TECHNICAL FIELD

The inventive concept relates to a dual-cylinder lock assembly. A dualcylinder lock assembly may be unlocked and locked by different keys to operate a door locking mechanism. More specifically, the inventive concept relates to a dualcylinder lock assembly with enhanced functionality for resisting tampering and forcible unlocking.

BACKGROUND

In order to describe the inventive concept which is to be implemented in a dual-cylinder lock assembly, a general description of dual-cylinder lock assemblies will first be presented.

A dual-cylinder lock assembly typically includes a first and a second lock cylinder operable by different keys. Each lock cylinder comprises a housing and a key-receiving plug rotatably received in the housing. Insertion and turning of an appropriate key into one of the plugs allows rotation of the plug to an unlock position. Especially, the first lock cylinder may be operable by a regular or resident key, and the second lock cylinder may be operable by a service personal key. Each lock cylinder may be mechanical or electromechanical. As an example, the resident key may be a mechanical key for operating a mechanical lock cylinder, while the service key may be a programmable electronic key for operating an electromechanical lock cylinder. A dual-cylinder lock assembly is typically arranged to operate a door locking mechanism, such as a rotatable latch.

US 474 783 discloses a lock operable by a master key or by a change key. A master-key cylinder is completely separated from a change-key cylinder. Each cylinder is provided with an associated gear. The cylinders are arranged such that the plug of each cylinder, when its mechanical tumblers are set by an appropriate key, may be pushed axially inwards by the key causing the associated gear to move axially and mesh with a common gear operating a door lock mechanism.

US 3 203 210 discloses a lock with two lock cylinder for operating a common latch mechanism, each lock cylinder including a rotatable plug. A key slot in each rotatable plug extends through the rear of the plug. A gear is mounted for free rotation on an inner end of each plug. When an appropriate key is inserted into a plug, the key tip extends through the rear of the plug to create a rotational connection between the plug and the associated gear.

US 10 253 526 discloses a dual-cylinder lock arrangement comprising first and second lock cylinders having first and second rotatable plugs. First and second cams are arranged each to actuate a door lock mechanism. The cams are co-axial and arranged to rotate independently of each other about the same axis as the first plug. The first cam is coupled to and rotatable directly by the first plug involving no gear transmission. The second cam is operated independently from the first cam by rotation of the second plug and via a gear transmission drivingly connecting the second plug to the second cam. The gear transmission is operatively associated with the second cylinder only.

EP 3 733 999 A1 discloses a dual-cylinder lock assembly comprising a gear and clutch mechanism for selectively connecting a first or a second cylinder plug to an output tailpiece. Four gears are moved axially in and out of engagement during operation. The solution requires keys extending rearwardly through the back side of one of the plugs to operate a clutch mechanism.

Prior-art dual-cylinder lock assemblies as disclosed in the above-mentioned documents are not well suited to resist tampering attempts.

SUMMARY OF INVENTION

An object is to provide a dual-cylinder lock assembly which is less subjectable to tampering attempts. Especially, it is an object to provide a dual-cylinder lock assembly with an enhanced protection against forcible unlocking.

The inventive concept provides a new solution compared to prior-art mechanical collapse designs used in some lock assemblies for handling unauthorized forcible unlocking attempts. Locks presenting a collapse functionality are as such known in the art. When forced or tampered with in an unauthorized fashion, such a design presents a breakable mechanism which when broken renders the lock assembly substantially tamperproof. For instance, a lock cylinder of a lock presenting a collapse design may include a breakable pin or similar which, when subjected to an excessive force or torque, collapses and prevents an applied torque, for instance by a screwdriver inserted into a cylinder plug, from being transferred into a rotation of a tailpiece connecting the lock to a door locking mechanism. The inventive concept provides a new and alternative way of protecting a lock assembly against forcible unlocking. In general, the inventive concept provides a solution for protecting mechanically weaker parts of the lock assembly The inventive concept may be combined with a collapse feature as will be described below, but may also be used in lock assemblies not having a collapse feature.

The inventive concept is designed to be used in a dual-cylinder lock assembly including a gear mechanism, and is especially useful for protecting the gear mechanism against damage in a situation where the lock assembly is forced or tampered with in an unauthorized fashion.

According to one aspect of the inventive concept, there is provided a dualcylinder lock assembly comprising: a housing; a first lock cylinder including a first cylinder body arranged in the housing, and a key-receiving first plug rotatably arranged within the first cylinder body and provided with a first lock mechanism arranged to interact with the first cylinder body; a second lock cylinder including a second cylinder body arranged in the housing, and a key-receiving second plug rotatably arranged in the second cylinder body and provided with a second lock mechanism arranged to interact with the second cylinder body; a gear mechanism drivingly connected to the first lock cylinder and the second lock cylinder such that a tailpiece may be operated by turning either the first plug or the second plug, said gear mechanism including a displaceable gear which is displaceable, in a direction transversely relative to a rotational axis of the displaceable gear, between a non-displaced normal position and at least one displaced position; and at least one brake member arranged to, in response to the displaceable gear being displaced into its displaced position, to interact with the displaceable gear to rotationally brake or rotationally lock the displaceable gear.

The displaceable gear may be arranged to be displaced into its at least one displaced position in response to a torque, in the following referred to as a “tampering torque”, being applied to the first plug or to the second plug when no appropriate key is present in either one of the first plug and the second plug, in an attempt to forcible unlock the lock assembly. The inventive concept has the technical effect of protecting mechanically weaker parts of the lock assembly, especially weaker part of the gear transmission. Such a weaker part may be a central part of a gear. As a result of the displaceable gear being displaced into its displaced position, in which the displaced gear is subjected to either a rotational lock or a brake force/torque by the at least one brake member, restricting rotation of the displaced gear, an applied tampering torque for forcibly unlocking the lock assembly is prevented from being transferred to and damage weaker parts of the assembly, especially rotationally locked and mechanically weaker parts of the gear transmission. The inventive solution has at the advantage of preventing mechanical failure of such weaker parts of the assembly, thereby preventing a forcible unlocking attempt from succeeding. The inventive solution has also the advantage of limiting the manufacturing costs of the lock assembly, especially since the inventive solution makes it possible to avoid the need for using very strong and expensive gears in the gear mechanism for preventing forcible unlocking.

Optional embodiments

The rotational axis of the displaceable gear may be arranged to be displaced together with the displaceable gear.

The at least one brake member may be arranged to interact directly with one or more teeth of the displaceable gear when the latter is displaced into in its at least one displaced position. As an alternative, the brake member may be arranged to interact indirectly with the displaceable gear, for instance by interacting with a rotating member which is mounted on the rotational axis of the displaceable gear and which is arranged to rotate together with the displaceable gear.

The brake member may be arranged to interact in different ways with the displaceable gear, but in general the brake member is arranged to take up at least part of a tampering torque transferred to or applied to the displaceable gear. In some embodiments, the brake member may be arranged to interact with the displaceable gear such that it provided provides a mechanical rotational lock of the displaceable gear, i.e. preventing any rotation of the displaced gear. In other embodiments, the brake member may be arranged to interact with the displaceable gear by applying a more conventional braking force or braking torque to the displaceable gear in order to take up at least part of the applied tampering toque. In some embodiments, the assembly may be designed such that the braking force or braking torque applied to the displaced gear is strong enough to substantially prevent any rotation of the displaced gear in its displaced position.

The brake member may be is located in the housing on one side of the rotational axis of the displaceable gear, for instance in the same plane as the displaceable gear.

Some embodiments may include a first and a second brake member arranged to interact with the displaceable gear depending on the rotational direction of the applied tampering torque. Such an embodiment may have the advantage of being mountable on door locking mechanism having either counterclockwise or clockwise unlocking.

When the displaceable gear is in its normal, non-displaced position, the brake member does not interact with the displaceable gear to provide a rotational lock or rotational brake. In preferred embodiments, the lock assembly further comprises at least one biasing member arranged to bias the at least one displaceable gear towards its normal position. Thereby, the brake member is prevented from interacting with the displaceable gear during normal operation of the lock assembly. It also ensures that the displaceable gear is reset to its normal, non-displaced position in case a tampering torque is removed.

