Patent Description:
Such lock devices are often applied in building doors of care homes or private residences where it is important that a care-giver is able to unlock the door by e.g. entering a code in a smartphone that activates the motorized locking arrangement in order to gain access to a resident in need of care. It is also important the resident should be able to operate the door lock in the conventional manner via a key at the external side and a knob on the inside, after a motorized operation has occurred.

An example of an electronic lock device is disclosed in <CIT>. The device is configured to operate a door lock by moving a lock bolt of an associated lock case between a retracted position and a protruded position and comprises an electrical motor and a transmission for connecting the motor to the lock case. The transmission includes a gear wheel that is drivingly connected to the motor, a lock shaft that is rotatable in order to move the lock bolt, an engagement member and an intermediate disc comprising a pivot joint, which is arranged concentrically with the gear wheel. The engagement member is pivotally attached to the intermediate disc, such that the engagement member is allowed to pivot upon rotation of the gear wheel and thus engage with the lock shaft when the gear wheel is driven by the motor. Engagement is effected by causing the motor to rotate in a first direction; disengagement is effected by causing the motor to rotate in the opposite direction.

The present invention defines a motorised lock device according to claim <NUM>. A motorized lock according to the present invention comprises a rotatable lock shaft, which is configured for connection to a cylinder lock of a building door, such that in use, rotation of the lock shaft operates a lock bolt associated with the cylinder lock.

The lock device comprises a coupling bush mounted around the lock shaft, which can be selectively coupled to the lock shaft to permit motorised operation of lock bolt, and which can be decoupled therefrom to enable manual operation. The lock device further comprises a gear wheel mounted around the coupling bush which engages with the coupling bush via an engagement member that extends in a radially inward direction, whereby the gear wheel is drivable by a pinion gear mounted to an output shaft of an electric motor.

The coupling bush is displaceable in axial direction between a disengaged position and an engaged position in which the bush and the gear wheel are rotationally coupled to the lock shaft, via an axially compressible engagement mechanism that engages with the coupling bush at a first axial end thereof. Axial displacement of the coupling bush towards the engaged position is effected by driven rotation of the gear wheel, via cooperation between at least one first cam provided on the coupling bush and at least one second cam provided on a further component of the arrangement, whereby at least one of the first and second cams comprises an inclined ramp surface. The coupling bush is further provided with anti-rotation means, which prevents rotation of the coupling bush when the gear wheel is driven and the coupling bush is displaced from the disengaged position towards the engaged position. The lock device further comprises a return mechanism for returning the coupling bush from the engaged position to the disengaged position.

The axially compressible engagement mechanism may be formed by one or more spring-loaded lock pins, spring plungers or other compressible components which are in fixed connection with the lock shaft. The first end of the coupling bush is suitably provided with a number of first recesses arranged at angular intervals for receiving the one or more compressible mechanisms in the engaged position. To effect engagement, the motor is activated which causes rotation of the gear wheel. The engagement member extends into an angular opening of the coupling bush, arranged between the first and second ends thereof. An axial dimension of the angular opening is sufficient to permit axial displacement of the bush relative to the gear wheel. Rotation of the gear wheel brings the engagement member into contact with a surface of the angular opening, permitting torque to be transferred to the coupling bush. Initially, rotation of the gear wheel causes axial displacement of the bush, due to the anti-rotation means and cooperation between the first and second cams. When the coupling bush has been displaced by a sufficient amount in axial direction to release the bush from the anti-rotation means, further rotation of the gear wheel causes rotation of the coupling bush to a position in which one of the first recesses in the bush is alignment with the one or more compressible components. Preferably the lock shaft is provided with two such components arranged at opposite sides of the lock shaft in circumferential direction. When the first recesses are not in angular alignment, axial displacement of the coupling bush presses the axial end face against an end face of the compressible components, which are moved in axial direction so as to compress a spring. Rotation of the coupling bush then brings the bush to an aligned position and the spring return force causes the compressible components to engage in a corresponding first recess, to rotationally couple the bush with the lock shaft. Further rotation of the gear wheel now causes rotation of the lock shaft, to operate the lock bolt. Disengagement is effected by rotating the gear wheel in an opposite direction, which enables the return mechanism to restore the coupling bush to the disengaged position.

