Patent Description:
Electronic locks ("locks" for short) become more and more popular as they allow for lean access management of infrastructure like offices, flats, hotel rooms, safes, cars, manufacturing sites, etc. Corresponding locking systems comprise at least one user device with an electronic identification for authentication of a user. The electronic identification is transmitted from the user device to the lock and if the key is considered valid by the lock, the lock changes its state from unlocked to locked or from locked to unlocked. The electronic identification takes the function of a mechanical key in a purely mechanical locking system. Presently, most electronic locking system use so called RFID-transponders as user devices. There are numerous applications explaining different aspects of this technique (see e.g. <CIT>, <CIT>, <CIT>, <CIT>, <CIT> to name only a few). Alternatively keypads, fingerprint scanners, iris scanners or any other human machine interface may be used to enter a code that functions as a key to the electronic lock.

When a lock changes its state from "locked" to "unlocked" a user gains access to a building, a room, a cabinet or a drawer or something else. One possibility to provide the access is to enable a user to operate a latch and/or a dead bolt (as well referred to as dead lock, see https://en. org/wiki/Dead bolt). Such dead bolt and the latch are hereinafter jointly referred to as "latch", unless explicitly stated. This can either be done by unblocking the latch, i.e. by releasing a coupling between the latch and a door leaf and/or a door frame. Alternatively, the latch may be coupled to a handle. In both cases a selective coupling needs to be opened and closed. Such selective couplings are as well referred to as clutches and are known from a number of publications, e.g. <CIT>, <CIT>, <CIT>, <CIT> to name only very few. The initially described clutch actuator has been suggested in <CIT>.

All these clutches have a clutch actuator mechanism. These clutch actuator mechanisms are reliable in that the motor for moving the coupling member from the closed position to the open position can be actuated without checking if the coupling member is blocked or jammed and in that the coupling member is moved in the corresponding position once the blockage or jamming is resolved due to an elastic connection between the motor's drive shaft and the coupling member being provided by the spring. The spring temporally decouples a movement of the coupling member from an actuation of the motor.

The object underlying the invention is to improve safety of a door lock with a clutch for coupling a handle shaft with a locking member shaft.

Solutions of the problem are defined by the independent claims. Advantageous embodiments are subjects of the dependent claims.

The clutch actuator according to the invention may be used to open and close a clutch for selectively coupling two preferably aligned shafts of a door lock mechanism. The clutch actuator may be integrated into at least one of the two shafts may be hence comprise a (first) shaft of these two shafts.

The first shaft (hereinafter "the shaft") has a longitudinal axis. In operation, the longitudinal axis may be the rotational axis of the shaft. The longitudinal axis implicitly defines an azimuthal direction (herein as well "the first direction"). The shaft further comprises a first azimuthal bearing surface, wherein the first azimuthal bearing surface provides a first block against a rotation in the azimuthal direction and extends in at least one other direction. This other direction will be referred to as well as second direction. Only to avoid misunderstandings, the first and the second direction are linearly independent. The first block can thus be considered as an abutment blocking a rotation in the azimuthal direction, while allowing for a movement along the surface of the block in the second direction. The azimuthal abutment, i.e. the azimuthal bearing surface, thus limits a rotation of a coupling member in the azimuthal direction, while allowing for a translation and/or a rotation and/or pivotal movement in at least the second direction (and of course opposite to the second direction). Thus, via the block a torque can be transferred by the coupling member in the azimuthal direction into the shaft and the coupling member can be moved, e.g. shifted, relative to the shaft from an open position and/or orientation (jointly "open position") into a closed position and/or orientation (jointly "closed position"). In other words, the coupling member is movably supported at least inter alia by the bearing surface between the open position and the closed position.

As already apparent, the coupling member preferably has a second azimuthal bearing surface, wherein the second azimuthal bearing surface provides a second block against a rotation in a direction opposite to the first direction. In case the azimuthal direction is clockwise, the opposite direction is counter clockwise and vice versa. In both cases, the second block may face towards the first block and may extend as well at least in the second direction.

