driver 36 is rotated relative to the piston guide 42. Furthermore, the driver 36 defines end stops 174 that abut end stops 176 of the piston guide 42 at the end of the dose delivery. The surfaces defining the end stops 174, 176 are arranged in parallel to a middle axis of the injection pen and face in a radial direction. The driver 36 also forms attachment means 177 in the form of a radially extending hook for attaching one end section of the spring 40 to the driver 36. The other end section of the spring 40 is attached to attachment means 179 (cf. Fig. 16C) at the outer circumferential surface of the piston rod guide 42.

According to an alternative version, the dose sleeve and the driver can be formed as separate parts that are axially movable relative to each other but rotationally fixed to each other and both, the dose sleeve and the driver, can have a thread that is threadedly coupled to the housing. The thread of the dose sleeve and the thread of the driver may have different pitches.

The piston guide 42 is axially and radially fixed to the housing 32 and can therefore be considered part of the housing. In order to axially fix the piston guide 42 to the housing 32, axial fixation means 178 in the form of a circumferentially extending groove are formed on the piston guide 42 that engage with axial fixation means 180 (cf. Fig. 1 1 A) in the form of a circumferentially extending rib formed on an inner circumferential surface of the housing 32. In order to rotationally fix the piston guide 42 to the housing 32, rotation fixation means 182 in the form of an axially extending groove are formed on an outer circumferential surface 262 of the piston guide 42 that engage with rotation fixation means 184 (cf. Fig. 1 1 A) in the form of an axially extending rib formed on an inner circumferential surface of the housing 32. The axial and rotational fixation means 178, 180, 182, and 184 allow attachment of the piston rod guide 42 to the housing 32 in exactly one relative rotational position. The piston guide 42 has an out of round axial opening 186 (cf. Fig. 15C) that corresponds to an out of round cross-section 188 (cf. Fig. 17B) of the piston rod 44. Therefore, the piston rod 44 is axially movable relative to the piston rod guide 42, but cannot rotate relative to the piston rod guide 42. The piston rod 44 forms an outer thread 190 that is in engagement with an inner thread 192 (cf. Fig. 14D) of the nut 38. The outer thread 190 and the inner thread 192 form a threaded connection 189 between the piston rod 44 as a first threaded element and the nut 38 at a second threaded element. The piston rod 44 and the nut 38 can move relative to each other in a compulsory guided combined axial and rotational movement. In a proximal end section of the nut 38, an annular pressing surface 194 extending in the distal direction is formed on the nut 38. This pressing surface 194 abuts a front surface 196 of the driver 36 during dose delivery. During dose delivery, the driver 36 moves in a combined axial and rotational movement relative to the piston rod guide 42 while the nut 38 is rotationally fixed to the housing 32. In order to reduce friction during dose delivery, a ball bearing and / or a glide disc made of low-friction material can be arranged between the pressing surface 194 and the front surface 196 of the driver 36. In both cases, during dose delivery, the driver 36 pushes the piston rod 44 via the nut 38 in the proximal direction 1 .

The piston rod 44, at its proximal end, forms coupling means 198 in the form of an undercut that engage with coupling means 200 in the form of radially inwardly extending ribs on an inner circumferential surface of the piston disc 46 (cf. Fig. 18A-18C).

Figs. 15A to 22B depict parts of a drug mixing or reconstitution unit 56 configured to mix different components, usually a lyophilized drug and a liquid solvent, to form an injectable liquid drug. In Figs. 19A to 19C, the dual chamber cartridge 48 is shown. The dual chamber cartridge 48 is made of a transparent material such as glass. As can be seen from Fig. 19C, the cartridge 48 forms a first chamber 202 and a second chamber 204. In the as-delivered state shown in Fig. 19C, the first chamber 202 being arranged in proximal to the second chamber 204 comprises a bypass 206. The first chamber 202 and the second chamber 204 are separated by a first sealing element 208, e.g. made of a rubber material, that is axially slid ably arranged inside the dual chamber cartridge 48. In other words, the first sealing element 208 forms a distal end of the first chamber 202 and a proximal end of the second chamber 204. A second sealing element 210, e.g. made of a rubber material, forms a distal end of the second chamber 204. The second sealing element 210 may also be called a plunger. The piston disc 46 abuts the distal end face of the second sealing element 210 during mixture of the two components.

In the as-delivered state the lyophilized drug is in the first chamber 202 and the solvent in the second chamber 204.

The dual chamber cartridge 48 is stored in the cartridge key 52 (cf. Fig. 21 A-22b). The cartridge key 52 is axially and rotationally fixed to the cartridge container 50. To achieve that, the cartridge key 52 forms axial fixation means 212 in the form of a circumferentially extending groove that engage with axial fixation means 214 (cf. Fig. 20A) in the form of a circumferentially extending rib on an inner circumferential surface of the cartridge container 50. Furthermore, the cartridge key 52 forms rotation fixation means 216 in the form of a radially extending rib that engage rotation fixation means 218 in the form of a radially extending groove on the inner circumferential surface of the cartridge container 50. When the cartridge key 52 is attached to the cartridge container 50, an annular end face 266 (Fig. 22B) is in aerial abutment with a corresponding annular end face 268 (Fig. 20A) of the cartridge container 50. Both annular end faces 266 and 268 can be arranged perpendicular to the longitudinal axis of the pen 10. Furthermore, when the cartridge key 52 is attached to the cartridge container 50, a window 220 formed in the cartridge key 52 is aligned with a window 222 in the cartridge container 50 so that the patient can see the drug inside the transparent dual chamber cartridge 48 during reconstitution. At the proximal end of the cartridge key 52, which also defines the proximal end of the injection pen 10, a thread 224 is formed for attaching a needle (not shown). The thread 224 surrounds an opening 252 at a proximal end of the cartridge holder 52. The opening 252 is configured to receive a needle that is in fluid connection with an interior of the cartridge 48 inserted into the cartridge holder 52.

The cartridge key 52 forms an inner surface 254 (Fig. 22B) that defines a cylindrical receptacle that receives the cartridge 48 and prevents tilting of the cartridge 48 with respect to the longitudinal axis. Tilting of the cartridge 48 is prevented by an areal contact between a cylindrical outer surface 256 of the cartridge and the inner surface 254 in a holding section 249 of the cartridge holder 52. Furthermore, the cartridge holder 52 forms a cut-out 221 to receive the bypass 206 of the dual chamber cartridge 48. The bypass 206 form-fittingly engages the cut-out 221 so that the dual chamber cartridge 48 is axially and rotationally fixed to the cartridge key 52. On the opposite side of the cut-out 221 , a slot 223 is formed extending in the axial direction. The slot 223 allows to reversibly widen the cartridge key 52 to axially insert the dual chamber cartridge 48 with the bypass 206.

In order to mix the different components in the dual chamber cartridge 48 and to prime the injection pen 10, the cartridge container 50 is screwed onto the piston rod guide 42 until a distal end surface 226 of the cartridge container 50 abuts a proximal surface 228 (cf. Fig. 15B) of the piston guide 42. In order to do so, the cartridge container 50 forms an outer surface 246 that can be grasped with one hand to screw the cartridge container 50 onto the piston rod guide 42. When the cartridge container 50 is screwed onto the piston rod guide 42, a proximal portion of the piston rod guide 42 enters an annular space 258 (Fig. 23B) between an outer circumferential surface 264 of the cartridge holder 52 and an inner circumferential surface 260 of the cartridge container 50 defining an inner space 248 of the cartridge container 260. In order to screw the cartridge container 50 onto the piston rod guide 42, a first thread 230 is formed on the inner circumferential surface 260 of the cartridge container 50 that is engaged with a second thread 232 formed on the outer circumferential surface 262 of the piston rod guide 42. As can be seen in Fig. 15A, the piston rod guide 42 forms a snap element 234. The snap element 234 allows screwing, i.e. a compulsory guided combined axial and rotational movement, of the cartridge container 50 relative to the piston rod guide 42 in the distal direction but blocks screwing of the cartridge container 50 relative to the piston rod guide 42 in the proximal direction 1 if the snap element 234 engages with one of the openings 236, 238, and 240. The first opening 236 (cf. Fig. 20B) is configured to define a starting position of the cartridge container 50 and makes sure that the cartridge container 50 cannot be detached from the piston rod guide 42. This starting position or as-delivered state is shown in Figs. 25A and 25B.

The second opening 238 defines a reconstitution state of the cartridge container 50. In this state, the second chamber 202 still contains air so that the injection pen 10 can be moved forth and back to ensure that the drug is homogenously mixed together. The second opening 238 may be omitted. Therefore, the present disclosure is also directed at an embodiment of the injection pen 10 that features the first 236 and third opening 240 but not the second opening 238. The third opening 240 defines a knob cover unfastening state of the cartridge container 50 where the most of the air is expelled from the second chamber 202, which now contains the reconstituted medicament ready for use.

In the following with regard to Figs. 23A to 33B, different states of the injection pen 10 are described during usage of the pen 10.

Figs. 23A to 25B depict the injection pen 10 in the as-delivered state. As can be seen in Fig. 23A, the knob cover 16 covers a distal end section of the injection pen 10 up to a joint between the housing 32 and the piston guide 42. Therefore, the dose setting knob 22 is fully covered by the knob cover 16 so that it is not possible for the user to prematurely set a dose in this state. Looking at Fig. 23B, it can be seen that in the as-delivered state, the drug reconstitution unit 56 forms two separate chambers 202, 204 divided by the first sealing element 208. That means that the two components of the drug, each being stored in one of the two chambers 202, 204 are not yet mixed together. As can be seen in Fig. 24, where the knob cover 16 is blanked out to show what is under the knob cover 16, the dose setting sleeve 34 indicates that the injection pen 10 is in a preset state which differs from a zero-dose state. Accordingly, the dose setting knob 22 is also in a preset position differing from a zero-dose position. As can be seen in Fig. 25A and 25B, the snap element 234 of the piston rod guide 42 is snapped into the first opening 236 of the cartridge container 50. In Fig. 24, the cartridge container 50 is depicted as semi-transparent in order to show the first thread 230 formed on the inner circumferential surface of the cartridge container 50. Secondly, the piston rod guide 42 is also depicted as semi-transparent to show the position of the piston rod 44 in the preset state.

To start preparation of the drug, as can be seen from comparing Figs. 25A and 26A, the cartridge container 50 is rotated by the user which causes the cartridge container 50 including the cartridge key 52 and the dual chamber cartridge 48 to move in the distal direction relative to the piston rod guide 42. The piston rod guide 42 thereby moves into the annular space 258 (Fig. 23B) between the cartridge container 50 and the cartridge holder 52. The piston disc 46 is snapped to the piston rod 44, which is rotationally fixed by the piston rod guide 42 and axially fixed by the nut 38. The piston disc 46 thus blocks the movement of the second sealing element 210 arranged in the dual chamber cartridge 48 so that the second sealing element 210 slides along the inner circumferential surface of the dual chamber cartridge 48 while the cartridge container 50 is further screwed onto the piston rod guide 42. The solvent stored in the second chamber 204 pushes against the first sealing element 208 which also causes the first sealing element 208 to slide along the inner circumferential surface of the dual chamber cartridge 48. This would cause an overpressure in the cartridge, but the air can escape through the double-ended needle the user attached to thread 224. When the first sealing element 208 reaches the bypass 206 (cf. Fig. 23B), the first chamber 202 and the second chamber 204 are connected by the bypass 206 and therefore, the lyophilized drug stored in the first chamber 202 and the solvent stored in the second chamber 204 mix.

In the reconstitution state shown in Figs. 26A to 27C, the mixed drug is stored in the first chamber 202 between the first sealing element 208 and the proximal end 14 of the dual chamber cartridge 48. As can be seen in Fig. 26B, a proximal end surface of the second sealing element 210 abuts a distal end surface of the first sealing element 208 so that no second chamber 204 is present anymore in the reconstitution state. As can be seen in Fig. 27C, the snap element 234 of the piston rod guide 42 is snapped into the second opening 238 of the cartridge container 50. In this state, the front chamber 202 still contains a significant amount of air, which helps to create turbulence when moving the pen, so that the mixing of the lyophilized drug is easier. As mentioned before, the second opening 238 can be omitted. In that case the mixing takes place with a low residual amount of air.

After the reconstitution of the drug is finished, the cartridge container 50 is further rotated by the user causing the cartridge container 50 to move further axially in the distal direction relative to the piston rod guide 42. This causes a displacement section 242 positioned at a distal end of the cartridge container 50 to engage with and spread the wings 58 of the knob cover 16 radially outwardly (cf. Fig. 28B). Spreading the wings 58 radially outwardly causes the form-fitting engagement means 60 of the knob cover 16 to disengage from the coupling surface 228 so that the knob cover 16 is axially movable relative to the housing 32. It is now possible to pull off the knob cover 16 from the housing 32 in the distal direction resulting in the state shown on Fig. 29A and 29B. When the cartridge container 50 is fully screwed onto the piston rod guide 42, a radial end stop 244 formed on the outer circumferential surface 262 of the piston rod guide 42 abuts a radial end stop (not shown) on an inner circumferential surface of the cartridge container 50. Furthermore, the snap element 234 of the piston rod guide 42 is snapped into the third opening 240. Consequently, the cartridge container 50 is rotationally locked to the piston rod guide 42 and the housing 32 of the device. Therefore, movement of the cartridge container 50 and the cartridge 48 respect to the housing 32 and the piston rod guide 42 is inhibited.

As can be seen in Fig. 29A and 29B, at this stage the knob key 30 is still clipped onto the outer circumferential surface of the dose selector 28 between the proximal edge 160 of the dose setting knob 22 and the distal edge 162 of the housing 32. The knob key 30 can be taken away from the dose selector 28 only after the knob cover 16 has been removed by slightly bending the knob key 30.

Afterwards, as can be seen when comparing Figs 29A and 30A, the dose setting knob 22 is rotated by the user the set a desired dose out of multiple possible settable doses. In this example, the dose setting knob 22 is rotated 180° to set the desired dose. While the dose setting knob 22 is rotated, the dose setting knob 22 makes a compulsory guided combined axial and rotational movement, namely a screw movement, in the distal direction.

Rotating the dose setting knob 22 causes rotation of the injection button 18, that is axially and rotationally connected to the dose setting knob 22 via the snap ring 20, the snap element 24, which is rotationally connected to the dose setting knob 22 via the teeth 108 intermeshing with the teeth 1 10, the driver 36, which is rotationally and axially coupled to the snap element 24, and the dose setting sleeve 34 which is rotationally and axially coupled to the driver 36. Rotation of the driver 36 causes the driver 36 to move axially in a distal direction due to the engagement of the outer thread 170 of the driver 36 and the inner thread 172 of the piston rod guide 42. The axial movement of the driver 36 causes the snap element 24 to move in a distal direction which pushes the injection button 18 and the dose setting knob 22 in the distal direction via the couplings means 102 of the snap element 24 interacting with the assembling means 98 of the injection button 18. This causes the dose setting knob 22 to perform a compulsory guided combined axial and rotational movement during dose setting.

Furthermore, rotating the dose setting knob 22 causes rotation of the injection button 18 that is rotationally coupled to the nut 38. Since the piston rod 44 is rotationally fixedly coupled to the piston rod guide 42 due to their corresponding out of round cross-sections 186, 188, the nut 38 moves in the distal direction when the dose setting knob 22 and therefore the nut 38 is rotated.

The amount of axial movement of the nut 38 relative to the piston rod 44 and the driver 36 relative to the piston guide 42 depends on the pitch of the respective thread. The outer thread 170 of the driver 36 has a greater pitch than the outer thread 190 of the piston rod 44 so that the driver 36 moves in the distal direction more than the nut 38. For example, the outer thread 170 of the driver 36 can have a pitch of 10.71 mm and the outer thread 190 of the piston rod 44 can have a pitch of 10.21 mm.

When the desired dose is set, the spiral torsion spring 40 applies a torque to the snap element 24 via the driver 36 to bring the dose definition element 1 16 in abutment with the respective dose stop 1 18a to 1 18d, namely with its side surface 122b. Due to the spring 40, the injection pen 10 is configured to rotationally self-align the snap element 24 and the dose selector 28 in different predefined rotational positions defining predefined doses.

If the user then pushes the injection button 18 on the distal end 12 of the injection pen 10, the dose setting knob 22 moves in the proximal direction 1 relative to the snap element 24. This results in the coupling means 100 being bend while passing the circumferential ledge 102 causes a counterforce in the distal direction which has to be overcome by the user to start the injections process. The dose setting knob 22 moving in the proximal direction 1 relative to the snap element 24 also results in the teeth 108 of the dose setting knob 22 disengaging with the teeth 1 10 of the snap element 24 and instead the teeth 108 of the dose setting knob 22 engaging with the teeth 1 14 of the connector 26. Since the connector 26 is rotationally coupled to the housing 32 via the dose selector 28, the dose setting knob 22 is rotationally fixed to the housing 32. Therefore, during dose delivery, the dose setting knob 22, the injection button 18, the dose selector 28, and the nut 38 do not rotate relative to the housing 32.

If the user further pushes injection button 18, the injection button 18 and the dose selector 28 move relative to the snap element 24 in the proximal direction 1 . Thereby, the dose definition element 1 16 of the snap element 24 passes through the circumferentially extending rib 156 on the dose selector 28 through the respective cut-out 158a-158d corresponding to the set dose. At the same time, the hard stop 126 of the dose selector 28 moves in the axial direction relative to the hard stop 124 on the snap element 24 which allows the dose selector 28 and the snap element 24 to rotate relative to each other past the pre-set dose position towards the zero-dose position.

