Protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool

Abstract

A protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool includes at least one rotationally drivable shaft and at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded. The protective device further including at least one wrap-spring clutch unit configured to brake the shaft.

Claims

1. A protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool, comprising: at least one rotationally drivable shaft; at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded; and at least one wrap-spring clutch unit configured to brake the shaft, wherein the wrap-spring clutch unit comprises: at least one wrap-spring element, one end of which is fixed to a driver element of the wrap-spring clutch unit, the driver element connected to the shaft for conjoint rotation, and the other end of which is fixed to a rotatably mounted activation element of an activation unit of the wrap-spring clutch unit.

2. The protective device according to claim 1, wherein the at least one wrap-spring element is configured to cooperate with the driver element in order to brake the shaft.

3. The protective device according to claim 1, wherein the at rotatably mounted activation element is configured to bring about a winding movement of a wrap-spring element of the wrap-spring clutch unit as a result of a relative movement.

4. The protective device according to claim 1, wherein the rotatably mounted activation element that is mounted so as to be twistable through an angle of less than 360.

5. The protective device according to claim 1, further comprising: at least one bearing flange on which the shaft is rotatably mounted, wherein the at least one wrap-spring element bears against the at least one bearing flange at least during a rotational movement of the shaft and is not in contact with the shaft or with the driver element.

6. The protective device according to claim 5, wherein: one end of the at least one wrap-spring element is fixed to the bearing flange and another end is fixed to the activation element, and the activation element is twistable through less than 360.

7. The protective device according to claim 1, further comprising: at least one bearing flange on which the shaft is rotatably mounted, wherein the activation unit has at least one magnetic element which is configured to produce a force fit between the at least one bearing flange and the wrap-spring element as a result of a rotational movement of the activation element being braked.

8. The protective device according to claim 1, wherein the at least one wrap-spring element includes two different coil diameters.

9. The protective device according to claim 1, wherein the at least one wrap-spring element is surrounded at least partially by the shaft.

10. The protective device according to claim 9, wherein the shaft has an internal cutout in which the wrap-spring element is fixed at least with one end.

11. The protective device according to claim 9, further comprising: at least one bearing flange on which the shaft is rotatably mounted, wherein the wrap-spring element extends through a cutout in the bearing flange.

12. The protective device according to claim 1, wherein the wrap-spring clutch unit is arranged at an end of the shaft which is remote from a further end of the shaft at which the overload clutch unit is arranged.

13. A portable power tool, comprising: at least one percussion mechanism unit; and at least one protective device configured to protect a user in the event of an uncontrolled blockage of the portable power tool, the protective device including (i) at least one rotationally drivable shaft, (ii) at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded, and (iii) at least one wrap-spring clutch unit configured to brake the shaft, wherein the wrap-spring clutch unit comprises: at least one wrap-spring element, one end of which is fixed to a driver element of the wrap-spring clutch unit, the driver element being connected to the shaft for conjoint rotation, and the other end of which is fixed to a rotatably mounted activation element of an activation unit of the wrap-spring clutch unit.

14. The portable power tool of claim 13, wherein the portable power tool is a hammer drill or a chipping hammer.

15. A protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool, comprising: at least one rotationally drivable shaft; at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded; and at least one wrap-spring clutch unit configured to brake the shaft, the wrap-spring clutch unit including: at least one driver element connected to a free end of the shaft for conjoint rotation; and at least one wrap-spring element configured to cooperate with the at least one driver element in order to brake the shaft, wherein: one end of the at least one wrap-spring element is fixed to the at least one driver element of the wrap-spring clutch unit, and the other end of which is fixed to a rotatably mounted activation element of an activation unit of the wrap-spring clutch unit.

16. A protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool, comprising: at least one rotationally drivable shaft; at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded; at least one wrap-spring clutch unit configured to brake the shaft; and at least one bearing flange on which the shaft is rotatably mounted, wherein the at least one wrap-spring clutch unit has at least one wrap-spring element which bears against the at least one bearing flange at least during a rotational movement of the shaft and is not in contact with the shaft or with a driver element, arranged on the shaft, of the at least one wrap-spring clutch unit, one end of the at least one wrap-spring element is fixed to the bearing flange and another end is fixed to an activation element of an activation unit of the at least one wrap-spring clutch unit, and the activation element is twistable through less than 360.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages can be gathered from the following description of the drawings. The drawings illustrate exemplary embodiments of the disclosure. The drawings, the description and the claims contain numerous features in combination. A person skilled in the art will also expediently consider the features individually and combine them into appropriate further combinations.