Suitably, the electric motor comprises control means configured to receive an activation signal and to control the motor such that the gear wheel is rotated to perform an engagement action and then a disengagement action.

A lock device in accordance with the invention thus provides a straightforward and energy efficient means for effecting motorised operation of the lock shaft and ensuring that after motorised operation, manual operation in the normal manner via a key or a knob is possible. Furthermore, the axially displaceable coupling bush enables the use of a gear wheel which is relatively compact in radial direction, meaning that the lock device has a compact width. As a result, a lock device according to the invention is suitable for application on a wide variety of door structures, including doors with relatively narrow doorposts and doors which open in an outward direction.

The first recesses of the coupling bush which receive the one or more compressible components may be essentially circular in shape and have a diameter that is slightly larger than a corresponding diameter of the compressible component. In a further development, the first recesses are formed by angular slots that permit more movement of the coupling bush in rotational direction. This has the advantage that during a disengagement action, the lock shaft does not visibly rotate, thereby reducing the likelihood that a person might grasp a knob associated with the lock shaft during motor operation.

The anti-rotation means may be formed by a number of angularly spaced protrusions that extend in a radially inward direction from a toothed ring that is mounted to or forms an integral part of a base plate of the lock device, through which the lock shaft extends. A second end of the coupling shaft is suitably provided with a number of angularly spaced second recesses which receive the protrusions or teeth of the toothed ring when the coupling bush is in the disengaged position.

In an advantageous further development, the toothed ring is mounted to the base plate in a manner that permits a limited amount of rotation of the toothed ring relative to the base plate, for example, <NUM> - <NUM> degrees. When the coupling bush is decoupled from the lock shaft and axially displaced back to the disengaged position, this makes it easier for the second recesses of the coupling bush to be brought into angular alignment with the protrusions of the toothed ring.

As mentioned, axial displacement of the coupling bush towards the engaged position is effected via cooperation between at least one ramp surface on a first or second cam. In some embodiments, the lock device comprises a plurality of first or second cams and a corresponding plurality of ramp surfaces. Advantageously, each of the ramp surfaces may have a helical form, to optimise contact in rotational direction with the cooperating cam.

In a first embodiment, the at least one ramp surface is provided on the coupling bush and the second cam is formed by the engagement member of the gear wheel. Suitably, the angular opening in the bush has a first portion that extends in a generally circumferential direction and a second portion that is delimited in a first direction of rotation by one ramp surface and is delimited in an opposite direction of rotation by a further ramp surface. The ramp surfaces extend in an axial direction towards the second end of the coupling bush, which can thus be axially displaced to the engaged position to effect motorized operation of the lock bolt in one direction of rotation to a retracted, unlocked position, and effect motorized operation of the lock bolt to a protruded, locked position in the opposite direction of rotation.

In one example of the first embodiment, the coupling bush is additionally provided with at least one second ramp surface with which the gear wheel engagement member cooperates during a disengagement action, such that driven rotation of the gear wheel effects axial displacement of the coupling bush out of the engaged position, to release the one or more compressible components, e.g. lock pins, from the corresponding first recesses of the coupling bush, back to the disengaged position. As will be understood, the coupling bush is suitably provided with a further second ramp surface for effecting axial displacement in an opposite direction of driven rotation of the gear wheel during a disengagement action.

In a further development, the return mechanism for restoring the coupling bush to the disengaged position comprises a compression spring arranged around the lock shaft between a housing of the lock device and the first end of the coupling bush. Axial displacement of the coupling bush to the engaged position compresses the spring against the housing and provides a return force for urging the coupling bush back to the disengaged position when motorized disengagement is initiated. This removes the need for second ramp surfaces on the coupling bush and the need to transfer torque during a disengagement action, which reduces power consumption. A further advantage is that in the event of manual operation of the lock shaft during a motorized disengagement action, there is no risk of the return action getting blocked, which would cause the coupling bush to remain in engagement with the lock pins of the lock shaft.

