The present invention relates to injection devices for injecting one or more doses of a liquid drug. In particular the present invention relates to injection devices for injecting one or more doses of drug from a held drug reservoir by means of an injection needle and improvements relating to the safety of the injection device during storage, handling and drug administration.

BACKGROUND

In relation to some diseases patients must inject a medicament on a regular basis such as once weekly, once daily or even a plurality of times each day. In order to help patients overcome fear of needles, some injection devices incorporate a needle shield or needle shroud for covering an injection needle either before or after a dose administration. Such needle shield or shroud typically hide the injection needle from the user's view, and in some forms, additionally provide a mechanical blocking preventing an individual from accidentally gaining access to the injection needle.

Some injection devices include a protective needle cap which prior to use is accommodated within the injection device, such as within an opening of the needle shield. Due to the outer dimensions of the needle cap this typically leaves a large opening once the needle cap has been removed. With the potential risk that patients, relatives, and health care medical staff are subjected to accidental needle stick injuries.

WO 2012/000839 discloses a safety device for a pre-filled syringe, wherein a needle shield comprises a central aperture of variable diameter. The variable diameter central aperture is obtained by using a flexible material that is located inside an aperture formed in a rigid needle shield. Although the disclosed safety devices theoretically may seem acceptable the safety devices still have some drawbacks due to the operating principle that is used. Issues such non-optimal a mechanical strength and potential issues with long-term material creep are likely to occur. An additional example of an injection device having projections to reduce the effective bore of a needle passage is disclosed in US patent No. 9,522,233.

Although the above references include disclosure of safety devices, there is still a need for medical injection devices with improved safety arrangements for preventing accidental needle stick injuries. SUMMARY

It is an object of the present invention to provide a medical drug injection device featuring improved needle safety. It is a further object of the invention to provide a simplified and robust design of such medicament injector.

In the disclosure of the present invention, embodiments and aspects will be described which will address one or more of the above objects or which will address objects apparent from the below disclosure as well as from the description of exemplary embodiments.

In a first aspect, the present invention relates to an injection device for expelling one or more doses of a drug from a drug reservoir through a hollow needle, the injection device comprising:

- a hollow needle extending along an axis towards a distal needle tip,

- a needle cap that removably mounts relative to the hollow needle, and

- a skin contacting member configured to encircle the hollow needle and the needle cap, the skin contacting member being configured for being held against the skin of a user during drug expelling. The skin contacting member comprises a central portion which connects to a peripheral portion of the skin contacting member, wherein the material of the central portion is made from a relatively flexible material and the peripheral portion is made from a relatively rigid material being more rigid than said relatively flexible material. The central portion comprises a distal end wall having a central lip portion defining a needle delivery aperture through which the hollow needle protrudes during drug expelling, wherein subsequent to drug expelling the skin contacting member and the hollow needle moves axially relative to each other so that the hollow needle is guarded by the skin contacting member.

The peripheral portion comprises a distal end wall having a central opening sized to encircle the needle cap, the peripheral portion distal end wall extending from said central opening and radially outwards towards an attachment area where the central portion is attached to the peripheral portion. The central portion distal end wall is arranged distally to the peripheral portion distal end wall in radially overlapping relationship. The central portion distal end wall, at locations radially inwards from said attachment area, is movable in distal direction relative to the peripheral portion distal end wall by flexing of the central portion. During removal of the needle cap distally relative to the hollow needle, the needle cap engages with the central lip portion to urge the central lip portion into a tensed state with an enlarged needle delivery aperture. Subsequent to removal of the needle cap, the needle cap disengages from the central lip portion to cause the central lip portion to assume a relaxed state with a reduced needle delivery aperture smaller than said central opening of the peripheral portion distal end wall.

This enables the central portion to be configured so that the reluctance against movement of the central lip portion in the proximal direction relative to the peripheral portion is greater than the reluctance against movement of the central lip portion in the distal direction relative to the peripheral portion.