(2) In the drawings:

(3) FIG. 1 shows a portable power tool according to the disclosure having at least one percussion mechanism unit and having at least one protective device according to the disclosure in a schematic illustration,

(4) FIG. 2 shows a sectional view of the protective device according to the disclosure in a schematic illustration,

(5) FIG. 3 shows a plan view of the protective device according to the disclosure in a schematic illustration,

(6) FIG. 4 shows a sectional view of a first alternative protective device according to the disclosure in a schematic illustration,

(7) FIG. 5 shows a sectional view of a second alternative protective device according to the disclosure in a schematic illustration, and

(8) FIG. 6 shows a sectional view of a third alternative protective device according to the disclosure in a schematic illustration.

DETAILED DESCRIPTION

(9) FIG. 1 shows a portable power tool 12a having at least one percussion mechanism unit 42a and having at least one protective device 10a. The portable power tool 12a is configured as a hammer drill or as a hammer drill and chipping hammer. The portable power tool 12a comprises a housing unit 44a at least for receiving the percussion mechanism unit 42a and the protective device 10a. Furthermore, the portable power tool 12a has at least one drive unit 46a and at least one transmission unit 48a. The drive unit 46a and the transmission unit 48a are arranged in the housing unit 44a. In addition, the portable power tool 12a comprises, in a front region 50a, a tool receptacle 52a for receiving an application tool 54a. On a side 56a remote from the front region 50a, the portable power tool 12a comprises a main handle 58a for guiding the portable power tool 12a and for transmitting a force from a user to the portable power tool 12a. The portable power tool 12a is embodied with a detachable auxiliary handle 60a. The auxiliary handle 60a can be fastened detachably to the portable power tool 12a via a latching connection or other connections that appear appropriate to a person skilled in the art. The auxiliary handle 60a is arranged on the portable power tool 12a in the vicinity of the tool receptacle 52a in order for the portable power tool 12a to be guided by the user. A main extension direction 62a of the portable power tool 12a extends from the main handle 58a in the direction of the tool receptacle 52a. The main extension direction 62a extends at least substantially parallel to a rotation axis 64a of the tool receptacle 52a. In order to generate a drive torque and to generate a percussive pulse by way of the percussion mechanism unit 42a, the portable power tool 12a has the drive unit 46a. The drive torque of the drive unit 46a is transmissible to the percussion mechanism unit 42a via the transmission unit 48a and/or the protective device 10a in order to generate the percussive pulse. The percussive pulse of the percussion mechanism unit 42a is able to be generated in a manner known to a person skilled in the art. A movement axis of a percussion element (not illustrated in more detail here), in particular a piston, a striker or an anvil, of the percussion mechanism unit 42a extends at least substantially parallel to the rotation axis 64a of the tool receptacle 52a. Furthermore, via the transmission unit 48a and/or via the protective device 10a, the drive torque is transmissible to the tool receptacle 52a in order to generate a rotational movement of the tool receptacle 52a via a hammer tube (not illustrated in more detail here) of the percussion mechanism unit 42a.

(10) FIG. 2 shows a sectional view of the protective device 10a. The protective device 10a is intended at least to protect a user in the event of an uncontrolled blockage of the portable power tool 12a. The protective device 10a comprises at least one rotationally drivable shaft 14a and at least one wrap-spring-free overload clutch unit 16a which is arranged on the shaft 14a and is intended to interrupt transmission of a drive force if a torque limit is exceeded. The shaft 14a is preferably configured as a pinion shaft. The shaft 14a comprises at least one drive-force transmission region 66a. The drive-force transmission region 66a is connected to the shaft 14a for conjoint rotation. In particular, the drive-force transmission region 66a is configured in one piece with the shaft 14a. The drive-force transmission region 66a is configured as a gear. The drive-force transmission region 66a is intended to mesh with a gear element (not illustrated in more detail here), arranged on the hammer tube, of the percussion mechanism unit 42a. The hammer tube is drivable in rotation by the shaft 14a, in a manner already known to a person skilled in the art, in at least one operating state, in particular in a hammer-drill operating state. The overload clutch unit 16a is arranged on the shaft 14a at least substantially in a manner adjoining the drive-force transmission region 66a. The overload clutch unit 16a is integrated in a gear 68a, in particular in a spur gear, of the transmission unit 48a and/or of the protective device 10a. The gear 68a is mounted rotatably on the shaft 14a. The gear 68a preferably engages in a drive shaft, in particular an armature shaft (not illustrated in more detail here), of the drive unit 46a. A connection for conjoint rotation of the gear 68a and the shaft 14a is producible by means of the overload clutch unit 16a.