The gear transmission may include at least a first gear and a second gear which are drivingly connected to each to rotate together, wherein the first gear is coupled to the first lock cylinder and the second gear is coupled to the second lock cylinder. The first gear and the second gear may be interconnected by a direct mesh engagement between the two gears, in which case they will rotate together but in opposite directions. The two gears may also be indirectly connected by a chain or the like to rotate together in the same direction.

In some embodiments, the lock assembly further comprises at least one intermediate gear arranged between and drivingly interconnecting a first gear and the second gear such that the first gear and the second gear rotate in the same direction and such that the first gear, the second gear and the intermediate gear rotate together. This embodiment may be an advantage in that the key rotational direction will be the same for both plugs for unlocking and locking, respectively. For example, if the door locking mechanism is designed to be unlocked by a counterclockwise rotation of the tailpiece, then the intermediate gear ensures that the lock assembly may be unlocked either by counterclockwise rotation of the first key or by counterclockwise rotation of the second key.

In such embodiments including at least one intermediate gear, said at least one intermediate gear may form the displaceable gear. As an illustrative, nonlimiting example, the first gear in such an embodiment may be the mechanically weakest part. A tempering torque applied to the second lock cylinder associated with the second gear may be transferred from the second gear to the intermediate gear. The first gear coupled to the first lock cylinder cannot be rotated due to the first lock cylinder being in its locked state. The intermediate gear is thereby subjected to, on the one hand, a tampering torque transferred from the second gear, and, on the other hand, a fixed engagement with the fixed non-rotatable first gear. As a result, the displaceable intermediate gear will be displaced from its normal position into its displaced position. In its displaced position, the displaced gear is prevented from transferring the tampering torque to the weaker first gear. Instead, the tampering torque is taken up entirely or partly by the brake member.

In some embodiments, the lock assembly may further comprise at least one breakable collapse member, which is arranged to break in response to a tampering torque being applied to one of the first plug and the second plug when no appropriate key is present in either one of the first plug and the second plug, during an attempt to forcible unlock the lock assembly. Such a collapse member may be arranged, if broken, to prevent rotation of any of the first or second plug from being transferred into a rotation of the tailpiece.

In such embodiments including a collapse member, the lock assembly may optionally further be structured such that the displaceable gear is displaced into its displaced position before the collapse member breaks. The displaceable gear may be arranged to be displaced into its displaced position in response to a tampering torque having an initial or lower first torque level, while the collapse member may be structured and arranged to brake in response to the tampering torque having a second higher torque level, higher than the first torque level.

The inventive concept may be implemented in different types of dual-cylinder lock assemblies. In an optional embodiment, the second cylinder body is a rotatable second cylinder body rotatably arranged in the housing, wherein the first plug and the rotatable cylinder body are drivingly interconnected by the gear transmission to rotate together. In such an optional embodiment, the first plug may be permanently, directly or indirectly, connected to the first gear. The first plug and the first gear may be arranged to rotate together about a first rotational axis. The rotatable second cylinder body may be permanently connected to the second gear. The rotatable second cylinder body and the second gear may be arranged to rotate together about a second rotational axis. The first cylinder body may be arranged in the housing such that the first cylinder body is prevented from rotating about a first rotational axis of the first plug. The first cylinder body may be completely fixedly arranged in the housing.

The inventive lock assembly is of dual-cylinder type, indicating that the lock assembly comprises at least two lock cylinders, each lock cylinder including at least a cylinder body and a key-receiving plug at least partly received in the cylinder body for rotation therein. Each plug is provided with an associated lock mechanism selectively interacting with the associated cylinder body in response to insertion of an appropriate key into the plug. The lock mechanism may be arranged partly in the plug and partly in the cylinder body.

In operation of the inventive lock assembly, a rotatable tailpiece (sometimes also referred to as a drive pin or a carrier) is driving ly connected to and operated by the second plug, optionally via a tailpiece adapter. In some embodiments, the second plug and the tailpiece are arranged to rotate together about the rotational axis of the second plug. In a final assembled state on a door, the tailpiece may extend out from a rear side of the lock assembly and into a door locking mechanism for operating a latch or bolt of a door locking mechanism. In some embodiments, the tailpiece may be directly connected to the second plug. In some embodiments, the tailpiece may be indirectly connected to the second plug via a tailpiece adapter. In some embodiments, the tailpiece may be coupled to a rear connecting member forming a rear part of the cylinder plug being axially movable in relation to a front part of the plug. In preferred embodiments.

When the lock assembly has been unlocked by an appropriate key, it can be operated to rotate the tailpiece between a locked rotational position and an unlocked rotational position for unlocking and locking the door locking mechanism. These rotational positions of the tailpiece correspond to a locked rotational position and an unlocked rotational position, respectively, of the second plug. In the inventive lock assembly, each plug is provided with a lock mechanism arranged to either restrict rotation of the plug in relation to its associated cylinder body when no appropriate key has been inserted, or to not restrict rotation of the plug in relation to its associated cylinder body in response to insertion of an appropriate key. In some embodiments, the lock mechanism of one plug or both plugs may be arranged to prevent essentially any rotation of the plug in relation to the associated cylinder body when no appropriate key has been inserted. In such embodiments, the lock mechanism of the plug may form a rotational lock, for instance implemented by a conventional mechanical solution including key operated tumblers, or an electrically operated lock pin or similar. However, the lock mechanism of one plug or both plugs may also be arranged to form a rotation restriction rather than a rotational lock between the plug and the associated cylinder body. In such embodiments, the lock mechanism of the plug may be arranged to restrict initial rotation of the plug in relation to the cylinder body to a few degrees only, insufficient to rotate the tailpiece its unlocked rotational position. After such an initial limited rotation of the plug, the lock mechanism operates as a rotational lock preventing any further rotation of the plug in relation to the cylinder body.

PCT/SE2021/050298 with the same applicant as the present application discloses an electronic lock in which an electromechanical plug can be rotated a few degrees only in relation to a cylinder body when no appropriate electronic key has been inserted, and which can be rotated to an unlocked rotational position only if an appropriate key has been inserted. If an inappropriate key is inserted, the key may be turned only a few degrees. An attempt to further turn the inappropriate key activates a rotational lock between the plug and the cylinder body, preventing any further relative rotation.

In some embodiments where at least one of the lock cylinders is electromechanical, the electronic key may be programmable. Such a programmable key, which is used to operate an electromechanical lock, may comprise an energy source, such as a battery, and a control unit powered by the energy source. The electronic key can access a cloud based or locally hosted access control system which transfer authorization data to the electric key and/or log information from the key via internet and a synchronization unit or via a mobile communication system such as the GSM net and a mobile device, such as a mobile phone. The electronic key is accessed from the synchronization unit or the mobile device by a physical contact, by near field communication, such as NFC, or by radio communication, such as Bluetooth. The electronic key can store all data necessary to access at least one specific electromechanical lock cylinder but cannot access any electromechanical lock cylinder for which it does not have the appropriate authorization data. Locking and unlocking using the programmable key is rendered possible only if the programmable key is synchronized appropriately via the synchronization unit or a mobile device. Further, such a programmable key may be provided with means by which electrical power, data and mechanical effort can be transmitted.

Terminology

The term lock plug or plug refers to a part into which a key is inserted and which the key turns. A mechanical lock plug may house the bottom pins of a pin tumbler cylinder mechanism or the discs and springs of a disc tumbler cylinder mechanism. An electromechanical or electronic lock plug may be provided with an electronically controlled lock mechanism.

The term “rotatably connected” as used in the present disclosure refers to a connection or coupling between two rotatable members structured and arranged such that a rotation of one member is transferred, directly or indirectly, into a rotation to the other member, and such that if the first member is prevented from rotating then the second member is also prevented from rotating.