Assuming the coupling member to be in its closed position, the movable support of the coupling member relative to the shaft hence allows to extend at least a portion of the coupling member into a recess of a second shaft of the clutch, thereby providing a positive locking of the first shaft and the second shaft in an azimuthal direction via the coupling member. Of course, the coupling member may alternatively or in addition be extended in its closed position over at least a portion of the second shaft to provide a positive locking. In other words, a recess of the coupling member may be shifted over at least a portion of the second shaft. In both cases, a positive locking can be obtained, typically if the recess and the corresponding portion of the second shaft or the coupling member, respectively are not continuously rotationally invariant, i.e. if they have broken rotational symmetries with respect to the longitudinal axis. In addition or as an alternative to the positive locking, the coupling may as well be provided by a releasable friction connection often as well referred to as force fit. In case the force fit is an alternative, at least one of the coupling member and the corresponding portion of the second shaft can be continuously rotationally invariant.

The movable support allows as well to retract the coupling member into its open position. In the open position, the positive locking and/or the force fit of the coupling member with the second shaft is released. In the open position, the torque proof connection provided by the azimuthal block of the first shaft may be released.

The coupling member has at least a first spring block and a second spring block. The first spring block and the second spring block face in mutually opposite directions. These mutual opposite directions are parallel to a third direction. The third direction and the second direction may preferably be parallel or anti-parallel to each other. This (anti) parallelism is a preferred example as it simplifies the clutch actuator, but it is not required.

A helical spring is movably supported to enable a movement parallel to the third direction, wherein the movement parallel to the third direction is limited in the third direction by the first spring block and in the opposite direction by the second spring block. The helical spring has multiple turns.

A spindle is torque proof connected to a motor shaft and rotatably supported, wherein a protrusion of the spindle engages in a void between two adjacent turns of the helical spring. Alternatively, the protrusion of the spindle may form a recess into which the filament forming the helical spring engages. Thus, operating the motor shifts the helical spring towards the corresponding spring block. Continued operation of the motor loads the helical spring against the corresponding spring block and - if the coupling member is not blocked or jammed-shifts the coupling member in or against the third direction. In other words, operating the motor allows to move the coupling member from its open position into its closed position and back into its open position, the latter by simply inverting the direction of rotation of the spindle.

In some embodiments, a movement in the open or in the closed direction of the coupling member may load a secondary spring. In this case, the secondary spring may push the coupling member back into the closed or open position, respectively (i.e. after the secondary spring has been loaded), respectively, if the force being applied by the helical spring is reduced by rotating the spindle in the corresponding direction. In this case, the surface of the coupling member against which the secondary spring pushes, may be considered as the first or the second spring block and the secondary spring may be considered as a portion of the helical spring, regardless of the type of the secondary spring.

In any case, the position of the coupling member is controlled by rotating the spindle. A rotation of the spindle shifts the coupling member in a position in which an equilibrium of the restoring forces of the at least one loaded spring is established (equilibrium position). If the coupling member is not blocked, it hence moves into this equilibrium position. If it is blocked it cannot move, but once the blocking is released, the coupling member will move in the direction into which it is preloaded. The spring(s) hence enable to decouple the point in time of controlling the drive which rotates the spindle and the point in time the coupling member moves as a result of the rotation of the spindle as the spring(s) store the work provided by the drive and provide it once blocking of the coupling member is released.

The coupling member has a first interlocking protrusion. The first interlocking protrusion extends towards the spindle. The spindle has a second interlocking protrusion extending towards the coupling member. When moving the coupling member from the open position to the closed position, the first interlocking protrusion is moved along a line and the movement of the contour of the first interlocking protrusion along this line defines a surface, being given by the set of trajectories of the points defining the contour. Herein, this surface will be referred to as "the path". Assuming the contour to be closed (not being required - only selected as vivid example) and the trajectories to be straight lines, the movement of the first interlocking protrusion from the open position to the closed position hence defines a cylinder surface (for a definition of a cylinder surface, see <NPL>). Of course, other trajectories are possible as well. The second interlocking protrusion intersects the path. Thus, the coupling member cannot be moved along the path unless at least one of the two interlocking protrusions is moved out of said path. An unauthorized temporal shift of the coupling member, e.g., being induced by an oscillation of the door leaf cannot cause the coupling member to move into its closed position. Even if oscillating the clutch actuator would provide the coupling member a momentum and sufficient kinetic energy to compress the helical spring to temporarily be moved into its closed position, such movement is reliably inhibited by the interaction of the first interlocking member and the second interlocking member, which simply abut each other and hence prevent the coupling member to be moved into its closed position.

