Patent Description:
Some lock devices comprise an electromechanical actuator for moving a coupling member back and forth between an uncoupled position and a coupled position. In the uncoupled position of the coupling member, an input member may rotate freely, for example by means of a knob, a handle, or a key, and the rotation is not transmitted to a rotation of an output member. The lock device is thereby locked. In the coupled position, a rotation of the input member is transmitted to a rotation of the output member. The lock device can thereby be unlocked. The actuator may control the coupling member to move from the uncoupled position to the coupled position in response to a granted authorization request from a user. The authorization request may for example be input wirelessly.

<CIT> discloses an engaging mechanism intended for electromechanical lock cylinders, including a slide which can be moved backwards and forwards by means of a spindle actuated by a motor, the slide bearing engaging pins which engage with an engagement disc during the forwards movement of the same. A cam is solidly connected to the engagement disc and the rotation thereof actuates the corresponding lock. As the slide moves, it is guided along rods provided in the corresponding cover of a rotor in which the assembly comprising the motor and the slide is housed. The coupling pins are associated with thrust springs which push the same into an emergency engaged position when said pins are located opposite the holes in the disc.

<CIT> discloses a clutch mechanism for a door lock. The clutch mechanism comprises a rotatable external handle, a rotatable square-section shaft, a slider that can be axially pushed into a profiled clutch hole of the external handle, an electric motor coupled with a worm screw, and a spring having two ends. One end of the spring is moved by the worm screw. A second end of the spring is a loop for pushing the slider.

<CIT> discloses a clutch structure device for a door lock. The clutch structure device comprises a reversible clutch plate, a clutch handle shaft, a push rod, a pin body, a motor having a motor body and a worm, and an elastic member having a first leg end and a second leg end. Rotation of the worm causes the push rod to move upwards via the elastic member. In this way, the push rod can extend into a groove of the clutch handle shaft.

One object of the present invention is to provide an arrangement for a lock device, which arrangement has a low power consumption.

A further object of the present invention is to provide an arrangement for a lock device, which arrangement has an energy efficient operation.

A still further object of the present invention is to provide an arrangement for a lock device, which arrangement has a less complicated design.

A still further object of the present invention is to provide an arrangement for a lock device, which arrangement has a cost-effective design.

A still further object of the present invention is to provide an arrangement for a lock device, which arrangement has a reliable operation.

A still further object of the present invention is to provide an arrangement for a lock device, which arrangement has a small size.

A still further object of the present invention is to provide an arrangement for a lock device, which arrangement solves several or all of the foregoing objects in combination.

A still further object of the present invention is to provide a lock device comprising an arrangement, which lock device solves one, several or all of the foregoing objects.

According to one aspect, there is provided an arrangement for a lock device, the arrangement comprising an input member rotatable about an input axis; an output member rotatable about an output axis; a coupling member movable between an uncoupled position, in which the coupling member does not transmit a rotation of the input member to a rotation of the output member, and a coupled position, in which the coupling member transmits a rotation of the input member to a rotation of the output member; an electromechanical actuator comprising an actuating member linearly movable between an uncoupling actuating position and a coupling actuating position; and a torsion spring having a first leg and a second leg movable away from each other against a deformation of the torsion spring, wherein the actuating member is arranged to engage the first leg and the second leg is arranged to engage the coupling member when the coupling member is in the uncoupled position and the actuating member moves from the uncoupling actuating position to the coupling actuating position, and wherein the actuating member is arranged to engage the second leg and the first leg is arranged to engage the coupling member when the coupling member is in the coupled position and the actuating member moves from the coupling actuating position to the uncoupling actuating position.

The torsion spring comprising the first leg and the second leg allows the actuating member to move uninterruptedly regardless of whether or not the coupling member can move from the uncoupled position to the coupled position, e.g. regardless of whether or not the coupling member is blocked. If the coupling member cannot move from the uncoupled position to the coupled position, e.g. if the coupling member is not rotationally aligned with the output member of if the coupling member is otherwise prohibited from moving, the movement of the actuating member from the uncoupling actuating position to the coupling actuating position causes the first leg to move away from the second leg to deform the torsion spring. The actuating member may thereby push, or force in another way, the first leg to move away from the second leg. The actuating member can then be stopped in the coupling actuating position while the deformation of the torsion spring causes the second leg to force the coupling member from the uncoupled position towards the coupled position. The torsion spring thereby exerts a constant force on the coupling member without any power consumption.