The term appropriate key as used in the present disclosure refers to a key which allows, when inserted into a rotatable plug, to turn the plug.

The term tailpiece as used in the present disclosure refers to a member that extends from the rear of the housing. The rotation of the tailpiece is what mechanically actuates the door locking mechanism.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The inventive concept, some non-limiting embodiments, and further advantages of the inventive concept will now be described with reference to the drawings in which:

Fig. 1 is a perspective view of a first embodiment of a lock assembly. Fig. 2 is an exploded view of the first embodiment.

Fig. 3 schematically illustrates a locked state.

Figs 4A to 4D illustrate a first unlocking sequence.

Fig. 5A to 5C illustrate a second unlocking sequence.

Fig. 6A to 6C schematically illustrates the operation of a second embodiment of a lock assembly.

Fig. 7 is an exploded view of an electromechanical lock cylinder.

Fig. 8A to 8D illustrate the operation of the electromechanical lock cylinder in Fig. 7.

Fig. 9 is an exploded view of a third embodiment of a lock assembly.

Fig. 10A to 10E illustrate the brake function of the first embodiment.

Figs 11 A to 11 C illustrate the brake function of an alternative embodiment with two gears only.

The inventive concept will now for the purpose of exemplification be described in more detailed by means of examples and with reference to the accompanying drawings illustrating embodiments and non-limiting examples of the inventive concept. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The inventive concept is directed to what is termed “brake function” in the present disclosure. Since the inventive concept is implemented in a dual-cylinder lock assembly, a general description of certain embodiments of such a dual-cylinder lock assembly will first be presented, to give the reader an understanding of the overall structure and operation of such embodiments. Thereafter, the structure and operation of embodiments implementing a brake function will be described.

The description in connection with Figs 1 , 2, 3, 4A to 4D, and 5A to 5C aims to describe the structure and the operation of a first embodiment of a lock assembly according to the inventive concept.

Figs 1 and 2 illustrate a dual-cylinder lock assembly 1 according to a first embodiment. The lock assembly 1 is arranged to be connected via a tailpiece 2 to a door locking mechanism 3 in a door 4. The door locking mechanism 3 may be of any kind known in the art and may be is arranged in a lock housing in a cavity of the door 4. As is also well known in the art, the locking mechanism 3 cooperates, via a lock bolt or latch 5, with a striking plate (not shown) arranged in a door frame (not shown) to lock the door 4. The door locking mechanism 3 controls the lock bolt 5 via the lock assembly 1 from the exterior side of the door 4.

The dual-cylinder lock assembly 1 comprises an elongate housing 6 containing the various parts of the assembly. In the illustrated first embodiment, the housing 6 has an elongate and rather narrow shape arranged to be mounted at an entrance door 4 of an apartment building, and is arranged to support a handle 7. The handle 7 does not have to form part of the lock assembly 1 . Embodiments for mounting on a door of a private residence may have other shapes of the housing 6 and not including support for the handle 7.

The lock assembly 1 is of dual-cylinder type, including a first lock cylinder 10 and a second lock cylinder 20. In the present disclosure, a lock cylinder comprises at least a cylinder body and a key-receiving plug rotatably received in the cylinder body. A lock mechanism is arranged to selectively interact with the cylinder body to selectively restrict rotation of the plug in relation to the cylinder body. The lock mechanism may be entirely or partly arranged in the plug and/or the cylinder body. Accordingly, in the illustrated first embodiment, the first lock cylinder 10 comprises a first cylinder body 11 and a first plug 12 arranged to receive an appropriate first key K1 (Fig. 4A), and the second lock cylinder 20 comprises a second cylinder body 21 and a second plug 22 arranged to receive an appropriate second key K2 (Fig. 5A). The door locking mechanism 3 may be unlocked or locked by using either key K1 or K2.

Each one of the first and the second lock cylinders 10 and 20 may be either a mechanical lock cylinder or an electromechanical lock cylinder. Thus, the two lock cylinders 10 and 22 may be of the same type or of different types. In the illustrated first embodiment, the first lock cylinder 10 is mechanical and is arranged to be operated by an appropriate mechanical first key K1 , while the second lock cylinder is electromechanical and is arranged to be operated by an appropriate electronic second key K2. As is known per se in the art, the mechanical cylinder lock 10 may be operated for instance by a resident’s mechanical key K1 , while the electromechanical lock cylinder 20 may be operated by an electronic service personnel key K2, especially a programmable electronic key programmed to operate the second plug 22 of a plurality of lock assemblies.

In use, the lock assembly 1 is operatively connected to the door locking mechanism 3 via the tailpiece 2 to unlock and lock the door locking mechanism 3. The tailpiece 2 may be of different length, and in some embodiments it may be adjustable in length for adaptation to different door dimensions. As an example, the tailpiece may be telescopic. As shown in Fig. 2, the illustrated first embodiment also uses a separate tailpiece adapter 2a for connecting the lock assembly 1 to the tailpiece 2. The tailpiece 2 or the tailpiece adapter 2a may or may not be considered as forming part of the lock assembly 1 .

For unlocking and locking of the door locking mechanism 3, the tailpiece 2 is rotatable between a locked rotational position and an unlocked rotational position, for instance a rotational movement of about 90 degrees. This rotation is accomplished in response to turning the appropriate first key K1 or turning the appropriate the second key K2. In preferred embodiments of the invention, the tailpiece 2 is rotated directly in response to turning of the first key K1 or the second key K2, i.e. with no rotational lag between the key turning and the tailpiece rotation. In preferred embodiments, there is a 1 :1 rotational relation between the key turning and the tailpiece rotation, i.e. the tailpiece 2 is rotated the same number of degrees as the key.

Only a single tailpiece 2 is used to operate the door locking mechanism 3 of the door 4. In this embodiment, the single tailpiece 2 is operated by the second plug 22. In other embodiments, the tailpiece may be operated by the first plug 12. The tailpiece 2 may be directly connected to the second plug 22, or indirectly connected to the second plug 22 as in the first embodiment using a tailpiece adapter 2a. The second plug 22 and the tailpiece 2 are arranged to rotate together about a common second rotational axis A2. From a functional perspective, the connection between the second plug 22 and the tailpiece 2 means that if the second plug 22 is prevented from rotating, then as a consequence the tailpiece 2 cannot be rotated and the door locking mechanism 3 cannot be unlocked. Also, as a consequence of the tailpiece 2 being operated by the second plug 22, any unlocking or locking of the door locking mechanism 3 will involve rotation of the second plug 22, not only when using an appropriate second key K2 but also when using an appropriate first key K1 as will be described in detail below.

In the first embodiment, the electromechanical second lock cylinder 20 is designed in accordance with applicant’s international application PCT/SE2021/050298, filed 1 April 2021 , the contents of which is hereby incorporated by reference. Other electromechanical designs may also be used. A specific functional feature of the electromechanical lock cylinder 20 designed according to applicant’s PCT application mentioned above is that the rotatable second plug 22 is actually not in a rotationally locked state in relation to the second cylinder body 21 when no key has been inserted into the second plug 22. Instead, the illustrated electromechanical lock cylinder 20 is designed so that the lock mechanism of the second plug 22, when an inappropriate second key K2, or some tool such as a screwdriver, is inserted and initially turned, will allow only a very limited rotation of the second plug 22 in the order of few degrees (e.g. 2-4 degrees) before the locking mechanism of the second plug 22 effectively prevents further rotation of the second plug 22 in relation to the second cylinder body 21 . On the other hand, if an appropriate electronic second key K2 is inserted into the electromechanical second plug 22, the appropriate electronic second key K2 will activate the locking mechanism of the second plug 22 to allow rotation of the second plug 22 in relation to the second cylinder body 21 between its locked rotational position and its unlocked rotational position. It should be noted that this specific design of the electromechanical second lock cylinder 20 is not essential to the inventive concept, and the inventive principle may be implemented with electromechanical lock cylinders arranged to form a complete rotational lock when no appropriate key has been inserted.