When the injection button 18 is pushed during dose delivery, the injection button 18 pushes the driver 36 via the snap element 24 in the proximal direction 1 . The spring 40 supports the axial movement of the driver 36 by applying a torque to the driver 36 resulting in an axial movement of the driver 36 in the proximal direction 1 due to the outer thread 170 of the driver 36. The driver pushes the nut 38 in the proximal direction 1 which causes the piston rod 44 to move in the proximal direction 1 . The movement of the piston rod 44 and the piston disc 46 in the proximal direction 1 causes the drug to be injected into the patient. Since the injection pen 10 is made to inject relatively large amounts of drug, the pen 10 does not have a so-called gearing. In other words, the parts that are configured to rotate relative to the housing during dose delivery are connected to the housing 32. This means that the distance the piston disc 46 advances is essentially equal to the distance the injection button 18 is pushed in the proximal direction 1 relative to the housing 32.

Since the driver rotates relative to the housing due to its outer thread 170, the dose setting sleeve 34 rotates during dose delivery. At the end of the dose delivery (cf. Fig. 33A and 33B) the dose setting sleeve 34 is in a rotational position in which a zero-dose label can be seen through the window 166 of the housing 32. The end of dose stop 174 (cf. Fig. 13B) of the driver 36 and the end of dose stop 176 (cf. Fig. 16C) of the piston rod guide 42 define an end of the movement of the injection button 18 in the proximal direction 1 during dose delivery.

At the end of the dose delivery, the coupling means 100 on the injection button 18 passes the coupling means 102 of the snap element 24 when initiating the injection, which permanently rotation- ally couples the dose setting knob 22 and the injection button 18 to the housing 32. Thus, the injection pen 10 is rendered inoperable, as the user cannot rotate the dose setting knob 22 to set a new dose.

The injection pen 10 allows for adjusting an axial position of the piston rod 44 with respect to the housing 32 in the preassembled state of the dose delivery mechanism 54. In the preassembled state, the injection button 18, which forms an adjusting element 18 of the dose delivery mechanism 54, engages with its distal assembling means 98a with the coupling means 102 of the snap element 24. This allows to position the injection button 18 in a more distal preassembled position compared to its assembled position in an assembled state of the dose delivery mechanism 54, in which assembled position the adjusting element 18 engages the coupling means 102 with its proximal assembling means 98b.

In the preassembled position, the adjusting element 18 protrudes from the dose setting element 22 and is free to rotate with respect to the dose setting element 22. Rotation of the adjusting element 18 then rotates the nut 38 with respect to the piston rod 44 and thereby causes axial movement of the piston rod 44 due to the threaded connection 189 between the piston rod 44 and the nut 38.

Adjustment of the piston rod 44 in the preassembled state is further detailed below in connection with a second injection pen 330 according to the present disclosure, which is a variant of the injection pen 10 shown in the previous figures.

Figs. 34 and 35 show the second injection pen 300 in the preassembled state, Fig. 36 shows an exploded view of the second injection pen and Fig. 37 shows a longitudinal cut through the second injection pen 300 in the preassembled state. As far as no differences are disclosed in the description or the Figures, the second injection pen 300 is configured as it is disclosed for the injection pen 10 of the previous Figures and vice versa.

The second injection pen 300 comprises a dose delivery mechanism 354. As far as no differences are disclosed in the description or the Figures, the dose delivery mechanism 354 of the second injection pen 300 is configured as it is disclosed for the dose delivery mechanism 54 of the injection pen 10 and vice versa.

The dose delivery mechanism 354 comprises a housing 332 that has an upper housing part 333 and a piston rod guide 342 that forms a lower housing part. The upper housing part 333 and the piston rod guide 342 are rigidly connected to each other via a form-fit connection. In particular, the upper housing part 333 and the piston rod guide 342 are axially and rotationally fixed to each other. The lower housing part formed by the piston rod guide 342 is configured to connect to a medicament container holder 305 that receives a medicament container 348. The medicament container holder 305 comprises a connector 307 that is located at a distal end of the medicament container holder 305. The connector 307 is configured to connect to a corresponding connector 343 of the piston rod guide 342, the corresponding connector 343 being accessible at a proximal side of the piston rod guide 342. The connectors 307, 343 provide a non-releasable form-fit connection between the medicament container holder 305 and the housing 332 after attachment of the medicament container holder 305 to the housing 332.

The medicament container 348 has a single medicament chamber that is sealed by a single plunger 210 at its distal end (see Fig. 35). The medicament chamber contains a fluid medicament. At its proximal needle end 349, the medicament container 348 comprises a septum that is configured to be punched upon attaching a double-sided cannula to a needle connector 306 located at the proximal end of the medicament container holder 305. A cap 301 is releasably attachable to the medicament container holder 305 during storage of the injection pen 300.

The dose delivery mechanism 354 comprises an injection button that constitutes an adjusting member 318, a snap element 24, a dosing element 334 and a driver 336. In the preassembled state and in the assembled state of the injection pen 300, the snap element 24 and the dosing element 334 are rigidly connected to each other and form a dosing member 323 of the dose delivery mechanism 354. The dosing element 334 is coupled to a housing 332 of the dose delivery mechanism 354 via a threaded connection 335. The threaded connection 335 comprises an outer thread on an outer surface of the dosing member 323 and an inner thread (not visible in Fig. 36) on an inner surface of the housing 332. With other embodiments, the dosing member 323 may also be configured as a single component.

The dosing member 323 constitutes a dose indication member of the dose delivery mechanism 354. Thereby, the dosing element 334 comprises markings that are visible through a window in the upper housing part 333 of the housing 332 upon rotation of the dosing member 323 with respect to the housing 332 during dose setting.

The driver 336 is connected to the housing 332 via a further threaded connection 337 that acts between the driver 336 and the piston rod guide 342, as it is described for the driver 36 and the piston rod guide 42 of the injection pen 10. The driver 336 is furthermore rotationally fixed and axially movable with respect to the dosing member 323 via a splined connection. Thereby, the driver 336 is received within the dosing element 334 of the dosing member 323. The splined connection comprises first spline elements on the outer circumference of the driver 336 that engage with corresponding second spline elements on the inner circumference of the dosing element 334. Simultaneous rotation of the driver 336 and the dosing member 323 requires axial movement of the driver 336 due to the further threaded connection 337 to the housing 332 and simultaneous axial movement of the dosing member 323 due to the threaded connection 335 to the housing 332.

A pitch of the threaded connection 335 between the dosing element 334 and the housing 332 deviates from a pitch of the further threaded connection 337 between the driver 336 and the housing 332. A ratio of these pitches defines a mechanical advantage of the dose delivery mechanism 354 during dose delivery and a forced proximal movement of the dosing member 334 by a first axial distance leads to a proximal movement of the driver 336 by a second axial distance that deviates from the first axial distance.

Fig. 38 shows a detailed view of a distal portion of the second injection pen 300 in the preassembled state. The adjusting element 318 deviates from the adjusting element 18 of the injection pen 10 in that it does not feature the coupling means 100 to axially lock the adjusting element 18 to the snap element 24 upon dose delivery. The second injection pen 300 therefore allows to repeatedly set and inject user definable doses. Apart from this modification, the adjusting element 318 is configured as it is disclosed for the adjusting element 18 and vice versa. In particular, the adjusting element 18 of the injection pen 10 is configured to adjust the position of the piston rod 46 in the preassembled state in the same way as it is disclosed in the following for the adjusting element 318 of the second injection pen 300. Furthermore, the adjusting element 318 forms an actuation member of the second injection pen 300. The actuation member is configured to be activated by a user to deliver a set dose. Exemplarily, the actuation member is configured to be pushed in the proximal direction by the user to deliver the set dose.

In the preassembled state shown in Figs. 37 and 38, the proximal assembling means 98b of the adjusting element 318 engage with the coupling means 102 of the snap element 24 to allow to position the adjusting element 318 in a preassembled position with respect to the housing 332. The preassembled position is the most distal axial position of the adjusting element 318 that is reached when the assembling means 98b engage with the coupling means 102 of the snap element 24 upon distal movement of the adjusting element 318. A biasing element 250 in the form of a spring, which biasing element 250 acts between the snap element 24 and the adjusting element 318, biases the adjusting element 318 in the distal direction into the preassembled position. Since the injection pen 10 does not feature the biasing element 250, the adjusting element 18 of the injection pen 10 is not held in the preassembled position. With the injection pen 10, an assembler of the device manually positions the adjusting element 18 in the preassembled position.

The assembling means 98b form a latch part of a latching mechanism 99 and the coupling means 102 of the snap element 24 form a latch counterpart of the latching mechanism 99. Furthermore, the dosing member 323 with the snap element 24 forms a counter member of the latching mechanism 99. The latching mechanism 99 prevents detachment of the adjusting element 318 from the housing 332 in the preassembled state.

In the preassembled position, the adjusting element 318 distally protrudes from the dose setting element formed by the dose knob 22. The rotation fixation means 90 of the adjusting element 318 then do not engage the rotation fixation means 94 of the snap ring 20 so that the adjusting element 318 is rotationally movable with respect to the housing 332 and the dose setting element 22.

In the preassembled position, an outer rim 19 of the adjusting element 318 is accessible to an assembler of the injection pen 300. When rotating the adjusting element 318 with respect to the housing 332 and the dose setting element 22, the adjusting element 318 rotates the nut 38. The nut 38 thereby does not axially move with respect to the housing 332 since it is restrained by the stationary driver 336 pushing on the pressing surface 194 at the proximal end of the nut 38. The threaded connection 189 between the piston rod 44, which forms a first threaded element, and the rotating nut 38, which forms a second threaded element, then causes the piston rod 44 to axially move with respect to the housing 332. The second injection pen 300 thus allows to adjust the axial position of the piston rod 44 by rotating the adjusting element 318 with respect to the housing 332 and the dose setting element 22. The same holds for the injection pen 10, the injection button 18 of which also forms an adjusting element. The dose delivery mechanisms 54, 354 of the injection pens 10, 300 each comprise a rotational lock 89, which is formed by the rotational fixation means 90 of the respective adjusting element 18, 318 and the toothed part 93 of the respective snap ring 20. The snap ring 20 thereby forms a connector between the respective adjusting element 18, 318 and the respective dose setting element 22 and the adjusting element 18, 318 is rotationally and/or axially fixed to the dose setting element 22 in the assembled state via the connector 20. Furthermore, the dose setting element 22 forms a counter element to which the adjusting element 18, 318 is attached in the assembled state of the respective dose delivery mechanism 54, 354.

Furthermore, the axial fixation means 82 of the adjusting elements 18, 318 and the rib 84 of the snap ring 20 each form an axial lock 81 that allows axial movement between the adjusting element 18, 318 and the dose setting element 22 in the preassembled state of the dose delivery mechanisms 54, 354 and that prevents axial movement between the adjusting elements 18, 318 and the dose setting element 22 in the assembled state.

The axial fixation means 82 of the adjusting elements 18, 318 and the rib 84 of the snap ring 20 also form a latching mechanism that acts between the adjusting elements 18, 318 and the counter element formed by the dose setting element 22. In the assembled state of the dose delivery mechanisms 54, 354, the latching mechanism blocks the movement of the adjusting elements 18, 318 from a second position with respect to the counter element into a first position with respect to the counter element. The second position thereby is the proximal position in which the adjusting elements 18, 318 are rotationally and axially fixed to the counter element and the first position is the distal position that the adjusting elements 18, 318 take up in the preassembled state and in which the adjusting elements 18, 318 are rotatable with respect to the counter element.

Fig. 39 shows a detailed view of a longitudinal cut through the distal end of the second injection pen 300 in the assembled state during dose setting and Fig. 40 shows a detailed view of a further longitudinal cut through the distal end of the second injection pen 300 in the assembled state during dose setting. Cut planes of the longitudinal cuts shown in Figs. 39 and 40 are orientated perpendicular to each other.

The injection pen 300 is transferred from the preassembled state into the assembled state by proximally moving the adjusting element 318 from the preassembled position into an assembled position with respect to the dose setting element 22 and the housing 332. This rotationally and axially locks the adjusting element 318 to the dose setting element 22 via the connector 20, the rotational lock 89 and the axial lock 81 . In the assembled state, the distal assembly means 98a of the adjusting element 318 engage with the coupling means 102 of the snap element 24 thus irreversibly blocking movement of the adjusting element 318 from the assembled position into the preassembled position.

The distal assembly means 98a of the adjusting element 318 forms a latch part of a latching mechanism 97 that is configured to prevent the adjusting element 318 from moving from the assembled position into the preassembled position with respect to the housing 332. The coupling means 102 of the snap element 24 forms a latch counterpart of the latching mechanism 97 and the dosing member 323 with the snap element 24 forms a counter member of the latching mechanism 97.

Fig. 41 shows a detailed view of a longitudinal cut through the distal end of the second injection pen 300 in the assembled state during dose delivery and Fig. 42 shows a detailed view of a further longitudinal cut through the distal end of the second injection pen 300 in the assembled state during dose delivery. Cut planes of the longitudinal cuts shown in Figs. 41 and 42 are orientated perpendicular to each other. Figs. 41 and 42 thereby show the injection pen 300 at the end of dose delivery when a set dose has been fully expelled and the adjusting element 318 is still pressed by a user of the injection pen 300 in the proximal direction 1 .

During dose setting in the assembled state, the adjusting element 318 is rotationally coupled to the dosing member 323 via a clutch mechanism 107 formed by the teeth 108 on the inside surface of the dose setting element 22 (see Fig. 5) and the teeth 1 10 on the outside surface of the snap element 24 (see Fig. 6). The dose setting element 22 forms a first clutch member of the clutch mechanism 107 and the snap element 24 forms a second clutch member of the clutch mechanism 107. The dosing members 23, 323 of the dose delivery mechanisms 54, 354 each form respective further members of the dose delivery mechanisms 54, 354.

With each dose delivery mechanism 54, 354, the respective clutch mechanism 107 rotationally couples the respective adjusting element 18, 318 to the respective further member in a closed state of the respective clutch mechanism 107 during dose setting in the assembled state and rotationally decouples the respective adjusting element 18, 318 from the respective further member in an opened state of the respective clutch mechanism 107 during dose delivery in the assembled state.

With other embodiments of the clutch mechanisms 107 that couple the adjusting elements 18, 318 to the further members, the second clutch members may also be integrally formed with the further members. For example, when integrally forming the snap element 24 and the dosing element 334 as a single-piece dosing member 323, this dosing member 323 constitutes the further member and, at the same time, the second clutch member.

During dose delivery, the clutch mechanism 107 is opened thus rotationally decoupling the adjusting element 318 and the dosing member 323. In the preassembled state, the clutch mechanism 107 is closed but the adjusting element 318 is rotationally decoupled from the clutch mechanism 107 so that the clutch mechanism 107 does not transfer rotation of the adjusting element 318 to the dosing member 323. In particular, the adjusting element 318 is rotationally decoupled from both the dose setting element 22 and the dosing member 323 in the preassembled state.

During dose delivery in the assembled state, the adjusting element 318 is rotationally coupled to the housing 332 via a further clutch mechanism 1 13, whereby the further clutch mechanism 1 13 is formed by the teeth 108 on the inside surface of the dose setting element 22 and the teeth 1 14 located on the outside surface of the connector 26. The dose setting element 22 thereby forms a first clutch member of the further clutch mechanism 113 and the connector 26 forms a second clutch member of the further clutch mechanism 113. If the further clutch mechanism 113 is in a closed state and the first clutch member engages with the second clutch member, the adjusting element 318 is rotationally fixed to an additional member, the additional member being formed by the housing 332.

During dose setting, the further clutch mechanism 113 is opened so that the adjusting element 318 is allowed to rotate with respect to the housing 332. During dose delivery, the further clutch mechanism 118 disclosed so that the adjusting element is rotationally fixed with respect to the housing. In the preassembled state, the adjusting element 318 is rotationally decoupled from the further clutch mechanism 113, since it is allowed to rotate with respect to both the first clutch member formed by the dose setting element 22 and the second clutch member formed by the connector 26.

Fig. 43 shows a longitudinal cut through the dose setting element 22 of the injection pen 10 and the second injection pen 300, Fig. 44 shows a perspective view of the longitudinal cut through the dose setting element 22, Fig. 45 shows a perspective distal view of the dose setting element 22 and Fig. 46 shows a prospective proximal view of the dose setting element 22 with the teeth 108 of the clutch mechanisms 107, 113.

With both the clutch mechanism 107 and the further clutch mechanism 113, the clutch mechanisms 107, 113 are in a closed state during one of dose setting and dose delivery and the clutch mechanisms 107, 113 are in an opened state during the other one of dose setting and dose delivery. The clutch mechanism 107 thereby is closed when the further clutch mechanism 113 is opened and the clutch mechanism 107 is opened when the further clutch mechanism 113 is closed.

Furthermore, with each clutch mechanism 107, 113, the adjusting element 318 takes up a dose setting position with respect to the respective second clutch member 24, 26 during dose setting and it takes up a dose delivery position with respect to the respective second clutch member 24, 26 during dose delivery. The dose delivery position thereby is axially shifted with respect to the dose setting position. Exemplarily, the dose delivery position is axially shifted in the proximal direction 1 .

With the dose delivery mechanisms 54, 354, the further clutch mechanism 113 also forms a locking mechanism that is configured to rotationally lock the adjusting element 18, 318 to the housing 32, 332 during dose delivery in the assembled state.

The dose selectors 28 of the dose delivery mechanisms 54, 354 each form a retaining member of the respective dose delivery mechanism 54, 354. Each adjusting element 18, 318 is located in a first axial position with respect to the retaining member in the preassembled state and each adjusting element 18, 318 is transferred from the first axial position into a second axial position with respect to the retaining member transferring the respective dose delivery mechanism 54, 354 from the preassembled state into the assembled state. Each adjusting element 18, 318 is rotatable with respect to the retaining member in the preassembled state.