If the coupling member can move from the uncoupled position to the coupled position, e.g. if the coupling member becomes rotationally aligned with the output member, the movement of the actuating member from the uncoupling actuating position to the coupling actuating position is transmitted by the torsion spring to a movement of the coupling member from the uncoupled position to the coupled position. The deformation of the torsion spring then causes the second leg to force the coupling member from the uncoupled position to the coupled position. When the coupling member adopts the coupled position, a user can manually rotate the input member, e.g. by means of a key or a handle, to thereby rotate the output member to unlock the lock device.

When the coupling member adopts the uncoupled position, the output member is uncoupled from the input member. When the coupling member adopts the coupled position, the coupling member establishes a coupling between the input member and the output member. The coupling member may be coupled directly or indirectly to the output member when the coupling member adopts the coupled position. The arrangement thus constitutes a coupling arrangement and functions as a clutch. The arrangement provides a very energy efficient way to transfer a movement of the actuating member from the uncoupling actuating position to the coupling actuating position to a movement of the coupling member from the uncoupled position to the coupled position, while also allowing the actuating member to move from the uncoupling actuating position to the coupling actuating position if the coupling member is prevented from moving from the uncoupled position to the coupled position.

Since the torsion spring comprises a first leg and a second leg, the torsion spring constitutes a pinching spring. The torsion spring may be a helical torsion spring comprising a helix. The helix may comprise at least one half turn, such as at least one full turn, such as at least three full turns.

The torsion spring may provide a substantially constant force. The torsion spring may be configured such that a force exerted by the second leg on the coupling member when the actuating member adopts the coupling actuating position and the coupling member adopts the coupled position is at least <NUM> %, such as at least <NUM> %, of a force exerted by the second leg on the coupling member when the actuating member adopts the coupling actuating position and the coupling member adopts the uncoupled position.

Each of the input member and the output member may be hollow and the coupling member may be configured to enter a respective opening of the input member and the output member. Alternatively, the coupling member may be hollow and each of the input member and the output member may be configured to enter first and second openings of the coupling member. In the latter case, the first and second openings may either be blind holes or may join in a common cavity.

The input member may be an input shaft, the coupling member may be a coupling shaft and/or the output member may be an output shaft. The input axis and the output axis may be concentric. In this case, the input axis and the output axis may thus be constituted by a common rotation axis.

The torsion spring may be rotatable about a spring axis. In case the torsion spring comprises a helix, the helix may be centered with respect to the spring axis. The arrangement may comprise a spring pin defining the spring axis. In this case, the torsion spring may be rotationally supported by the spring pin.

The actuating member may be linearly movable along an actuating axis. In this case, the actuating axis may be substantially perpendicular to, or perpendicular to, the spring axis. Alternatively, the spring axis may be inclined, such as <NUM> degrees, to the actuating axis. In any case, the coupling member may be arranged between the input member and the output member along the actuating axis. Alternatively, the input member may be arranged between a protruding part of the coupling member and the output member in the uncoupled position.

The actuating member may be arranged to engage the first leg at a first engagement point. In this case, the first engagement point and the actuating axis may lie in a plane substantially parallel with, or parallel with, the spring axis.

Alternatively, or in addition, the actuating member may be arranged to engage the second leg at a second engagement point. In this case, the second engagement point and the actuating axis may lie in a plane substantially parallel with, or parallel with, the spring axis. In any case, a line between the first engagement point and the second engagement point may be substantially parallel with, or parallel with, the actuating axis.

The coupling member may be linearly movable between the uncoupled position and the coupled position along a coupling axis. In this case, the coupling axis may be substantially perpendicular to, or perpendicular to, the spring axis.

The actuating member may be positioned between the spring axis and the coupling member. A shortest distance between the spring axis and the actuating axis may be <NUM> % to <NUM> %, such as <NUM> % to <NUM> %, of a shortest distance between the spring axis and the coupling axis.

The actuator may comprise a lead screw. In this case, the actuating member may be a nut engaging the lead screw. The lead screw may be rotatable about the actuating axis. The use of a lead screw and a nut engaging the lead screw enables a first engagement point between the actuating member and the first leg, and/or a second engagement point between the actuating member and the second leg, to be provided close to the actuating axis. In this way, a "sticky drawer effect", i.e. a tilting torque between the actuating member and the lead screw, can be reduced and the energy efficiency can thereby be improved.