The electromechanical second lock cylinder 20 may be configured to be powered by and communicate a programmable electronic second key K2 upon the insertion of the electronic second key K2 in the second plug 22. To this end, the second electromechanical lock cylinder 20 may comprise power receiving means, communication means and an electrical control unit (all not shown). The electromechanical second lock cylinder 20 may further comprise an access control device (not shown) for controlling access of an inserted electronic key K2. Further details regarding the structure and the operation of this specific electromechanical cylinder lock 20 will be provided later in the description with reference to Fig. 7 and Figs 8A to 8D.

In other embodiments of the lock assembly 1 including one or two electromechanical cylinder locks, such locks may have a different design, for instance a design where the lock mechanism of the electromechanical second plug 20 is provided by at least one selectively movable lock pin, which in the locked state of the electromechanical cylinder lock provides a complete rotational lock between the plug and the cylinder body. For illustration purposes only, in the schematic figures (see Fig. 3 and Fig. 4D) illustrating the operation of the lock assembly 1 , the electromechanical second cylinder lock 20 is shown as comprising such a selectively movable lock pin 23.

Each one of the first plug 12 and the second plug 22 is provided with a locking mechanism arranged to either restrict rotation of the plug in relation to its associated cylinder body when no appropriate key has been inserted, or to not restrict rotation of the plug in relation to its associated cylinder body in response to insertion of an appropriate key. The term “restrict rotation” covers embodiments where the lock mechanism of a plug is arranged to prevent any rotation of the plug in relation to its associated cylinder body when no appropriate key has been inserted. In such embodiments, the lock mechanism of the plug is arranged, when no appropriate key has been inserted, to restrict rotation by forming a complete rotational lock where no plug rotation is possible in relation to the associated cylinder body. This is the case for the mechanical first lock cylinder 10 in the illustrated embodiment where tumblers 13 create such a rotational lock unless the appropriate mechanical first key K1 is inserted.

However, the term “restrict rotation” also covers embodiments where the lock mechanism of a plug is arranged to form a rotation restriction rather than an initial complete rotational lock between the plug and the associated cylinder body. Also, such a restriction may be activated first when someone tries to turn the plug without having an appropriate key inserted. Put in other words, in some embodiments, the plug of a cylinder lock, especially an electromechanical cylinder lock, may actually be non-locked in the absence of an appropriate key, but becomes rotationally locked in response to the plug being initially turned by inappropriate means. Applicant’s above-mentioned PCT application discloses an electronic lock in which an electromechanical plug can be initially rotated a few degrees in relation to a cylinder body when no appropriate electronic key has been inserted, and which can be rotated freely to an unlocked rotational position only if an appropriate key has been inserted. If an inappropriate key is inserted, the key may be initially turned a few degrees only, insufficient to turn the tailpiece to its unlocked rotational position. Any attempt to further turn the inappropriate key beyond such few degrees brings the lock mechanism of the plug to activate a complete rotational lock between the plug and the cylinder body, preventing any further relative rotation. The first cylinder body 11 is arranged in the housing 10 such that it is prevented from rotating about the first rotational axis A1 of the first plug 11 . Other movements of the first cylinder body may be possible in certain embodiments. In the illustrated first embodiment of the lock assembly 1 , the first cylinder body 11 is fixedly arranged within the housing 6 in a first opening 51 with a shape corresponding to the shape of the first cylinder body 11 . In contrast and for reasons that will become apparent in the following, the second cylinder body 21 is rotatably arranged within the housing 10 for rotation about the second rotational axis A2 of the second plug 22. In the illustrated embodiment, the housing 6 is provided with a cylindrical second opening 52 in which the second cylinder body 22 is rotatably received.

In the present disclosure, the expression “arranged within the housing 10” also covers embodiments where a lock cylinder 10, 20 is only partly received within the housing 6. A lock cylinder 10, 20 may be insertable into and retractable from the housing 6 as a separate unit during installation, which especially allows an existing mechanical lock cylinder to be reused during installation of a dual-cylinder lock assembly 1 according to the invention. As is known in the art, suitable means may be provided to prevent the cylinder bodies 11 and 21 from being retracted from the housing 6.

As shown in the figures, first cylinder body 11 may have a non-cylindrical elongate and general oval shape and is received in the correspondingly shaped cavity 51 in the housing 10, thus preventing rotation of the first cylinder body 11 about the first rotational axis A1 relative to the housing 10. In preferred embodiments as shown in the figures, the rotatable second cylinder body 21 may have a general shape of a cylinder or cylindrical sleeve, rotatably received in the correspondingly shaped cylindrical cavity 52 of the housing 6, thereby allowing the second cylinder body 21 to be rotatably supported by the housing 6.

The inventive concept may be implemented by other shapes of the second cylinder body 21 . Especially, the inventive brake functionality may be implemented in dual-cylinder lock assemblies having two non-rotatable, fixed cylinder bodies.

It may be noted that in the illustrated embodiment there is no direct locking mechanism between the rotatable second cylinder body 21 and the housing 6. The rotatability of the rotatable second cylinder body 21 in relation to the housing 6 is controlled by other means as will be described below. The lock assembly 1 further comprises a first gear 14 connected to the first plug 12 so that the first gear 14 rotates with the first plug 12. In the illustrated embodiment, the first gear 14 is permanently and directly connected to the first plug 12, and arranged to rotate together with the first plug 12 about the first rotational axis A1 , parallel and spaced from the second rotational axis A2 of the second cylinder lock 20.

In the illustrated embodiment presented as an example only, the rotational or operative connection between the first plug 12 and the first gear 14 is accomplished by a cross-shaped end portion 15 of the first plug 12 (see Fig. 4B) received in a corresponding cross-shaped central opening 16 of the first gear 14. In alternative embodiments, the first gear 14 may be drivingly connected to the first plug 11 in other way and by other shapes of the members 15,16, for instance indirectly connected. Also, it would be possible to form the first plug 11 and the first gear 14 as a one-piece, integrally formed member.

The lock assembly 1 further comprises a second gear 24 connected to the rotatable second cylinder body 21. It may be noted that the second gear 24 is not directly coupled to the second plug 22, but instead connected to the rotatable second cylinder body 21 . The second gear 24 and the second cylinder body 21 are arranged to rotate together about the second rotational axis A2. From a functional perspective, they may be considered as forming a single rotatable part.

In the first embodiment, the second gear 24 is permanently and directly connected to the second cylinder body 21 , and is arranged to rotate together with the second cylinder body 21 about the second rotational axis A2. In the illustrated first embodiment presented as an example only, the rotational or operative connection between the rotatable second cylinder body 21 and the second gear 24 is accomplished by a non-cylindrical end portion 25 (see Fig. 2) of the second plug 22 being received in a corresponding non-cylindrical central opening 26 of the second gear 24.

The purpose using a gear transmission in the lock assembly 1 , including at least the first gear 14 and the second gear 24, is to provide an operative or rotatable connection between the first plug 12 and the rotatable second cylinder body 21 . The first plug 12 and the second cylinder body 21 are connected to each other via a gear transmission which includes at least the first gear 14 and the second gear 24 and which is arranged such that the first plug 12 and the rotatable second cylinder body 21 either rotate together or stand still together.

In some embodiments, the gear transmission may include the first and second gears 14, 24 only, wherein the two gears 14, 24 are in direct meshed engagement with each other during all operation of the lock assembly 1 . Such an alternative embodiment is shown in Fig. 10. In such an alternative embodiment, the two gears 14, 24 rotate in opposite directions. However, it may be an advantage especially for a user if the first plug 12 and the second plug 22 are rotated in the same rotational direction (normally counter-clockwise) when unlocking the door 4, and rotated in the same rotational direction (normally clockwise) when locking the door 4. In alternative embodiments, this could have been accomplished by a chain or the like between the first gear 14 and the second gear 24. However, in the illustrated first embodiment, the gear transmission further includes an intermediate third gear 34, which is drivingly arranged between the first gear 14 and the second gear 24. The main purpose of the third gear 34 is to ensure that the first gear 14 and the second gear 24 rotate together in the same rotational direction, which in its turn ensures that the user can unlock the door 4 by turning either the first key K1 or the second key K2 in the same rotational direction. Fig. 11 illustrates an alternative embodiment including two intermediate gears 34a, 34b. The operation is essentially the same.