In a further embodiment of a lock device according to the invention, the at least one ramp surface is provided on the gear wheel engagement member. The coupling bush is provided with at least one first cam which cooperates therewith to effect axial displacement of the bush towards the engaged position in one direction of driven rotation of the gear wheel. Suitably, the gear wheel engagement member is provided with a further ramp surface to effect axial displacement in an opposite direction of driven rotation of the gear wheel. The at least one first cam may be formed by axially extending protrusion arranged between the first and second ends of the bush which has straight camming surfaces. Suitably, the return mechanism comprises a compression spring as described above.

In a still further embodiment, the at least one ramp surface is provided on the anti-rotation means. The protrusions of the toothed ring that is mounted to the base plate suitably comprise first and second ramp surfaces which are inclined in axial direction towards the coupling bush. The second recesses of the coupling bush are shaped to receive these protrusions, such that the coupling bush comprises a number of first cams. The protrusions of the toothed ring act as second cams, whereby driven rotation of the gear wheel in a first direction of rotation causes each first cam to cooperate with the first ramp surface of each second cam and driven rotation of the gear wheel in a second direction of rotation causes each first cam to cooperate with the second ramp surface of each second cam, thereby effecting axial displacement of the bush towards the engaged position. The return mechanism for restoring the bush to the disengaged position suitably comprises a compression spring as described above.

The angular opening of the coupling bush into which the engagement member of the gear wheel extends has a first portion arranged towards the first end of the bush, which is delimited in angular direction by first and second edges, which create rotational stops for the engagement member when the bush is in the disengaged position. A second portion of the angular opening has a greater extent in angular direction than the first portion, and likewise has first and second edges which form rotational stops for the gear wheel engagement member, when axial displacement of the bush towards the engaged position has released the second recesses of the bush (first cams) from the protrusions (second cams) of the toothed ring.

Advantageously, the first and second edges of each portion of the angular opening are straight edges. When the at least one ramp surface is provided on the bush, rotational force on the ramp surface and is partly converted in axial direction, leading to a reduction in the rotational torque. By implementing the ramp surfaces on the toothed ring, the coupling bush can be provided with straight surfaces that engage with the gear wheel engagement member, thereby improving the efficiency of the torque transfer. A further advantage of having the ramp surfaces on the toothed ring is that when the bush is returned to the disengaged position, there is an increased likelihood that the tooth-shaped second recesses of the bush will be in angular alignment with the tooth-shaped protrusions on the ring. If a slight misalignment remains after a disengagement operation, a small manual operation of the lock shaft will bring the second recesses and tooth-shaped protrusions into alignment with each other, to restore the bush to the disengaged position and enable manual operation of the lock shaft in the normal manner.

Preferably, the coupling bush is provided with first and second angular openings, at opposite sides of the bush in circumferential direction, and the gear wheel is provided with first and second engagement members at opposite circumferential sides of the gear wheel.

The interface between the first and second portions of each angular opening in the bush creates a stepped portion that generally faces in axial direction towards the second end of the bush. This stepped portion may be an essentially straight surface. In a further development, the stepped portion comprises a ramp surface which cooperates with the engagement member of the gear wheel and which is inclined so as to effect a small, additional axial displacement of the bush in the direction of engagement, after the bush has been released from the anti-rotation means. This has the advantage that the second end of the bush is free from contact with the protrusions of the toothed ring and prevents any rattling rotation of the bush.

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter and with reference to the accompanying drawings.

It should be noted that items which have the same reference numbers in different figures, have the same structural features and the same functions.

A first embodiment of a motorized lock device according to the invention is depicted in <FIG> in an exploded, perspective view and in assembled view in <FIG>.