The actuator may further comprise an electric motor. In this case, the electric motor may be arranged to rotationally drive the lead screw. The electric motor may comprise a rotatable motor shaft.

The actuator may further comprise a transmission. The transmission may be arranged to transmit a rotation of the motor shaft to a rotation of the lead screw. According to one example, the transmission comprises two or more gear wheels.

The actuating member may be arranged to engage the first leg at a first engagement point. In this case, a distance between the first engagement point and the lead screw may be less than a diameter of the lead screw. Alternatively, or in addition, the actuating member may be arranged to engage the second leg at a second engagement point. In this case, a distance between the second engagement point and the lead screw may be less than a diameter of the lead screw. In these ways, a "sticky drawer effect" between the actuating member and the lead screw can be greatly reduced and the energy efficiency can thereby be greatly improved. The diameter of the lead screw may be a diameter of a major thread of the lead screw.

The actuator according to the present invention may however be a linear actuator of other types than using a lead screw to engage a nut. Examples of such linear actuators include synchronous linear motors, three-phase linear induction motors, piezoelectric motors, hydraulic actuators and pneumatic actuators.

The coupling member may be configured to engage the output member by means of a shape fit when the coupling member adopts the coupled position. To this end, the coupling member may be a spline shaft or may comprise a polygonal cross-sectional profile. The output member may comprise a corresponding shape for establishing the shape fit with the coupling member. The coupling member may comprise a male profile and the output member may comprise a female profile for receiving the coupling member. Alternatively, the output member may comprise a male profile and the coupling member may comprise a female profile for receiving the output member.

The coupling member may engage the input member by means of a shape fit. The coupling member may engage the input member by means of the shape fit both in the uncoupled position and in the coupled position. The coupling member may thus be slidable relative to the input member. The coupling member may comprise a male profile and the input member may comprise a female profile for receiving the coupling member. Alternatively, the input member may comprise a male profile and the coupling member may comprise a female profile for receiving the input member.

The first leg and the second leg may be substantially parallel, or parallel, when the actuating member adopts the uncoupling actuating position and the coupling member adopts the uncoupled position.

Each of the first leg and the second leg may be substantially straight, or straight. Each of the first leg and the second leg may be straight between the actuating member and the coupling member.

The actuating member is arranged to engage the second leg and the first leg is arranged to engage the coupling member when the coupling member is in the coupled position and the actuating member moves from the coupling actuating position to the uncoupling actuating position. The movement of the actuating member from the coupling actuating position to the uncoupling actuating position thereby causes the coupling member to move from the coupled position to the uncoupled position.

The coupling member may comprise a protruding coupling part. In this case, the protruding coupling part may be arranged between the first leg and the second leg. The protruding coupling part may for example be a collar or other structure than can be engaged by the first and second legs.

The actuating member may comprise a protruding actuating part. In this case, the protruding actuating part may be arranged between the first leg and the second leg. The protruding actuating part may protrude in a direction substantially parallel with, or parallel with, the spring axis and/or in a direction substantially perpendicular to, or perpendicular to, the actuating axis.

The protruding actuating part may for example be a pin. A width of the protruding actuating part in a direction parallel with the actuating axis may be substantially the same as (e.g. differ less than <NUM> % from), or the same as, a width of the protruding coupling part in a direction parallel with the coupling axis.

The arrangement may further comprise a control system, the control system comprising at least one data processing device and at least one memory having a computer program stored thereon, the computer program comprising program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform the steps of evaluating an authorization request; and commanding the actuator to drive the actuating member from the uncoupling actuating position to the coupling actuating position in response to a granted evaluation of the authorization request. The computer program may further comprise program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform, or command performance of, various steps as described herein.

The control system may further comprise a receiving unit, such as an antenna, for receiving the authorization request. The control system may be configured to determine whether or not authorization should be granted based on the authorization request. If access is granted, e.g. if a valid credential is presented, the actuator is commanded to drive the actuating member from the uncoupling actuating position to the coupling actuating position.

The arrangement may further comprise a printed circuit board, PCB. The control system may be provided on the PCB.