During dose setting in the assembled state, each adjusting element 18, 318 is rotatable with respect to the respective retaining member and, during dose delivery in the assembled state, each adjusting element 18, 318 is rotationally fixed with respect to the respective retaining member. With the dose delivery mechanisms 54, 354, each adjusting element 18, 318 is axially fixed with respect to the respective retaining member in the assembled state.

With the dose delivery mechanisms 54, 354, the first threaded element formed by the piston rod 44 is axially stationary with respect to a third element of the dose delivery mechanism 54, 354 during dose setting in the assembled state. The third element thereby is the housing 32, 332. Furthermore, the second threaded element formed by the nut 38 is axially moved with respect to the third element during dose setting in the assembled state. During adjustment of the piston rod 44 in the preassembled state, the first threaded element formed by the piston rod 44 is axially moved with respect to the third element formed by the housing 32, 332 and the second threaded element formed by the nut 38 is axially stationary with respect to the third element formed by the housing 302, 332.

The dose definition mechanism 1 15 acting between the snap element 24 and the dose selector 28 of the dose delivery mechanisms 54, 354 is not active in the preassembled state since the adjusting element 318 is rotationally decoupled from the snap element 24 so that the snap element 24 does not rotate upon rotation of the adjusting element 318.

With both dose delivery mechanisms 54, 354, the adjusting element 18, 318 is configured to be rotated in the preassembled state until the bearing 46 touches the distal surface of the plunger 210 after having attached the medicament container 48, 348. A method for adjusting the position of the piston rod 44 in the preassembled state of the dose delivery mechanism 54, 354 may comprise a step of attaching the medicament container 48, 348 to the housing 32, 332 and a step of rotating the adjusting element 18, 318 until the bearing 46 touches the distal surface of the plunger 210. The adjusting element 18, 318 then may further be rotated until the rotation requires a predetermined torque. The dose delivery mechanism 54, 354 may then be transferred from the preassembled state into the assembled state.

The adjusting element 18, 380 may also be rotated until the bearing 46 is located at a distance larger than zero from the distal surface of the plunger 210, thus forming a gap between the distal surface of the plunger 210 and the proximal surface of the bearing 46. The distance may, for example, be measured by measuring the position of the bearing 46 with respect to the plunger 210 through the medicament container 305, which may be made from a transparent material.

Alternatively, the method may also comprise a step of adjusting the position of the piston rod 44 by rotating the adjusting element 18, 318 without the medicament container 48, 348 being attached to the housing 32, 332. The method then may comprise a step of placing the dose delivery mechanism 54, 354 in the preassembled state in an assembly jig and rotating the adjusting element 18, 318 until the proximal surface of the bearing 46 touches a reference surface provided by the assembly jig. The reference surface thereby may be located within the proximal cylindrical portion of the connector 43 of the injection pen 10.

For example, with the injection pen 300, the medicament container 348 may be attached to the housing 332 and the adjusting element 318 then may be rotated until a bearing 46 touches the distal surface of the plunger 210. The adjusting element 318 then may be further rotated until the rotation requires a predetermined torque.

With the dose delivery mechanism 54 of the injection pen 10, the proximal part of the piston rod guide 42 forms a connector 43 that is configured to connect the medicament container 48 axially movable to the housing 32 so that medicament container 48 may perform an axial movement from a receiving position into an operating position after connection to the housing 32. The receiving position thereby is defined by the snap element 234 of the connector 43 engaging with the distal opening 236 of the medicament container holder 50, 52. The operating position is defined by the snap element 234 engaging with the proximal opening 240 of the medicament container holder 50, 52 after having screwed the medicament container holder 50, 52 onto the connector 43.

With the injection pen 10, the dose delivery mechanism 54 may be provided without the medicament container holder 50, 52 being attached to the housing 32 and the position of the piston rod 44 may be adjusted by rotating the adjusting element 18 prior to attaching the medicament container holder 50, 52 to the housing 32. For example, the dose delivery mechanism 54 may be placed in an assembly jig. The adjusting element 18 then may be rotated until the bearing 46 touches a reference surface of the assembly jig and the bearing 46 and the piston rod 44 have reached a predetermined position with respect to the housing 32.

The piston rod 44 thereby is adjusted to a position with respect to the housing 32 that ensures that the bearing 46 gets into contact with the plunger 210 during the movement of the medicament container 48 from the receiving position into the operating position. Furthermore, the position of the piston rod 44 is adjusted to ensure that an amount of the liquid medicament is expelled from the medicament container 48 at the end of the movement into the operating position. For example, the position may be adjusted so that the amount of medicament is expelled only during the last quarter turn of the screwing motion of the medicament container holder 50, 52 onto the proximal part of the piston rod guide 42.

With both the first injection pen 10 and the second injection pen 300, the piston rod 44 may be advanced by a first distance into the proximal direction 1 upon proximal movement of the actuation member 18 by a second distance, wherein the second distance is less than 1 .5 times the first distance. With the first injection pen 10, the first distance equals the second distance. Furthermore, the actuation member 18 is traveling the second distance while the piston rod 44 travels the first distance. With the second injection pen 300, the ratio between the second distance and the first distance is given by the ratio of the pitch of the threaded connection 335 between the dosing member 323 and the pitch of the further threaded connection 337 between the driver 336 and the housing 332.

Alternative embodiments of the second injection pen 300 may also comprise a single threaded connection between all members of the second injection pen 300 that rotate during dose delivery and the housing 332. Such alternative embodiments may comprise the dosing member 23 of the first injection pen 10. Like with the first injection pen 10, the dosing member 23 may comprise the driver 36, the dosing element 34 and the snap element 24 shown in Fig. 1 .

Additionally or alternatively, the second injection pen 300 may also comprise the drug reconstitution unit 56 of the first injection pen 10. Such a second injection pen 300 then may be configured to receive the double chambered cartridge 48 and to perform reconstitution of a lyophilized drug prior to drug delivery.

Additionally or alternatively, the second injection pen 300 may also be configured to permanently axially lock an actuation member, like the actuation member formed by the adjusting element 318, and/or the dose setting element 22 to the dosing member 323 upon dose delivery. The second injection pen 300 then may comprise the coupling means 100 described in connection with the first injection pen 10.

Generally speaking, the first injection pen 10 and the second injection pen 300 each may comprise a blocking mechanism that is configured to prevent setting and/or delivery of a second dose after having delivered a first dose with the respective injection pen 10, 300. The blocking mechanism may be configured to permanently fix the dose setting element 22 at least rotationally to the housing 32, 332 upon dose delivery, such as upon delivery of a first set dose. Additionally or alternatively, the blocking mechanism may be configured to permanently axially fix the actuation member 18 to a counter member, whereby the actuation member 18 is moved relative to the counter member to initiate delivery of a set dose. With the injection pens 10, 300, the respective counter member is exemplarily formed by the dosing members 23, 323.

The blocking mechanism may comprise a first blocking part that engages a second blocking part to prevent setting and/or delivery of the second dose. With the first and second injection pen 10, 300, the first blocking part is exemplarily formed by the coupling means 100 and the second blocking part is exemplarily formed by the coupling means 102.

The injection pen 10, 300 may comprise a clutch mechanism that rotationally locks the dose setting element 22 to the housing during dose delivery in a closed state of the clutch mechanism. The blocking mechanism may permanently fix the dose setting element 22 at least rotationally to the housing 32, 332 by locking said clutch mechanism in the closed state. The clutch mechanism may, for example, be the clutch mechanism 107. The clutch mechanism may comprise, for example, a first clutch part, such as the teeth 1 14 of the connector 26, that engages with a second clutch part, such as the teeth 108 of the dose setting element 22, in the closed state of the clutch mechanism and that disengage from the second clutch part in the opened state of the clutch mechanism. For example, the first and second clutch parts may engage and disengage from each other upon axial relative movement with respect to each other. The clutch mechanism may, for example, be locked in the closed state by axially locking the first clutch part to the second clutch part.

Embodiments of the second injection pen 300 may be configured, like the first injection pen 10, to restrain a user from prematurely activating the second injection pen 300. Embodiments of the second injection pen 300 may be configured, like the first injection pen 10, to axially lock the actuation member 318 with respect to the housing 332 prior to setting and delivering a first dose. Like the first injection pen 10, the second injection pen 300 may comprise the knob cover 16 and/or the knob key 30.

Like the first injection pen 10, also the second injection pen 300 may be, in an as-delivered condition, preset to an injectable dose that is higher than zero. For example, the dosing member 323 may be preset to a position that corresponds to a set dose higher than zero. The second injection pen 300 may be, like the first injection pen 10, configured to prevent reduction of the preset injectable dose to zero.

With both the first and second injection pen 10, 300, the dosing member 23, 323 is stopped from rotating in a rotational direction at a first angular position during dose setting and stopped from rotating in the rotational direction at a second angular position during dose delivery, whereby the second angular position is spaced in the rotational direction from the first angular position by a distance that corresponds to the preset dose higher than zero. The second angular position may, for example, be taken by the dosing member 23, 323 at the end of dose delivery.

The first and second injection pen 10, 300 may comprise a first stop that limits rotation in the rotational direction at the first angular position during dose setting and/or a second stop that limits rotation of the rotational direction at the second angular position during dose delivery, for example at the end of dose delivery. The first stop may, for example, be the stop 126 shown in Fig. 9 and/or the second stop may, for example, be the end stops 174, 176 shown in Figures 13B and 15D.

With alternative embodiments, a stop that prevents the rotation of the dosing members 23, 323 at the end of dose delivery may also be provided at the respective dose selector 28. The stop may, for example, interact with a corresponding stop provided at the dosing member 23, 323, such as the hard stop 124. Such a stop is disclosed in document WO 2020015980 A1 , the disclosure of which is incorporated into the present disclosure in its entirety by reference, including the configuration of the stop, which is referred to as zero dose hard stop in document WO 2020015980 A1 . Fig. 47 shows a perspective view of a third injection pen 500 according to the present disclosure, Fig. 48 shows an exploded view of the third injection pen 500 and Fig. 49 shows a longitudinal cut through a dose delivery mechanism 554 of the third injection pen 500 in an assembled state during dose setting. As far as no differences are disclosed in the description or the Figures, the third injection pen 500 is configured as it is disclosed for the second injection pen 300 and vice versa.

The dose delivery mechanism 554 comprises a housing 532 that is configured to connect to a medicament container holder 505 via a non-releasable form-fit connection. The connection comprises a connector 506 located at the distal end of the medicament container holder 505. The connector 506 is configured to engage with a corresponding connector 543 located at the proximal end of the housing 532, see Fig. 49. The connection is configured as a non-releasable snap fit connection.

The medicament container holder 505 is configured to receive the medicament container 348 already described in connection with the second injection pen 300. At a proximal end, the medicament container holder 505 comprises a needle connector 306 that is configured to receive a double ended needle assembly 501 having a double ended cannula 502. The needle connector 300 connects to the needle assembly 501 via a threaded connection. Alternatively, the connection could also be configured as a Luer lock, a snap fit connection or the like. Upon mounting the needle assembly 501 onto the medicament container holder 505, a distal end of the cannula 502 pierces the septum at the proximal needle end 349 of the medicament container 348. The proximal end of the cannula 502 is covered by a needle cap 503 that is removed before use of the injection pen 500. During storage of the injection pen 500, a cap 504 covers the medicament container holder 505.

The dose delivery mechanism 554 comprises a dosing member 523 that is axially fixed and rotationally movable with respect to the housing 532 by a rotatable fixation 560. Fig. 50 depicts a perspective distal view of the dosing member 523 and Fig. 51 depicts a longitudinal cut through the dosing member 523. The rotatable fixation 560 comprises an annular rim 561 located at the proximal end of the dosing member 523 and corresponding holding lugs 533 at the proximal end of the housing 532. The holding lugs 533 snap behind the annular rim 561 and thus axially fix the dosing member 523 to the housing 532.

The dose delivery mechanism 554 further comprises a piston rod 44, which is shown in Fig. 52 in a perspective view. The piston rod 44 is received in an opening 567 at the proximal end of the dosing member 523. Thereby, the piston rod 44 is connected to the dosing member 523 via a threaded connection 189. The threaded connection 189 comprises an inner thread within the opening 567 of the dosing member 523 and an outer thread provided at the outer circumference of the piston rod 44. The piston rod 44 forms a first threaded element of the threaded connection 189 and the dosing member 523 forms a second threaded element of the threaded connection 189. At its proximal end, the piston rod 44 comprises coupling means 198 that connect a bearing 46 axially fixed and rotationally movable to the piston rod 44. Fig. 53 depicts a perspective distal view of an extension 525 of the dose delivery mechanism 554, Fig. 54 depicts a distal view of the extension 525 and Fig. 55 depicts a proximal view of the extension 525. The extension 525 is received within the dosing member 523. It is held axially fixed and rotationally movable within the dosing member 523 by a rotatable fixation 570. The rotatable fixation 570 exemplarily comprises an annular ridge 571 located at the proximal end of the extension 525 and corresponding lugs 566 provided at the proximal end of the dosing member 523. The lugs 566 snap behind the annular ridge 571 from the proximal side of the extension 525 and thereby axially fix the extension 525 to the dosing member 523.

The piston rod 44 is axially movable and rotationally fixed with respect to the extension 525. At its proximal end, the extension comprises a non-circular opening 573 that is adapted to a corresponding non-circular outer shape of the piston rod 44. The piston rod 44 is received within the opening 573, thereby rotationally locking the piston rod 44 to the extension 525, while allowing relative axial movement between the piston rod 44 and the extension 525.

Fig. 56 depicts a perspective view of a coupling element 520 of the dose delivery mechanism 554. The coupling element 520 comprises an end plate 580 located at its distal end and two bars 582 that extend axially and parallel to each other in the proximal direction.

The coupling element 520 is rotationally fixed and axially movable with respect to the piston rod 44. It thereby is coupled to the piston rod 44 via the extension 525. As can be seen from Fig. 57, the bars 582 of the coupling element 520 are received in between two ridges 575 of the extension 525 that radially extend from an inside surface of the extension 525. The ridges 575 thereby run parallel to each other along the axial direction. The bars 582 and the ridges 575 provide an axially movable connection between the coupling element 520 and the extension 525 that rotationally fixes the coupling element 520 to the extension 525.

As further can be seen from Fig. 57, an adjusting element 518 is axially and rotationally fixed to the distal end of the coupling element 520. Fig. 58 depicts a proximal perspective view of the adjusting element 518, Fig. 59 depicts a side view of the adjusting element 518, Fig. 60 depicts a radial cut through the adjusting element 518 along the line A-A in Fig. 59 and Fig. 61 depicts a radial cut through the adjusting element 518 along the line B-B in Fig. 59.

The adjusting element 518 is axially and rotationally fixed to the coupling element 520. The adjusting element 518 and the coupling element 520 thus form a single member of the dose delivery mechanism 554. As can be seen from Fig. 56, the coupling element 520 comprises an axial fixation element 584 that is part of an axial fixation acting between the adjusting element 518 and the coupling element 520 and that engages with a corresponding axial fixation element provided at adjusting element 518. The axial fixation element 584 of the coupling element 520 thereby is configured as a snap hook and the corresponding axial fixation element of the adjusting element 518 is configured as a circumferential edge that engages with the snap hook. The coupling element 520 further comprises at least one rotational fixation element 585, for example several rotational fixation elements 585. The rotational fixation elements 585 engage with corresponding rotational fixation elements provided at the adjusting element 518 and thereby rotationally lock the adjusting element 518 to the coupling element 520. The rotational fixation elements 585 of the coupling element 520 are configured is longitudinally ridges that run parallel to the axial direction. The ridges are received in between corresponding longitudinal recesses 586 provided within the adjusting element 518. With other embodiments of the dose delivery mechanism 554, the adjusting element 518 and the coupling element 520 may also be configured as a one-pieced single member.

Fig. 62 depicts a perspective view of a coupling member 524 of the dose delivery mechanism 554. The coupling member 524 is configured as a hollow member. As can be seen from Fig. 49, the coupling member 524 is located in between the dosing member 523 and the extension 525. Thereby, the coupling member 524 is placed within the dosing member 523 and receives the extension 525 in an inner cavity. The coupling member 524 is rotationally fixed to the dosing member 523 via an axially movable rotation fixation 563. The rotation fixation 563 comprises longitudinal recesses 590 provided on an outer surface of the coupling member 524 that engage corresponding longitudinal ridges 564 provided on an inside surface of the dosing member 523, see Figs. 50 and 51 .

Fig. 63 depicts a perspective distal view of a sleeve 528 of the dose delivery mechanism 554 and Fig. 64 depicts a longitudinal cut through the sleeve 528. The sleeve 528 is configured as a hollow member. As can be seen from Fig. 49, the sleeve 528 is located in between the housing 532 and the dosing member 523.

The sleeve 528 is threadedly connected to and threadedly engaged with the dosing member 523. A threaded connection between the sleeve 528 and the dosing member 523 comprises an inner thread 612 provided on an inside surface of the sleeve 528 that engages an outer thread 562 provided on an outer surface of the dosing member 523.