In some embodiments, the central portion is configured so that the peripheral portion axially supports a portion of the central portion so that the reluctance against movement of the central lip portion in the proximal direction relative to the peripheral portion is greater than the reluctance against movement of the central lip portion in the distal direction relative to the peripheral portion.

The injection device may be so formed that, subsequent to removal of the needle cap, the central portion distal end wall, at locations radially inwards from said attachment area, engages the peripheral portion distal end wall to limit movement of the central portion distal end wall in proximal direction relative to the peripheral portion distal end wall.

In some embodiments the peripheral portion distal end wall is arranged substantially orthogonally with respect to the axis. In further embodiments, the peripheral portion further defines a lateral wall which connects to the peripheral portion distal end wall, the peripheral portion forming an enclosure for accommodating the hollow needle and at least partly accommodating the needle cap. In some variants, the central portion distal end wall, when the central lip portion assumes the relaxed state with reduced needle delivery aperture, is arranged substantially orthogonally with respect to the axis. Said attachment area may in some variants be located radially closer to the lateral wall than to the central opening of the peripheral portion distal end wall.

The injection device may comprise a syringe which includes said hollow needle, the syringe comprising:

- a barrel for containing a volume of a drug,

- the hollow needle arranged at a distal end of the barrel, the hollow needle having a distal skin penetrating needle tip, and

- a plunger that is distally movable within the barrel. In some embodiments the needle cap defines a proximal capping portion encircling the hollow needle and a distal finger gripping portion, wherein a bridge portion connects the proximal capping portion and the distal finger gripping portion, the bridge portion including a cross sectional dimension being narrower than the proximal capping portion. In some embodiments, when the needle cap is mounted relative to the hollow needle, the bridge portion of the needle cap protrudes through the needle delivery aperture so that the narrower portion is located axially at the location of the needle delivery aperture. Upon distal removal of the needle cap from the hollow needle, the proximal capping portion of the needle cap engages with the central lip portion to urge the central lip portion into a tensed state with an enlarged needle delivery aperture.

The skin contacting member may be formed so that it comprises a tubular elongated section arranged coaxially with the hollow needle, wherein the tubular elongated section having a distal rim portion, and wherein the central portion is attached to the distal rim portion of the tubular elongated section.

In some forms the skin contacting member forms a needle shroud. In some forms the needle shroud is axially movable relative to a housing of the injection device. In some variants the needle shroud is axially movable for causing the held injection needle to protrude through the central needle aperture. In other forms the skin contacting member forms a distal most face of the housing of the injection device. In such variants, the injection needle, and optionally the drug reservoir, may be formed so that the injection needle and the drug reservoir is axially slideable relative to the housing causing the held injection needle to protrude through the central needle aperture.

In a second aspect, the present invention relates to an injection device for expelling one or more doses of a drug from a drug reservoir through a hollow needle, the injection device comprising:

- a hollow needle extending along an axis towards a distal needle tip,

- a needle cap that removably mounts relative to the hollow needle, the needle cap defining a proximal capping portion encircling the hollow needle and a distal finger gripping portion, wherein a bridge portion connects the proximal capping portion and the distal finger gripping portion, the bridge portion including a cross sectional dimension being narrower than the proximal capping portion, and

- a skin contacting member configured to encircle the hollow needle and the needle cap, the skin contacting member defining a distal end face configured for being held against the skin of a user during drug expelling, wherein the distal end face comprises a central portion which connects to a peripheral portion of the skin contacting member, wherein the material of the central portion is made from a relatively flexible material and the peripheral portion is made from a relatively rigid material being more rigid than said relatively flexible material. The central portion of the distal end face of the skin contacting member has a central lip portion defining a needle delivery aperture through which the hollow needle protrudes during drug expelling, wherein subsequent to drug expelling the skin contacting member and the hollow needle moves axially relative to each other so that the hollow needle is guarded by the skin contacting member.

When the needle cap is mounted relative to the hollow needle, the bridge portion of the needle cap protrudes through the needle delivery aperture so that the narrower portion is located axially at the location of the needle delivery aperture. Upon distal removal of the needle cap from the hollow needle, the proximal capping portion of the needle cap engages with the central lip portion to urge the central lip portion into a tensed state with an enlarged needle delivery aperture, and wherein subsequent to removal of the needle cap, the proximal capping portion disengages from the central lip portion to cause the central lip portion to assume a relaxed state with a reduced needle delivery aperture.