In the first embodiment, the three gears 14, 24, and 34 are located in a common vertical plane. The third gear 34 is in meshed engagement with both the first gear 14 and the second gear 24. In the first embodiment, the third gear is in permanent meshed engagement with both the first gear 14 and the second gear 24 during all normal states of the lock assembly 1 . This is an advantage compared to certain prior art solutions in which the operation relies on selective gear coupling and decoupling.

Referring to Fig. 2 and 4A, a cover member 53 is secured by four screws (not shown) to the rear side of the housing 6 for covering the gears 14, 24, 34 and for keeping the gears in correct axial position. Two screws 54 extend through corresponding openings 55 in the cover member 53 and are in engagement with the first cylinder body 11 to prevent the first lock cylinder 10 from being retracted from the housing 6. The cover member 53 is further provided with a first opening 56 coaxial with the first rotational axis A1 , and a second opening 57 coaxial with the second rotational axis A2. The second opening 57 allows the tailpiece 2 to be connected to the second plug 22 via the tailpiece adapter 2a.

The first embodiment shown in Fig. 2 also includes a brake structure at reference numerals 90-94, and 98a, 98b. The structure and the operation of these parts will be described later.

In the illustrated first embodiment, the first gear 14 is partly received in the first opening 56 of the cover member 53. The first opening 56 may act as a rotational control or bearing for the first gear 14. The second opening 57 may act as a rotational control or bearing for the second gear 24.

In the first embodiment, the number of teeth of the first gear 14 is equal to the number of teeth of the second gear 24, resulting in that a certain angular rotation of the first plug 12 by the first key K1 is translated into the same angular rotation of the tailpiece 2. Furthermore, the number of teeth of the intermediate third gear 34 is less than the number of teeth of the first gear 14 and the second gear 24. Its diameter is also smaller. This allows a reduced overall dimension of the lock assembly 1 , and it also allows the two lock cylinder 10, 20 to be located closer to each other. The gears 14, 24, and 34 are preferably made from metal, such as steel.

It will be appreciated that there is a sequential and permanent rotational connection present between the following five parts and in named order: the first plug 12 - the first gear 14 - the intermediate third gear 34 - the second gear 24 - the rotatable second cylinder body 21 . This rotational connection between these five parts ensures that they either all rotate together, or that they all do not rotate. Especially, if one of these five parts is prevented from rotating, rotation of the other four parts is also prevented as a consequence. This is especially the case when no appropriate first key K1 has been inserted into the first plug 12, preventing the first plug 12 from rotating and, consequently, preventing the other four parts from rotating.

Operation of first embodiment

The general unlocking and locking operation of the first embodiment will now be described. Further down, the brake operation will be described. The details of the operation of the electromechanical lock mechanism of the second lock cylinder 20 will not be provided at this time since the understanding of such details is not needed for the understanding of the overall inventive concept.

In general, the illustrated dual-cylinder lock assembly 1 has three operational states: a locked state when the lock mechanism 3 of the door 4 cannot be unlocked; a first unlocked state where the lock mechanism 3 of the door 4 can be operated using an appropriate first key K1 ; and a second unlocked state where the lock mechanism 3 of the door 4 can be operated using an appropriate second key K2. The general description of the operation of the first embodiment applies to all other embodiments. Thus, what is stated in the description of the first embodiment in terms of structure and operation applies also to embodiments where both lock cylinders are mechanical, and where both lock cylinders are electromechanical.

Locked state

Fig. 3 is provided to give a better understanding of the locked state. Fig. 3 schematically illustrates the various parts. In all schematical figures, parts that are prevented from rotating are marked with an x inside a circle. In the locked state in Fig. 3, all parts are marked as being prevented from rotating. In order to simplify the schematical illustration in Fig. 3, the second lock mechanism of the second plug 22 is not shown in accordance with the more advanced design in Fig. 7, but is instead schematically illustrated as a movable lock pin 23, which can be selectively moved into and out of engagement with the rotatable second cylinder body 21 in response to insertion of an appropriate electronic second key K2. In Fig. 3, the lock pin 23 is in its locked position. Movement of the lock pin 26 can be accomplished in any suitable electromechanical way, such as by using solenoids.

The locked state is present when no appropriate key K1 or K2 has been inserted into the lock assembly 1 . The locked state may be present when no key has been inserted at all, or if only a non-appropriate key has been inserted. In the locked state, neither the first lock mechanism of the first plug 12, nor the second lock mechanism of the second plug 22 has been activated by an appropriate key. In the locked state, relative rotation between each plug 12, 22 and its associated cylinder body 11 , 21 is restricted by the lock mechanism of the plug.

A specific feature of the inventive concept is that, in the locked state of the lock assembly 1 , the second plug 22 is prevented from rotating to its unlocked rotational position by “using” or “borrowing” the rotation-restricted state of the first plug 12: in the locked state, the second plug 22 is prevented from rotating to its unlocked rotational position as a consequence of the first lock mechanism 13 of the first plug 12 is restricting rotation of the first plug 12 in relation to the stationary first cylinder body 11. As a result, rotation of the entire gear transmission 14, 24, 34 is also restricted. This in its turn also restricts rotation of the rotatable second cylinder body 21 which is drivingly connected to the second gear 24. Finally, since the second lock mechanism 23 of the second plug 22 in the locked state of the lock assembly 1 has not been activated and thus restricts rotation of the second plug 22 in relation to the second cylinder body 21 , rotation of the second plug 22 is also restricted and it cannot be rotated to its unlocked rotational position. As a final consequence, the tailpiece 2 is prevented from being rotated to its unlocked rotational position in the locked state of the lock assembly 1.

1 ^st unlocked state

Figs 4A to 4D illustrates the first unlocked state of the lock assembly 1 starting from the situation in Fig. 4A where the assembly is still in its locked state. In Fig. 4B, an appropriate first key K1 has been inserted into the first plug 12 and no appropriate electronic second key K2 has been inserted into the second plug 22. The assembly 1 is now in its first unlocked state. As shown in Fig 4C and 4D, in response to turning the appropriate mechanical first key K1 , the tailpiece 2 can be rotated from its locked rotational position to its unlocked rotational position for unlocking the door locking mechanism 3. As an example, this may be a rotational movement counterclockwise over an angle of about 90 degrees.

When the first key K1 is inserted, the mechanical first lock mechanism 13 of the mechanical first plug 12 is operated by the appropriate mechanical first key K1 to no longer restrict rotation of the first plug 12 in relation to the stationary first cylinder body 11 . In the first unlocked state, the second lock mechanism 23 of the second plug 22 is not operated or activated by any appropriate second key K2 and, thereby, is arranged to restrict rotation of the second plug 22 in relation to the rotatable second cylinder body 21 . This is illustrated schematically by the lock pin 23 in Fig. 4D. Now, since the above-mentioned five interconnected components (the first plug 12, the first gear 14, the third gear 34, the second gear 24, and the second cylinder body 21 ) are all drivingly interconnected to each other, turning the appropriate first key K1 in relation to the first cylinder body 11 will result in a rotation of the components in the following order: the first plug 12 the first gear the third gear 34 the second gear 24 the second cylinder body 21 (via the second lock mechanism 23 of second plug 22) the second plug 22 the pintail 2.