Furthermore, the sleeve 528 is rotationally fixed and axially movable connected to the housing 532. A connection between the sleeve 528 and the housing 532 thereby comprises a connector 620. The connector 620 is located at the distal end of the housing 532. It is axially and rotationally fixed with respect to the housing 532. With other embodiments, the connector 620 may also be formed integrally with the housing 532. The connector 620 comprises a pair of radial lugs 622 that are provided at an outer surface of the connector 620. The radial lugs 622 engage with corresponding openings 535 accessible at an inside surface of the housing 532. The connector 620 further comprises an outer annular rim 626 provided at a distal end of the connector 620. The annular rim 626 rests against the distal surface of the housing 532, thereby preventing the connector 620 from moving in the proximal direction.

On an inside surface of the connector 620, longitudinal recesses 624 are provided that engages with corresponding longitudinal ridges 616 on an outer surface of the sleeve 528. This provides a rotationally fixed and axially movable connection between the housing 532 and the sleeve 528. The dose sleeve 523 is configured as a dose indication member and comprises markings on its outer surface that serve to indicate a set dose. A window 610 is formed within the sleeve 528, through which the dose sleeve 523 is visible. The window 610 of the sleeve 528 is aligned with a housing window 534 provided within the housing 532, so that the dose sleeve 523 is visible from the outside of the housing 532. A set dose is then indicated by the marking that is visible through the windows 534, 610.

The coupling member 524 is axially fixed and rotationally movable with respect to the sleeve 528. A connection between the coupling member 524 and the sleeve 528 comprises a connector 527.

Fig. 66 depicts a perspective view of the connector 527 and Fig. 67 depicts a perspective view of a longitudinal cut through the connector 527. The connector 527 is axially and rotationally fixed with respect to the sleeve 528. It comprises longitudinal ridges 632 on its outer surface that engage with corresponding recesses 618 (see Fig. 64) provided on the inside surface of the sleeve 528. Furthermore, the connector 527 comprises radially extending lugs 630 that engage with openings 614 accessible on the inside surface of the sleeve 528. This engagement prevents the connector 527 from being removed from the sleeve 528.

On an inside surface of the connector 527, a distal blocking element 635 and proximal blocking elements 654 are formed. The blocking elements 635, 654 provide an axially fixed and rotationally movable connection to the coupling member 524. Thereby, an annular rim 592 that is provided on the outer surface of the coupling member 524 and that extends in the radial direction (see Fig. 62), is received in between the blocking elements 635, 654.

Furthermore, a radial stop 568 is formed between the sleeve 528 and the dosing member 523. This radial stop 568 is configured to stop relative rotation between the dosing member 523 and the sleeve 528 and thus also between the dosing member 523 and the housing 532 at the end of dose delivery. The radial stop 568 comprises at least one stop surface 569 provided at the dosing member 523 and a corresponding stop surface 636 provided at the connector 527. The stop surfaces 569, 636 are orientated parallel to each other and configured to engage with each other at the end of dose delivery. The stop surfaces 569, 636 form an angle with a radial plane orientated perpendicular to the longitudinal axis of the dose delivery mechanism 554. With the third injection pen 500, the stop surfaces 569, 636 are orientated parallel to the longitudinal axis. While the stop surface 636 is provided at the connector 527, the stop surface 636 may also be provided directly at the sleeve 528 with other embodiments.

With the third injection pen 500, the adjusting element 518 forms a dose setting member of the dose delivery mechanism 554. To set a dose to be delivered, a user rotates the adjusting element 518 with respect to the housing 532 in the assembled state. Fig. 68 depicts a side view of the third injection pen 500 in an assembled state during dose setting, when no dose is set. Fig. 69 depicts a side view of the third injection pen 500 in a preassembled state. In the preassembled state, the adjusting element 518 is located in a preassembled position with respect to the housing 532 and in the assembled state during dose setting and with no dose being set, the adjusting element 518 is in an assembled position with respect to the housing 532. Thereby, the assembled position is located more proximally than the preassembled position.

Fig. 70 shows a detailed view of a longitudinal cut through the distal end of the third injection pen 500 in the assembled state during dose setting and Fig. 71 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen 500 in the assembled state during dose setting. Thereby, a longitudinal cut plane of the view shown in Fig. 71 is orientated perpendicular to a longitudinal cut plane of the view shown in Fig. 70.

During dose setting, the adjusting element 518 is rotationally fixed with respect to the coupling member 524 by a clutch mechanism 507. Rotation of the adjusting element 518 then causes rotation of the piston rod 44 due to the rotational fixation via the extension 525 and the coupling element 520 and simultaneous rotation of the dosing member 523 due to the rotational fixation via the coupling element 520, the clutch mechanism 507 and the coupling member 524. Since both the piston rod 44 and the dosing member 523 rotate with respect to the housing 532 at the same speed during dose setting, the piston rod 44 does not change its axial position with respect to the housing 532 despite the threaded connection 189 between the piston rod 44 and the dosing member 523.

Rotation of the dosing member 523 with respect to the sleeve 528 during dose setting causes the sleeve 528 to move axially in the distal direction with respect to the housing 532 due to the threaded connection 562, 612. This also causes distal movement of the adjusting element 518 and the coupling element 520. Furthermore, the coupling member 524 is also moved distally due to the axially fixed and rotationally movable connection to the sleeve 528 via the connector 527.

As can be seen from Figs. 70 and 71 , the adjusting element 518 is coupled to the sleeve 528 by a latching mechanism 597 that prevents distal movement of the adjusting element 518 and the coupling element 520 with respect to the sleeve 528. As can be seen from Figs. 58 to 61 , 63 and 64, the latching mechanism 597 comprises a latch part 600 located at the proximal end of the adjusting element 518 that engages with a latch counterpart 529 of the sleeve 528. The latch counterpart 529 of the sleeve 528 is configured as an annular edge located at the outside surface of the sleeve 528. The latch part 600 of the adjusting element 518 is configured as corresponding radial lugs provided on an inner surface of the adjusting element 518. In the assembled position of the adjusting element 518, the radial lugs 600 engage with the annular edge 529, thus preventing further distal movement of the adjusting element 518 into the preassembled. The adjusting element 518 and the coupling element 520 are biased with respect to the sleeve 528 in the distal direction by a biasing member 250, which is configured as a compression spring and which is shown in Fig. 48 and which is not visible in Figs. 70 and 71 .

During the rotation of the dosing member 523 and the axial movement of the sleeve 528 with respect to the housing 532 during dose setting, the window 610 of the sleeve 528 axially moves along the dosing member 523. Thereby, a respective marking on the dose sleeve 523 that is visible through the window 610 indicates a dose that is currently set.

To deliver a set dose, a user of the third injection pen 500 pushes the adjusting element 518 and the coupling element 520 in the proximal direction 1 against the force of the biasing member 250.

Fig. 72 shows a detailed view of a longitudinal cut through the distal end of the third injection pen 500 in the assembled state during dose delivery and Fig. 73 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen 500 in the assembled state during dose delivery, whereby a longitudinal cut plane is orientated perpendicular to a longitudinal cut plane of the view in Fig. 73. Figs. 72, 73 thereby show the dose delivery mechanism 554 of the third injection pen 500 at the end of dose delivery, when the set dose has been fully expelled and the user still presses the adjusting element 518 and the coupling element 520 in the proximal direction.

During dose delivery, the adjusting element 518 and the coupling element 520 are rotationally locked to the housing 532 via the sleeve 528. This is because proximal movement of the coupling element 520 and the adjusting element 518 with respect to the sleeve 528 at the beginning of dose delivery closes a clutch mechanism 513 between the adjusting element 518 and the sleeve 528. The clutch mechanism 513 comprises teeth 515 formed at the adjusting element 518 and corresponding teeth 514 formed at the distal end of the sleeve 528. The clutch mechanism 513 also rotationally locks the piston rod 44 to the housing 532 during dose delivery via the extension 525, the coupling element 520, the adjusting element 518 and the sleeve 528.

Proximal movement of the coupling element 520 with respect to the coupling member 524 at the beginning of dose delivery causes the clutch mechanism 507 between the coupling element 520 and the coupling member 524 to open so that the coupling member 524 becomes rotatable with respect to the coupling element 520. After disengagement of the clutch mechanism 507, further proximal movement of the coupling element 520 pushes the sleeve 528 in the proximal direction 1 . The proximal movement of the sleeve 528 rotates the dosing member 523 via the threaded connection 612 between the sleeve 528 and the dosing member 523. Since the piston rod 44 is rotationally locked to the housing 332 during dose delivery, rotation of the dosing member 523 causes proximal movement of the piston rod 44, which proximal movement is driven via the threaded connection 189.

Fig. 74 shows a detailed view of a longitudinal cut through the distal end of the third injection pen

500 in a preassembled state of the dose delivery mechanism 554 and Fig. 75 shows a detailed view of a further longitudinal cut through the distal end of the third injection pen 500 in the preassembled state, whereby a longitudinal cut plane is orientated perpendicular to a longitudinal cut plane of the view in Fig. 74.

In the preassembled state, the adjusting element 518 and the coupling element 520 are located in the adjusting position with respect to the housing 532 and the sleeve 528. In the adjusting position, the adjusting element 518 and the coupling element 520 are shifted in the distal direction with respect to their respective assembled positions in the assembled state.

The dose delivery mechanism 554 comprises a further latching mechanism 599 that prevents detachment of the adjusting element 518 and the coupling element 520 in the preassembled state. The further latching mechanism 599 comprises the latch part 600 of the adjusting element 518 and a further latch counterpart 530 located at the distal end of the sleeve 528. The further latch counterpart 530 thereby is located distally from the latch counterpart 529.

The further latch counterpart 530 is configured as an angular recess that receives the radial lugs of the latch part 600 of the adjusting element 518. The latch parts 600 formed by the radial lugs thereby are releasably engaged with the further latch counterpart 530 and allow proximal movement of the adjusting element 518 while blocking distal movement.

In the preassembled state, the clutch mechanism 507 between the coupling element 520 and the coupling member 524 is opened so that the adjusting element 518 is rotationally decoupled from the dosing member 523. At the same time, the adjusting element 518 is rotationally coupled and rotationally fixed with respect to the piston rod 44 by the coupling element 520 and the extension 525. Rotation of the adjusting element 518 with respect to the housing 532 thereby causes the piston rod 44 to rotate with respect to the housing 532 and the dosing member 523. Due to the threaded connection 189 between the dosing member 523 and the piston rod 44, the piston rod 44 moves axially with respect to the housing 332 upon rotation of the adjusting element 518.

With the clutch mechanism 507, the coupling element 520 forms a first clutch member of the clutch mechanism 507 and the coupling member 524 forms a second clutch member of the clutch mechanism 507. The dosing member 523 of the dose delivery mechanism 554 forms a further member of the dose delivery mechanisms 54, 354 to which the adjusting element 518 is rotationally coupled during dose setting in the assembled state and from which the adjusting element 518 is rotationally decoupled during dose delivery in the assembled state.

The coupling element 520 comprises a first clutch part 508 of the clutch mechanism 507. The first clutch part 508 is configured as radial teeth that are provided on an outer surface of the coupling element 520. The coupling member 524 comprises a second clutch part 509 of the clutch mechanism 507. The second clutch part 509 is configured as radial teeth that are located on the inside surface of the coupling member 524. In the closed state of the clutch mechanism 507, the first clutch part 508 is engaged with the second clutch part 509, as it is shown in Fig. 71 . During the adjustment of the piston rod in the preassembled state, the clutch mechanism 507 is in an opened state. Thereby, the first clutch part 508 and the second clutch part 509 are brought out of engagement by locating them at an axial distance from each other. The first clutch part 508 thereby is shifted in a distal direction from the second clutch part 509, the distal direction being opposite the proximal direction 1 , see Figs. 74. During dose delivery in the assembled state, the clutch mechanism 507 is also in an opened state. Thereby, the first clutch part 508 and the second clutch part 509 are also brought out of engagement by locating them at an axial distance from each other, whereby the second clutch part 509 is shifted in the proximal direction 1 from the first clutch part 508, see Fig. 72.

Furthermore, the adjusting element 518 forms a first clutch member of the clutch mechanism 513 and the sleeve 528 forms a second clutch member of the clutch mechanism 513. The housing 532 of the dose delivery mechanism 554 forms an additional member of the dose delivery mechanism 554 to which the adjusting element 518 is rotationally coupled during dose setting in the assembled state and from which the adjusting element 518 is rotationally decoupled during dose delivery in the assembled state.

The sleeve 528 forms a retaining member for the adjusting element 518.

The dose delivery mechanism 554 comprises a dose definition mechanism 115 that defines the doses settable by a user. Engagement features 116 of the dose definition mechanism 115 are provided at the adjusting element 518, see Fig. 58. The engagement features 116 are configured as radially extending lugs that are flexible in the radial direction. The engagement features 116 engage with corresponding dose stops 118 that are provided at a distal end of the sleeve 528, see Figs. 63, 64. The dose stops 118 are configured as longitudinally recesses formed at an inner surface of the sleeve 528. During dose setting, the adjusting element 518 and the coupling element 520 are configured to perform more than one full revolution about the longitudinal axis of the dose delivery mechanism 554.

During adjustment of the piston rod 44 in the preassembled state, the dose definition mechanism

115 of the dose delivery mechanism 554 is not active. This is because the engagement features

116 are axially shifted with respect to the dose stops 118 to bring the engagement features 116 and the dose stops 118 out of mutual engagement, see Fig. 75.

With the dose delivery mechanism 554, the housing 532 forms a third element and the first threaded element formed by the piston rod 44 is rotated with respect to that third element during adjustment of the piston rod in the preassembled state, while the second threaded element formed by the dosing member 523 is rotationally fixed with respect to the third element. During dose delivery in the assembled state, the first threaded element formed by the piston rod 44 is rotationally fixed with respect to the third element formed by the housing 532 and the second threaded element formed by the dosing member 523 is rotated with respect to the third element. With the third injection pen 500, the piston rod 44 may be configured to advance by a first distance into the proximal direction 1 upon proximal movement of the actuation member 520 by a second distance, wherein the second distance is less than 1 .5 times the first distance. With the third injection pen 500, the ratio between the second distance and the first distance is given by the ratio of the pitches of the threaded connection 189 between the piston rod 44 and the dosing member 523 and of the further threaded connection 562 between the sleeve 528 and the dosing member 523.

Additionally or alternatively, the third injection pen 500 may also comprise the drug reconstitution unit 56 of the first injection pen 10. Such a third injection pen 500 then may be configured to receive the double chambered cartridge 48 and to perform reconstitution of a lyophilized drug prior to drug delivery.

Embodiments of the third injection pen 500 may be configured, like the first injection pen 10, to restrain a user from prematurely activating the third injection pen 500. Embodiments of the third injection pen 500 may be configured, like the first injection pen 10, to axially lock the actuation member 520 with respect to the housing 532 prior to setting and delivering a first dose. Like the first injection pen 10, the third injection pen 500 may comprise the knob cover 16 and/or the knob key 30.

Fig. 76 shows a perspective view of a fourth injection pen 700 according to the present disclosure. The fourth injection pen 700 is a variant of the third injection pen 500. As long as no differences are disclosed in the description or the Figures, the fourth injection pen 700 is configured as it is disclosed for the third injection pen 500. In the following, components of the fourth injection pen 700 that perform the same functions as corresponding components of the third injection pen 500 are labeled with the same reference signs. These components may, however, differentiate among the third injection pen 500 and the fourth injection pen 700 in shape and/or appearance.

Fig. 77 shows a side view of the fourth injection pen 700 in an assembled state during dose setting. Thereby, no dose is set and an adjusting element 518 of a dose delivery mechanism 754 of the fourth injection pen 700 is positioned in an assembled position with respect to a housing 532 of the dose delivery mechanism 754.

Fig. 78 shows a side view of the fourth injection pen 700 in a preassembled state with the adjusting element 518 being in a preassembled position with respect to the housing 532. In the preassembled position, the adjusting element 518 is shifted in a distal direction from its assembled position, whereby the distal direction is orientated perpendicular to a proximal direction 1 .

Fig. 79 shows a side view of the fourth injection pen in the preassembled state with the adjusting element 518 in an adjusting position. In the adjusting position, the adjusting element 518 is shifted in the proximal direction compared to the preassembled position. Fig. 80 shows an exploded view of the fourth injection pen 700 and Fig. 81 shows a longitudinal cut through the dose delivery mechanism 754 of the fourth injection pen 700 in the assembled state during dose setting with no dose set.

Like the dose delivery mechanism 554 of the third injection pen 500, the dose delivery mechanism 754 of the fourth injection pen 700 comprises a coupling element 720 that is rotationally fixed and axially movable with respect to a piston rod 44. Unlike the dose delivery mechanism 554, the dose delivery mechanism 754 does not feature the extension 525. Instead, the coupling element 720 directly engages with the piston rod 44 to rotationally fix the coupling element 720 to the piston rod 44 and to allow axial movement between the coupling element 720 and the piston rod 44.

The dose delivery mechanism 754 furthermore comprises a biasing element in the form of a spring, which is not shown in Figs. 80 and 81 . The biasing element biases the adjusting element 518 in the distal direction both in the preassembled state and in the assembled state of the dose delivery mechanism 754.

Fig. 82 shows a perspective view of the coupling element 720 of the dose delivery mechanism 754 and Fig. 83 shows a radial cut through the coupling element 720 along the line A-A shown in Fig. 82. The coupling element 720 is configured as a tubular member that extends along the longitudinal direction. It has a non-circular inner cross-section that is configured to receive the piston rod 44. The piston rod 44, which is shown in Fig. 84, has a distal section 45 having an outer shape that is configured to engage with the non-circular inner cross-section of the coupling element 720 to rotationally lock the piston rod 44 and the coupling element 720 and to allow axial movement between the coupling element 720 and the piston rod 44.