Generally, the first interlocking protrusion and the second interlocking protrusion preferably have a radial overlap, wherein "radial" references to the spindle axis. Radial overlap, as usual, means that the intersecting set of the extension of the first interlocking protrusion in the radial direction and set of the extension of the second interlocking protrusion is not empty. Thus, an appropriate azimuthal alignment of the first interlocking protrusion and the second interlocking protrusion assumed, the interlocking protrusions block a movement of the coupling member from the open position towards its closed position.

On the other hand, the spindle is rotated to drive the coupling member into the closed position. With the spindle, the second interlocking protrusion rotates relative to the coupling member and thus enables the first protrusion to pass the path.

The first interlocking protrusion and the second interlocking protrusion each have passage (first passage and second passage, respectively), wherein the first interlocking protrusion fits into or through the second passage and the second interlocking protrusion fits into or through the first passage, while the spindle is rotated relative to the coupling member to load the helical spring towards or against the second direction and to thereby move the coupling member from its open position into its closed position or from the closed position into the open position, respectively. The passages may be considered as recesses having an azimuthal extension allowing the corresponding other interlocking protrusion to pass the respective passage while the spindle is rotated and the coupling member moves towards its closed position. The first passage is thus between at least two surfaces that connect the two axially facing sides of the first interlocking protrusion and the second passage is in between of at least two surfaces that connect the two axially facing sides of the second interlocking protrusion, wherein axially references to the spindle axis. Only to avoid ambiguities, the spindle axis may be at least essentially aligned with the longitudinal shaft axis, such alignment is preferred but not required.

Summarizing, the invention is, inter alia, based on the observation, that the elastic connection between the coupling member and the motor for driving the coupling member as well provides the risk, that the coupling member is shifted into its closed position by inducing an oscillation of the coupling member, e.g., by hammering against the door leaf, hitting the door lock or the like. This may in some cases allow a non-authorized person to bring the coupling member at least for short period of time into a position in which the coupling member engages with its counterpart (closed position). If in this moment the clutch is loaded by operating the handle, the coupling member is jammed by the load and the latch and/or the dead bolt can be retracted. The interaction of the first and the second interlocking protrusions, however, protects against such un-authorized movement of the coupling member into the closed position. Unauthorized access to a door having a door lock with the claimed clutch actuator can be avoided. The safety of door locks can be enhanced by the clutch actuator.

In a preferred example, at least one of the first interlocking protrusion and the second interlocking protrusion is a helical structure aligned with the spindle axis or in other words at least one of the first interlocking protrusion and the second interlocking protrusion is and/or forms a screw thread being aligned with the spindle axis, while the respective other interlocking member is configured to temporarily engage and travel through the voids between turns of the helical structure while the spindle is rotated. In a first example, the first interlocking member is a pin and the second interlocking protrusion is a helical structure. In a second example, the first interlocking protrusion is a helical structure and the second interlocking protrusion is a pin. In a third example, the first interlocking protrusion and the second interlocking protrusion are both helical structures. In all these three examples, the void between the turns of at least one helical structure provides a helical passage for the respective other interlocking protrusion. In the example, in which an interlocking protrusion is a radially or an anti-radially extending pin, the passage provided by said radially or an anti-radially extending pin is formed by the azimuthal void connecting the two azimuthally facing sides of the pin.