(11) The overload clutch unit 16a comprises at least one movably mounted form-fitting and/or force-fitting element 70a which is intended to cooperate in a form-fitting and/or force-fitting manner with the gear 68a, in particular with an inner wall, facing the form-fitting and/or force-fitting element 70a, of the gear 68a. The form-fitting and/or force-fitting element 70a is movably mounted in a torque transmission element 84a of the overload clutch unit 16a. The torque transmission element 84a is connected to the shaft 14a for conjoint rotation. A movement axis of the form-fitting and/or force-fitting element 70a extends at least substantially perpendicularly to a rotation axis 72a of the shaft 14a. The rotation axis 72a of the shaft 14a extends preferably at least substantially transversely, in particular perpendicularly, to the rotation axis 64a of the tool receptacle 52a and/or to the movement axis of the percussion mechanism element of the percussion mechanism unit 42a. The rotation axis 72a of the shaft 14a extends in particular at least substantially parallel to a drive axis 82a of the drive unit 46a.

(12) The overload clutch unit 16a furthermore comprises at least one spring element 74a which is intended to subject the form-fitting and/or force-fitting element 70a to a spring force in the direction of the gear 68a. The form-fitting and/or force-fitting element 70a is able to be pressed against the gear 68a by means of the spring element 74a in order to produce a holding force between the gear 68a and the torque transmission element 84a. If a torque acting on the gear 68a, and thus a force resulting therefrom, exceeds the holding force between the gear 68a and the form-fitting and/or force-fitting element 70a, transmission of a drive force is interrupted in particular in a manner already known to a person skilled in the art. It is conceivable for the overload clutch unit 16a to have a multiplicity of form-fitting and/or force-fitting elements 70a and/or a multiplicity of spring elements 74a which are intended to allow a drive force to be interrupted, in a manner already known to a person skilled in the art, if a torque limit is exceeded.

(13) Furthermore, the protective device 10a comprises at least one wrap-spring clutch unit 18a, which is intended to brake the shaft 14a. The wrap-spring clutch unit 18a is arranged at an end of the shaft 14a that is remote from a further end of the shaft 14a at which the overload clutch unit 16a is arranged. The wrap-spring clutch unit 18a comprises at least one driver element 20a connected to a free end of the shaft 14a, and at least one wrap-spring element 22a, wherein the wrap-spring element 22a cooperates with the driver element 20a in order to brake the shaft 14a. The free end of the shaft 14a is that end of the shaft 14a that is remote from the overload clutch unit 16a. The driver element 20a is connected to the shaft 14a for conjoint rotation. The driver element 20a can be connected to the shaft 14a for conjoint rotation by means of a screw connection, by means of a press-fit connection, by means of an adhesive or welded connection or some other manner of connection that appears appropriate to a person skilled in the art. The driver element 20a is configured as a sleeve, in particular as a brake sleeve which cooperates with the wrap-spring element 22a in order to brake the shaft 14a. In particular, in order to generate a brake force in order to brake the shaft 14a, an external surface of the driver element 20a cooperates with an internal surface of the wrap-spring element 22a.

(14) The protective device 10a furthermore comprises at least one bearing flange 28a on which the shaft 14a is rotatably mounted, wherein the wrap-spring clutch unit 18a has at least the wrap-spring element 22a, which bears against the bearing flange 28a, at least during a rotational movement of the shaft 14a, and is not in contact with the shaft 14a and/or with the driver element 20a, arranged on the shaft 14a, of the wrap-spring clutch unit 18a. The wrap-spring clutch unit 18a furthermore comprises at least one activation unit 24a which has at least one movably mounted activation element 26a which is intended, as a result of a relative movement, to bring about a winding movement of the wrap-spring element 22a of the wrap-spring clutch unit 18a. The wrap-spring clutch unit 18a comprises at least the activation unit 24a, which has at least one movably mounted activation element 26a that is mounted so as to be twistable through an angle of less than 360. The activation element 26a is configured as an actuating sleeve. The activation element 26a is mounted so as to be twistable relative to the bearing flange 28a through an angle of less than 360 about the rotation axis 72a of the shaft 14a. The bearing flange 28a has a receiving region in which the activation element 26a is guided in a twistable manner. The activation element 26a surrounds the wrap-spring element 22a, in particular in a circumferential direction extending about the rotation axis 72a of the shaft 14 (FIG. 3). In addition, the activation element 26a surrounds the driver element 20a and the shaft 14a, in particular in the circumferential direction extending about the rotation axis 72a of the shaft 14 (FIG. 3).

