IP Library Granted Patent US 10,682,747
Granted Patent B2
US 10,682,747 · App. 15/083,026 · Granted Jun 16, 2020

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

Inventors: Axel Kuhnle (Freiberg, DE); Lars Schmid (Nuertingen, DE); Carsten Diem (Ludwigsburg, DE)
Assignee: Robert Bosch GmbH
B25D16/003B25F5/001B25D2250/141B25D2250/145B25D2250/165B25D2250/221B25D2250/371
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Quick Facts
Patent No.
US 10,682,747
App. No.
15/083,026
Granted
Jun 16, 2020
Kind
B2
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 (50)

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°.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 23, 2016
From: KUHNLE, AXEL; SCHMID, LARS; DIEM, CARSTEN
To: ROBERT BOSCH GMBH
Reel/Frame 038688/0001 →
Priority Claims (1)
DE 10 2015 205 689 · Mar 30, 2015 · national
Continuity (1)
Related Publication 20160288308A1 · Oct 6, 2016