It may be noted that the second locking mechanism (represented by the lock pin 23 in Fig. 4D) of the second plug 22, in the absence of an inserted appropriate second key K2, is not used to prevent the second plug 22 from rotating. Instead, the non-activated second lock mechanism 23 of the second plug 22 is here used to actually transfer rotation to the second plug 22 to make it rotate. It may also be noted that both the first plug 12 and the second plug 22 rotate when the lock assembly 1 is operated in its first unlocked state. In addition, it may be noted that the gear transmission 14, 24, 34 and the rotatability of the second cylinder body 21 is used when operating the lock assembly 1 in its first unlocked state to transfer rotation of the first plug 12 into a rotation of the second plug 22. It will be appreciated that the gear transmission 14, 24, 34 has in fact at least the following two functions:

First function of the gear transmission: in the locked state of the lock assembly 1 , the gear transmission 14, 24, 34 operates to transfer the rotational locked state of the first plug 12 into a rotationally locked state of the rotatable second cylinder body 21 , ensuring that the second plug 22 and the tailpiece 2 cannot be rotated.

Second function of the gear transmission: In the first unlocked state of the lock assembly 1 , the gear transmission 14, 24, 34 instead operates to transfer the turning of the first key K1 and the rotation of the first plug 12 into a rotation of the rotatable second cylinder body 21 , with the result that also the second plug 22 and the tailpiece 2 are rotated since relative rotation between the second plug 22 and the second cylinder body 21 is restricted in the first unlocked state by the second lock mechanism (represented by the lock pin 23) of the second plug 22. 2 ^nd unlocked state

Figs 5A to 5C illustrate the second unlocked state of the lock assembly 1 . An appropriate electronic second key K2 has been inserted into the second plug 22 and no appropriate mechanical first key K1 has been inserted into the first plug 12. In response to turning the appropriate electronic second key K2 in the second unlocked state, the tailpiece 2 can be rotated to its unlocked rotational position for unlocking the door locking mechanism 3. In the second unlocked state of the lock assembly 1 , the second lock mechanism 23 of the second plug 22 is activated by the appropriate second key K2 to not restrict rotation of the second plug 22 in relation to the second cylinder body 21. In this second unlocked state of the lock assembly 1 , the second plug 22 is thereby drivingly disconnected from the five interconnected components “first housing 10 - first plug 12 - first gear 14 third gear 34 - second gear 24 - second cylinder body 21”, and can be rotated in relation to the second cylinder body 21 for rotating the tailpiece 2 to its unlocked rotational position. It may be noted that the second plug 22 thus rotates both when the lock assembly 1 is operated in its first unlocked state by the appropriate first key K1 and when the lock assembly 1 is operated in its second unlocked state by the appropriate second key K2.

2 ^nd embodiment

Figs 6A to 6C schematically illustrate the structure and operation of a second embodiment in which both lock cylinders are mechanical. The general operation of this embodiment is essentially the same as for the first embodiment.

Electronic plug

The details of the more advanced design of the electromechanical second cylinder lock 20 will now be described with reference to Fig. 7 and Figs 8A to 8D. The embodiment of the lock cylinder 20 in Fig. 7 differs in one aspect from the embodiment shown in the previous figures, in that the second cylinder body 21 shown in Fig. 7 is not cylindrical, but rather of the same oval elongate shape as the mechanical first cylinder lock 10. However, the operation is essentially the same, and for functional aspects involving rotation of the second cylinder body 21 the latter can just be imagined as cylindrical and rotatably mounted, as illustrated in for example Fig. 2 and Fig. 4A illustrating a cylindrical second cylinder body 21 . If the first cylinder lock 10 is instead of electromechanical type, the design of the cylinder body 21 shown in Fig. 7 may be used.

The second lock cylinder 20 includes, going from the left to the right in the exploded view in Fig. 7, the following components: the second plug 22, a blocking member 100, a biasing member 101 in the form of a spring, a rotatable and slidable annular member 102, an electromechanical coupling device 103, a connecting member 104, the second cylinder body 21 , and the tailpiece adapter 2a.

The blocking member 100 is fixedly arranged in the cylinder body 21 , and is especially prevented from rotating in relation to the cylinder body 21. To this end, the blocking member 100 is provided with a peripheral groove 105 arranged to receive a locking pin (not shown) to engage the cylinder body 21 . The rear side of the blocking member 100 is provided with a tooth-shaped blocking surface 100b the purpose of which is to prevent the annular member 102 from rotating in certain states of the cylinder lock 20.

The annular member 102 is rotatably mounted on the second plug 22 for rotation about the second rotational axis A2 in relation to the plug 22. The annular member 102 is also mounted for axial displacement relative to the second plug 22 along the second rotational axis A2. The annular member 102 can be rotationally locked relative to the second plug 22 by inserting an appropriate key K2. If instead an inappropriate key is inserted and turned, the annular member 102 will rotate and/or axially move relative to the second plug 22 as described below. The front side of the annular member 102 is provided with a tooth-shaped blocking surface 102a corresponding to the tooth-shaped blocking surface 100b of the locking member 100. The rear side of the annular member 102 is provided with a waveshaped engagement surface 102b.

The biasing member 101 , here in the form of a spring, is arranged between the blocking member 100 and the annular member 102 to bias the annular member 102 away from contacting the blocking member 100 and into engagement with the connecting member 104.

The electromechanical coupling device 103 is received in and rotated together with the plug 22. The coupling device 103 is arranged to, upon insertion of an appropriate key K2, to rotationally couple the annular member 102 to the plug 22. This mechanical locking is indicated by a dotted arrow in Fig. 7. The rotational lock is accomplished by a selectively movable locking pin at 105 (which should not be confused with the schematical lock pin 23 in Fig. 3) of the electromechanical coupling member 103 engaging an opening 106 in the annular member 102. To this end, the coupling member 103 may comprise an actuator configured to communicate with an access control device (not shown). The electromechanical coupling member 103 is thus arranged, upon the insertion of an appropriate electronic second key K2, to rotationally lock the annular member 102 to the plug 22. As will be described below, this will prevent the cylinder lock 20 from being locked upon turning the key K2.

The front side of the connecting member 104 is provided with a wave-shaped engagement surface 104a, arranged to interact with the wave-shaped engagement surface 102b of the annular member 102. The rear side of the connecting member 104 is rotationally connected to the tailpiece adapter 2a. The connecting member 104 is further provided with side openings 104c arranged to receive a break pin 120 shown in Fig. 8B.

The purpose of the connecting member 104 is to rotationally connect the plug 22 to the tailpiece adapter 2a. To this end, the connecting member 104 is rotationally secured to the plug 22 by means of a locking arrangement 110, 112 (Fig. 8A) which is arranged to rotationally secure the plug 22 to the connecting member 104 in an absence of an axial movement of the annular member 102, and to rotationally unsecure the connecting member 104 from the plug 22 upon a rotation of the plug 22 relative to the annular member 102 when the annular member 102 is in engagement with the stationary blocking member 100.

The general operation of the electromechanical cylinder lock 20 in Fig. 7 will now be described with reference to Figs 8A to 8D.

In a resting state of the cylinder lock 20 with no key inserted, the spring 101 holds the annular member 102 biased to the right in Fig. 8C against the connecting member 104. In this position, there is a full engagement between the two wave shaped engagement surfaces 102b and 104a. In this resting state of the cylinder lock 20, there is also a rotational connection between the rear end of the plug 22 at 110 and the front end of the connecting member 104 at 112, i.e. a rotational connection between the plug 22 and the tailpiece adapter 2a.

In response to insertion of an appropriate key K2, the electromechanical coupling device 103 will activate to form a rotational lock between the plug 22 and the annular member 102 at 105/106. As a consequence, a subsequent turning of the inserted appropriate second key K2 will rotate the annular member 102 together with the plug 22. As a result, the plug 22, the annular member 102, the connecting member 104, and the tailpiece adapter 2a will all rotate together, whereby the door locking mechanism 3 may be opened. It may be noted that the plug 22 was actually not rotatably locked before the second key K2 was inserted, and that the second key 2 actually did not unlock any rotational lock. Instead, the appropriate second key activated the coupling member 103 to prevent the lock cylinder 20 from being locked upon key turning.