In this way it is ensured that material creep will not arise for the flexible material portions during long-term storage of the injection device.

In some embodiments the proximal capping portion of the needle cap comprises a needle boot that in a mounting position seals off the hollow needle.

In further embodiments, the proximal capping portion of the needle cap comprises a rigid needle shield (RNS) that encircles at least a part of the needle boot.

In some forms the distal finger gripping portion is more radially wide than the bridge portion, and wherein the distal finger gripping portion forms a part that is mounted onto the proximal capping portion via the bridge portion.

In some variants the central lip portion defining the needle delivery aperture comprises a slitted area that at least comprises one diagonally arranged slit.

In such variants, the bridge portion may be formed so that it has an axial cross sectional shape that substantially corresponds to the shape of the slitted area of the central lip portion.

In a third aspect, the invention relates to an injection device for expelling a drug from a drug reservoir, the injection device comprising:

a housing,

- a drug reservoir having a distally arranged hollow needle arranged along an axis, and a needle cap removably mounted relative to the hollow needle,

an expelling assembly configured for expelling one or more doses of a drug from the drug reservoir, and

a needle shroud operably coupled to the expelling assembly and configured for translational movement relative to the housing along an axis from a distal position wherein expelling is prevented to a proximal position wherein expelling is enabled, the needle shroud having an axial opening at the distal end face leading into an internal cavity, the internal shroud cavity configured to at least partly accommodate said needle cap in a mounting position, wherein the housing comprises a deflectable beam, and the needle shroud comprises a blocking means configured to engage the deflectable beam of the housing, wherein the cap, when fitted in the mounting position, engages with the deflectable beam of the housing to prevent the deflectable beam from deflecting out of blocking engagement with respect to the blocking means of the needle shroud to thereby prevent the needle shroud from moving from the distal position to the proximal position, and wherein the cap, upon removal from the mounting position, enables the deflectable beam to deflect out of blocking engagement with respect to the blocking means of the needle shroud, enabling the needle shroud to move from the distal position to the proximal position to enable expelling.

In such embodiment, the injection device forms a device wherein accidental triggering of the device is effectively prevented.

In certain embodiments, the deflectable beam of the housing is configured to deflect radially by ramped engagement between the deflectable beam and the blocking means of the needle shroud. In some embodiments, the deflectable beam is configured to become deflected radially outwards by the blocking means upon proximal movement of the needle shroud. In other embodiments, the deflectable beam is configured for being deflected radially inwards. In still other embodiments, the deflectable beam is configured for being deflected in a circumferential direction relative to the axis. In further embodiments, the cap comprises a rigid needle shield (RNS) that encircles at least a part of a needle boot that in the mounting position seals the needle. In some embodiments, when the cap is fitted in the mounting position, the part of the cap that engages with the deflectable beam of the housing to prevent the deflectable beam from deflecting out of blocking engagement with respect to the blocking means of the needle shroud is provided by the rigid needle shield. It is further to be noted that any variants or individual feature noted above in accordance with to the first aspect, the second aspect and the third aspect may be combined with other variants of the said first, second and third aspects in agreement with the teaching provided within this disclosure in its entirety.

As used herein, the term "drug" is meant to encompass any drug-containing flowable medicine or combinations of separately held plurality of drug-containing flowable medicines capable of being passed through a delivery means such as a cannula or hollow needle in a controlled manner, such as a liquid, solution, gel or fine suspension.