The lock device <NUM> comprises a base plate <NUM> and a lock shaft <NUM> that extends through an opening in the base plate which, in use of the lock device, extends through an opening in a building door. The lock shaft is configured to be mounted to a lock cylinder comprising a lock bolt, which inserts into a mortise lock of the building door. A Euro-profile cylinder is one example of a suitable lock cylinder. The lock shaft <NUM> is rotatable in order to move the associated lock bolt between a protruded, locked position and a retracted, unlocked position in a conventionally known manner. In use, the lock bolt can be operated manually from an exterior side via a key and can be operated from an interior side via e.g. a knob.

To permit motorized unlocking and locking, the lock device is provided with a coupling arrangement which can be driven by an electric motor. The arrangement comprises a coupling bush <NUM>, which is mounted around the lock shaft <NUM> and is displaceable in axial direction from a disengaged position, in which there is no rotational coupling with the lock shaft <NUM>, to an engaged, rotationally coupled position. <FIG> shows a cross-sectional view of the arrangement when the coupling bush <NUM> is in the disengaged position. The bush is generally cylindrical in shape and has a first end in axial direction, which will be defined as the end which faces away from the base plate <NUM>, and has a second end which will be defined as the end which faces towards the base plate. This definition of first and second ends in axial direction will also be used for further components of the lock device.

In the disengaged position, the second end of the bush <NUM> suitably bears against the base plate <NUM>. The first end of the bush has an end face <NUM> provided with a plurality of first recesses <NUM>, which are arranged at angular intervals (refer <FIG>) and are adapted to receive first and second lock pins 122a, 122b that are mounted to the lock shaft <NUM>. The lock shaft comprises first and second axially extending openings in which the first and second lock pins 122a, 122b are received (refer <FIG>). A first end of the lock pins bears against corresponding first and second compression springs 123a, 123b which are arranged in the openings. A second end of the lock pins 122a, 122b protrudes from the opening and is axially delimited by a stepped portion of the lock shaft <NUM>. The coupling bush <NUM> is axially displaceable by an amount that enables the second end of the lock pins to be received in the first recesses <NUM>. During axial displacement of the bush towards the engaged position, it may occur that the second end of the lock pins 122a, 122b make contact with the end face <NUM> of the bush <NUM>. The lock pins 122a, 122b are then pushed into the corresponding openings in the lock shaft and compress the corresponding springs 123a, 123b. Rotation of the bush <NUM> will bring the second ends of the lock pins into alignment with the first recesses <NUM> of the bush <NUM>, in which aligned position the springs urge lock pins into engagement with the first recesses. The bush <NUM> is then rotationally coupled with the lock shaft <NUM> and rotation of bush will cause rotation of the lock shaft, to operate the lock bolt.

The initial axial displacement and then rotational displacement of the coupling bush <NUM> is effected via driven rotation of a gear wheel <NUM>, which engages with the bush. The gear wheel <NUM> is mounted against an interior side of the base plate <NUM> in a manner that permits rotation of the gear wheel. In the depicted embodiment, the base plate comprises an annular protrusion <NUM> which supports the gear wheel in radial direction. A sliding bearing made of e.g. PTFE may be arranged between the base plate and an opposing surface of the gear wheel, for reducing friction. The gear wheel has radially extending gear teeth <NUM>, which suitably engage with gear teeth of a pinion gear <NUM> (refer <FIG>) that is coupled to the output shaft of the electric motor (not visible) that is mounted in a housing <NUM> of the device.