In case an interlocking protrusion is a pin, it is preferred if the pin is elastically supported. For example, the pin may be a leg of a torsion spring. Such elastic bearing of the pin increases reliability and reduces wear of the clutch actuator.

Preferably, the length of the helical structure measured parallel to the spindle axis is shorter than the distance between the open position and the closed position. This measure increases reliability of the clutch actuator.

Preferably, the second interlocking protrusion is in the first half, first third, first fourth and/or first sixth of the path the first interlocking protrusion is moved if the coupling member is moved from the open position to the closed position. Thereby, a potential engagement of the first interlocking protrusion and the second interlocking protrusion is released, well before the coupling member reaches its closed position and blocking of the spindle by a jammed or blocked coupling member is reliably avoided, because the spindle and the coupling member are connected only via the helical spring.

Preferably, the sum of the widths of the first interlocking protrusion and the second interlocking protrusions measured parallel to the third direction is smaller than the distance the coupling member is moved in the third direction by n or less than n revolutions of the spindle, wherein <MAT>. This ensures, that the interlocking of the interlocking protrusions is released reliably after the corresponding number of n turns. In particular if n = <NUM> or <MAT> the passages do not need to be helical (but may be).

The second direction and/or the third direction may be at least essentially parallel to the longitudinal axis of the first shaft. In this case, the coupling member moves forth and back parallel to the first shaft's axis. In a preferred example of this embodiment, the first shaft and the coupling member are two parts of a telescopic shaft. Alternatively, the second direction (and hence as well the third direction) may be the radial (including anti-radial) direction, relative to the first shaft's axis. In this alternative, the coupling member is moved radially inwardly and outwardly to open or close the clutch. Superpositions of these preferred directions are as well possible. The first and the second directions are assumed to match herein, but this is not required. They are linearly independent. This is obtained, e.g., if one transforms a movement along the azimuthal bearing surface e.g. by a lever in another direction.

Preferably, the coupling member has a grove that extends longitudinally. Or in other words, the optional groove has a longitudinal groove direction, wherein the longitudinal groove direction is preferably parallel to the third direction and/or to the second direction. At least one of the ends of the helical spring may engage into said groove, thereby blocking a rotation of the helical spring, while allowing for an axial movement of the corresponding end of the helical spring.

The clutch actuator may be integrated in a door lock clutch. The corresponding door lock thus comprises the clutch actuator and a second shaft with a second azimuthal abutment. If the coupling member in its open position, there is no azimuthal overlap of the coupling member and the second block. No overlap means in this case, that a rotation of the coupling member around the first shaft axis is not blocked by the second block. In less vivid but as well less functional wording one may say that the contour of a body being formed by rotating the coupling member around the first shaft's axis does not intersect the contour of the second shaft. In the closed position of the coupling member, there is preferably such azimuthal overlap to thereby provide a positive locking between the coupling member and the second shaft in the azimuthal direction. In the less preferred case of an only frictional connection based coupling, there is of course no such overlap. In this case the coupling member is simply pressed against the second shaft.

A door handle may comprise at least a clutch having an input shaft and an output shaft. The door handle can be, e.g., a lever type door handle or a door knob to provide only two examples. Such door handles typically have an output shaft that can be coupled to a transmission of a door lock. Wherein the transmission may convert a rotation of the handle portion of the door handle into a movement of the latch and/or the dead bolt to thereby convert actuation of the handle portion into a retraction and/or extension of at least one of a latch and a dead bolt. Actuating the door handle may hence cause a retraction of the latch and/or the dead bolt. Only for simplicity we will not distinguish herein between a door lever and a door knob or any other type of door handle. The handle lever is considered as a handle portion of a door handle being configured to be pivoted and/or rotated or translated manually by a person opening or closing a door.

The handle lever is preferably being torque proof connected to the input shaft of the clutch, wherein the first shaft of the clutch actuator may be the input shaft of the door lever and the second shaft of the door lock clutch may be the output shaft of the door handle or at least torque proof connected to the output shaft. In other words, two torque proof connected shafts shall be considered as a single shaft. The torque proof connection may be provided by any kind of torque coupling. In another example, the second shaft of the clutch actuator may be the input shaft of the door lever and the first shaft of the door lock clutch may be the output shaft of the door handle or at least torque proof connected to the output shaft. Again, in this context, two torque proof connected shafts shall be considered as a single shaft.