According to a further aspect, there is provided a lock device comprising an arrangement according to the present invention. The lock device may be an electromechanical lock device. The lock device may comprise a DIN cylinder or a Scandinavian cylinder.

The lock device may be an energy harvesting lock device. To this end, the lock device may comprise an electromagnetic generator arranged to be driven by rotation of the input member to thereby generate electric energy. The actuator may be electrically powered by energy harvested by the generator. Alternatively, or in addition, the lock device may comprise a battery and the actuator may be electrically powered by the battery. The lock device may be configured to harvest electric energy sufficient for the actuator to drive the actuating member from the uncoupling actuating position to the coupling actuating position and back to the uncoupling actuating position.

The lock device may further comprise a manually operable member. In this case, the input member can be rotated by means of manual rotation of the manually operable member. The manually operable member may be fixed to the input member, arranged to drive the input member, or connectable to the input member. The manually operable member may for example be a knob, a lever or a physical key.

The lock device may further comprise a locking member. The locking member may be moved from a locking position to an unlocking position by rotation of the output member. The locking member may be fixed to the output member or arranged to be driven by the output member.

According to an example useful for understanding the invention, not encompassed by the wording of the claims, there is provided a method of controlling a lock device, the method comprising providing a lock device according to the present invention; and driving the actuating member from the uncoupling actuating position to the coupling actuating position in response to a granted authorization request from a user. If the authorization request is not granted or if no authorization request is received, the actuating member remains in the uncoupling actuating position. The method may further comprise driving the actuating member from the coupling actuating position to the uncoupling actuating position after expiration of a time limit, e.g. <NUM> seconds.

Further details, advantages and aspects of the present invention will become apparent from the following description taken in conjunction with the drawings, wherein:.

In the following, an arrangement for a lock device and a lock device comprising such arrangement, will be described. The same or similar reference numerals will be used to denote the same or similar structural features.

<FIG> schematically represents a perspective side view of an arrangement <NUM> for a lock device. The arrangement <NUM> comprises an input shaft <NUM> and an output shaft <NUM>. The arrangement <NUM> further comprises a housing <NUM>. The input shaft <NUM> and the output shaft <NUM> protrude from opposite sides of the housing <NUM>. The input shaft <NUM> and the output shaft <NUM> are examples of an input member and an output member, respectively, according to the present invention.

The input shaft <NUM> is rotatable about an input axis <NUM>. The output shaft <NUM> is rotatable about an output axis <NUM>. In this example, the input axis <NUM> and the output axis <NUM> are concentric, i.e. constituted by a common rotation axis. The housing <NUM> comprises a track <NUM>. The track <NUM> extends in parallel with the input axis <NUM>. The input shaft <NUM> comprises an input opening <NUM>.

<FIG> schematically represents a partial perspective side view of the arrangement <NUM>. In <FIG>, the housing <NUM> is removed to improve visibility. The arrangement <NUM> further comprises a coupling shaft <NUM>, an electromechanical actuator <NUM> and a torsion spring <NUM>. The coupling shaft <NUM> is one example of a coupling member according to the present invention. The arrangement <NUM> comprises a stationary structure, here exemplified as a plate <NUM>. The plate <NUM> in <FIG> is a circuit board.

In <FIG>, the coupling shaft <NUM> is in an uncoupled position <NUM>. The coupling shaft <NUM> is linearly movable along a coupling axis <NUM>. The coupling shaft <NUM> is arranged between the input shaft <NUM> and the output shaft <NUM> along the coupling axis <NUM>. In this example, the coupling axis <NUM> is concentric with the input axis <NUM> and the output axis <NUM>.

The coupling shaft <NUM> comprises a collar <NUM>. The collar <NUM> is one example of a protruding coupling part according to the present invention. The collar <NUM> is circular in a plane perpendicular to the coupling axis <NUM>. Except for the collar <NUM>, the coupling shaft <NUM> has a polygonal exterior profile along its length, here a hexagonal exterior profile. The input opening <NUM> of the input shaft <NUM> has a corresponding interior profile. The polygonal profiles of the input shaft <NUM> and the coupling shaft <NUM> form one example of a shape fit between the input shaft <NUM> and the coupling shaft <NUM>. The coupling shaft <NUM> is received in the input opening <NUM> of the input shaft <NUM>. The coupling shaft <NUM> is slidable relative to the input shaft <NUM> along the coupling axis <NUM> while being maintained connected to the input shaft <NUM> by means of the shape fit. The input shaft <NUM> and the coupling shaft <NUM> thus rotate in common. In the uncoupled position <NUM>, a rotation of the coupling shaft <NUM> about the coupling axis <NUM> is not transmitted to a rotation of the output shaft <NUM>.

