Power tool braking device

Patent metadata

Field	Value
Publication number	US-9243674-B2
Application number	US-201113881826-A
Country	US
Kind code	B2
Filing date	Sep 22, 2011
Priority date	Oct 29, 2010
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A power tool braking device, in particular a hand-held power tool braking device, of a portable power tool has at least one magnetic field braking unit. The power tool braking device comprises at least one mechanical activation unit.

First claim

The invention claimed is:

1. A power tool braking device of a portable power tool, comprising:
at least one magnetic field braking unit including a first braking element, a second braking element and a third braking element, the first braking element being moveable with respect to the second braking element; and
at least one mechanical activation unit positioned on a side of the at least one magnetic field braking unit opposite at least one drive unit of the portable power tool and including a mechanical actuation switch configured to move a lever arm in engagement with the first braking element to move the first braking element with respect to the second braking element between relative positions to selectively change a characteristic of a magnetic field generated between the first braking element and the second braking element to selectively brake the third braking element.

2. The power tool braking device as claimed in claim 1 , wherein the at least one of the first braking element and the second braking element comprises a permanent magnet.

3. The power tool braking device as claimed in claim 1 , wherein:
the first braking element comprises a first permanent magnet;
the second braking element comprises a second permanent magnet; and
the at least one mechanical activation unit is configured to change a pole position of the first permanent magnet relative to second permanent magnet.

4. The power tool braking device as claimed in claim 1 , wherein the at least one magnetic field braking unit includes an eddy current brake.

5. The power tool braking device as claimed in claim 1 , wherein the at least one magnetic field braking unit includes a hysteresis brake.

6. The power tool braking device as claimed in claim 1 , further comprising:
the at least one drive unit including at least one drive element on which at least one of the first braking element, the second braking element, and the third braking element is supported.

7. The power tool braking device as claimed in claim 6 , wherein the at least one drive element is configured as an armature shaft.

8. The power tool braking device at least as claimed in claim 6 ,
wherein the at least one braking element is supported on a side of the at least one drive unit facing away from a driving side.

9. The power tool braking device as claimed in claim 1 , wherein the at least one magnetic field braking unit includes an assembly module.

10. A portable power tool comprising:
a drive unit; and
a power tool braking device including; (i) at least one magnetic field braking unit including a first braking element, a second braking element and a third braking element operably coupled to the drive unit, the first braking element being moveable with respect to the second braking element; and (ii) at least one mechanical activation unit positioned on a side of the at least one magnetic field braking unit opposite the drive unit and including a mechanical actuation switch configured to move a lever arm in engagement with the first braking element to move the first braking element with respect to the second braking element between relative positions to selectively change a characteristic of a magnetic field generated between the first braking element and the second braking element to selectively brake the third braking element.

11. A power tool braking device of a portable power tool, comprising:
at least one magnetic field braking unit including a first braking element, a second braking element and a third braking element, the first braking element being rotatable with respect to the second braking element; and
at least one mechanical activation unit including: (i) a first output element rotationally coupled to the first braking element and defining an edge region; and (ii) a second output element rotationally coupled to the second braking element and defining a corresponding edge region configured to selectively engage the edge region of the first output element,
wherein the first output element is configured to rotate the second output element with the edge region of the first output element in engagement with the edge region of the second output element; and
wherein the first output element is further configured to rotate relative to the second output element with the edge region of the first output element out of engagement with the edge region of the second output element to rotate the first braking element relative to the second braking element between relative positions to change a characteristic of a magnetic field generated between the first braking element and the second braking element to selectively brake the third braking element.

12. The power tool braking device as claimed in claim 11 ,
wherein at least one the first output element and the second output element comprises a bevel gear.

13. The power tool braking device as claimed in claim 12 , wherein the at least one magnetic field braking unit is positioned at least in part after an input gearwheel of the bevel gear along a flux of force.

14. The power tool braking device as claimed in claim 11 , wherein the at least one of the first braking element and the second braking element comprises a permanent magnet.

15. The power tool braking device as claimed in claim 11 , wherein:
the first braking element comprises a first permanent magnet;
the second braking element comprises a second permanent magnet; and
the at least one mechanical activation unit is configured to change a pole position of the first permanent magnet relative to the second permanent magnet.

16. The power tool braking device as claimed in claim 11 , wherein the at least one magnetic field braking unit includes an eddy current brake.

17. The power tool braking device as claimed in claim 11 , wherein the at least one magnetic field braking unit includes a hysteresis brake.

18. The power tool braking device at least as claimed in claim 11 , wherein the at least one braking element is supported on a side of the at least one drive unit facing away from a driving side.

Assignees

• Esenwein Florian
• Bosch Gmbh Robert

Inventors

• Esenwein Florian

Classifications

• B23Q11/0092 Primary

  actuating braking or stopping means · CPC title

• B25F5/00

  Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for · CPC title

• F16D63/002 Primary

  Brakes with direct electrical or electro-magnetic actuation · CPC title

• H02K7/145

  Hand-held machine tool · CPC title

• H02P3/06

  for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter · CPC title