A door lock comprising a latch bolt and/or a dead lock may in addition comprise the door lock clutch as described above. For example, the first shaft or the second shaft of the door lock clutch may be coupled via a transmission to the latch bolt and/or the dead lock. The respective other shaft may be configured to be driven by an operator, e.g., by a handle portion of a key or by a door handle. Thus, if the door lock clutch is closed, operating the handle portion may retract and/or extend a latch or a dead bolt or the door lock.

The method according to the invention may comprise operating the above described clutch actuator. The method comprises at least the following steps: A method step is moving a coupling member being movably but torque proof connected to a first shaft with respect to a first direction, which first direction is an azimuthal direction relative to the first shaft's axis, from an open position in a second and/or a third direction towards a second shaft of a door lock clutch. In the example of the above described clutch actuator, this may be obtained by powering the motor to thereby drive the spindle.

Prior to or while said moving, the method comprises rotating a first interlocking protrusion of the coupling member through a passage in a second interlocking protrusion of a spindle and the second interlocking protrusion through a passage of the first interlocking member. In the above described example, this is accomplished by driving the spindle as well. But the rotating step can as well be controlled by operating a different actuator.

As already apparent, the step of moving the coupling member may comprise loading a first spring, wherein the first spring is force transmittingly connected to the coupling member towards the second and/or the third direction, i.e. towards the closed position of the coupling member, to thereby apply a force in the second direction to the coupling member. Opening the coupling member may be accomplished by reversing the method: namely by moving the coupling member from its closed position towards its open position and while said moving or after said moving rotating the first interlocking protrusion of the coupling member through the passage in the second interlocking protrusion and the second interlocking protrusion through the passage of the first interlocking protrusion at least until the two interlocking protrusions provide mutually interlocking blocks thereby preventing a movement of the coupling member into the closed position without again rotating the interlocking protrusions relative to each other as already explained above.

As usual in the technical field, "parallel" and is not to be understood in an exact mathematical sense, but in that two lines are considered parallel even if there exists a deviation from perfect parallelism if the angle ±αdp of deviation from perfect parallelism is smaller or equal to αp, i.e. |αdp| ≤ αp and αp ∈ {<NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°}. Smaller angles αp are preferred. Similarly, "radial" and "anti-radial" shall be considered to include deviations from the perfect (anti) radial direction if the angle of deviation ±αdr from the perfect (anti-) radial direction is smaller or equal to αr, i.e. |αdr| ≤ αr and αr ∈ {<NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°}.

As usual, the term friction connection describes that two parts are force and/or torque transmittingly connected, wherein the force and/or torque transmission between the parts is due to frictional forces between the two parts. A positive locking in contrast provides for a force and/or torque transmission by complementary abutments. Of course, these two types of connection can be combined.

There is no substantial difference between a door and a pivotable or slideable window. The term "door" shall thus include the notion of "window" as well. The door lock clutch actuator may thus as well be used to selectively couple a window handle with a window twistlock or any other locking mechanism of a window. Similarly, the door handle may as well be a window handle and the door lock may be a window lock.

In <FIG>, a first embodiment of a clutch actuator <NUM> is shown. The clutch actuator <NUM> comprises a first shaft <NUM>, <NUM> that may comprise one or more shaft sections. In <FIG> two shaft sections, namely a first shaft section <NUM> and a second shaft section <NUM> are depicted, but any other integer number is possible. The shaft <NUM>, <NUM> comprises, as shown, at least one azimuthal bearing surface <NUM>. In this example the shaft has four of these azimuthal bearing surfaces <NUM>, but only a single one is visible in <FIG>. Other numbers are as well possible. At least two azimuthal bearing surfaces <NUM> facing in opposite azimuthal directions are preferred. Reference numeral <NUM> indicates one of these two azimuthal directions, which is referred to as "first direction", as well.