The output shaft <NUM> comprises an output opening <NUM>. The output opening <NUM> has an interior profile corresponding to the exterior profile of the coupling shaft <NUM>.

The actuator <NUM> comprises a nut <NUM>. The nut <NUM> is one example of an actuating member according to the present invention. The actuator <NUM> can alternatively employ an actuating member other than a nut. In <FIG>, the nut <NUM> is in an uncoupling actuating position <NUM>. The nut <NUM> is linearly movable along an actuating axis <NUM>.

The nut <NUM> of this specific example has a cuboidal shape. The nut <NUM> engages the track <NUM> of the housing <NUM>. In this way, the housing <NUM> prevents the nut <NUM> from rotating about the actuating axis <NUM>.

The nut <NUM> comprises an actuating pin <NUM>. The actuating pin <NUM> is one example of a protruding actuating part according to the present invention. The actuating pin <NUM> protrudes from the nut <NUM> in a direction perpendicular to the actuating axis <NUM>. A width of the actuating pin <NUM> in a direction parallel with the actuating axis <NUM> is the same as a width of the collar <NUM> in a direction parallel with the coupling axis <NUM>.

The actuator <NUM> of this example further comprises a lead screw <NUM>. The nut <NUM> threadingly engages the lead screw <NUM>. The lead screw <NUM> is rotatable about the actuating axis <NUM>.

The actuator <NUM> of this example further comprises an electric motor <NUM>. The electric motor <NUM> comprises a rotatable motor shaft <NUM>. The electric motor <NUM> is secured to the plate <NUM>.

The actuator <NUM> of this example further comprises a transmission <NUM>. The transmission <NUM> comprises a first gear wheel <NUM> and a second gear wheel <NUM> meshing with the first gear wheel <NUM>. The first gear wheel <NUM> is fixed to the motor shaft <NUM>. The second gear wheel <NUM> is fixed to the lead screw <NUM>. The transmission <NUM> is thus arranged to transmit a rotation of the motor shaft <NUM><NUM> to a rotation of the lead screw <NUM>. The electric motor <NUM> is thereby arranged to drive the lead screw <NUM> to rotate about the actuating axis <NUM>.

The torsion spring <NUM> comprises a first leg <NUM> and a second leg <NUM>. The first leg <NUM> and the second leg <NUM> are movable away from each other against a deformation of the torsion spring <NUM>. In the state of the torsion spring <NUM> in <FIG>, the torsion spring <NUM> is deformed such that the first leg <NUM> and the second leg <NUM> pinches each of the actuating pin <NUM> and the collar <NUM>. The first leg <NUM> engages the actuating pin <NUM> at a first engagement point <NUM>. The second leg <NUM> engages the actuating pin <NUM> at a second engagement point <NUM>, on an opposite side of actuating pin <NUM> with respect to the first engagement point <NUM>.

When the nut <NUM> is in the uncoupling actuating position <NUM> according to <FIG>, the first leg <NUM> and the second leg <NUM> hold the coupling shaft <NUM> in the uncoupled position <NUM>. In the uncoupled position <NUM>, the coupling shaft <NUM> is separated from the output shaft <NUM> along the coupling axis <NUM>. A rotation of the input shaft <NUM> is transmitted to a rotation of the coupling shaft <NUM>.

However, a rotation of the coupling shaft <NUM> is not transmitted to a rotation of the output shaft <NUM> when the coupling shaft <NUM> is in the uncoupled position <NUM>. The output shaft <NUM> is uncoupled from the input shaft <NUM> when the coupling shaft <NUM> is in the uncoupled position <NUM>. The lock device is thus locked.

The torsion spring <NUM> of the example in <FIG> is a helical torsion spring comprising a helix. The arrangement <NUM> further comprises a spring pin <NUM>. The helix of the torsion spring <NUM> is wound around the spring pin <NUM>, here almost five full turns. The spring pin <NUM> thereby supports the torsion spring <NUM>. The spring pin <NUM> and the helix each defines a spring axis <NUM>. The torsion spring <NUM> is rotatable about the spring axis <NUM>. The nut <NUM> is positioned between the spring axis <NUM> and the coupling shaft <NUM>.

