Hand power tool

• US 5,996,707 A
• Filed: 10/28/1996
• Issued: 12/07/1999
• Est. Priority Date: 11/02/1995
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Klein, Manfred, Meixner, Gerhard, Frauhammer, Karl, Schnerring, Heinz, Hellbach, Manfred, Thome, Ludwig
• Primary Examiner(s): Smith, Scott A.
• Application Number:
  US08/740,363
• Time in Patent Office: 1,135 Days
• Field of Search: 173/104, 173/109, 173/200, 173/201, 173/217, 173/176, 173/48, 173/213, 173/117, 173/20, 173/2, 173/171
• US Class Current: 173/2
• CPC Class Codes: B25D 16/003 Clutches specially adapted therefor
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for

Abstract

A hand power tool has a machine housing, a drive motor accommodated in the machine housing, a drive train connected with the drive motor and provided with a tool receptacle for rotation of a tool insertable in the tool receptacle, a detecting device for detecting an uncontrolled operation of the hand power tool by detecting a blocking of the tool in a workpiece with a resulting impact-like turning of the machine housing, a blocking device provided for the drive train and releasable by the detecting device, the locking device having a locking toothing arranged in the drive train and a blocking member movably supported in the machine housing and form-lockingly engagable in the locking toothing so as to non-rotatably fix the drive train relative to the machine housing, the detecting device being formed so that it produces an electrical release signal in an uncontrolled operation, the blocking device being releasable by the electrical release signal, and further has electromagnet device actuatable by the release signal so that the locking member is engagable by the electromagnet device into the locking toothing.

Claims

1. A hand power tool, comprising a machine housing;

a drive motor accommodated in said machine housing;

a drive train connected with said drive motor and provided with a tool receptacle for rotation of a tool insertable in said tool receptacle;

detecting means for detecting an uncontrolled operation of the hand power tool by detecting a blocking of the tool in a workpiece with a resulting impact-like turning of said housing;

blocking means provided for said drive train and releasable by said detecting means, said blocking means having a locking toothing arranged in said drive train and a blocking member movably supported in said machine housing and form-lockingly engageable in said locking toothing so as to non-rotatably fix said drive train relative to said machine housing, said detecting means being formed so that said detecting means produces an electrical release signal in an uncontrolled operation, said blocking means being releasable by said electrical release signal; and

electromagnet means actuatable by said release signal so that said blocking member is engageable by said electromagnet means into said locking toothing.

2. A hand power tool as defined in claim 1, wherein said blocking member is directly arrestable in said locking toothing by said electromagnet means actuatable by said release signal.

3. A hand power tool as defined in claim 1, wherein said blocking member is indirectly arrestable in said locking toothing by said electromagnet means actuatable by said release signal.

4. A hand power tool as defined in claim 1, wherein said blocking member has one side provided with a locking tooth engageable with said locking toothing, said blocking member being radially displaceable relative to said locking toothing so that said locking tooth by displacement of said blocking member is engageable with and disenageable from said locking toothing.

5. A hand power tool as defined in claim 4, wherein said locking toothing has several teeth each having a locking surface facing in a rotary direction and a free surface facing in another direction, said locking surface being oriented substantially radially outwardly and said free surface being inclined tangentially to said locking surface.

6. A hand power tool as defined in claim 1, wherein said drive train has an intermediate shaft, said locking toothing being provided on said intermediate shaft.

7. A hand power tool as defined in claim 6, and further comprising a separating coupling arranged before said intermediate shaft as considered in a driving direction, said separating coupling automatically separating a driven part of said drive train from said drive motor in response to a signal of said detecting means.

8. A hand power tool as defined in claim 7;

and further comprising a separating coupling arranged before said intermediate shaft as considered in a driving direction, said separating coupling automatically separating a driven part of said drive train from said drive motor after engagement of said blocking member in said locking tooth.

9. A hand power tool as defined in claim 6;

and further comprising a separating coupling arranged before said intermediate shaft as considered in a driving connection, said separating coupling automatically separating a driven part of said drive train from said drive in response to a signal of said detecting means and after engagement of said blocking member into said locking toothing.

10. A hand power tool as defined in claim 9, and further comprising restoring means for restoring said blocking member from a blocking position to an initial position.

11. A hand power tool as defined in claim 10, wherein said restoring means has a hand-actuated restoring slider provided with a restoring cam and extending substantially perpendicularly to an actuation direction of said restoring means in a restoring direction of said blocking member, and a projection provided on said blocking member with which said restoring slider cooperates.

12. A hand power tool as defined in claim 11, wherein said restoring means has an electromagnet for actuation of said restoring slider.

13. A hand power tool as defined in claim 1, wherein said locking means has a shoulder projection;

and further comprising a spring which pre-stresses said blocking member in an engaging direction;

a locking pin provided in said electromagnet means and engageable in a displacement path of said blocking member and engageable with said shoulder projection of said blocking member, so that said locking member is then holdable by said blocking pin out of engagement with said locking toothing, and for release of said blocking member, said locking pin being actuatable in response to the electrical release signal of said detection means.

14. A hand power tool as defined in claim 13;

and further comprising a further spring which prestresses said locking pin in direction to an engaging position with said locking member.

15. A hand power tool as defined in claim 1;

and further comprising a magnet plate, said blocking member being directly engagable with and disengageable from said magnet plate.

16. A hand power tool as defined in claim 15, wherein said magnet plate has two currentless stable end positions.

17. A hand power tool as defined in claim 16;

and further comprising permanent magnets which produce said end positions, said magnet plate having an armature;

an adjusting member connected with said armature; and

two current-actuated coils which reciprocatingly displace said armature between end positions.

18. A hand power tool as defined in claim 17, wherein said blocking member has a locking tooth;

and further comprising a spring arranged between said armature and said locking tooth.