Fig. 8D illustrates the operation if an inappropriate key is inserted and turned. Since the key is not an appropriate key, the electromechanical coupling device 103 will not be activated. Therefore, no rotational lock will be formed between the plug 22 and the annular member 102 at 105/106. In this state, the annular member 102 is rotatable in relation to the plug 22. On the other hand, the annular member 102 is subjected to a force holding it in a rotational position in relation to the cylinder body 21. To this end, the annular member 102 is provided with an axial engagement groove 102c (Fig. 7). A spring loaded engagement element (not shown) arranged in the cylinder body 21 is in engagement with the axial engagement groove 104c of the annular member 104, thereby preventing rotation of the annular body 104 in this state. This engagement at groove 104c is disengaged when the plug 22 and the annular member 102 is rotated by an appropriate key K2.

An initial turning of the inappropriate key, in the order of a few degrees only, the following will take place: Turning of the inappropriate key results in a slight rotation of the plug 22 and thereby the connecting member 104. Since the annular member 102 is not forced to rotate together with the plug 22 and is held in a nonrotating state by the engagement at groove 104c, the wave-shaped engagement at engagement surfaces 102b and 104a will make the annular member 104 move to the left in Fig. 8D into blocking contact with the blocking member 100 at the blocking surfaces 100b and 102a. The annular member 102 is now completely rotationally blocked and also cannot move any further axially to the left. Since the annular member 102 cannot be rotated, a continued rotation of the plug 22 will make the connecting member 104 move away from the plug 22 to the right, due to the engagement at the wave shaped engagement surfaces 102b and 104a. As a result, the rotational connection at 110/112 between the plug 22 and the connecting member 104 is disconnected, and the tailpiece adapter 2a can no longer be operated.

The design shown in Fig. 7 further comprise an additional collapse feature here implemented by a break pin 120. It may here be noted that the inventive concept of the brake function may be implemented with or without also having a collapse functionality. If combined with a collapse functionality, the collapse mechanism may be designed in other ways than what shown in Fig. 7.

As described above, the plug 22 and the connecting member 104 are normally rotationally connected at 110/112 by complementary shaped parts arranged to transfer rotational forces. However, the connecting member 104 may also be connected to the plug 22 via a break pin 120. The break pin 120 is located in a through-going opening in the end portion of the plug 22 as shown to the left in Fig. 8A. End portions of the break pin 120 are located in the side openings 104c of the connecting member 104. During normal unlocking of the cylinder lock 20, the rotational forces applied to the plug 22 are transferred to the connecting member 104 at the rotational connection at 110/120 with no rotational forces acting on the break pin 120. However, in the situation described above with a continued turning of an inappropriate key, the connection member 104 will be axially separated from the annular member 102. As a result, the break pin 120 will break and the lock cylinder 20 has to be repaired before being possible to unlock. It will be appreciated that the break pin 120 is accordingly not designed to take up rotational forces during normal unlocking, but design to brake if subjected to strong enough axial forces.

The electromechanical lock cylinder 20 shown in the first embodiment is of the design now described with reference to Fig. 7 and Figs. 8A to 8D. the operation of the lock cylinder 20 is special in the first unlocked state of the lock assembly 1 , as now will be explained. It will first be recalled that the blocking member 105 is rotationally locked to the housing body. Thus, referring to Fig. 2, the blocking member 105 is rotationally locked to the rotatable and sleeve-shaped second cylinder body 22. Accordingly, when the second cylinder body 22 is rotated in the first unlocked state by turning the first appropriate key K1 , then also the blocking member 105 will be rotated. It will also be recalled that the annular member 102 is held in rotational position in relation to the second housing body 21 by mean of spring loaded engagement members engaging the axial engagement groove 102c of the annular member. Furthermore, it will be recalled that the second plug 22 is not activated by a second key K2 in the first unlocked state. Accordingly, in the first unlocked state, the annular member 102 is not rotationally locked to the second plug 22 at 105, 106.

With these facts in mind, it will be appreciated that the following will occur when the first key K1 is turned in the first unlocked state of the lock assembly 1 . The key turning is transferred via the gear transmission into a rotation of the rotatable second cylinder body 21 . This rotation, in its turn, is transferred into a rotation of the annular member 102 due to the engagement at the engagement groove 102c. At this situation, there is an engagement at the wave-shaped engagement surfaces 102b and 104a. Depending on the friction of the door locking mechanism 3 (low or high) the following will occur.

If the friction of the door locking mechanism 3 is relatively low, the engagement at the engagement groove 102c will be sufficiently strong to rotate the connecting member 104 and thereby the tailpiece 2 for unlocking the door locking mechanism 3.

If, on the other hand, the friction of the door locking mechanism 3 is relatively high, the connecting member 104 will initially not rotate due to the frictional-induced rotational resistance from the tailpiece 2. A continued turning of the first key K1 will therefore now instead cause the annular member 102 to move axially away from the connecting member 104 into blocking engagement with the blocking member 100. It may be noted that the rotational connection between the plug 22 and the connection member 104 at 110, 112 is still intact. However, the blocking member 100 is fixed to and rotates together with the rotating second cylinder body 21. Therefore, the second cylinder body 21 and the annular member 102 will rotate together. As a consequence, due to the engagement between the wave-shaped engagement surfaces 102b and 104a the rotating annular member 102 will cause the connecting member 104 to rotate. The situation is now as illustrated in Fig. 8D. Thus, as a final result, the turning of the first key K1 and the first plug 12 is transferred into a rotation of the first plug 22 and the tailpiece 2 for unlocking the door locking mechanism 2. A specific feature of this unlocking sequence is that the blocking member 100 is actually used to cause the tailpiece 2 to rotate 3rd embodiment

Fig. 9 illustrates an embodiment with two electromechanical lock cylinders 10, 20, both of the design and operation as described in connection with Fig. 7 and Figs 8A to 8D.

Brake function

Reference is now made to Figs. 10A to 10E, illustrating the structure and the operation of an embodiment of the inventive brake functionality, here implemented in the first embodiment shown in Figs 1 , 2, 3, 4A-4D, and 5A to 5C.

The brake function is designed to restrict rotation of at least a part of the gear transmission, such as rotationally brake or rotationally block part of the gear transmission, in case someone tries to unlock the lock assembly 1 by inserting an inappropriate key or some tool, such as a screwdriver, and applying an excessive torque to the second plug.

For illustration purposes and for presenting an example of an advantage of using the inventive brake function, reference is first made to Fig. 3, which schematically illustrates the locked state of the lock assembly 1. For illustration purposes only, it may be assumed that the most critical part of the assembly 1 in terms of mechanical strength is the mechanical connection between the first plug 12 and the first gear 14, at reference numerals 15 and 16. More specifically, it may be assumed for illustration purposes only that the weakest part will be at the center of the first gear 14 at its opening 16. If a tool T (Figs 12C and 12D) such as a screwdriver is inserted into the second plug 22 during an attempted burglary, and an excessive torque (tampering torque) is applied to the second plug 22 by the tool T, this tampering torque will be transferred to the rotationally locked first plug 21 via the second cylinder body 21 and the gears 24, 34, 14. Since the first plug 21 is rotationally locked, the gear mechanism will be subjected to the excessive tampering torque. Such an excessive tampering torque may - without the use of the inventive brake function - result in that the center of the first gear 14 will mechanically break at reference 16, drivingly disconnecting the first gear 14 completely from the first plug 12. In such a break condition, the second plug 22 and the tailpiece 2 can be rotated freely by the tool T, thereby unlocking the door locking mechanism 3. As described above in connection with Fig. 7 and Fig. 8A to 8D, the illustrated design of the electromechanical second lock cylinder 20 in the shown embodiment is provided with a collapse member in the form of a break pin 120. As described above, the break pin 120 will break if the second plug 22 is subjected to an excessive axial force applied by inappropriate means, thereby disconnecting the tailpiece 2 from the second plug 22.