Figs. 85 to 89 depict the adjusting element 518 of the dose delivery mechanism 754. The adjusting element 518 engages with a distal part of the coupling element 720. The adjusting element 518 thereby is rotationally fixed with respect to the coupling element 720 both in the preassembled state and in the assembled state of the dose delivery mechanism 704. A rotational lock between the coupling element 720 and the adjusting element 518 comprises a non-circular outer cross section of the coupling element 720 that matches and engages with a corresponding inner shape of a central opening 519 of the adjusting element 518.

A latching mechanism 597 acts between the coupling element 720 and the adjusting element 518. In the assembled state of the dose delivery mechanism 754, the latching mechanism 597 prevents the adjusting element 518 from moving distally from the assembled position into the preassembled position with respect to the housing 532. The latching mechanism 597 comprises latch parts 600 formed at the adjusting element 518 and latch counterparts 529 formed at the coupling element 720. The latch parts 600 are configured as flexible hooks that protrude radially inward from the inner surface of the adjusting element 518 at the opening 519. The latch counterparts 529 are configured as recesses located at the outer surface in the distal part of the coupling element 720. The coupling element 720 may form a retaining member of the dose delivery mechanism 754.

In the preassembled state of the dose delivery mechanism 754, the adjusting element 518 is located at a more distal position with respect to the coupling element 720 than in the assembled state. In this position, the adjusting element 518 is prevented from being detached from the dose delivery mechanism 754 and the coupling element 720 by a further latching mechanism 599. A further latch part of the further latching mechanism 599 is formed by the latch part 600 and a further latch counterpart 530 of the further latching mechanism 599 is formed by an additional recess at the outer surface of the coupling element 720. The further latch counterpart 530 is thereby located at a distal side from the latch counterpart 529.

Figs. 90 to 93 show a sleeve 528 of the dose delivery mechanism 754 that is rotationally fixed and axially movable with respect to the housing 532. The sleeve 528 comprises longitudinal recesses on its outer surface that engage with corresponding longitudinal ridges on an inside surface of the housing 532 to rotationally fix the sleeve 528 to the housing 532. The sleeve 528 comprises an outer part 528a and insert 528b that is rotationally and axially fixed within the outer part 528a at a distal end of the outer part 528a.

A dose definition mechanism 115 of the dose delivery mechanism 754 acts between the adjusting element 518 and the sleeve 528. The dose definition mechanism 115 comprises engagement features 116 that are configured as flexible hooks and provided at a proximal end of the adjusting element 518. The engagement features 116 interact with dose stops 118 provided in a proximal part of an inside surface of the insert 528b of the sleeve 528.

Furthermore, the dose delivery mechanism 754 comprises a clutch mechanism 513 that acts between the adjusting element 518 and the sleeve 528. The clutch mechanism 513 comprises teeth 515 that are located at a proximal outer surface of the adjusting element 518. When closing the clutch mechanism 513, the teeth 515 engage with corresponding teeth 514 provided in a distal part of the inside surface of the insert 528b. The inside surface thereby is a side surface of a cavity formed at the distal end of the insert 528b and the sleeve 528.

The adjusting element 518 forms a first clutch member of the clutch mechanism 513 and the sleeve 528 forms a second clutch member of the clutch mechanism 513. The housing 532 of the dose delivery mechanism 754 forms an additional member of the dose delivery mechanism 754 to which the adjusting element 518 is rotationally coupled during dose setting in the assembled state and from which the adjusting element 518 is rotationally decoupled during dose delivery in the assembled state. Furthermore, the clutch mechanism 513 forms a locking mechanism that rotationally locks the adjusting element 718 to the housing 532 during dose delivery in the assembled state of the dose delivery mechanism 754.

Figs. 94 to 96 show a coupling member 524 of the dose delivery mechanism 754. The coupling member 524 is axially fixed to the sleeve 528 by a rim 592 provided at a distal end of the coupling member 524. The rim 592 is held between proximal blocking elements 634 and a distal blocking element 635 provided at a proximal end of the insert 528b. The proximal blocking elements 634 are configured as flexible hooks and the distal blocking element 635 is formed by a radial surface of the insert 528b.

A clutch mechanism 507 acts between the coupling member 524 and the coupling element 720, which is received within the coupling member 524. The clutch mechanism 507 comprises a first clutch part 508 that is located on an outside surface of the coupling element 720 and that comprises longitudinal teeth. The clutch mechanism 507 further comprises a second clutch part 509, which is located on an inside surface of the coupling member 524. The second clutch part 509 is configured as longitudinal teeth that mesh with the longitudinal teeth of the first clutch part 508 in the closed state of the clutch.

The coupling element 520 forms a first clutch member of the clutch mechanism 507 and the coupling member 524 forms a second clutch member of the clutch mechanism 507. The dosing member 523 of the dose delivery mechanism 754 forms a further member of the dose delivery mechanism 754 to which the adjusting element 518 is rotationally coupled during dose setting in the assembled state and from which the adjusting element 518 is rotationally decoupled during dose delivery in the assembled state.

Figs. 97 and 98 show a dosing member 523 of the dose delivery mechanism 754. A radial stop 568 is provided between the dosing member 523 and the insert 528b of the sleeve 528. The radial stop 568 comprises a stop surface 636 at a proximal extension of the insert 528b and a corresponding stop surface 569 at the distal end of the dosing member 523.

As can be seen from Fig. 99 and 100, which show the dose delivery mechanism 754 in the assembled state during dose setting with no dose set, the clutch mechanism 507 between the coupling element 720 and the coupling member 524 is closed and the clutch mechanism 513 between the adjusting element 518 and the sleeve 528 is opened during dose setting. Dose setting is then effected by rotating the adjusting element 720 in the same way as it is described for the third injection pen 500.

Figs. 101 and 102 depict the dose delivery mechanism 754 in the assembled state during dose delivery when a set dose has been completely expelled and the user still pushes the adjusting element 518 in the proximal direction 1 . During dose delivery, the clutch mechanism 507 is opened, thus allowing rotation between the piston rod 44 and the dosing member 523, and the clutch mechanism 513 is closed, thus rotationally locking the piston rod 44 to the housing 532.

Fig. 103 and 104 depict the dose delivery mechanism 754 in the preassembled state. Compared to the assembled state, the adjusting element 518 is shifted in the distal direction with respect to the coupling element 720 and the housing 532. The latch part 600 of the adjusting element 518 then engages with the further latch counterpart 530 provided distally from the latch counterpart 529 at the coupling element 720. In the state depicted in Figs. 103 and 104, the adjusting element 518 is positioned in a preassembled position with respect to the housing 532.

To adjust the position of the piston rod 44 in the preassembled state, the adjusting element 518 is pushed in the proximal direction 1 from the preassembled position into an adjusting position against the biasing force of the spring acting between the adjusting element 518 and the sleeve 528, as it is depicted in Figs. 105 and 106. Proximal movement of the adjusting element 518 results in proximal movement of the coupling element 720 and in opening of the clutch mechanism 507. At the same time, the clutch mechanism 513 remains opened and the teeth 515 of the adjusting element 518 are prevented from engaging with the teeth 514 of the sleeve 528. This is due to an axial offset between the teeth 513 and the teeth 514.

When an assembler of the fourth injection pen 700 rotates the adjusting element 518 in the adjusting position depicted in Figs. 105 and 106, the piston rod 44 rotates together with the adjusting element 518 and the dosing member 523 does not rotate due to the opened clutch mechanism 507. Rotation of the piston rod 44 with respect to the dosing member 523 then axially moves the piston rod 44 with respect to the housing 532 via the threaded connection 189.

With the fourth injection pen 700, the piston rod 44 may be configured to advance by a first distance into the proximal direction 1 upon proximal movement of the actuation member 518 by a second distance, wherein the second distance is less than 1 .5 times the first distance. With the fourth injection pen 700, the ratio between the second distance and the first distance is given by the ratio of the pitches of the threaded connection 189 between the piston rod 44 and the dosing member 523 and of the further threaded connection 562 between the sleeve 528 and the dosing member 523.

Additionally or alternatively, the fourth injection pen 700 may also comprise the drug reconstitution unit 56 of the first injection pen 10. Such a fourth injection pen 700 then may be configured to receive the double chambered cartridge 48 and to perform reconstitution of a lyophilized drug prior to drug delivery.

Embodiments of the fourth injection pen 700 may be configured, like the first injection pen 10, to restrain a user from prematurely activating the fourth injection pen 700. Embodiments of the fourth injection pen 700 may be configured, like the first injection pen 10, to axially lock the actuation member 520 with respect to the housing 532 prior to setting and delivering a first dose. Like the first injection pen 10, the fourth injection pen 700 may comprise the knob cover 16 and/or the knob key 30.

The mechanism may comprise a dose definition mechanism that allows a user of the device to set at least one dose of medicament for delivery. For example, the dose definition mechanism may be configured to allow only a single predetermined dose to be set. Alternatively, the dose definition mechanism may also be configured to allow a multitude of differing predetermined doses to be set by the user, such as two or more differing doses.

With the injection pens 10, 300, 500, 700, the dose delivery mechanisms 54, 354, 554, 754 each comprises a dose definition mechanism 1 15, wherein the respective dose definition mechanism 1 15 acts between the respective dose setting element 18, 318, 518, and the housing 32, 332, 532 during dose setting. The dose definition mechanism 1 15 thereby has at least one dose stop 1 18 and a counter element 1 16, wherein the counter element 1 16 is configured to rotate with respect to the dose stop 1 18 when the dose setting element 38, 318, 518 rotates during dose setting and wherein the counter element 1 16 is configured to engage the dose stop 1 18 when the dose has been set. The counter elements 1 16 are formed by the respective engagement features 1 16 of the dose delivery mechanisms 54, 354, 554, 754.

The dose definition mechanism 1 15 may define the rotational positions of the dose setting element 22, 518 with respect to the housing 32, 332, 532 that correspond to settable doses. For each settable dose, the dose definition mechanism 1 15 may comprise a separate dose stop 1 18. The dose setting element 22, 518 then may be configured to only perform less than a full rotation during dose setting. With the third and fourth injection pen 500, 700, the dose definition mechanisms 1 15 may also comprise individual dose stops 1 18 that define more than a single dose, for example, the individual dose stops 1 18 may be configured to engage with the counter element 1 16 once upon each full rotation of the counter element 1 16 with respect to the dose stops 1 18.

The counter element 1 16 may be configured as a flexible element that snaps over the dose stop 1 18 upon setting the dose. For example, the counter element 1 16 may be configured as a flexible protrusion at a component of the respective dose delivery mechanisms 54, 354, 554, 754. The counter element 1 16 may, for example, be integrally formed with the component of the respective dose delivery mechanisms 54, 354, 554, 754 it is fixed to. With the first and second injection pen 10, 300, said component is formed by the dosing member 23, 323, with the third and fourth injection pen 500, 700, it is formed by the dose setting element 518.

With the first and second injection pen 10, 300, engagement of the counter element 1 16 with the dose stop 1 18 prevents the spring 40 from releasing the energy stored upon rotation of the dose setting element 22 during dose setting. The dose definition mechanism 1 15 thereby may provide a latching function that keeps the spring 40 in a tensioned state until the dose is delivered by transferring the respective dose delivery mechanism 54, 354 from the dose setting state to the dose delivery state.

With the first and second injection pen 10, 300, the counter element 1 16 is configured to disengage from the dose stop 1 18 upon transfer of the respective dose delivery mechanism 54, 354 from the dose setting state into the dose delivery state. This prevents the dose definition mechanism 1 15 from interfering with the delivery of the set dose. Furthermore, it may allow the spring 40 to release the energy stored upon rotation during dose setting. With embodiments having more than a single dose stop 118, the counter element 116 may be configured to disengage from all dose stops 118 upon transfer of the respective dose delivery mechanisms 54, 354 into the dose delivery state. This may allow the counter element 116 to rotate back to its initial position during dose delivery without interfering with the dose stops 118. The initial position may correspond to a zero dose position in which no dose has been set.

For example, the counter element 116 may be configured to disengage from the dose stop 118 by axially moving with respect to the dose stop 118.

With the injection pens 10, 300, 500, 700, one of the dose stop 118 and the counter element 116, such as the dose stop 118, is rotationally fixed with respect to the housing 32, 332, 532. The one of the dose stop 118 and the counter element 116 then may be axially movable with respect to the dose setting element 22, 518.

With the first and second injection pen 10, 300, the one of the dose stop 118 and the counter element 116, such as the dose stop 118, is axially fixed with respect to the button 18, 318. This allows to move the one of the dose stop 118 and the counter element 116 together with the button 18, 318 upon transfer of the respective dose delivery mechanism 54, 354 from the dose setting state into the dose delivery state. The one of the dose stop 118 and the counter element 116 than may disengage from the other one of the dose stop 118 and the counter element 116 by this movement. For example, the one of the dose stop 118 and the counter element 116 may be linearly guided at the housing 32, 332.

With some embodiments, the one of the dose stop 118 and the counter element 116 is fixed to an outer housing part of the respective dose delivery mechanism 54, 354, 554, 754. The outer housing part may be fixed to a connection for coupling a medicament container 48, 348 to the respective dose delivery mechanism 54, 354, 554, 754. Alternatively, the outer housing part may also be movable with respect to the connection, such as axially movable. Additionally, the outer housing part may be rotationally fixed with respect to the connection. For example, the outer housing part may be a housing connector, such as a housing connector that engages with the housing 32, 332, 532 via an axially movable and rotationally fixed connection. With the first and second injection pen 10, 300, the outer housing part is formed by the dose selector 28, with the third and fourth injection pen 500, 700, it is formed by the sleeve 528.

With the first and second injection pen 10, 300, the dose definition mechanism 115 acts between the dosing member 23, 332 and the housing 32, 332, 532. It then defines rotational positions of the dosing member 23, 332 with respect to the housing 32, 332 that correspond to settable doses.

With the first and second injection pen 10, 300, the other one of the dose stop 118 and the counter element 116, such as the counter element 116, is rotationally fixed with respect to the dosing member 23, 332. Exemplarily, the other one of the dose stop 118 and the counter element 116 is permanently rotationally fixed with respect to the dosing member 23, 332. The other one of the dose stop 1 18 and the counter element 1 16 is exemplarily additionally fixed to the dosing member 23, 332, such as to the first part of the dosing member 23, 332 that is movable with respect to the housing 32, 332, 532.

With the first, second, third and fourth injection pen 10, 300, 500, 700, the other one of the dose stop 1 18 and the counter element 1 16, such as the counter element 1 16, is axially movable with respect to the button 18, 318, 518. The one of the dose stop 1 18 and the counter element 1 16, such as the dose stop 1 18, is axially fixed with respect to the button 18, 318, 518. This allows to disengage the dose stop 1 18 from the counter element 1 16 by moving the button with respect to the housing 32, 332, 532, as it is the case for the first and second injection pen 10, 300.

With the second injection pen 300, the dose delivery mechanisms 354 comprises a blocking mechanism having a first element and a second element, wherein the first element engages the second element upon release of the button 318 during dose delivery to prevent a transfer of the respective dose delivery mechanism 354 from the dose delivery state to the dose setting state. This keeps the respective dose delivery mechanism 354 in the dose delivery state and prevents a change of the dose setting upon an interruption of dose delivery due to the torque provided by the spring 40. The blocking mechanism may block distal movement of the button 318 against a biasing force biasing the button 318 in the distal direction. The biasing force may be provided by the biasing element 250.

The blocking mechanism is configured to disengage the first element from the second element at a zero dose position at which a set dose has been fully delivered. This allows the dose delivery mechanisms 354 to return to the dose setting state so that a subsequent dose can be set after having completed a previous medicament delivery.

Exemplarily, the first element rotates with respect to the second element in a first direction during dose setting and rotates in a second direction opposite the first direction during dose delivery. Relative movement between the first and second element may bring the first and second element in relative positions that prevent mutual engagement at the end of dose delivery and/or when a dose has been set.

With the second injection pen 300, the first element is configured as the circumferential rib 156 that longitudinally extends around an axis of the housing 332 and the second element is configured as a stop or counter element formed by the engagement feature 1 16 of the snap element 24 that travels along the circumferential rib 124 during dose delivery.

Exemplarily, the second element passes the first element upon release of the button 318 at the end of dose delivery. For example, the second element may pass through an opening within the first element. The second element may rotate into alignment with the opening at the end of dose delivery. Additionally or alternatively, the blocking mechanism may be configured to prevent transfer of the dose delivery mechanism 354 from the dose setting state into the dose delivery state unless a dose has been set. Such a blocking mechanism is exemplarily also implemented in the dose delivery mechanism 54 of the first injection pen 10. Exemplarily, the second element passes the first element upon transfer of the dose delivery mechanism 54, 354 from the dose setting state into the dose delivery state. Exemplarily, the second element passes through one of the openings or cutouts 158 within the first element. The second element exemplarily rotates into alignment with the opening 158 when a dose has been set.

Exemplarily, the second element passes through one of the openings or cut-outs 158 within the first element upon transfer of the mechanism from the dose setting state into the dose delivery state. Such openings 158 prevent blocking and thus allow axial movement of the button 18, 318 to initiate dose delivery.

Exemplarily, the first element of the blocking mechanism and one of the dose stop 1 18 and the counter element 1 16, such as the dose stop 1 18, are fixed to the same member of the dose delivery mechanism 54, 354. Furthermore, the second element of the blocking mechanism and the other one of the dose stop 1 18 and the counter element 1 16, such as the counter element 1 16, are fixed to the same further member of the dose delivery mechanism 54, 354. This allows to precisely align the elements of the blocking mechanism and the elements of the dose definition mechanism 1 15 and enhances reliability of the dose delivery mechanism 54, 354.