(15) One end of the wrap-spring element 22a is fixed to the bearing flange 28a. Furthermore, a further end of the wrap-spring element 22a is fixed to the activation element 26a of the activation unit 24a of the wrap-spring clutch unit 18a, said activation element 26a being twistable through less than 360. The wrap-spring element 22a has a transverse protrusion 76a, by means of which the wrap-spring element 22a is fixed to the activation element 26a. The activation element 26a has a cutout in which the transverse protrusion 76a engages. The transverse protrusion 76a extends at least substantially perpendicularly to the rotation axis 64a of the shaft 14a. Furthermore, the wrap-spring element 22a has a longitudinal protrusion 78a, by means of which the wrap-spring element 22a is fixed to the bearing flange 28a. The bearing flange 28a has a cutout in which the longitudinal protrusion 78a engages. The longitudinal protrusion 78a extends at least substantially parallel to the rotation axis 64a of the shaft 14a. However, it is also conceivable for the wrap-spring element 22a to be fixed to the activation element 26a and/or to the bearing flange 28a in some other manner that appears appropriate to a person skilled in the art, for example by means of a screw connection, by means of a clamping connection, by means of a latching connection, or the like.

(16) Furthermore, the activation unit 24a has at least one actuator 80a (FIG. 3), which is intended to move the activation element 26a and/or to hold it in position. Preferably, the actuator 80a is configured as a magnetic element, in particular as an electromagnet. However, it is also conceivable for the actuator 80a to have some other configuration that appears appropriate to a person skilled in the art, for example a configuration as a spring element, as an electric motor, as a linear drive element, or the like.

(17) The wrap-spring element 22a is arranged under pretension on the bearing flange 28a and on the driver element 20a. A coil internal dimension, in particular a coil inside diameter, of the wrap-spring element 22a is smaller than a maximum external dimension, in particular an outside diameter, of the bearing flange 28a and smaller than a maximum external dimension, in particular an outside diameter, of the driver element 20a, in the region of a bearing position of the bearing flange 28a with respect to a mounting of the shaft 14a, in particular in an unloaded state of the wrap-spring element 22a. The wrap-spring element 22a bears against an external surface of the driver element 20a and against an external surface of the bearing flange 28a in a braking position of the wrap-spring element 22a, in particular in the region of the bearing position of the bearing flange 28a with respect to a mounting of the shaft 14a. Twisting of the driver element 20a relative to the bearing flange 28a in the rest state of the portable power tool 12a can advantageously be prevented. As a result of the connection for conjoint rotation between the driver element 20a and the shaft 14a, a rotational movement of the shaft 14a as a result of a force-fitting connection between the driver element 20a and the bearing flange 28a is avoidable and/or preventable. In order to enable a rotational movement of the shaft 14a, it is necessary to release the force-fitting connection between the driver element 20a and the bearing flange 28a (FIG. 3). The wrap-spring element 22a is able to be unwound in order to release the force-fitting connection between the driver element 20a and the bearing flange 28a. As a result of the wrap-spring element 22a being unwound, individual coils of the wrap-spring element 22a are movable away from the driver element 20a and the bearing flange 28a. During the unwinding of the wrap-spring element 22a, the wrap-spring element 22a, in particular individual coils of the wrap-spring element 22a, come to bear uniformly against an internal surface of the activation element 26a. It may be advantageous for brushing of the wrap-spring element 22a against the driver element 20a rotating in a machining state of the portable power tool 12a to be avoided.

(18) The actuator 80a is intended to twist the activation element 26a and/or hold it in an enabling position in which the wrap-spring element 22a is arranged at a distance from the bearing flange 28a and from the driver element 20a by the activation element 26a. As a result of the twisting of the activation element 26a, unwinding of the wrap-spring element 22a is able to be brought about. The actuator 80a is preferably configured as a rotary magnet. When an energy supply, in particular a power supply, of the actuator 80a is interrupted, automatic twisting of the activation element 26a takes place as a result of a spring force of the wrap-spring element 22a. The wrap-spring element 22a wraps around the driver element 20a and the bearing flange 28a. The force-fitting connection between the driver element 20a and the bearing flange 28a brings about a brake force for braking the shaft 14a, which is connected to the driver element 20a for conjoint rotation. The actuator 80a can be controlled as a result of a sensor signal which is able to be generated in dependence on the occurrence of an uncontrolled blockage of the portable power tool 12a.