The gear wheel further comprises an engagement member <NUM> that extends in a radially inward direction into an angular opening <NUM> in the coupling bush <NUM>. In accordance with the invention, axial displacement of the coupling bush <NUM> is effected via cooperating first and second cams, one of which comprises an inclined surface that extends in axial direction, which will be defined as a ramp surface. In the depicted embodiment, the engagement member <NUM> of the gear wheel acts as a drive cam and the opening in the coupling bush has ramp surface <NUM> that is inclined in axial direction towards the second end of the bush. The ramp surface may have a helical form. The angular opening <NUM> in the coupling bush comprises a first portion that generally extends in circumferential direction and is arranged towards the first end of the bush. In the disengaged position, the engagement member <NUM> of the gear wheel extends into this first portion of the opening <NUM>. With reference to <FIG>, driven rotation of the gear wheel in anticlockwise direction will bring the engagement member into contact with an edge of the opening <NUM> that forms the start of the ramp surface <NUM>. Further rotation of the gear wheel causes the ramp surface <NUM> to follow the engagement member <NUM> and cause axial displacement of the coupling bush <NUM>. As will be understood, the angular opening in the bush suitably comprises a further ramp surface that extends from the first portion of the angular opening <NUM> at an opposite circumferential side, for effecting axial displacement of the bush when the gear wheel is driven in an opposite direction of rotation.

Transformation of the rotational movement of the gear wheel into axial displacement of the bush is possible in that the lock device comprises anti-rotation means, which prevents the coupling bush <NUM> from rotating with the gear wheel when the device is in the disengaged position. In the depicted embodiment, a radially outer surface of the coupling bush is provided, at the second end thereof, with a number of second recesses <NUM>. These recesses may have a square or rectangular shape. The annular protrusion <NUM> on the base plate over which the gear wheel <NUM> is mounted is formed by a toothed ring and comprises a number of protrusions or teeth <NUM> arranged with an angular spacing that extend in a radially inward direction. The teeth <NUM> of the ring <NUM> have a square or rectangular shape that fits into the second recesses. In the disengaged position, these teeth <NUM> engage in the second recesses <NUM> of the coupling bush and prevent rotation of the coupling bush until a sufficient amount of axial displacement has occurred which releases the second recesses <NUM> from the teeth <NUM>. Suitably, the device is configured such that this occurs when the gear wheel engagement member <NUM> reaches the end of the ramp surface <NUM> and encounters a straight edge 135a of the bush opening. Further rotation of the gear wheel <NUM> now causes rotation of the coupling bush <NUM>, allowing it to adopt an angular orientation in which the first and second lock pins 122a, 122b engage in the first recesses <NUM> of the bush as described above, such that further rotation of the gear wheel <NUM> causes rotation of the lock shaft <NUM>.

To decouple the bush <NUM> from the lock shaft, to permit manual operation of the shaft <NUM>, a lock device of the invention is provided with a return mechanism for returning the coupling bush to the disengaged position. In the depicted first embodiment of the invention, the bush <NUM> is axially displaced back towards the base plate <NUM> via driven rotation of the gear wheel <NUM>. The angular opening <NUM> in the coupling bush <NUM> is provided with a second ramp surface <NUM>, with which the gear wheel engagement member <NUM> cooperates when the gear wheel is drivingly rotated in the opposite direction. In the engaged position, the coupling bush <NUM> is prevented from rotating with the gear wheel via the lock pins 122a, 122b engaging in the first recesses <NUM>, such that rotation of the gear wheel is transformed into axial displacement of the bush back towards the base plate <NUM>, until the lock pins are released from the first recesses <NUM> in the bush <NUM>.

In order for the coupling bush <NUM> to fully return to the disengaged position, the second recesses <NUM> need to be in an angular position relative to the teeth <NUM> of the base plate ring <NUM> that permits the teeth to extend into the second recesses. It might occur that during the return movement, a second end face of the bush makes contact with the teeth <NUM>, which blocks axial displacement. In a further development, the base plate ring is mounted to the base plate in a manner that permits a limited amount of rotation of the ring relative to the base plate, such that the ring may adopt different angular positions. An example of such a ring is shown in shown in <FIG>. The base plate <NUM> comprises angular slots <NUM> at either side of a central opening through which the lock shaft <NUM> extends. The toothed ring <NUM> is provided with an axial extension <NUM> that fits into each slot <NUM> and allows angular displacement of the ring <NUM> by e.g. <NUM> -<NUM> degrees. Further components of the lock device depicted in <FIG> are identical to those depicted in <FIG>. Thus, if the second end face of the coupling bush <NUM> encounters teeth <NUM> of the ring <NUM> during the return movement, the ring <NUM> can be angularly displaced into a position of alignment with the second recesses <NUM> of the bush <NUM>, such that bush is restored to the disengaged position.