The member of the mechanism that comprises the first element of the blocking mechanism and the one of the dose stop 1 18 and the counter element 1 16 exemplarily is the dose selector 28 of the dose delivery mechanism 54, 354. The further member of the dose delivery mechanism 54, 354 that comprises the second element of the blocking mechanism and the other one of the dose stop 1 18 and the counter element 1 16 is exemplarily a carrier that is rotationally movable with respect to the dose selector 28. The carrier exemplarily is a part of the dosing member 23, 332, namely by the snap element 24 of the dosing member 23, 323.

The dose selector 28 exemplarily is at least partly located within an outer housing of the dose delivery mechanism 54, 354, namely the housing 32, 332. The dose selector 28 exemplarily is configured to protrude from the outer housing.

Exemplarily, one of the first element and second element of the blocking mechanism and one of the dose stop 1 18 and the counter element 1 18 are formed by a single element. As an example, the second element of the blocking mechanism and the counter element 1 16 of the dose definition mechanism 1 15 are formed by the single element. This facilitates alignment of the components of the blocking mechanism with respect to the components of the dose definition mechanism 1 15.

The single element exemplarily is a flexible element that is configured to snap over the dose stop 1 18 upon rotation with respect to the dose stop 1 18. With the first and second injection pen 10, 300, the dose delivery mechanisms 54, 354 comprise a maximum dose mechanism that restrains further rotation of the dose setting element 22 upon dialing past a maximum dose setting, wherein the maximum dose mechanism comprises a maximum dose stop 126 that is exemplarily formed by the hard stop 128 and a blocking part 124 that is exemplarily formed by the hard stop 124 and wherein the blocking part 124 is configured to engage the maximum dose stop 126 128 upon dialing past the maximum dose setting. This provides a well-defined rotational end position of the dose setting element 22. The maximum dose stop 126 128 may also absorb a torque provided by a user and direct the torque to the housing 32, 332 of the dose delivery mechanism 54, 354.

The blocking part 124 exemplarily engages the maximum dose stop 126 128 right at the maximum dose setting. With other embodiments, the blocking part 124 may only engage the maximum dose stop 126 128 after having dialed past the maximum dose setting by a predefined amount.

The blocking part 124 exemplarily is configured as a hard stop that is rigidly connected, such as integrally formed, with a component of the mechanism. Likewise, the maximum dose stop 126 126 exemplarily is configured as such a hard stop.

Exemplarily, the maximum dose stop 126 126 and the blocking part 124 are configured to rotate with respect to each other during dose setting. As an example, one of the maximum dose stop 126 126 and the blocking part 124, namely the maximum dose stop 126 126, may be rotationally fixed with respect to the housing 32, 332 during dose setting and the other one of the maximum dose stop 126 126 and the blocking part 124, such as the blocking part 124, may be rotationally fixed with respect to the dose setting element 22 during dose setting. The other one of the maximum dose stop 126 126 and the blocking part 124 may be rotationally movable with respect to the dose setting element 22 during dose delivery.

Exemplarily, the maximum dose stop 126 is configured as a radial stop and the blocking part 124 is configured to rotate against the maximum dose stop 126 upon dialing past the maximum dose.

Such a radial stop provides a well-defined rotational position in which the blocking part 124 and the maximum dose stop 126 get into engagement.

The maximum dose stop 126 and the blocking part 124 exemplarily comprise engagement surfaces that engage with each other. The engagement surfaces exemplarily are orientated essentially perpendicular, namely perpendicular, to a circumferential direction around the longitudinal axis of the dose delivery mechanism 54, 354.

Exemplarily, one of the maximum dose stop 126 and the blocking part 124, such as the maximum dose stop 126, is rotationally fixed with respect to the housing 32, 332. The one of the maximum dose stop 126 and the blocking part 124 exemplarily are permanently rotationally fixed with respect to the housing 32, 332, both during dose setting and dose delivery. Exemplarily, the one of the maximum dose stop 126 and the blocking part 124 is fixed to an outer housing part of the dose delivery mechanism 54, 354. The outer housing part is exemplarily configured as a housing connector that is located between the dose setting element 22 and the housing 32, 332 of the injection pen 10, 300. The outer housing part is configured as the dose selector 28.

Exemplarily, the other one of the maximum dose stop 126 and the blocking part 124, such as the blocking part 124, is rotationally fixed with respect to the dosing member 23, 332. The other one of the maximum dose stop 126 and the blocking part 124 then rotates with respect to the housing 332, 32 during both dose setting and dose delivery. This allows to reset the maximum dose mechanism during dose delivery. With embodiments, in which a rotational position of the dosing member 23, 332 defines the dose that has been set, rotationally fixing the one of the maximum dose stop 126 and the blocking part 124 to the dosing member 23, 332 precisely defines a maximum dose position in which the maximum dose stop 126 and the blocking part 124 engage with each other.

Exemplarily, the other one of the maximum dose stop 126 and the blocking part 124 is fixed to a coupling member that rotationally couples the dosing member 23, 332 to the dose setting element during dose setting. The coupling member is formed by the snap element 24.

Exemplarily, one of the dose stop 1 18 and the counter element 1 16, such as the dose stop 1 18, and one of the maximum dose stop 126 and the blocking part 124, such as the maximum dose stop 126, are fixed to the same member of the dose delivery mechanism 54, 354. This allows to precisely define the relative positions of the components of the dose definition mechanism 1 15 with respect to the components of the maximum dose mechanism. The member of the dose delivery mechanism 54, 354 exemplarily is the dose selector 28.

Exemplarily, the other one of the dose stop 1 18 and the counter element 1 16, such as the counter element 1 16, and the other one of the maximum dose stop 126 and the blocking part 124, such as the blocking part 124, are fixed to the same further member of the dose delivery mechanism 54, 354. This also allows to precisely define the relative positions of the components of the dose definition mechanism 1 15 with respect to the components of the maximum dose mechanism. The further member may, for example, be the carrier that is rotationally movable with respect to the dose selector 28 and that is formed by the snap element 24.

Exemplarily, the dose delivery mechanisms 54, 354 of the first and second injection pen 10, 300 comprise a zero dose mechanism that prevents further axial movement of the nut 38 at the end of dose delivery, wherein the zero dose mechanism comprises a zero dose stop and a further blocking part and wherein the further blocking part is configured to engage the zero dose stop at the end of dose delivery. This provides a well-defined end position for the piston rod 44 at the end of dose delivery and thus contributes to precisely define the amount of medicament delivered. With the first injection pen 10, the zero dose stop is formed by the end stop 176 at the piston rod 44 guide 42 and the further blocking part is formed by the end stop 174 at the driver 36. With the second injection pen 300, the zero dose stop is formed as a protrusion on the inside surface of the dose selector 28 and the further blocking part is formed by the hard stop 124 at the snap element 24.

The further blocking part 124, 174 is exemplarily configured as a hard stop that is rigidly connected, such as integrally formed, with a component of the dose delivery mechanisms 54, 354. Likewise, the zero dose stop 176 exemplarily is configured as such a hard stop.

Exemplarily, the zero dose stop 176 and the further blocking part 124, 174 are configured to rotate with respect to each other during dose delivery. For example, one of the zero dose stop 176 and the further blocking part 124, 174, such as the zero dose stop 176, is rotationally fixed with respect to the housing 32, 332 during dose setting and the other one of the zero dose stop 176 and the further blocking part 124, 174, such as the further blocking part 124, 174, is rotationally fixed with respect to the dose setting element 22 during dose setting. The other one of the zero dose stop 176 and the further blocking part 124, 174 exemplarily is rotationally movable with respect to the dose setting element 22 during dose delivery.

Exemplarily, the zero dose stop 176 is configured as a radial stop and the further blocking part 124, 174 is configured to rotate against the zero dose stop 176 at the end of dose delivery. Such a radial stop provides a well-defined rotational position in which the further blocking part 124, 174 and the zero dose stop 176 become engaged with each other.

The zero dose stop 176 and the further blocking part 124, 174 exemplarily comprise engagement surfaces that engage with each other. The engagement surfaces may be orientated essentially perpendicular, such as perpendicular, to a circumferential direction around the longitudinal axis of the dose delivery mechanism 54, 354.

Exemplarily, one of the zero dose stop 176 and the further blocking part 124, 174, such as the zero dose stop 176, is rotationally fixed with respect to the housing 32, 332. The one of the zero dose stop 176 and the further blocking part 124, 174 exemplarily is permanently rotationally fixed with respect to the housing32, 332, both during dose setting and dose delivery.

Exemplarily, the one of the zero dose stop 176 and the further blocking part 124, 174 is fixed to an outer housing part of the dose delivery mechanism 54, 354. With the second injection pen 300, the outer housing part exemplarily is configured as a housing connector that is located between the dose setting element 22 and the housing 332 of the second injection pen 300. Also the first injection pen 10 may alternatively comprise such a zero dose stop 176.

Exemplarily, the other one of the zero dose stop 176 and the further blocking part 124, 174 is rotationally fixed with respect to the dosing member 23, 332. The other one of the zero dose stop 176 and the further blocking part 124 then rotates with respect to the housing 32, 332 during both dose setting and dose delivery. This allows to reset the zero dose mechanism during dose setting. With embodiments, in which a rotational position of the dosing member 23, 332 defines the dose that has been set, rotationally fixing the one of the zero dose stop 176 and the further blocking part 124, 174 to the dosing member 23, 332 precisely defines a zero dose position in which the zero dose stop and the further blocking part 124 engage with each other.

With the second injection pen 200, the other one of the zero dose stop 176 and the further blocking part 124, 174 is fixed to a coupling member that rotationally couples the dosing member 23, 332 to the dose setting member 22 during dose setting. The coupling member is formed by the snap element 24 of the dosing member 323. Also the first injection pen 10 may comprise such a configuration.

Exemplarily, one of the dose stop 1 18 and the counter element 1 16 of the second injection pen 300, such as the dose stop 1 18, and one of the zero dose stop and the further blocking part 124 of the second injection pen 300, such as the zero dose stop, are fixed to the same member of the dose delivery mechanism 354. This allows to precisely define the relative positions of the components of the dose definition mechanism 1 15 with respect to the components of the zero dose mechanism. The member of the dose delivery mechanism 354 exemplarily is the dose selector 28. Also the first injection pen 10 may have such a configuration.

Exemplarily, the other one of the dose stop 1 18 and the counter element 1 16 of the second injection pen 300, such as the counter element 1 16, and the other one of the zero dose stop and the further blocking part 124 of the second injection pen 300, such as the further blocking part 124, are fixed to the same further member of the dose delivery mechanism 354. This also allows to precisely define the relative positions of the components of the dose definition mechanism 1 15 with respect to the components of the zero dose mechanism. The further member may, for example, be the carrier that is rotationally movable with respect to the dose selector 28. Also the first injection pen 10 may have such a configuration.

Exemplarily, the second injection pen 300, one of the maximum dose stop 126 and the blocking part 124 of the maximum dose mechanism and one of the zero dose stop and the further blocking part 124 of the zero dose mechanism, such as the maximum dose stop 126 and the zero dose stop, are fixed to the same member of the mechanism. Furthermore, the other one of the maximum dose stop 126 and the blocking part 124 of the maximum dose mechanism and the other one of the zero dose stop and the further blocking part 124 of the zero dose mechanism, such as the blocking part 124 and the further blocking part 124, are fixed to the same further member of the mechanism. This provides for a precise alignment between the components of the maximum dose mechanism and the components of the zero dose mechanism. Also the first injection pen 10 may have such a configuration. Irrespective of whether they are fixed to the same member of the mechanism or not, the maximum dose stop 126 and/or the minimum dose stop may be integrally formed with the member they are fixed to. Analogously, the blocking part 124 and/or the further blocking part 124 may be integrally formed with the member they are fixed to.

Exemplarily, with the second injection pen 300, the blocking part 124 of the maximum dose mechanism forms the further blocking part 124 of the minimum dose mechanism. This allows to precisely define the distance between the maximum dose position and the zero dose position. Also the first injection pen 10 may have such a configuration.

In general, the dose delivery mechanisms 54, 354, 554, 754 may comprise a clutch mechanism 113 having a first engaging part and a second engaging part, wherein the clutch mechanism 113 is closed during one of dose setting and dose delivery and opened during the other one of dose setting and dose delivery. The clutch mechanism 113 is in the opened state when the first engaging part and the second engaging part do not engage with each other and the clutch mechanism 113 is in the closed state when the first engaging part and the second engaging part engage with each other.

Exemplarily, the dose delivery mechanisms 54, 354 of the first and second injection pen comprise a clutch mechanism 113, wherein the clutch mechanism 113 rotationally locks the nut 38 to the piston rod 44 during dose delivery and rotationally releases the nut 38 from the piston rod 44 during dose setting. By rotationally locking the nut 38 to the piston rod 44, the clutch mechanism 113 forces simultaneous proximal movement of the nut 38 together with the piston rod 44. Exemplarily, the clutch mechanism 113 rotationally locks the threaded connection 189 that couples the nut 38 to the piston rod 44. The clutch mechanism 113 locks the nut 38 to the piston rod 44 in a closed state and rotationally release the nut 38 from the piston rod 44 in an opened state.

The clutch mechanism 113 exemplarily comprises a first engaging part and a second engaging part and the first and second engaging parts are configured to engage with each other to rotationally lock the nut 38 to the piston rod 44. The first engaging part and the second engaging part exemplarily are configured to become disengaged from each other by relative axial movement with respect to each other. The first engaging part is exemplarily formed by the teeth 114 of the connector 26 and the second engaging part is exemplarily formed by the teeth 108 of the dose setting element 22.

The clutch mechanism 113 exemplarily is configured to be transferred from the opened state into the closed state upon movement of the button 18, 318 and transfer of the dose delivery mechanisms 54, 354 from the dose setting state to the dose delivery state. One of the first engaging part and the second engaging part, such as the second engaging part, is axially fixed with respect to the button 18, 318 and the other one of the first engaging part and the second engaging part, such as the first engaging part, is axially fixed with respect to the housing 32, 332. Additionally or alternatively, the first engaging part is axially fixed with respect to the dosing member 23, 332.

Exemplarily, the first engaging part is rotationally fixed to the housing 32, 332 and the second engaging part is rotationally fixed to the nut 38.

The second engaging part exemplarily is rotationally fixed to the button 18, 318 and/or the dose setting element 22.

Exemplarily, the clutch mechanism 1 13 rotationally fixes the nut 38 to the piston rod 44 during dose delivery via the housing 32, 332 and, for example, via the dose setting element 22 and/or the button 18, 318.

Exemplarily, the clutch mechanism 1 13 acts between the button 1 , 318 and the housing 32, 332 and/or between the dose setting element 22 and the housing 32, 332.

Exemplarily the button 18, 318 is rotationally coupled, such as permanently rotationally coupled, to one of the first engaging part and the second engaging part. As an example, the button 18, 318 constitutes the one of the first engaging part and the second engaging part.

Exemplarily, the dose delivery mechanisms 54, 354 comprise a further clutch mechanism 107, wherein the further clutch mechanism 107 rotationally locks the dose setting element 22 to one end of the spring 40 during dose setting and decouples the dose setting element 22 from the one end of the spring 40 during dose delivery. Furthermore, the further clutch mechanism 107 has a further first engaging part and a further second engaging part, wherein the further first engaging part is configured to move into engagement with the further second engaging part to rotationally lock the dose setting element 22 to the one end of the spring 40. The further clutch mechanism 107 allows to tension the spring 40 during dose setting and at the same time prevents the dose setting element 22 from rotating during dose delivery when the spring 40 relaxes again. The further first engaging part is exemplarily formed by the teeth 1 10 at the snap element 23 and the further second engaging part is exemplarily formed by the teeth 108 at the button 22.

The further clutch mechanism 107 exemplarily is transferred from a closed state, in which the further first engaging part engages with the further second engaging part, into an opened state, in which the further first engaging part is disengaged from the further second engaging part, by movement of the button 18, 318. The movement of the button 18, 318 exemplarily is the movement that transfers the dose delivery mechanisms 54, 354 from the dose setting state into the dose delivery state.

Exemplarily, one of the further first engaging part and the further second engaging part, such as the further second engaging part, is rotationally and axially fixed to the dose setting element 22. This allows to open and close the further clutch mechanism 107 by relative movement of the dose setting element 22 with respect to the other one of the further first engaging part and the further second engaging part.

Exemplarily, the one of the further first engaging part and the further second engaging part is rotationally and axially fixed to the button 18, 318. The dose setting element 22 thereby is at least rotationally fixed to the button 18, 318.

Exemplarily, the further clutch mechanism 107 acts between the dosing member 23, 332 and the dose setting element 22. The dosing member 23, 332 then may rotationally couple the dose setting element 22 to the one end of the spring 40.

Exemplarily, one of the further first engaging part and the further second engaging part, such as the further first engaging part, is rotationally fixed to the dosing member 23, 332. Exemplarily, the one of the further first engaging part and the further second engaging part may be axially fixed to the dosing member 23, 332.

Exemplarily, the clutch mechanism 1 13 comprises the first engaging part that engages the second engaging part to rotationally fix the nut 38 to the piston rod 44 during dose delivery, wherein the further second engaging part of the further clutch mechanism 107 forms the first engaging part of the clutch mechanism 1 13. This provides a compact construction of the clutch mechanisms 107, 1 13.

The nut 38 exemplarily is rotationally fixed with respect to the button 18, 318 and/or the dose setting element 22. As an example, the nut 38 is rotationally fixed and axially movable with respect to the button 18, 318 and/or the dose setting element 22. It is coupled to the button 18, 318 and/or the dose setting element 22 by a rotation lock. The rotation lock is formed by the nut 38 and one of the button 18, 318 and the dose setting element 22, such as the button 18, 318.