The arrangement <NUM> further comprises two position sensors <NUM>. In <FIG>, only one position sensor <NUM> can be seen. By means of the position sensors <NUM>, a position of the nut <NUM> can be determined. The position sensors <NUM> of this example are Hall effect sensors. A magnet (not visible) is provided on the nut <NUM>. The position sensors <NUM> sense proximity of the nut <NUM> by measuring a magnetic field from the magnet.

Each of the actuating axis <NUM> and the coupling axis <NUM> is perpendicular to the spring axis <NUM>. As shown in <FIG>, the first engagement point <NUM>, the second engagement point <NUM> and the actuating axis <NUM> lie in a plane parallel with the spring axis <NUM>. Moreover, the first engagement point <NUM> and the second engagement point <NUM> are positioned close to the actuating axis <NUM>. This contributes to avoid the "sticky drawer effect" of the nut <NUM>. A line between the first engagement point <NUM> and the second engagement point <NUM> is parallel with the actuating axis <NUM>. The actuating pin <NUM> protrudes in a direction parallel with the spring axis <NUM>.

Each of the first leg <NUM> and the second leg <NUM> is straight between the nut <NUM> and the coupling shaft <NUM>. In this example, the first leg <NUM> comprises a bent portion <NUM>. Except for the bent portion <NUM>, the first leg <NUM> is straight between the helix and the coupling shaft <NUM>. The first leg <NUM> is thus substantially straight. The second leg <NUM> of this example is straight between the helix and the coupling shaft <NUM>. As shown in <FIG>, in the uncoupling actuating position <NUM> of the nut <NUM> and the uncoupled position <NUM> of the coupling shaft <NUM>, the first leg <NUM> and the second leg <NUM> are parallel.

In order to couple the input shaft <NUM> to the output shaft <NUM>, the electric motor <NUM> is driven to rotate the lead screw <NUM>, e.g. in response to a granted evaluation of an authorization request. The rotation of the lead screw <NUM> causes the nut <NUM> to move linearly along the actuating axis <NUM> (to the right in <FIG>) from the uncoupling actuating position <NUM> to a coupling actuating position.

<FIG> schematically represents a partial perspective side view of the arrangement <NUM> after movement of the nut <NUM> from the uncoupling actuating position <NUM> to the coupling actuating position <NUM>. This movement of the nut <NUM> can be effected with very low power consumption. In <FIG>, a valid credential has been presented and the actuator <NUM> has thereby driven the nut <NUM> to the coupling actuating position <NUM>.

During movement of the nut <NUM> from the uncoupling actuating position <NUM> in <FIG> to the coupling actuating position <NUM> in <FIG>, the actuating pin <NUM> pushes the first leg <NUM> away from the second leg <NUM>. The torsion spring <NUM> is thereby further deformed. Due to the deformation of the torsion spring <NUM>, the second leg <NUM> pushes on the collar <NUM> and thereby exerts a constant force on the coupling shaft <NUM> (to the right in <FIG>). Once the nut <NUM> has moved to the coupling actuating position <NUM>, the electric motor <NUM> is stopped. Thus, no more electric energy needs to be supplied to the arrangement <NUM> when adopting the state in <FIG>.

Since the coupling shaft <NUM> is not rotationally aligned with the output shaft <NUM> in <FIG>, the coupling shaft <NUM> cannot enter the output opening <NUM> to engage the output shaft <NUM>. The nut <NUM> can however move from the uncoupling actuating position <NUM> to the coupling actuating position <NUM> regardless of whether or not the coupling shaft <NUM> is rotationally aligned with the output shaft <NUM>.

<FIG> schematically represents a partial perspective side view of the arrangement <NUM>. In <FIG>, the input shaft <NUM> is rotated about the input axis <NUM> such that also the coupling shaft <NUM> is rotated to align with the output shaft <NUM>. The rotation of the input shaft <NUM> may be effected by manual rotation of a manually operable member, such as a knob, a lever or a physical key (not shown). Once the coupling shaft <NUM> is aligned with the output shaft <NUM> according to <FIG>, in this example when the polygonal exterior profile of the coupling shaft <NUM> aligns with the polygonal interior profile of the output opening <NUM> of the output shaft <NUM>, the second leg <NUM> pushes the coupling shaft <NUM> into the output shaft <NUM>. The coupling shaft <NUM> thereby moves from the uncoupled position <NUM> to a coupled position.