An example of a second embodiment of a lock device <NUM> according to the invention is shown in exploded view in <FIG> and in assembled view in <FIG>. In the second embodiment, the return mechanism for restoring the coupling bush to the disengaged position comprises a compression spring <NUM> arranged around the lock shaft <NUM>. A first end of the spring bears against an inside surface of the device housing <NUM> and a flange part <NUM> of the coupling bush <NUM>. The provision of a compression spring removes the need to have a second ramp surface <NUM> on the coupling bush as described with reference to <FIG>. This has the advantage of eliminating any risk that motorized return movement of the bush gets blocked in the event of manual operation of the lock shaft <NUM> during this movement. The mechanism for effecting axial displacement of the coupling bush from the disengaged position to the engaged position is the same as that described for the first embodiment. The coupling bush <NUM> has first recesses <NUM> that receive the first and second lock pins 122a, 122b in the engaged position and has second recesses <NUM> that receive the teeth <NUM> of the base plate ring when the bush is in the disengaged position. The base plate ring may also be angularly displaceable relative to the base plate <NUM> such as described with reference to <FIG>. The coupling bush <NUM> is provided with an angular opening <NUM> having a first ramp surface <NUM> which is contacted by the engagement member <NUM> of the gear wheel <NUM> to effect axial displacement of the bush <NUM> via rotation of the gear wheel and then rotational displacement of the bush when the engagement member encounters a straight edge or stop 235a in the angular opening <NUM> in a first direction of rotation and the second recesses <NUM> have been released from the teeth <NUM>. Suitably, the angular opening <NUM> comprises a second ramp surface, which ends in a straight stop surface, at an opposite side in circumferential direction, for moving the bush <NUM> from the disengaged position to the engaged position when the gear wheel is rotated in a second direction of rotation. As mentioned, the coupling bush <NUM> comprises a flange part <NUM>, generally arranged at the first end of the bush which axially retains the compression spring <NUM>. Axial displacement of the bush towards the engaged position compresses the spring against the device housing.

Let us assume that the gear wheel <NUM> has been rotated in clockwise direction to displace the bush <NUM> to the engaged position. Disengagement is effected by rotating the gear wheel <NUM> in anti-clockwise direction, which brings the gear wheel engagement member <NUM> from the stop 235a into a central portion of the angular opening <NUM>. This central portion has a larger dimension in axial direction than a corresponding axial extension of the engagement member <NUM>, such that the compressed spring <NUM> urges the bush back towards the disengaged position. If the second recesses <NUM> of the bush are not in angular alignment with the teeth <NUM> of a base plate ring <NUM>, a small amount of manual rotation of the lock shaft <NUM> will bring them into alignment, such that further axial displacement is permitted which releases the lock pins from the first recesses <NUM> and returns the bush to the disengaged position.

In a third embodiment of a lock device according to the invention, the ramp surface for effecting axial displacement of the coupling bush towards the engaged position, in one direction of rotation, is provided on the gear wheel. An example of such a lock device <NUM> is depicted in exploded view in <FIG> and in assembled view in <FIG>. The gear wheel <NUM> has an engagement member <NUM> which makes contact with at least one cam on coupling bush <NUM>. The cam is formed by a protrusion <NUM> that extends in axial direction from a central region of the coupling bush. Preferably, the bush is provided with a further cam at an opposite side in circumferential direction. Only the first cam <NUM> is visible in <FIG>. Suitably, the cams <NUM> have straight camming surfaces. Each cam extends into an angular opening <NUM> in the engagement member, whereby the opening is delimited in angular direction by a first ramp surface <NUM> for engagement with one cam in one direction of rotation and by a second ramp surface for engaging with the cam and effecting axial displacement in an opposite direction of rotation. Suitably, each ramp surface <NUM> ends with a straight stop edge 347a. The ramp surfaces may have a helical form.