The nut 38 is rotationally movable with respect to the piston rod 44 when the dose delivery mechanisms 54, 354 are in the dose setting state and the nut 38 is rotationally fixed with respect to the piston rod 44 when the dose delivery mechanisms 54, 354 are in the dose delivery state. Rotation of the nut 38 with respect to the piston rod 44 during dose setting leads to axial movement due to the threaded connection between the nut 38 and the piston rod 44. By rotationally locking the nut 38 to the piston rod 44 during dose delivery, the threaded connection between the nut 38 and the piston rod 44 is blocked and the nut 38 and the piston rod 44 become axially fixed with respect to each other.

The nut 38 is turned by the dose setting element 22 during dose setting and performs an axial movement due to the threaded connection to the piston rod 44. The rotation of the nut 38 causes the nut 38 to translate axially in the distal direction along the thread located on the piston rod 44 during dose setting and to translate in the proximal direction during dose cancellation. Axial movement of the nut 38 with respect to the piston rod 44 defines the axial movement of the piston rod 44 during dose delivery and thus the amount of medicament expelled during dose delivery. Some general remarks concerning the disclosure:

The second threaded connection 170, 172 may be provided between the driver 36 and the piston rod guide 42. However, there are multiple other options where the second threaded connection 170, 172 could be provided. For example, the second threaded connection could be provided between the dosing element 34 and the housing 32. The second threaded connection 170, 172 preferably acts between any part that is rigidly connected to the driver 36 and any part that is rigidly connected to the housing 32.

Preferably, the actuation member 18, 20, 22 is coupled via the nut 38 to the piston rod 44 in a way that an axial movement of the actuation member 18, 20, 22 during dose delivery causes an axial movement of the nut 38 and the piston rod 44. To apply an axial force from the nut 38 to the piston rod 44 to move the piston rod 44 in the axial direction via the nut 38 during dose delivery, the nut 38 forms a first threaded connection with the pistion rod 44 via the outer thread 190 meshing with the inner thread 192. The nut 38 and the piston rod 44 are blocked from relative rotational movement during dose delivery so that an axial movement of the nut 38 causes an axial movement of the piston rod 44.

Regarding the optional feature that “all parts that are configured to rotate relative to the housing 32 during dose delivery, are connected to the housing 32 via exactly one threaded connection 170, 172, it is pointed out that the dose delivery mechanism 54 may comprise a driver 36, a dose sleeve 34 and/or a snap element 24. One or more of these parts may be configured to rotate relative to the housing 32 during dose delivery. Furthermore, the delivery mechanism 54 may have one or more further parts that are configured to rotate relative to the housing 32 during dose delivery. All parts of the delivery mechanism 54 that are configured to rotate relative to the housing 32 during dose delivery may form a sub-assembly. This sub-assembly may form exactly one threaded connection 170, 172 with the housing 32 or any part rigidly connected to the housing 32.

The coupling means 100, 102 can be formed on the injection button and the snap element 24. However, the coupling means 100 can alternatively be formed on the snap ring 20 or the dose setting knob 22. The coupling means 102 could generally be formed on any part that is not axially movable relative to the housing. The person skilled in the art understands that there are multiple options where to place the coupling means 100, 102. If the coupling means 100, 102 are configured to permanently axially lock the dose setting knob 22 to the dose setting device or the housing 50, this can be done by multiple ways, e.g. by a permanent form fitted connection or by a permanent friction fitted connection.

Generally, the dose setting mechanism may comprise a clutch that connects a nut 38 to a piston rod 44, with the nut 38 being rotationally fixed to the piston rod 44 during dispensing and rotational relative to the piston rod 44 during dose setting. Preferably, rotating the dose setting knob effects rotation of the nut 38 relative to the piston rod 44 during dose setting. There are multiple ways how to design a connection between the dose setting knob and the nut 38.

Generally, the piston rod 44 can be rotationally fixed with respect to the housing during dose deliv- ery/dispensing.

The proximal end 14 comprises a dispensing outlet. The distal end 12 is arranged at an opposite end of the proximal end 14. The dispensing outlet may comprise one of a needle, a cannula, and a point of connection for a needle or cannula.

The cover 16 may cover the part of the dose delivery activation mechanism configured to activate dose delivery. The dose delivery activation mechanism are the parts that are configured to permit a dose dispensing from the delivery device. The activation mechanism can comprise the injection button 18 forming a distal end face of the injection pen. The cover 16 can also cover the dose setting knob 22. Thereby, the cover 16 prevents setting the dose and/or activating the injection before a mixing of the two components is done.

The as-delivered condition is a condition in which all parts of the dose delivery mechanism 54 are arranged at the same relative position with respect to one another as they are following manufacture of the dose delivery mechanism 54. In other words, the as-delivered condition is a condition in which the user has not rotated or otherwise changed the position of the dose setting member 34 relative to the housing. Hence, when a dose has been set by the user, the dose delivery mechanism 54 is not in an “as-delivered condition” anymore but instead in a “set state”. According to an embodiment, in the “as-delivered condition”, the dose setting knob 22 is not rotatable towards a zero-dose position. According to an embodiment, the actuation is blocked in the “as-delivered condition” to prevent accidential activation.

The dose delivery mechanism may comprise the activation member 18, the dose setting knob 22, the snap element 24, the dose selector 28 and/or the clip 30. The activation member 18 can be configured to to be pushed by the user to start the injection process. The snap element 24 is preferably configured to engage with the dose selector 28, preferably in different rotational positions, to define a settable dose. The clip 30 may be used in combination with the knob cover 16 to avoid movement of the activation member 18 relative to the housing 32 when the pen drops onto its proximal end 14. List of reference signs

1 proximal direction

10 injection pen

12 distal end

14 proximal end

16 knob cover

16a closed circumference

16b closed face

18 injection button/adjusting element

18a cylindrical portion

19 outer rim

20 snap ring/connector

22 dose setting knob/dose setting element

23 dosing member

24 snap element

26 connector

28 sleeve/dose selector

30 knob key

32 housing

32a surface

34 dose setting sleeve/dosing element

36 driver

38 nut

40 spring

42 piston rod guide

43 connector

44 piston rod

45 distal section

46 piston disc/bearing

48 cartridge

50 cartridge container/medicament container

52 cartridge key/cartridge holder

54 dose delivery mechanism

56 drug reconstitution unit

58 wing

60 lug

62 window

64 elevation

66 abutment

66a front surface

68 cut-out 69 chamfered portion

70 axial abutment elevation

72 clearance

74 linear recess

76 anti-rolling means

78 anti-rolling means

80 front surface

81 axial lock

82 axial fixation means

84 rib

86 axial fixation means

88 undercut

89 rotational lock

90 rotation fixation means

92 rotation fixation means

93 toothed part

94 rotation fixation means

96 rotation fixation means

97 latching mechanism

98 assembling means

98a latch part

98b further latch part

100 coupling means 100a chamfered surface 101 cut-out

102 coupling means/latch counterpart

104 rib

106 groove

107 clutch mechanism

108 teeth

110 teeth

112 coupling surface

114 teeth

115 dose definition mechanism

116 engagement feature

118 dose stop 118a dose stop 118b dose stop

118c dose stop 118d dose stop 120 elastically deformable section 121 cut-out 122a-d side surface

123a-d side surface

124 hard stop

126 hard stop

128 hard stop

130 opening

132 slot

134 rib

136 protrusion

136a chamfered surface

138 rib

140 groove 142 axial fixation means 144 intake 146 axial fixation means 148 rotation fixation means 150 rotation fixation means 152 rotation fixation means 154 rotation fixation means 156 rib 158a cut-out 158b cut-out 158c cut-out

158d cut-out 160 proximal edge 162 distal edge 164 holding protrusion 166 window 168a label 168b label 168c label 168d label 168e label 169a out-of-round outer circumferential surface 169b out-of-round inner circumferential surface

170 outer thread 171 fixing section 172 inner thread 173 face surface 174 end stop 176 end stop 177 attachment means 178 axial fixation means

179 attachment means

180 axial fixation means

182 rotation fixation means

184 rotation fixation means

186 opening

188 cross-section

189 threaded connection

190 outer thread

192 inner thread

194 pressing surface

196 front surface

198 coupling means

200 coupling means

202 first chamber

204 second chamber

206 bypass

208 first sealing element

210 second sealing element/plunger

212 axial fixation means

214 axial fixation means

216 rotation fixation means

218 rotation fixation means

220 window

221 cut-out

222 window

223 slot

224 thread

226 end surface

228 surface

230 first thread

232 second thread

234 snap element

236 opening

238 opening

240 opening

242 displacement section

244 radial end stop

246 outer surface

248 inner space

249 holding section

250 biasing element 252 opening

254 inner surface

256 outer surface

258 annular space

260 inner circumferential surface

262 outer circumferential surface

264 outer circumferential surface

266 end face

268 end face

300 medicament delivery device

301 cap

305 container holder

306 needle connector

307 connector

318 adjusting element

323 dosing member

332 housing

333 upper housing part

334 dosing element

335 threaded connection

336 driver

337 further threaded connection

342 piston rod guide

343 connector

348 medicament container

349 needle end

354 dose delivery mechanism

500 medicament delivery device

501 needle assembly

502 cannula

503 needle cap

504 cap

505 container holder

506 connector

507 clutch

508 first clutch part

509 second clutch part

513 clutch mechanism

514 teeth

515 teeth

518 adjusting element

520 coupling element 523 dosing member

524 coupling member

525 extension

527 connector

528 sleeve

528a outer part

529 latch counterpart

530 further latch counterpart

532 housing

533 holding lug

534 housing window

535 opening

543 connector

554 dose delivery mechanism

560 rotatable fixation

561 annular rim

562 thread

563 rotation fixation

564 longitudinal ridge

566 lug

567 opening

568 radial stop

569 stop surface

570 rotatable fixation

571 annular rim

573 opening

575 ridge

580 end plate

582 bar

584 axial fixation

585 rotational fixation

586 recess

587 clicker

590 recess

592 rim

597 latching mechanism

599 further latching mechanism

600 latch part

610 window

612 thread

614 opening

616 ridge 618 recess

620 connector

622 lug

624 recess 626 annular rim

630 lug

632 ridge

634 proximal blocking element

635 distal blocking element 636 stop surface

700 medicament delivery device

720 coupling element

754 dose delivery mechanism L1 length

L2 length

W1 width

W2 width

The disclosure also relates to the following first set of enumerated embodiments:

1 . A dose setting mechanism (54) configured to set a desired dose for an injection device (10), the dose setting mechanism (54) comprising a housing (32), a dose setting knob (18, 22) and a dose setting device (24), wherein said dose setting knob (22) is configured to set the desired dose by a compulsory guided combined axial and rotational movement of the dose setting knob (22) relative to the housing (32), wherein said dose setting mechanism (54) comprises one or more coupling means (100), and wherein, on drug delivery, said dose setting knob (18, 22) is moved axially relative to the dose setting device (24) and/or the housing (32) and said one or more coupling means (100) are configured to engage at least one of the dose setting device (24) and the housing (32) to thereby permanently axially lock the dose setting knob (18, 22) to the respective one of the dose setting device (24) and the housing (32).

2. The dose setting mechanism according to embodiment 1 , wherein the dose setting mechanism is configured to set a desired dose for a single use injection device that is rendered inoperable when the dose setting knob is axially locked to the respective one of the dose setting device and the housing.

3. The dose setting mechanism (54) according to embodiment 1 or 2, wherein the dose setting knob (18, 22) is non-rotatable relative to the dose setting device (24) and/or the housing (32) when the dose setting knob (18, 22) is axially locked to the respective one of the dose setting device (24) and the housing (32).

4. The dose setting mechanism according to any one of the preceding embodiments, wherein said one or more coupling means (100) are configured to cooperate between the dose setting device (24) and the dose setting knob (18, 22).

5. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein said dose setting knob (18, 22) comprises said one or more coupling means (100) configured to cooperate with the respective one of the dose setting device (24) and the housing (32).

6. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the one or more coupling means (100) are arranged on an outer circumferential surface of the dose setting knob (18, 22) and corresponding coupling means (102), e.g. a circumferentially extending ledge, are arranged on an inner circumferential surface of the dose setting device (24).

7. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the one or more coupling means (100) comprise one or more snap elements, in particular one or more elastically deformable tongues. . The dose setting mechanism according to embodiment 7, wherein the one or more snap elements have a chamfered surface that is configured to engage with a protrusion (102), in particular a circumferentially extending ledge, to elastically deform the snap element. . The dose setting mechanism (54) according to any one of the preceding embodiments, wherein a cut-out (101 ) is provided next to at least one of the one or more coupling means (100). 0. The dose setting mechanism according to embodiment 9, wherein the cut-out (101 ) is provided sectionally around the at least one of the one or more coupling means (100). 1 . The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the dose setting device (24) comprises one or more projections (1 16) for setting said desired dose and cooperating with a dose selector (28). 2. The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) is coupled to a dose selector (28) in a rotationally fixed manner on drug delivery and/or wherein the dose setting knob (18, 22) rotates relative to the housing (32) while the dose selector (28) does not rotate relative to the housing (32) on dose setting. 3. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) forms an end face for manually pushing the dose setting knob (18, 22) in an axial direction relative to the dose setting device (24) and/or the housing (32) on drug delivery. 4. The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) and the dose setting device (24) are axially moveable relative to one another on dose setting by rotating the dose setting knob (18, 22) relative to the housing (32). 5. The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting device (24) and the dose setting knob (18, 22) are rotationally fixed to each other during dose setting and/or wherein the dose setting device (24) and the dose setting knob (18, 22) rotate relative to each other on drug delivery. 6. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the dose setting device (24) rotates relative to the housing (32) on drug delivery and/or the dose setting knob (18, 22) does not rotate relative to the housing (32) on drug delivery.

17. The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) and the dose setting device (24) are axially moveable relative to the housing (32) on dose setting.

18. The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) and the dose setting device (24) are configured to not move relative to one another on dose setting.

19. The dose setting mechanism (54) according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) comprises an injection button (18) and said one or more coupling means (100) are configured to permanently axially lock said injection button (18) to the respective one of the dose setting device (24) and the housing (32).

20. The dose setting mechanism according to any one of the preceding embodiments, wherein at least a part of the dose setting knob (18, 22) is axially moved on dose dispensing.

21 . The dose setting mechanism according to any one of the preceding embodiments, wherein the dose setting knob (18, 22) comprises an injection button (18) and said injection button (18) is axially moved on dose dispensing.

22. The dose setting mechanism according to any one of the preceding embodiments, wherein, on drug delivery, said dose setting knob (18, 22) is moved axially relative to said dose setting device (24) and said one or more coupling means (100) are configured to engage the dose setting device (24) to thereby permanently axially lock the dose setting knob (18, 22) to the dose setting device (24) due to the relative movement of the dose setting knob (18, 22) and the dose setting device (24).

23. A medicament delivery device (10), in particular an injection device, comprising a dose setting mechanism (54) according to any one of the preceding embodiments.

24. Single use and single dose pen with one or more doses being selectable for the single use with a dose setting mechanism (54) according to any one of the preceding embodiments.

25. Method of locking a medicament delivery device (10), in particular an injection pen (10), following first use of the injection pen (10), the method comprising the steps of: setting a dose by a compulsory guided combined axial and rotational movement of the dose setting knob (18, 22) relative to the housing (32), and moving a dose setting knob (18, 22) of a dose setting mechanism (54) axially relative to a dose setting device (24) and/or a housing (32), thereby activating one or more coupling means (100) to permanently axially lock the dose setting knob (18, 22).

26. Method of locking a medicament delivery device (10), in particular an injection pen (10), according to embodiment 25, the method comprising the steps of: moving said dose setting knob (18, 22) of the dose setting mechanism (54) axially relative to the dose setting device (24) and/or the housing (32), thereby moving one or more coupling means (100) of the dose setting knob (18, 22) into engagement with the dose setting device (24) or the housing (32) and axially locking the dose setting knob (18, 22) to the dose setting device (24) and/or the housing (32).

27. Method of locking an injection pen according to embodiment 25 or 26, wherein at least a part of the dose setting knob (18, 22) is axially moved on dose dispensing.

28. Method of locking an injection pen according to any one of the method embodiments, wherein the dose setting knob (18, 22) comprises an injection button (18) and wherein the injection button (18) is axially moved on dose dispensing.

29. Method of locking an injection pen according to any one of the method embodiments, wherein the moving of the dose setting knob (18, 22) of the dose setting mechanism (54) axially relative to the dose setting device (24) and/or the housing (32) is done by manually pushing the dose setting knob (18, 22) in an axial direction.

30. Method of locking an injection pen according to any one of the method embodiments, wherein the dose setting knob (18, 22) is axially moved backwards relative to the housing (32) to set a desired dose for a medicament delivery device, in particular for an injection device (10), prior to moving of the dose setting knob (18, 22) of the dose setting mechanism (54) axially forward relative to the dose setting device (24) and/or the housing (32).

31 . Method of locking an injection pen according to any one of the method embodiments, wherein the dose setting knob (18, 22) is axially moved backwards relative to the housing (32) by rotating the dose setting knob (18, 22) relative to the housing.

The present disclosure is also related to following second set of enumerated embodiments

1 . Set comprising a medicament delivery device (10) with a dose delivery activation mechanism (54) that is configured to adjust the medicament delivery device (10) from an inactive state to an active state in which a dose is deliverable, and a cover (16), the cover (16) being mechanically attached to the medicament delivery device (10) prior to use of the medicament delivery device (10), the cover (16) being configured to cover at least a part of the dose delivery activation mechanism (54) so that a user is restrained from prematurely activating the medicament delivery device (10), and the cover (16) being configured to be movable in a distal direction to uncover said part of the dose delivery activation mechanism (54) to activate the medicament delivery device (10) during use of the medicament delivery device (10).