<FIG> schematically represents a partial perspective side view of the arrangement <NUM> after movement of the coupling shaft <NUM> from the uncoupled position <NUM> to the coupled position <NUM>. The movement of the nut <NUM> from the uncoupling actuating position <NUM> to the coupling actuating position <NUM> is transmitted by the torsion spring <NUM> to the movement of the coupling shaft <NUM> from the uncoupled position <NUM> to the coupled position <NUM>.

As shown in <FIG>, the first leg <NUM> and the second leg <NUM> are parallel between the actuating pin <NUM> and the collar <NUM> when the nut <NUM> adopts the coupling actuating position <NUM> and the coupling shaft <NUM> adopts the coupled position <NUM>. The first leg <NUM> and the second leg <NUM> thereby pinches each of actuating pin <NUM> and the collar <NUM>. A force exerted by the second leg <NUM> on the collar <NUM> in <FIG> (nut <NUM> in coupling actuating position <NUM> and coupling shaft <NUM> in coupled position <NUM>) is at least <NUM> % of a force exerted by the second leg <NUM> on the collar <NUM> in <FIG> (nut <NUM> in coupling actuating position <NUM> and coupling shaft <NUM> in uncoupled position <NUM>). The torsion spring <NUM> thus provides a substantially constant force.

When the coupling shaft <NUM> adopts the coupled position <NUM>, the coupling shaft <NUM> enters the output opening <NUM> and thereby engages the output shaft <NUM> by means of a shape fit. When the coupling shaft <NUM> moves between the uncoupled position <NUM> and the coupled position <NUM>, the coupling shaft <NUM> moves relative to the input shaft <NUM> but the shape fit therebetween is maintained. The coupling shaft <NUM> thereby establishes a coupling between the input shaft <NUM> and the output shaft <NUM> when the coupling shaft <NUM> adopts the coupled position <NUM>. A rotation of the input shaft <NUM> about the input axis <NUM> is now transmitted by the coupling shaft <NUM> to a rotation of the output shaft <NUM> about the output axis <NUM>. When the coupling shaft <NUM> is in the coupled position <NUM>, a user can rotate the output shaft <NUM> by rotating the input shaft <NUM>, e.g. by means of a manually operable member, to unlock the lock device.

The electric motor <NUM> may be automatically commanded to drive the lead screw <NUM> in an opposite direction after expiration of a certain time limit, e.g. five seconds. The rotation of the lead screw <NUM> thereby causes the nut <NUM> to move linearly along the actuating axis <NUM> (to the left in <FIG>) from the coupling actuating position <NUM> back to the uncoupling actuating position <NUM>.

When the nut <NUM> moves from the coupling actuating position <NUM> back to the uncoupling actuating position <NUM>, the actuating pin <NUM> pushes the second leg <NUM> at the second engagement point <NUM> (to the left in <FIG>). Since the coupling shaft <NUM> is not prevented to move from the coupled position <NUM> back to the uncoupled position <NUM>, the movement of the second leg <NUM> causes the first leg <NUM> to push the collar <NUM> to move the coupling shaft <NUM> from the coupled position <NUM> back to the uncoupled position <NUM>. The lock device is thereby locked again.

<FIG> schematically represents a cross-sectional front view of the arrangement <NUM> in <FIG>. As shown in <FIG>, a shortest distance between the spring axis <NUM> and the actuating axis <NUM> is approximately <NUM> % of a shortest distance between the spring axis <NUM> and the coupling axis <NUM>.

<FIG> further shows that a distance <NUM> between the first engagement point <NUM> and the lead screw <NUM> is approximately <NUM> % of a diameter <NUM> of a major thread of the lead screw <NUM>. Although not shown in <FIG>, the same applies for the second engagement point <NUM>. In this way, friction losses between the torsion spring <NUM>, the nut <NUM> and the lead screw <NUM> can be reduced and the overall energy efficiency of the arrangement <NUM> can be improved. The positioning of the first engagement point <NUM> and the second engagement point <NUM> close to the actuating axis <NUM> also contributes to a compact design of the arrangement <NUM>.