Further, the coupling bush is provided with first recesses for receiving the spring-loaded lock pins in the engaged position and with second recesses which engage with anti-rotation means when the bush is in the disengaged position, as described for the previous embodiments. The lock device is further provided with a compression spring <NUM> as described with reference to <FIG> for returning the bush to the disengaged position after the gear wheel has been rotated in an opposite direction that brings each cam <NUM> into a central region of the corresponding angular opening <NUM> in the gear wheel engagement member <NUM>.

A fourth embodiment of a lock device according to the invention is depicted in exploded view in <FIG> and in assembled view <FIG>. In the fourth embodiment, the ramp surfaces for effecting axial displacement of the coupling bush are provided on the anti-rotation means.

The device <NUM> comprises a toothed ring <NUM> that is preferably mounted to the base plate <NUM> so as to permit a small amount of angular displacement of the ring <NUM> relative to the base plate. The ring <NUM> comprises a plurality of teeth <NUM>, which extend in a radially inward direction. Each tooth is additionally provided with a first ramp surface 417a and a second ramp surface 417b that taper in axial direction towards the coupling bush <NUM>. The base plate teeth <NUM> therefore additionally acts as cams. A side view of the coupling bush is shown in <FIG>. The bush <NUM> has plurality of second recesses <NUM> which are shaped to receive the teeth <NUM> of the base plate ring <NUM> when the bush <NUM> is in the disengaged position. The second recesses <NUM> have an axial depth X and create cams <NUM> on the bush. Rotation of the gear wheel <NUM> in a first direction of rotation effects axial displacement of the bush via cooperation of the first ramp surface 417a of each tooth <NUM> and a corresponding cam <NUM> on the bush. Rotation of the gear wheel <NUM> in a second direction of rotation effects axial displacement of the bush via cooperation of the second ramp surface 417a of each tooth <NUM> and a corresponding cam <NUM> on the bush.

Torque is transferred from rotation of the gear wheel <NUM> to the coupling bush <NUM> by first and second engagement members 445a, 445b, suitably arranged at opposite sides of the gear wheel in circumferential direction. The engagement members extend axially over the coupling bush and radially into first and second angular openings in the coupling bush. The bush is suitably provided with first and second axially extending slots <NUM> to permit mounting. <FIG> shows the first slot <NUM> and the first angular opening <NUM>. Each angular opening has a first portion and a second portion, whereby the second portion has a greater angular dimension than the first. The first portion of the opening is delimited in angular direction by first and second edges 434a, 434b, which form rotation stops for the first engagement member 445a in first and second directions of rotation when the bush is in the disengaged position. The dimension in axial direction of the first portion may be essentially equal to the axial depth X of the second recesses <NUM>. When the gear wheel <NUM> is drivingly rotated in a first direction, the first engagement member 445a will make contact with the first stop 434a. Further rotation transfers torque to the coupling bush <NUM>, which initially causes axial displacement of the bush <NUM> by the amount X, until the camming teeth <NUM> of the base plate ring <NUM> have been released from the second recesses <NUM> on the bush. This also releases the engagement member 445a from the first portion of the angular opening into the second portion. The second portion of the opening is delimited in angular direction by first and second edges 435a, 435b and form stops for the first engagement member 445a in first and second directions of rotation. Further rotation of the gear wheel in the first direction brings the engagement member into the contact with the first edge 435a of the second portion of the angular opening and still further rotation transfer torque which causes rotation of the bush and rotation of the lock shaft <NUM> when the lock pins engage in the first recesses of the bush.

