Oscillatory drive

1. An oscillatory drive comprising: an output shaft that can be driven rotatingly oscillatingly about its longitudinal axis and that comprises a free end; a holding fixture located at said free end of said output shaft and comprising a contact surface for attachment of a tool; a mounting section provided on said holding fixture being raised relative to said contact surface; a plurality of projections located on said mounting section projecting radially outwardly and being configured for form-locking connection with a mounting opening of said tool placed in contact with said contact surface; and a tension element comprising a spring exerting a biasing force on a securement holding said tool with its mounting opening on said holding fixture; wherein said tool is held on said mounting section to resiliently yield in axial direction under the action of a torque, against said biasing force; and wherein said mounting section permits said tool to rotate by a certain angle of rotation when said tool gives way axially.

2. The oscillatory drive of claim 1 , wherein said projections have a symmetric design, related to the direction radial to the longitudinal axis, and each of them comprises two flanks that are interconnected by a common curved area that faces away from said longitudinal axis.

3. The oscillatory drive of claim 2 , wherein said flanks approach each other at an angle of between 5° and 35°.

4. The oscillatory drive of claim 2 , wherein said flanks approach each other at an angle of between 10° and 25°.

5. The oscillatory drive of claim 2 , wherein said flanks approach each other at an angle of between 12° and 18°.

6. The oscillatory drive of claim 2 , wherein said flanks terminate by an undercut in an area close to said longitudinal axis.

7. An oscillatory drive comprising: an output shaft that can be driven rotatingly oscillatingly about its longitudinal axis and that comprises a free end; a holding fixture located at said free end of said output shaft and comprising a contact surface for attachment of a tool; a mounting section provided on said holding fixture being raised relative to said contact surface, projecting radially outwardly and being configured for form-locking connection with a mounting opening of said tool placed in contact with said contact surface; and a tension element comprising a spring exerting a biasing force on a securement holding said tool with its mounting opening on said holding fixture; wherein said tool is held on said mounting section to resiliently yield in axial direction under the action of a torque, against said biasing force; and wherein said mounting section permits said tool to rotate by a certain angle of rotation when said tool gives way axially.

8. The oscillatory drive of claim 2 , wherein said mounting section widens at least over a certain area in a direction parallel to said longitudinal axis and toward said contact surface.

9. The oscillatory drive of claim 2 , wherein said mounting section comprises a plurality of projections that project radially outwardly, related to the longitudinal axis.

10. The oscillatory drive of claim 9 , wherein each projection forms at least one flank starting from said contact surface and having a straight line as a base line on said contact surface.

11. The oscillatory drive of claim 10 , wherein a surface of said flank forms a planar trapezoid.

12. The oscillatory drive of claim 10 , wherein between said flank and said longitudinal axis an angle is enclosed which is between 5° and 40°.

13. The oscillatory drive of claim 10 , wherein between said flank and said longitudinal axis an angle is enclosed which is between 10° and 25°.

14. The oscillatory drive of claim 10 , wherein between said flank and said longitudinal axis an angle is enclosed which is between 13° and 17°.

15. The oscillatory drive of claim 2 , wherein said securement comprises a section being selected from the group formed by an elastic section and a resilient section.

16. The oscillatory drive of claim 2 , wherein said mounting section has a polygonal cross-section.

17. The oscillatory drive of claim 2 , wherein said mounting section has a hexagonal cross-section.

18. An oscillatory drive comprising: an output shaft that can be driven rotatingly oscillatingly about its longitudinal axis and that comprises a free end; a holding fixture located at said free end of said output shaft and comprising a contact surface for attachment of a tool; a mounting section provided on said holding fixture being raised relative to said contact surface, projecting radially outwardly and being configured for form-locking connection with a mounting opening of said tool placed in contact with said contact surface; and a securement for fixing the tool with its mounting opening on said holding fixture; wherein said tool is held on said mounting section to resiliently yield in axial direction under the action of a torque, against a pre-stress; and said mounting section permitting said tool to rotate by a certain angle of rotation when said tool gives way axially.

19. The oscillatory drive of claim 18 , wherein said output shaft comprises a tension element on which said securement is received.

20. The oscillatory drive of claim 19 , wherein said tension element is biased by a spring element.