As shown, the azimuthal bearing surface(s) <NUM> extend, i. , parallel to the longitudinal axis in a second direction, being indicated as <NUM>.

The clutch actuator <NUM> further comprises a coupling member <NUM>. The coupling member <NUM> may as well comprise azimuthal bearing surfaces that may extend in the second direction. The azimuthal bearing surfaces provide for a torque proof bearing of the coupling member <NUM> with the first shaft <NUM>, <NUM> while allowing to move the coupling member <NUM> parallel and antiparallel to the second direction <NUM> relative to the first shaft <NUM>, <NUM>. The coupling member <NUM> may further comprises a first section (see ref. numeral <NUM>), a second section <NUM> and a torsion spring <NUM>. A leg <NUM> of the torsion spring <NUM> may provide a first interlocking protrusion <NUM> extending as pin <NUM> towards a spindle <NUM> (see <FIG>).

The clutch actuator <NUM> further comprises a helical spring <NUM> and the spindle <NUM>. The spindle <NUM> has a protrusion <NUM> (preferably a radial protrusion) which may extend in a void between two adjacent turns of the helical spring <NUM>. In <FIG> the protrusion <NUM> compresses the helical spring <NUM> towards the open direction (anti-parallel to the second direction <NUM>). In <FIG> and <FIG> the protrusion has been rotated to compress the helical spring towards the second direction <NUM>.

The spindle may be driven by a motor <NUM> which is coupled by a transmission <NUM> to the spindle <NUM>.

<FIG> show the assembled clutch actuator <NUM> in the open position, i.e. the coupling member <NUM> is in its open position. The housing <NUM>, <NUM> may provide a radial and an axial bearing for the spindle <NUM>, and accordingly the spindle <NUM> is preferably rotatably supported relative to the shaft <NUM>, <NUM>. In this example, the longitudinal axis <NUM> of the shaft <NUM>, <NUM>, the spindle axis and the helical spring axis and the coupling member <NUM> are essentially aligned. As can be seen in <FIG> the free ends of the helical spring <NUM> extend through a longitudinally extending groove <NUM> of the coupling member <NUM> and as well into a longitudinally extending groove of the shaft <NUM>, <NUM>. The helical spring <NUM> is thus axially movable in the shaft <NUM>, <NUM> and as well in the coupling member <NUM>, but a rotation of the helical spring <NUM> is blocked by the boundary walls of the longitudinal grooves <NUM> (see as well <FIG>). The movement of the helical spring <NUM> parallel and antiparallel to the second direction is limited by a first spring block <NUM> and a second spring block <NUM>. Only to avoid confusion, claim <NUM> defines a movement of the helical spring in a third direction, but as explained above the second and the third directions are preferably parallel and this is the case in the depicted example. As can be seen best in <FIG>, in the open position, the first interlocking protrusion <NUM> may be located at the "open" side of the second interlocking protrusion <NUM>. Open side means here the side of the second interlocking protrusion <NUM> which faces against the second direction <NUM> or in other words the side which faces in the direction the coupling member <NUM> is moved when being moved towards its open position. Thus, an externally applied force on the coupling member <NUM> cannot shift the coupling member in the second direction <NUM> towards its closed position. A movement of the coupling member <NUM> towards the closed position (without driving the spindle <NUM>) is blocked by the interaction of the first interlocking protrusion <NUM> with the second interlocking protrusion <NUM>.

<FIG> show the assembled clutch actuator <NUM> in an intermediate position between the open and the closed state. Assuming the open state as the starting point, the spindle has been rotated. Hence the first protrusion <NUM> has been moved through a void being formed by a turn of the second interlocking protrusion <NUM>, which may like in this example be a helical structure. As well due to the rotation, the spindle's protrusion <NUM> rotated through the winding of the helical spring <NUM>, thereby shifting the helical spring <NUM> in the second direction <NUM>. The helical spring <NUM> thus preloads the coupling member <NUM> towards its closed position. In <FIG> it is assumed that the coupling member <NUM> is blocked in the intermediate position, but only for illustrative purposes.