Each first edge 435a and each second edge 435b are straight surfaces that extend in axial direction. During the initial axial displacement, rotational force is transferred from the engagement member 445a, 445b to the bush <NUM> via the corresponding first straight edge 434a of the angular opening <NUM>. As a result, none of the applied rotational force has an axial component, as is the case when torque is transferred via an inclined ramp surface is provided on the bush or on the gear wheel engagement member. The efficiency of torque transfer is thus improved. This is one advantage of implementing the ramp surfaces 417a, 417b on the teeth of the ring component <NUM>. A further advantage is that the resulting essentially triangular shape of the teeth <NUM>, and correspondingly shaped second recesses <NUM> of the bush, make it more likely that these teeth and recesses will adopt a position of alignment with each other that enables the compression spring to restore the bush to the disengaged position in a disengagement action.

4d shows a detail of the assembled arrangement when the coupling bush <NUM> has been axially displaced to the engaged position and the first engagement member 445a is in contact with the first edge of the second portion of the angular opening. Disengagement is effected by rotation of the gear wheel in the second direction until the engagement member 445a has passed a stepped portion <NUM> of the angular opening, which forms an interface between the first and second portions. The compression spring <NUM> arranged between the bush and the device housing is then able to axially displace the coupling bush <NUM> back towards the disengaged position.

In the example shown in <FIG> and <FIG>, the stepped portion has a straight surface. In a further development, the stepped portion has a ramp surface, such as shown in <FIG>. The angular opening has a first and second ramp surfaces, whereby only the second ramp surface 436b is visible in <FIG>. Each ramp surface is inclined such that rotation of the gear wheel <NUM> in the direction which moves the coupling bush towards the engaged position causes a small amount of additional axial displacement of the bush <NUM>. The total amount of axial displacement of the bush, relative to the disengaged position, is Y, which is greater than X. This ensures that an axial end face of the cams <NUM> on the bush are not in contact with the camming teeth <NUM> of the base plate ring <NUM> during the final phase of the engagement action. This has the advantage of preventing any rattling rotation of the bush.

Examples, embodiments or optional features, whether indicated as non-limiting or not, are not to be understood as limiting the invention as claimed.

Claim 1:
A motorised lock device (<NUM>, <NUM>, <NUM>, <NUM>) comprising a rotatable lock shaft (<NUM>) configured for mounting to a cylinder lock of a building door, such that in use, rotation of the lock shaft operates a lock bolt associated with the cylinder lock, the device further comprising a coupling bush (<NUM>, <NUM>, <NUM>, <NUM>) mounted around the lock shaft, and a gear wheel (<NUM>, <NUM>. <NUM>, <NUM>) mounted around the coupling bush, which engages therewith via an engagement member (<NUM>, <NUM>, <NUM>, 445a, 445b) that extends in a radially inward direction, whereby the gear wheel is drivable by a pinion gear (<NUM>) mounted to an output shaft of an electric motor; characterized in that:
• the coupling bush is displaceable in axial direction between a disengaged position and an engaged position in which the bush (<NUM>, <NUM>, <NUM>, <NUM>) and the gear wheel (<NUM>, <NUM>, <NUM>, <NUM>) are rotationally coupled to the lock shaft (<NUM>) via an axially compressible engagement mechanism that engages with the coupling bush at a first end thereof;
• axial displacement of the coupling bush towards the engaged position is effected by driven rotation of the gear wheel (<NUM>, <NUM>, <NUM>, <NUM>), via cooperation between at least one first cam (<NUM>, <NUM>) provided on the coupling bush and at least at least one second cam (<NUM>, <NUM>, <NUM>, <NUM>) provided on a further component of the lock device, whereby at least one of the first and second cams comprises a ramp surface (<NUM>, <NUM>, <NUM>, 417a, 417b) inclined in axial direction, and whereby the lock device is provided with anti-rotation means, which prevent rotation of the coupling bush during displacement from the disengaged position towards the engaged position; and
• the lock device further comprises a return mechanism (<NUM>, <NUM>) for returning the coupling bush from the engaged position to the disengaged position.