2. Set according to embodiment 1 , wherein the cover (16) is detachable from the medicament delivery device (10).

3. Set according to embodiment 1 or 2, wherein the medicament delivery device (10) and the cover (16) comprise form-fitting engagement means (58, 228) that are used to releasably attach the cover (16) to the medicament delivery device (10) prior to use of the medicament delivery device (10).

4. Set according to embodiment 3, wherein the form-fitting engagement means (58, 228) comprise one, two or more snap-fit- ting connections.

5. Set according to embodiment 3 or 4, wherein the form-fitting engagement means (58, 228) comprise one, two or more wings (58) that can be deflected outwardly, in particular in a radial direction, with respect to a longitudinal axis extending through the medicament delivery device (10).

6. Set according to one of embodiments 3 to 5, wherein the form fitting engagement means comprise one, two or more lugs, in particular lugs having a triangular shaped outer crosssection in at least one plane thereof.

7. Set according to embodiment 6, wherein the one, two or more lugs are arranged directly adjacent to a window of the cover.

8. Set according to embodiment 7, wherein an abutment is arranged at an opposite side of the window with respect to the lug.

9. Set according to embodiment 8, wherein the abutment is configured to contact a housing of the medicament delivery device.

10. Set according to embodiment 8 or 9, wherein the abutment is configured to contact a cutout in the medicament delivery device. 1 . Set according to embodiment 6 to 10, wherein the lugs are arranged at a proximal end of a wing, in particular wherein one lug is provided per wing. 2. Set according to any one of the preceding embodiments, wherein detaching means (242) are provided to detach the cover (16) from the medicament delivery device (10), preferably wherein the detaching means (242) engage wings (58), in particular lugs, to outwardly deflect the wings (58) for removal of the cover (16). 3. Set according to embodiment 12, wherein the set comprises a detaching element (50) that is attachable or pre-attached to the medicament delivery device (10) and wherein the detaching element (50) comprises the detaching means (242). 4. Set according to embodiment 13, wherein the detaching element (50) is a cartridge container. 5. Set according to embodiment 14, wherein the cartridge container (50) is configured to be attached, in particular screwed, to the medicament delivery device (10), in particular a housing (32, 42) of the medicament delivery device (10), and the detaching means (242) are configured to detach the cover (16) from the medicament delivery device (10) while or after the cartridge container (50) is attached, in particular screwed, to the medicament delivery device (10). 6. Set according to any one of the preceding embodiments, wherein the dose delivery activation mechanism (54) comprises a dose setting assembly for manually setting a dose. 7. Set according to any one of the preceding embodiments, wherein the dose setting assembly comprises a knob (22) and wherein the knob (22) is rotated in order to set a dose, preferably wherein the knob (22) is rotatable in one direction to increase the dose and in an opposite direction to decrease the dose. 8. Set according to any one of the preceding embodiments, wherein the cover (16) is rotationally and/or axially constrained with respect to the medicament delivery device (10) in an assembled state of the set. 9. Set according to any one of the preceding embodiments, wherein a housing of the medicament delivery device has a chamfered portion, in particular wherein cut-outs are provided in the chamfered portion, and the cover comprising a complementary shaped collar abutting the chamfered portion. 20. Set according to any one of the preceding embodiments, wherein a distal end of the cover, in particular remote from wings, is one of open and closed.

21 . Set according to any one of the preceding embodiments, wherein an inner shape of the cover (16) is shaped complementary to an outer shape of at least a part of the medicament delivery device (10) housing the dose delivery activation mechanism (54) .

22. Set according to any one of the preceding embodiments, wherein the medicament delivery device (10) is part of a pen-type injector (10).

23. Set according to any one of the preceding embodiments, wherein the medicament delivery device comprises a snap element and a dose selector that are rotated relative to each other to set a dose.

24. Set according to any one of the preceding embodiments, wherein the medicament delivery device comprises a nut with an internal thread and a piston rod with an external thread meshing with the internal thread of the nut.

25. Set according to any one of the preceding embodiments, wherein the cover has the form of a sleeve that is put on the medicament delivery device in an axial direction.

26. Set according to any one of the preceding embodiments, wherein the cover is put on the medicament delivery device from a distal end of the medicament delivery device.

27. Set according to any one of the preceding embodiments, the cover (16) being configured to cover at least a part of the dose delivery activation mechanism (54) so that a user is restrained from activating the medicament delivery device (10), in particular setting a dose, prior to preparing the medicament in a container cartridge (48), in particular prior to mixing two or more components of a medicament in a container cartridge (48).

28. Set according to embodiment 27, wherein the container cartridge is configured for preparing the medicament while the container cartridge is being attached to, in particular screwed on, the medicament delivery device

29. Cover for a medicament delivery device, configured to be mechanically attached to the medicament delivery device to cover at least a part of a dose setting assembly of the medicament delivery device so that a user is restrained from prematurely setting a dose of the medicament delivery device. 30. Method for avoiding a premature dose setting on a medicament delivery device (10), comprising attaching a cover (16) to the medicament delivery device (10) for covering a dose delivery activation mechanism (54) of the medicament delivery device (10) so that a user is restrained from prematurely setting a dose before the medicament delivery device (10) is used, and so that the cover (16) is movable in a distal direction to uncover the dose delivery activation mechanism (54) to activate the medicament delivery device (10) during use of the medicament delivery device (10).

31 . Method according to embodiment 30, wherein the cover is detached from the medicament delivery device before the medicament delivery device is used, preferably after a drug preparation step has been performed.

32. Method according to embodiment 31 , wherein the cover is detached by detaching means provided on a cartridge container that is attached to the medicament delivery device.

33. Method according to embodiment 31 or 32, wherein the cover is detached from the medicament delivery device by decoupling a snap- fit connection between the cover and the medicament delivery device.

34. Method according to any one of the method embodiments, wherein the medicament delivery device is used by

A) setting a dose with a dose setting assembly, and

B) injecting the set dose.

The present disclosure further relates to the following third set of enumerated embodiments

1 . A dose delivery mechanism (54) comprising: a housing (32), a piston rod (44) that is configured to act on a plunger (46) sealing a fluid compartment (48) and to move in an axial direction relative to the housing (32) to deliver a set dose, and a dose setting member (34) that is movable relative to the piston rod (44), wherein a position of the dose setting member (34) relative to the housing (32) defines the set dose, and wherein in an as-delivered condition the dose setting member (34) is preset to a position that corresponds to a set dose higher than zero.

2. The dose delivery mechanism (54) according to embodiment 1 , wherein in the as-delivered condition the position of the dose setting member (34) corresponds to a dose between a zero-dose and a minimum dose, e.g. a minimum dose per a therapy the dose delivery mechanism is intended for, deliverable by the dose delivery mechanism (54).

3. The dose delivery mechanism (54) according to any one of the preceding embodiments, further comprising a dose indication member (34) that indicates a set dose depending on a rotational position of the dose indication member (34) relative to the housing (32).

4. The dose delivery mechanism (54) according to embodiment 3, wherein the dose setting member (34) is configured as the dose indication member (34).

5. The dose delivery mechanism (54) according to embodiment 3 or 4, wherein in the as-delivered condition the dose indication member (34) indicates the set dose to be different from a zero-dose.

6. The dose delivery mechanism according to embodiment 5, wherein the dose indication member in the as-delivered condition indicates the set dose to be a dose between a zero-dose and a minimum dose, e.g. a minimum dose per a therapy the dose delivery mechanism is intended for, deliverable by the dose delivery mechanism.

7. The dose delivery mechanism (54) according to any one of the preceding embodiments, wherein the dose setting member (34) is configured to move, e.g. rotate, relative to the housing (32) to set a dose, e.g. a dose given by the therapy or one of the doses given by the therapy, that differs from the preset dose.

8. The dose delivery mechanism (54) according to embodiment 7, wherein the dose setting member (34) is not directly movable, e.g. rotatable, from a preset position to a zero-dose position.

9. The dose delivery mechanism according to embodiment 8, wherein two parts arranged inside the housing of the dose delivery mechanism are configured to cooperate with each other to prevent moving, e.g. rotating, a first one of the two parts relative to a second one of the two parts to block movement of the dose setting member from the preset position directly to the zero-dose position.

10. The dose delivery mechanism according to embodiment 9, wherein the two parts each form a hard stop and wherein the two hard stops are configured to cooperate with each other to prevent moving, e.g. rotating, the first one of the two parts relative to the second one of the two parts to block movement of the dose setting member from the preset position to the zero-dose position.

1 1 . The dose delivery mechanism according to embodiment 10, wherein the two hard stops are configured to be brought out of alignment during delivery of a set, e.g. therapeutic, dose so that the two hard stops are movable, e.g. rotatable, past each other during said dose delivery.

12. The dose delivery mechanism (54) according to any one of the preceding embodiments, further comprising an activation member (18) that is configured to be moved, for example in a proximal direction, to initiate delivery of the set dose, wherein the activation member (18) is blocked from initiating delivery of the set dose when the dose setting member (34) is in the preset position.

13. The dose delivery mechanism (54) according to embodiment 12, wherein a separate element (30), e.g. a clip, is provided to prevent a premature moving of the activation member (18), e.g. due to the dose delivery mechanism (54) falling onto the proximal end (14) of said dose delivery mechanism (54), relative to the housing (32) before the separate element (32) is removed.

14. The dose delivery mechanism (54) according to embodiment 12 or 13, wherein two parts (24, 28) arranged inside the housing (32) of the dose delivery mechanism (54) are configured to cooperate with each other to prevent an unintended moving of the activation member (18), for example in the proximal direction, relative to the housing (32) starting from the preset position.

15. The dose delivery mechanism (54) according to embodiment 14, wherein a first of the two parts forms a blocking structure (156), in particular a circumferentially extending rib (156), and a second of the two parts forms an engagement feature (1 16) that is configured to engage with the blocking structure (156) when the two parts are moved relative to each other in order to block the activation member (18) from initiating delivery of the set dose when the dose setting member (34) is in the preset position.

16. The dose delivery mechanism according to embodiment 15, wherein cut-outs are provided in the blocking structure in, e.g. angular, positions where the engagement feature is arranged when a, e.g. therapeutic, dose that differs from the preset dose is set so that the engagement feature can be moved through the respective cut-out past the blocking structure during dose delivery of the set dose.

17. The dose delivery mechanism according to embodiment 16, wherein the cut-outs are provided next to corresponding dose definition elements.

18. The dose delivery mechanism according to embodiment 15 to 17, wherein the engagement feature is provided on a snap element.

19. The dose delivery mechanism (54) according to any one of the preceding embodiments, wherein two parts arranged inside the housing (32) of the dose delivery mechanism (54) comprise respective dose definition elements (116, 118a-118d) that are configured to cooperate with each other to define multiple relative positions to each other corresponding to settable doses. The dose delivery mechanism according to embodiment 14 and 19, wherein the two parts arranged inside the housing of the dose delivery mechanism that are configured to cooperate with each other to prevent an unintended moving of the activation member, for example in the proximal direction, relative to the housing starting from the preset position are the two parts that comprise respective dose definition elements that are configured to cooperate with each other to define multiple relative positions to each other corresponding to settable doses. The dose delivery mechanism (54) according to embodiment 19 or 20, wherein the positions are defined by dose stops (118a-118d) formed on a first of the two parts which are configured to get in contact with a snap element (116) on a second of the two parts. The dose delivery mechanism according to embodiment 21 , wherein the snap element (116) is preloaded against the respective dose stop (118a-118d) by a spring (40), in particular a torsion spring. The dose delivery mechanism according to any one of embodiments 21 or 22, wherein at least one of the dose stops has a chamfered surface to guide the snap element over the dose stop during setting of a higher dose and/or wherein at least one of the dose stops has a surface opposite the chamfered surface that is configured to allow movement of the snap element during setting of a lower dose. The dose delivery mechanism according to embodiment 19 to 23, wherein the two parts are configured to cooperate with each other to prevent an unintended moving of one of the parts relative to the other one of the parts so that the activation member is blocked from moving relative to the housing starting from the preset position. The dose delivery mechanism according to any one of the preceding embodiments, wherein at an end of the dose delivery procedure, the dose delivery mechanism is configured to arrive in a zero-dose state. The dose delivery mechanism according to any one of the preceding embodiments, wherein at an end of the dose delivery procedure, a dose indication member indicates that the dose delivery mechanism is in a zero-dose position. The dose delivery mechanism according to any one of the preceding embodiments, wherein the dose delivery mechanism comprises a nut in meshing engagement with the piston rod, and wherein an axial movement of the nut relative to the piston rod corresponds to an amount of dose set by the dose delivery mechanism. A dose delivery mechanism according to embodiment 27, wherein the piston rod is non-rotatably mounted to the housing. A dose delivery mechanism according to embodiment 27 or 28, wherein the piston rod is linearly guided in the housing. A dose delivery mechanism according to any one of embodiments 27 to 29, wherein the nut is configured not to rotate relative to the housing and the piston rod during dose delivery. A dose delivery mechanism according to any one of the preceding embodiments, wherein a driver that is configured to apply a force onto a nut to move the piston rod via the nut in a proximal direction is forced to rotate relative to the housing during dose delivery. A dose delivery mechanism according to any one of the preceding embodiments, wherein the dose delivery mechanism is configured to be disposable after a single use. A medicament delivery device (10), in particular an injection device, with a dose delivery mechanism (54) according to any one of the preceding embodiments. An assembly of a dose delivery mechanism and a removable element, e.g. a clip, the dose delivery mechanism comprising: a housing, a piston rod that is configured to act on a plunger sealing a fluid compartment and to move in an axial direction relative to the housing to deliver a set dose, a dose setting member that is movable relative to the piston rod, wherein a position of the dose setting member relative to the housing defines the set dose, and an activation member movable, in particular in a proximal direction, relative to the housing to deliver the set dose, wherein the removable element is arranged between the housing and the activation member to prevent a premature moving of the activation member relative to the housing, in particular in said proximal direction, before the removable element is removed. An assembly according to embodiment 34, further comprising a cover, the cover being mechanically attached to the dose delivery mechanism prior to use of the dose delivery mechanism, the cover being configured to cover at least a part of the dose delivery mechanism and/or at least a part of the removable element so that the removable element is blocked from being removed from the dose delivery mechanism, and wherein the cover being configured to be movable to uncover said part of the dose delivery mechanism and/or part of the removable element so that the removable element is removable from the dose delivery mechanism. A dose delivery mechanism comprising: a housing, a dose adjusting member that is movable relative to the housing to adjust a dose and/or an activation member to deliver a set dose, and a dose indication member that indicates a set dose depending on a rotational position of the dose indication member relative to the housing, wherein in an as-delivered condition the dose delivery mechanism is preset to a dose higher than zero. The dose delivery mechanism according to embodiment 36, wherein in the as-delivered condition the dose adjusting member and/or the activation member is/are preset to a position that corresponds to a dose higher than zero. The dose delivery mechanism according to embodiment 35 or 36, wherein in the as-delivered condition the dose delivery mechanism is preset to a dose between a zero-dose and a minimum dose, e.g. a minimum dose per a therapy the dose delivery mechanism is intended for. The dose delivery mechanism according to any one of the preceding embodiments 36 to 38, wherein in the as-delivered condition the dose indication member indicates the set dose to be different from a zero-dose. The dose delivery mechanism according to embodiment 39, wherein the dose indication member in the as-delivered condition indicates the set dose to be a dose between a zerodose and a minimum dose, a minimum dose per a therapy the dose delivery mechanism is intended for. A dose delivery mechanism according to any one of the preceding embodiments 36 to 40, wherein the dose adjusting member and the activation member are fixedly connected to each other or formed integrally with each other. A method for providing a dose delivery mechanism having a housing, a dose adjusting member that is movable relative to the housing to set a dose and/or an activation member to deliver a set dose, and a dose indication member that indicates a set dose depending on a rotational position of the dose indication member relative to the housing, comprising the steps of: delivering the dose delivery mechanism to a costumer in a state preset to a dose higher than zero.

43. An assembly of a dose delivery mechanism and a removable element, e.g. clip, the dose delivery mechanism comprising a housing, a dose indication member that indicates a set dose depending on a rotational position of the dose indication member relative to the housing, and an activation member movable, in particular in a proximal direction, relative to the housing to deliver the set dose, wherein the removable element is arranged between the housing and the activation member to prevent a premature moving of the activation member relative to the housing, in particular in said proximal direction, before the removable element is removed.

44. An assembly according to embodiment 43, further comprising a cover, the cover being mechanically attached to the dose delivery mechanism prior to use of the dose delivery mechanism, the cover being configured to cover at least a part of the dose delivery mechanism and/or at least a part of the removable element so that the removable element is blocked from being removed from the dose delivery mechanism, and wherein the cover being configured to be movable to uncover said part of the dose delivery mechanism and/or part of the removable element so that the removable element is removable from the dose delivery mechanism.

45. A method for providing a dose delivery mechanism (54) having a housing (32), a piston rod (44) that is configured to act on a plunger (46) sealing a fluid compartment (48) and to move in an axial direction relative to the housing (32) to deliver a set dose, and a dose setting member (34) that is movable relative to the piston rod (44), wherein a position of the dose setting member (34) relative to the housing (32) defines the set dose, comprising the steps of: delivering the dose delivery mechanism (54), in particular a medicament delivery device (10) with a dose delivery mechanism (54), to a costumer in a state preset to a dose higher than zero.