BRIEF DESCRIPTION OF DRAWINGS

In the following the invention will be further described with reference to the drawings, wherein fig. 1 a shows a cross sectional side view of an embodiment of an injection device 1 in accordance with the present invention, during storage of the device before initial use (State I),

fig. 1 b shows a cross sectional side view in a cross section perpendicular to the cross section shown in fig. 1 a,

fig. 1 c and 1 d show perspective views of the cross sections shown respectively in fig. 1 a and 1 b,

figs 2a-2f show the device 1 of figs. 1 a-1 d in six consecutive states during use in a cross- sectional perspective view corresponding to fig. 1 c,

figs. 3a and 3b show the front part of the device 1 during cap removal (State II) in views corresponding to figs. 1 a and 1 b,

figs. 4a and 4b show the front part of the device 1 after cap removal but before administration (State III) in views corresponding to figs. 1 a and 1 b,

fig. 4c is a perspective view of the front part of the device 1 in a cross section corresponding to the cross section shown in fig. 4b,

figs. 5a and 5b show views corresponding to figs. 1 a and 1 b of the front part of the device 1 where a skin contacting member 100 has been pressed against the skin of a user (State IV), figs. 6a and 6b show views corresponding to figs. 1 a and 1 b of the front part of the device 1 after expelling and after the skin contacting member 100 has been removed from the skin of a user (State V), and figs. 7 a and 7b show schematic views corresponding to figs. 1 a and 1 b of the front part of the device 1 wherein a person attempts to reach into the injection device (State VI).

Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale, and certain features may be exaggerated or omitted in some of the drawings in order to better illustrate and explain the present invention.

DESCRIPTION

In the context of the present disclosure it may be convenient to define that the term "distal end" in the appended figures is meant to refer to the end of the injection device which usually carries the injection needle whereas the term "proximal end" is meant to refer to the opposite end of the injection device pointing away from the injection needle. The shown figures are schematical representations for which reason the configuration of the different structures as well as the relative dimensions are intended to serve illustrative purposes only.

Figs. 1 a-1 d show four different views of an embodiment of a medical injection device 1 for injecting a pre-determined amount of a liquid drug from a held drug reservoir through an injection needle. In the shown embodiment, which discloses different aspects of the invention, the injection device 1 is formed as an auto-injector which incorporates a dose expelling mechanism for automatically expelling a dose from the drug reservoir. The depicted embodiment shown in the figures is provided as an auto-injector where energy is stored in a pre-stressed spring, wherein a skin contacting member in the form of a needle shroud is operated to activate the device to thereby trigger the expelling procedure and for injecting a fixed dose of drug from the reservoir. In figs. 1 a-1 d the device 1 is shown in a state during storage of the device before initial use (state I), and with a removable protective needle cap 30 still attached. Injection devices in accordance with the invention need not include a mechanism for performing drug expelling procedure automatically but may include other kinds of expelling mechanisms such as a manually driven expelling mechanism. It is therefore to be noted that the shown injection device only forms a suitable but non-limiting example and that the principles of the present invention regarding needle safety can be used together with other types of injection devices. Referring to the embodiment shown in fig. 1 a through 1 d, the injection device 1 includes an elongated generally tubular outer housing 10 configured for being gripped by the palm of the user. A rear cap 19 closes off the outer housing 10 at the proximal end. In the shown embodiment, an inner housing 14 is formed in one piece with the outer housing and serves for holding the drug reservoir inside the injection device 1. In other forms the inner housing may be formed as a reservoir holder that is formed separate from the outer housing but attached relative to the outer housing, either axially slidable, or fixedly attached. In the shown embodiment, the inner housing 14 accommodates a drug reservoir in form of a prefilled syringe 20 having a cylindrical barrel 22 with a hollow injection needle 25 fixedly attached at its distal end. The needle extends along a central longitudinal axis of the syringe and is arranged coaxially with a central axis of the tubular outer housing 10. In alternative embodiments, a drug cartridge may be employed instead, configured for cooperation with a separate injection needle.