As a non-limiting example only, the weak connection at 15, 16 between the first plug 11 and the first gear 14 may brake if an inappropriate tampering torque in the order of 7 Nm or higher is applied to the second plug 22 in the locked state of the assembly 1. As a non-limiting example only, the break pin 120 of the second plug 22 may break if an inappropriate axial force in the order of 13 Nm or higher is applied to the second plug 22 in the locked state of the assembly 1. In such embodiments presenting these two break values and without the inventive brake function, the connection at 15, 16 will break before the break pin 120 breaks, whereby the door locking mechanism 3 may be unlocked by the tool tampering tool T. The purpose of the brake function is to prevent such a situation from occurring due to mechanical breakage of weaker parts of the assembly. The brake function is also useful in embodiments without a collapse function.

According to the inventive concept, at least one of the gears of the lock assembly 1 is displaceable. The displaceable gear is displaceable transversely relative to a rotational axis of the displaceable gear, between a non-displaced normal position and at least one displaced position. The displacement direction may for instance be 90 degrees in relation to the rotational axis. Other angles than 90 degrees is also possible. In the embodiment in Figs 10A to 10E, the intermediate gear 34 forms the displaceable gear. The lock assembly 1 is arranged to restrict rotation of the displaceable gear when the latter is in its a displaced position. The rotational restriction, accomplished by one or more brake members interacting directly or indirectly with the displaced gear, may be a complete rotational block arranged to prevent any further rotation of the displaced gear, or a more “conventional” brake function arranged to take up a substantial amount of the torque applied to the displaced gear, optionally take up the entire torque.

In Figs 10A and 10B, the brake function is implemented by parts 90, 91 , 93, 94, 96, 98a and 98b. A slider 90 is received in the housing 6 for linear displacement in a direction transversely to the third rotational axis A3. In the illustrated embodiment, the slider 90 is displaceable in opposite directions, i.e. both left and right. In other embodiments, the slider 90 is displaceable in one direction only. The slider 90 is provided with a projecting axle 91 forming a rotational axle for the intermediate gear 34. The slider 90 and the gear 34 are thus displaceable together in the directions indicated by arrows in Fig. 10A. The gear 34 is received in the housing 6 with a clearance sufficient to allow a certain displacement of the gear 34.

One or more biasing members 94 may be arranged to bias the slider 90 towards its normal non-displaced position. In this embodiment, such biasing members comprise two springs 94 arranged on piston-like members 96 received in holders 93. The members 96 are in engagement with opposite sides of the slider 90.

The implementation of the brake function comprises at least one structure arranged to restrict rotation of the displaceable gear when it is in a displaced position. Restricting rotation may be implemented as a rotational brake and/or a rotational block. Such a brake structure may interact with the displaceable gear either directly with the gear, or indirectly with the gear, such as interacting with a rotational part arranged on the same axle as the displaceable gear, or interacting directly with the rotational axle. The brake structure may be implemented as one or more brake members, for mounting in the housing, or be implemented as one or more integral parts of the housing, or a combination thereof.

In the embodiment illustrated in Fig. 10A to 10E, the brake structure includes two brake members 98a and 98b arranged on either side of the gear 34. Each brake member 98a, 98b has a brake side facing the gear 34. The brake side may be concave as shown, or have other shapes. These brake members 98a and 98b are fixedly connected to the housing 6. In other embodiments, the structure for braking can be implemented directly in the housing 6. Such an embodiment with a housing 6 having an integrated brake structure is illustrated in Figs 11 A to 11 C.

In the normal position of the gear 34, there is a clearance between the gear 34 and the brake members 98a, 98b. In its normal non-displaced position, the brake members 98a, 98b do not interact with the gear 34.

In a displaced position of the gear 34 (see Figs 10C to 10E), the gear 34 is in contact with one of the brake members 98a, 98b. In this displaced position, the contacting brake member will restrict rotation of the displaced gear 34. In the illustrated embodiment, the brake sides of the brake members 98a, 98b are provided with engagement grooves shaped to receive one or more teeth of the gear 34. Accordingly, in the displaced state in Figs 10C to 10E, there is mechanical engagement forming a complete rotational lock of the gear 34 in its displaced position. In other embodiments, the brake function may be implemented by a nongrooved brake surface acting as a conventional brake against the periphery of the gear 34. In such an embodiment, the brake structure may be designed to take up a majority of the torque applied to the gear 34 such that only a minor torque is transferred to the first gear 14. In general, the brake structure should be designed to at least restrict rotation of the displaced gear.

The operation of the brake function will now be described with reference to Figs 10C to 10E which illustrate a situation where someone using a screwdriver ? is trying to forcibly unlock the lock assembly 1 by inserting the screwdriver T into the second plug 22 and by a applying a substantial tampering torque on the second plug 22. In this embodiment, the lock assembly 1 is designed to be unlocked by turning the plugs 11 , 21 counterclockwise. The torque applied by the screwdriver T is transferred from the second plug 22 and the second cylinder body 21 to the gear transmission. The first gear 14 is rotationally locked due to the first lock cylinder 10 being locked. As a result, when the applied tampering torque is transferred from the second plug 22 into a slight rotation of the second gear 24, as indicated by a dashed arrow to the right in Fig. 10E, the intermediate gear 34, having contact both with the rotating second gear 24 and the rotationally locked first gear 14, will be displaced to the left in the figures, as indicated by an empty arrow in Fig. 10E. The gear 34 is displaced into brake contact with the brake member 98a, whereby the gear 34 is rotationally locked. As a result, the brake function prevents the tampering torque applied on the second plug 22 from being transferred to the weaker connection at 15, 16 between the first gear 14 and the first plug 12, thereby eventually preventing unauthorized unlocking of the door.

Should the attempted burglary situation stop in the situation shown in Fig. 10D, i.e. if the applied tampering torque should be removed, then the springs 94 will return the slider 90 and the gear 34 to their normal position, and the lock assembly 1 is again fully functional.

On the other hand, should the applied tampering torque continue and also increase, then the brake function will continue to protect the connection at 15, 16. A continued increase of the applied tampering torque will eventually result in breaking of the break pin 120 and disconnection of the second plug 22 from the tailpiece 2.

Fig. 10D illustrates the brake function in a lock assembly 1 where the door lock mechanism 3 is instead unlocked by a clockwise rotation of the tailpiece 2. In this embodiment, the gear 34 will instead move to the right into engagement with the opposite brake member 98b. It will be appreciated that an advantage of providing a lock assembly 1 with dual brake members 98a, 98b, and displaceability of the slider 90 in opposite directions, allows the lock assembly 1 to be used on doors having either counterclockwise unlocking or clockwise unlocking.

Figs 11A to 11 C illustrate an embodiment including brake function but having two gears 14, 24 only. In this embodiment, it is the first gear 14 which forms the displaceable gear. In order to make the first gear 14 displaceable as shown in Fig. 11A, the entire first lock cylinder 10 is slightly movably arranged in the housing 6. The cavity 51 is a bit oversized. However, the first cylinder body 11 is prevented from rotating about the first rotational axis A1 . In the illustrated embodiment, the first cylinder body 11 is movably arranged in the housing 6 such that a displacement of the first gear 14 and of the first rotational axis A1 is possible. For instance, the first cylinder body 11 may be slightly linearly displaceable in relation to the housing 6, or it may be arranged to rotate slightly about a vertical rotational axis.

In the embodiment shown in Figs 11A to 11 C, the brake structure is not implemented by separate brake members as in the embodiment in Figs 10A to 10E. Instead, the brake structure is implemented directly in the housing 6. The housing 6 is provided with a brake structure 198a and 198b integrally formed with the housing 6. In this example, the brake structure comprises a pair of brake edges 198a, 198a, and 198b, 198b, respectively, on either side of the first gear 14. Upon gear displacement, the teeth of the first gear 14 will be in rotational lock engagement with such brake edges 198a or 198b as shown in Fig. 11 C.

If nothing else is stated, relevant parts of the electromechanical lock assembly 1 may manufactured from a durable material such as stainless steel, aluminum, brass, or any suitable compound thereof. Involved electrical conductors typically comprise highly conductive metals, such as copper, silver, gold, or any adequate highly conducting alloy.