Once the assumed blockage is removed, the coupling member <NUM> is shifted by the energy being stored in the compressed spring <NUM> in the closed position being shown in <FIG>. A non-rotationally invariant portion <NUM> of the coupling member <NUM> now extends radially from the corresponding portion of the first shaft <NUM>, <NUM> and may engage in corresponding recess of a second shaft. The clutch is now closed. Opening the clutch can be accomplished by simply rotating the spindle <NUM> in the other direction. The spindle <NUM> now loads the helical spring <NUM> in the open direction (opposite to the second direction <NUM>) until the first interlocking protrusion <NUM> abuts the second interlocking protrusion <NUM>. Continuing to drive the spindle <NUM> will cause the first interlocking protrusion <NUM> to pass the passage of the second interlocking protrusion <NUM> until the coupling member reaches again the open position as depicted in <FIG>.

<FIG> show another example of the second portion <NUM> of the coupling member <NUM> as shown in <FIG> The second portion <NUM> of the coupling member <NUM> as shown in <FIG> may replace the second portion <NUM> of the coupling member <NUM> of the example being shown in <FIG>.

The second portion <NUM> of the coupling member <NUM> supports a pin <NUM> and can hence as well be referred to as pin support <NUM>. In this example, the pin support has a first ring segment 61and a segment ring segment <NUM> being centered relative to the longitudinal axis <NUM>. In between of the two ring segments <NUM>, <NUM> is a slot with a width w<NUM>. An elastic pin <NUM> having a width w<NUM> extends through the slot and is configured, i.e. located, to abut axially against the second interlocking protrusion <NUM> if pushed in the corresponding direction. The two ring segments <NUM> and <NUM> are supported by a flange portion <NUM>.

Claim 1:
A clutch actuator (<NUM>) for a door lock, the clutch actuator (<NUM>) comprising:
- a first shaft (<NUM>, <NUM>) with a longitudinal shaft axis (<NUM>) and an azimuthal bearing surface (<NUM>), wherein
∘ the azimuthal bearing surface (<NUM>) provides a first block against a rotation in a first direction (<NUM>),
o the first direction (<NUM>) is an azimuthal direction and
o the first block extends in at least one second direction (<NUM>)
o the first and the second direction are linearly independent;
- a coupling member (<NUM>), being movably supported relative to the first shaft (<NUM>,<NUM>) by the azimuthal bearing surface (<NUM>) between an open position and a closed position, wherein the coupling member (<NUM>) has at least a first spring block (<NUM>) and a second spring block (<NUM>) and wherein the first spring block (<NUM>) and the second spring block (<NUM>) face in mutually opposite directions, said mutual opposite directions being parallel to a third direction;
- at least one helical spring (<NUM>) is movably supported relative to the first shaft (<NUM>, <NUM>) to enable a movement parallel to the third direction, wherein the movement parallel to the third direction is limited in the third direction by the first spring block (<NUM>) and in the opposite direction by the second spring block (<NUM>) and wherein the helical spring (<NUM>) has multiple windings;
- a spindle (<NUM>), wherein the spindle (<NUM>) is torque proof connected to a motor shaft and rotatably supported relative to the first shaft (<NUM>,<NUM>), wherein a protrusion (<NUM>) of the spindle (<NUM>) is configured to engage in a void between two adjacent turns of the helical spring (<NUM>) or the protrusion forms a recess into which the filament forming the helical spring engages;
characterized in that
(i) the coupling member (<NUM>) has a first interlocking protrusion (<NUM>) extending towards the spindle (<NUM>),
(ii) the spindle (<NUM>) has a second interlocking protrusion (<NUM>) extending towards the coupling member (<NUM>),
(iii) in the open position of the coupling member (<NUM>) the second interlocking protrusion intersects (<NUM>) the path of the first interlocking protrusion (<NUM>) when the coupling member (<NUM>) is moved from the open position to the closed position.