The cylindrical barrel 22 of syringe 20 includes a narrowed neck section 23 at its distal end onto which the injection needle 25 is mounted. The barrel 22 accommodates a slidable plunger 27 made of a rubber or similar material, the plunger sealing the syringe barrel at a rear portion thereof. A removable proximal capping portion 32, including a boot 31 , is arranged at the distal end of syringe 20 for protecting and sealing the injection needle 25. In the shown embodiment the proximal capping portion 32 and the boot 31 are part of a protective needle cap assembly generally referred to by numeral 30, the boot 31 and the proximal capping portion 32 forming a rigid needle shield (RNS). After the protective needle cap assembly 30 including the boot 31 has been removed from the syringe 20, the slideable plunger 27 can be pushed in the distal direction to expel liquid from the syringe barrel through the injection needle 25. The outer housing 10 includes two opposing windows 12 which allow visual inspection of the drug contained within the syringe 20. In addition, the windows enable a user of the device to determine whether or not the device 100 has already been used for a dose expelling operation.

A drive spring 60 is arranged within the outer housing with the proximal end of drive spring 60 seated at the rear cap 19. A plunger rod 50 serves for forwarding a force of the drive spring 60 to the plunger 27. In the shown exemplary embodiment, the plunger rod 50 is hollow and the drive spring 60 is arranged within the plunger rod 50 biasing the plunger rod in the distal direction against the rear cap 19. In the state shown in figs. 1 a-1 d, the drive spring 60 is in a tensed compressed state with sufficient accumulated energy for driving forward the plunger 27 for delivering the full dose of drug contained in barrel 22.

In the figures of the shown embodiment a plunger release mechanism 70 is included, and acts to prevent release of the plunger rod 50 until triggering of the device. The release mechanism 70 is only schematically shown and will not be discussed further herein. In the art of auto-injectors, many different trigger release principles have been shown which may either be operated by a push-button, a skin contacting member, or operated by a combination of buttons and skin contacting members.

In the shown embodiment, the plunger release mechanism 70 is intended to be exclusively operated by a skin contacting member arranged at the distal end of the device. In the shown embodiment the skin contacting member is provided in the form as a needle shroud 100 protruding distally relative to the housing 10. A needle shroud spring 40 is arranged between a seat in the housing 10/14 and an interior annular seat in the needle shroud 100. The needle shroud spring 40 urges the needle shroud 100 towards a distal limiting extended position but the needle shroud may be moved against the bias of the needle spring 40 towards a proximal limiting retracted position simply by pushing the needle shroud 100 against the skin of a user. Upon removal of the device, and thereby the needle shroud 100, from the skin, the needle shroud spring urges the needle shroud towards its distal limiting extended position.

As sketched above, the plunger release mechanism 70 retains the plunger rod 50 prior to retraction of the needle shroud 100 relative to the housing 10/14 and releases the plunger rod 50 once the needle shroud 100 is sufficiently retracted. In an exemplary embodiment, a shroud lock mechanism 15, 1 15 is arranged to prevent retraction of the needle shroud 100 relative to the housing 10/14 when the protective cap portion 32 is in place, thereby avoiding unintentional activation of the injection device 1 . In the shown embodiment, the needle shroud 100 is formed by two main parts, attached to each other, and made of materials having different material properties, i.e. a first main part 1 10 and a second main part 120, the second main part 120 arranged most distally on the needle shroud 100, i.e. on the distal side of the first main part 1 10, and primarily extending along a distal end wall of the first main part 1 10. The first main part 1 10 forms a peripheral tubular element defining lateral walls which slides axially at the inner side of the outer housing 10. The lateral walls of the main part 1 10 connects to a main part distal end wall 1 14 that includes a central opening 1 12 having a diameter sized slightly larger than the protective cap portion 32 so as to allow passage of the cap portion 32 during removal of the cap 30. A cylindrical wall 1 15 extends in the proximal direction from the rim portion of the central opening 1 12 and forms an enclosure for the cap portion 32 and the needle 25 of the syringe 20.

The second main part 120 comprises a distal end wall 124 that has a central lip portion 122 arranged at the central axis and defining a needle delivery aperture 125 through which the hollow needle 25 protrudes during drug expelling.