(19) FIGS. 4 to 6 show further exemplary embodiments of the disclosure. The following descriptions and the drawing are limited substantially to the differences between the exemplary embodiments, wherein, with regard to components with identical designations, in particular with regard to components with identical reference signs, reference can also be made in principle to the drawing and/or the description of the other exemplary embodiments, in particular FIGS. 1 to 3. In order to distinguish between the exemplary embodiments, the letter a is positioned after the reference signs in the exemplary embodiment in FIGS. 1 to 3. In the exemplary embodiments in FIGS. 4 to 6, the letter a is replaced by the letters b to d.

(20) FIG. 4 shows a sectional view of an alternative protective device 10b. The protective device 10b is intended to protect a user in the event of an uncontrolled blockage of a portable power tool (not illustrated in more detail here). The portable power tool has a configuration analogous to the portable power tool 12a described in the description given for FIGS. 1 to 3. The protective device 10b comprises at least one rotationally drivable shaft 14b and at least one wrap-spring-free overload clutch unit 16b which is arranged on the shaft 14b and is intended to interrupt transmission of a drive force if a torque limit is exceeded. The protective device 10b illustrated in FIG. 4 comprises an at least substantially analogous configuration to the protective device 10a described in the description given for FIGS. 1 to 3. In contrast to the protective device 10a described in the description given for FIGS. 1 to 3, the protective device 10b illustrated in FIG. 4 has a wrap-spring clutch unit 18b which comprises at least one wrap-spring element 22b, one end of which is fixed to a driver element 20b, connected to the shaft 14b for conjoint rotation, of the wrap-spring clutch unit 18b, and a further end of which is fixed to a rotatably mounted activation element 26b of an activation unit 24b of the wrap-spring clutch unit 18b. In FIG. 4, the wrap-spring element 22b is arranged in a rotation-enabling position, in which a rotational movement of the shaft 14b is enabled. The activation element 26b is arranged in a rotationally movable manner on the bearing flange 28b. The activation element 26b is rotatably connected to the driver element 20b via the wrap-spring element 22b. The wrap-spring element 22b is fixed to the driver element 20b by way of a transverse protrusion 76b of the wrap-spring element 22b. The wrap-spring element 22b is fixed to the activation element 26b by way of a further transverse protrusion 32b of the wrap-spring element 22b.

(21) Furthermore, the protective device 10b comprises at least one bearing flange 28b on which the shaft 14b is rotatably mounted, wherein the activation unit 24b has at least one magnetic element 30b which, as a result of braking, brought about in particular by a magnetic force of the magnetic element 30b, of a rotational movement of the activation element 26b, is intended to produce a force fit between the bearing flange 28b and the wrap-spring element 22b. The magnetic element 30b is preferably configured as an electromagnet. However, it is also conceivable for the magnetic element 30b to have some other configuration that appears appropriate to a person skilled in the art. As a result of the magnetic element 30b being activated, the activation element 26b is attractable by a magnetic force of the magnetic element 30b. A rotational movement of the activation element 26b is brakable by an action of a magnetic force of the magnetic element 30b. As a result of a relative movement of the activation element 26b relative to the driver element 20b, said relative movement being brought about by braking of the activation element 26b, the wrap-spring element 22b is wound up. The wrap-spring element 22b is placeable against the bearing flange 28b while it is being wound up. As a result of the wrap-spring element 22b bearing thereagainst, a force-fitting connection between the driver element 20b and the bearing flange 28b is able to be produced via the wrap-spring element 22b. The driver element 20b is brakable by the force-fitting connection between the driver element 20b and bearing flange 28b. As a result of the connection for conjoint rotation between the driver element 20b and the shaft 14b, the shaft 14b is likewise brakable while the driver element 20b is being braked. With regard to further functions and features of the protective device 10b illustrated in FIG. 4, reference may be made to the protective device 10a described in the description given for FIGS. 1 to 3.