<FIG> further shows the magnet <NUM> provided on the nut <NUM>. By sensing the magnetic field of the magnet <NUM> by the position sensors <NUM>, it can be determined whether the nut <NUM> is in the uncoupling actuating position <NUM> or in the coupling actuating position <NUM>.

<FIG> schematically represents a side view of one example of a lock device 88a comprising the arrangement <NUM>. The arrangement <NUM> further comprises a control system <NUM>. The control system <NUM> of this example comprises a data processing device <NUM>, a memory <NUM> and an antenna <NUM>. The memory <NUM> has a computer program stored thereon. The computer program comprises program code which, when executed by the data processing device <NUM>, causes the data processing device <NUM> to evaluate an authorization request received by the antenna <NUM>, and to command the electric motor <NUM> to drive the nut <NUM> from the uncoupling actuating position <NUM> to the coupling actuating position <NUM> in response to a granted evaluation request. The authorization request may for example be received by the antenna <NUM> via Bluetooth Low Energy, BLE. Components of the control system <NUM> may be arranged on a common PCB, e.g. fixed to the plate <NUM>.

The lock device 88a comprises a knob <NUM>. The knob <NUM> is one example of a manually operable member according to the present invention. In this example, the knob <NUM> is fixed to the input shaft <NUM>.

The lock device 88a further comprises a locking member <NUM>. The locking member <NUM> of this example is fixed to the output shaft <NUM>. When the coupling shaft <NUM> adopts the coupled position <NUM>, a rotation of the knob <NUM> is transmitted to a rotation of the locking member <NUM> to unlock the lock device 88a.

<FIG> schematically represents a side view of a further example of a lock device 88b comprising the arrangement <NUM>. Mainly differences with respect to the lock device 88a in <FIG> will be described.

The lock device 88b of the example in <FIG> is a key cylinder lock. The lock device 88b comprises a key <NUM>, an outer casing <NUM> and a plug <NUM> rotatably arranged in the outer casing <NUM>. The plug <NUM> is a further example of an input member according to the present invention. Similarly to the input shaft <NUM>, the plug <NUM> is connected to the coupling shaft <NUM> by means of a shape fit. By inserting a correct key <NUM> into the plug <NUM> and presenting a valid credential to the control system <NUM> such that the coupling shaft <NUM> moves from the uncoupled position <NUM> to the coupled position <NUM>, a rotation of the key <NUM> is transmitted to a rotation of the locking member <NUM> to unlock the lock device 88b.

Claim 1:
An arrangement (<NUM>) for a lock device (88a, 88b), the arrangement (<NUM>) comprising:
- an input member (<NUM>, <NUM>) rotatable about an input axis (<NUM>);
- an output member (<NUM>) rotatable about an output axis (<NUM>);
- a coupling member (<NUM>) movable between an uncoupled position (<NUM>), in which the coupling member (<NUM>) does not transmit a rotation of the input member (<NUM>, <NUM>) to a rotation of the output member (<NUM>), and a coupled position (<NUM>), in which the coupling member (<NUM>) transmits a rotation of the input member (<NUM>, <NUM>) to a rotation of the output member (<NUM>);
- an electromechanical actuator (<NUM>) comprising an actuating member (<NUM>) linearly movable between an uncoupling actuating position (<NUM>) and a coupling actuating position (<NUM>); and
- a torsion spring (<NUM>) having a first leg (<NUM>) and a second leg (<NUM>) movable away from each other against a deformation of the torsion spring (<NUM>), wherein the actuating member (<NUM>) is arranged to engage the first leg (<NUM>) and the second leg (<NUM>) is arranged to engage the coupling member (<NUM>) when the coupling member (<NUM>) is in the uncoupled position (<NUM>) and the actuating member (<NUM>) moves from the uncoupling actuating position (<NUM>) to the coupling actuating position (<NUM>), characterised in that
the actuating member (<NUM>) is arranged to engage the second leg (<NUM>) and the first leg (<NUM>) is arranged to engage the coupling member (<NUM>) when the coupling member (<NUM>) is in the coupled position (<NUM>) and the actuating member (<NUM>) moves from the coupling actuating position (<NUM>) to the uncoupling actuating position (<NUM>).