The first main part 1 10 may be made of a relatively rigid material, such as thermoplastics plastics material. The second main part 120 may be made of a resilient flexible rubber-like material, such as an elastomer, silicone or silicone elastomer. The second main part 120 is attached to the first main part 1 10 at locations along the periphery of the first main part. Due to the elastic nature of the material of the second main part 120, this enables the second main part to become stretched when forces act in distal direction on the central lip portion 122 around the needle delivery aperture 125. It also enables the needle delivery aperture 125 to elastically expand from a relaxed state with a relatively small diameter needle delivery aperture 125 to a tensed state with a larger needle delivery aperture 125, which is needed when the protective needle cap assembly 30 is to be removed from the injection device 1 .

In the relaxed state, as shown in fig. 1 a-1 d, the central portion distal end wall 124 is arranged distally to the peripheral portion distal end wall 1 14 in abutment therewith and in radially overlapping relationship.

In the relaxed state the needle delivery aperture 125 has a smaller aperture than the central opening 1 12 of the first main part 1 10. The first main part 120 thus defines a central portion whereas the first main part 1 10 may be referred to as a peripheral portion. However, in the embodiment shown, the first main part 120 extends radially beyond an outer rim portion arranged at the distal end of the first main part 1 10. At this point the central portion 120 attaches to the peripheral portion 1 10 along an attachment area 130 (see fig. 3a). Exemplary attachment methods may be provided by adhering or otherwise fusing the central portion 120 to the peripheral portion 1 10. Alternatively, the central portion 120 and the peripheral portion 1 10 may be formed by a 2k moulding process with the attachment provided by interleaved material parts along the attachment area 130. Due to the choice of materials at the radially overlapping areas of the central portion 120 and the peripheral portion 1 10, the two materials may be configured for slipping, i.e. non-sticking relative to each other at locations radially inwards from the attachment area 130, enabling the central portion distal end wall 124 to be movable in distal direction relative to the peripheral portion distal end wall 1 14 by flexing of the central portion 120.

In the embodiment shown in figs. 1 a-ad, the boot 31 and the proximal capping portion 32 of the protective needle cap assembly 30 is accommodated inside the enclosure formed by the needle shroud 100. A gripping portion 35 of the protective needle cap assembly 30 connects via a bridge portion 34 to the proximal capping portion 32. In the shown embodiment, the bridge portion 34 includes a cross sectional dimension being narrower than the proximal capping portion 32. When the protective needle cap assembly 30 is mounted relative to the hollow needle 25, the bridge portion 34 of the needle cap protrudes through the needle delivery aperture 125 so that the narrow portion is located axially at the location of the needle delivery aperture. During storage of the device 1 the central lip portion 122 of the needle delivery aperture is thus allowed to remain in the relaxed state or a substantially relaxed state with a reduced needle delivery aperture 125. Hence, for such embodiment, the risk of material creep of the central lip portion 122 of the central portion 120 of needle shroud 100 is minimized. It should be noted that other designs and configurations of a protective needle cap assembly 30 may be utilized while still benefiting from the advantages of the design of the needle shroud 100. For example, the bridge portion 34 may include other designs or entirely omitted. Also, the proximal capping portion 32 of the protective needle cap assembly 30 may be formed with shapes other than cylindrical, tapered or conical shapes.

Figs. 2a-2f show the device 1 of figs. 1 a-1 d in six consecutive states during use in a cross- sectional perspective view corresponding to fig. 1 c. Fig. 2a shows the device in State I, i.e. during storage of the device before initial use.

Fig. 2b shows a cross section of the entire device whereas figs. 3a and 3b only depict the front part of the device 1 during cap removal (State II). Upon distal removal of the needle cap assembly 30 from the injection needle 25, the proximal capping portion 32 of the protective needle cap assembly 30 engages with the central lip portion 122 so that the central portion distal end wall 124, at locations radially inwards from the attachment area 130, is moved in distal direction relative to the peripheral portion distal end wall 1 14 by flexing of the central portion 120. This urges the central lip portion into a tensed state with an enlarged needle delivery aperture 125. By continued distal movement of the protective needle cap assembly 30, the proximal capping portion 32 is allowed to escape entirely from the needle shroud 100. This condition is shown in figs. 2c, 4a, 4b and 4c (State III). As can be seen, the central lip portion 122 assumes a relaxed state with a reduced needle delivery aperture 125 smaller than said central opening 1 12 of the peripheral portion distal end wall 1 14. In this state the injection device 1 is ready to be used for performing an injection.