(22) FIG. 5 shows a sectional view of a further alternative protective device 10c. The protective device 10c is intended to protect a user in the event of an uncontrolled blockage of a portable power tool (not illustrated in more detail here). The portable power tool has a configuration analogous to the portable power tool 12a described in the description given for FIGS. 1 to 3. The protective device 10c comprises at least one rotationally drivable shaft 14c and at least one wrap-spring-free overload clutch unit 16c which is arranged on the shaft 14c and is intended to interrupt transmission of a drive force if a torque limit is exceeded. The protective device 10c illustrated in FIG. 5 has an at least substantially analogous configuration to the protective device 10b described in the description given for FIG. 4. In contrast to the protective device 10b described in the description given for FIG. 4, the protective device 10c illustrated in FIG. 5 has at least one wrap-spring clutch unit 18c which comprises at least one wrap-spring element 22c which has two different coil diameters 34c, 36c. In the region of a driver element 20c of the wrap-spring clutch unit 18c, the wrap-spring element 22c has a smaller coil diameter 34c than a coil diameter 36c of the wrap-spring element 22c in the region of a bearing flange 28c of the protective device 10c. With regard to further functions and features of the protective device 10c illustrated in FIG. 5, reference may be made to the protective device 10a described in the description given for FIGS. 1 to 3 and/or to the protective device 10b described in the description given for FIG. 4.

(23) FIG. 6 shows a sectional view of a further alternative protective device 10d. The protective device 10d is intended to protect a user in the event of an uncontrolled blockage of a portable power tool (not illustrated in more detail here). The portable power tool has a configuration analogous to the portable power tool 12a described in the description given for FIGS. 1 to 3. The protective device 10d comprises at least one rotationally drivable shaft 14d and at least one wrap-spring-free overload clutch unit 16d which is arranged on the shaft 14d and is intended to interrupt transmission of a drive force if a torque limit is exceeded. The protective device 10d illustrated in FIG. 6 has an at least substantially analogous configuration to the protective device 10a described in the description given for FIGS. 1 to 3. In contrast to the protective device 10a described in the description given for FIGS. 1 to 3, the protective device 10d illustrated in FIG. 6 has at least one wrap-spring clutch unit 18d which comprises at least one wrap-spring element 22d which is surrounded at least partially by the shaft 14d. In FIG. 6, the wrap-spring element 22d is arranged in a rotation-enabling position in which a rotational movement of the shaft 14d is enabled. The shaft 14d has an internal cutout 38d in which the wrap-spring element 22d is fixed at least by one end, in particular by means of a force-fitting connection. The wrap-spring element 22d has, in particular when considered in an unloaded state of the wrap-spring element 22d, a maximum external dimension which is greater than a maximum internal dimension of the internal cutout 38d.

(24) Furthermore, the protective device 10d comprises at least one bearing flange 28d on which the shaft 14d is rotatably mounted, wherein the wrap-spring element 22d extends through a cutout 40d in the bearing flange 28d. The wrap-spring element 22d extends along a rotation axis 72d of the shaft 14d through the cutout 40d in the bearing flange 28d. The cutout 40d has a larger internal dimension compared with a maximum external dimension of the wrap-spring element 22d, in particular when considered in an unloaded state of the wrap-spring element 22d. The wrap-spring element 22d is fixed to a driver element 20d of the wrap-spring clutch unit 18d by a further end, in particular to an internal surface of an internal cutout in the driver element 20d. The wrap-spring element 22d is intended to connect the driver element 20d rotatably to the shaft 14d.

(25) Furthermore, the wrap-spring clutch unit 18d has at least one magnetic element 30d which is intended to cooperate with the driver element 20d. The magnetic element 30d is preferably configured as an electromagnet. However, it is also conceivable for the magnetic element 30d to have some other configuration that appears appropriate to a person skilled in the art. As a result of the magnetic element 30d being activated, the driver element 20d is attractable by a magnetic force of the magnetic element 30d. The driver element 20d forms an activation element of an activation unit 24d of the wrap-spring clutch unit 18d. A rotational movement of the driver element 20d is brakable by an action of a magnetic force of the magnetic element 30d. As a result of a relative movement of the driver element 20d relative to the bearing flange 28d and to the shaft 14d, said relative movement being brought about by the driver element 20d being braked, the wrap-spring element 22d is unwound. The wrap-spring element 22d is placeable against an internal surface of the cutout 40d in the bearing flange 28d as a result of unwinding. As a result of the wrap-spring element 22d bearing against the internal surface of the cutout 40d in the bearing flange 28d, a force-fitting connection between the shaft 14d and the bearing flange 28d is able to be produced via the wrap-spring element 22d. The shaft 14d is brakable by the force-fitting connection between the shaft 14d and the bearing flange 28d. With regard to further functions and features of the protective device 10d illustrated in FIG. 6, reference may be made to the protective device 10a described in the description given for FIGS. 1 to 3.