Figs. 2d, 5a and 5b show the injection device 1 in a state wherein the injection device 1 has been pushed towards a target site for performing an injection. This has caused the needle shroud 100 to be moved into the proximal retracted position relative to the housing 10/14 (State IV). In this position, the tip portion and a part of the injection needle 25 has been moved through the needle delivery aperture 125 to protrude a predefined distance from the central portion distal end wall 124. In this position, the movement of the needle shroud 100 has acted upon the plunger release mechanism 70 so that the plunger release mechanism has released the plunger rod 50 for initializing the dose expelling procedure.

Figs. 2e, 6a and 6b show the injection device 1 in State V where the drive spring 60 has pushed the plunger 50 and the plunger 27 distally so that the entire dose of drug has been expelled from the syringe 20. The injection device 1 has been removed from the target site so that the needle shroud 100, acted upon by the force of the needle shroud spring 40, has been moved axially back into its distal extended position relative to the housing 10/14. A not shown needle shield lock mechanism may be included to irreversibly arrest the needle shroud 100, subsequent to an injection, in its distal extended position.

Finally, figs. 2f, 7a and 7b show the injection device 1 in a State VI, which schematically depict a situation wherein a finger of a child or an adult accidentally attempts to gain access to the central opening 1 12 of the peripheral portion of the needle shroud 100. Due to the presence of the central portion 120 of the needle shroud 100, and the support of the radially overlapping areas of peripheral portion 1 10 relative to the central portion 120, the central lip portion 122 of central portion 120 exhibits a large degree of stiffness thereby limiting the central lip portion 122 with regard to being moved in the proximal direction. As shown in figs. 2f, 7 a and 7b, even for a person with small hands and slim fingers, such as the fingers of a child, access to the central opening 1 12 is effectively blocked by the central lip portion 122 of central portion 120. Hence, the hollow needle 25 is effectively guarded by the needle shroud 100. It is to be noted that the same safety issue is addressed in State III of the injection device, i.e. in the situation right after removal of the protective needle cap assembly 30.

Turning back to figs. 4a and 4b, it is seen that the inner housing 14 comprises two deflectable beams 15 arranged diametrically opposed to each other. Each of the two deflectable beams 15 has a distal most end which is deflectable radially inwards. In the state shown in figs. 4a and 4b. the deflectable beams are located axially opposite a blocking means formed by cylindrical wall 1 15. In the state shown in figs. 1 a through 1 d, the proximal capping portion 32 fills the cavity between the two deflectable beams 15. The beams are therefore prevented from being deflected radially inwards as long as the needle cap assembly 30 is located in the mounted position relative to the injection needle 25. However, as depicted in figs. 5a and 5b, when the needle cap assembly 30 has been removed, and when the needle shroud 100 is pushed towards its proximal limiting position, the pair of deflectable beams 15 will by ramped engagement with the blocking means provided by cylindrical wall 1 15 be deflected inwards, allowing the cylindrical wall 1 15 to travel proximally and pass the pair of deflected beams 15 (see fig. 5b).

In accordance with the mechanism 15/1 15, when the needle cap assembly 30 is fitted in the mounting position, the cap engages with the deflectable beams 15 of the housing 10/14 to prevent the deflectable beams 15 from deflecting out of blocking engagement with respect to the blocking means 1 15 of the needle shroud 100 to thereby prevent the needle shroud 100 from moving from the distal position to the proximal position. Hence, an effective safety mechanism is provided configured for avoiding premature and accidental triggering of the injection device 1.

The description above with respect to the figures has been provided to give background information on the use of an exemplary injection device applicable for use with the present invention. However, the injection device described is one of many different available injection devices that can be utilized with the principles according to the present invention. It should be stressed that the invention is not limited to the shown embodiment and the described variants, but may be embodied in other ways within the subject matter defined in following claims and within the remaining disclosure.