Striking mechanism and hand-held power tool

Patent metadata

Field	Value
Publication number	US-9259830-B2
Application number	US-65731110-A
Country	US
Kind code	B2
Filing date	Jan 19, 2010
Priority date	Jan 21, 2009
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

A striking mechanism includes a working space whose first section is surrounded by a first electromagnet and whose second section is surrounded by a second electromagnet; a striking element that can move along a striking axis inside the working space and that has a magnetizable material; an anvil whose striking surface delimits the working space in the striking direction and which protrudes into the first magnetic coil and which is made of a magnetically soft material. A spring element is provided which exerts a force onto the striking element in every position in the working space in the direction of the anvil.

First claim

What is claimed is:

1. A striking mechanism having a working space whose first section is surrounded by a first electromagnet and whose second section is surrounded by a second electromagnet, and comprising:
a striking element moveable along a striking axis inside the working space and that has a magnetizable material;
an anvil whose striking surface delimits the working space in the striking direction; and
a spring element exerting a force on the striking element in every position in the working space in a direction of the anvil.

2. The striking mechanism as recited in claim 1 wherein the spring element is a mechanical spring and/or an air spring.

3. The striking mechanism as recited in claim 2 wherein the spring is an air spring formed by a pneumatic space.

4. The striking mechanism as recited in claim 3 wherein the pneumatic space is formed by a section of the working space that is delimited with respect to the anvil by the striking element.

5. The striking mechanism as recited in claim 1 wherein the spring element has a progressive characteristic curve in which the spring constant rises opposite to the striking direction.

6. The striking mechanism as recited in claim 1 wherein the first electromagnet has a first magnetic coil and a first magnetic field guide surrounding an outside of the first magnetic coil, and the first magnetic field guide borders on the anvil, and/or the second electromagnet has a second magnetic coil and a second magnetic field guide surrounding an outside of the second magnetic coil, and the second magnetic field guide borders on the anvil.

7. The striking mechanism as recited in claim 6 wherein the anvil protrudes into the first magnetic coil.

8. The striking mechanism as recited in claim 6 wherein the anvil protrudes into the first electromagnet in such way that at least half of the magnetic flux of the first electromagnet flows through the anvil.

9. The striking mechanism as recited in claim 6 wherein first electromagnet has a length and the anvil protrudes into first electromagnet or into the first magnetic coil by at least one-tenth of the length of the first electromagnet.

10. The striking mechanism as recited in claim 6 wherein the first or the second magnetic coil has a certain length and winding thickness, a ratio of the certain length to the winding thickness being less than 1.25.

11. The striking mechanism as recited in claim 1 wherein the anvil protrudes into the first magnetic coil and is made of a magnetically soft material, and a diameter of a striking surface of the striking element and a further diameter of the a striking surface of the anvil differ by less than 20%.

12. The striking mechanism as recited in claim 11 wherein the anvil protrudes into the first electromagnet in such way that at least half of the magnetic flux of the first electromagnet flows through the anvil.

13. The striking mechanism as recited in claim 1 wherein the working space is delimited on a side facing away from the anvil by a stop protruding into a second magnetic coil of the second electromagnet and that is made of a magnetically soft material.

14. The striking mechanism as recited in claim 1 wherein the surface of the striking element has lengthwise grooves or holes passing through the striking element.

15. A power tool comprising a striking mechanism as recited in claim 1 .

16. The striking mechanism as recited in claim 1 further comprising a housing delimiting the working space opposite the anvil, a bearing on the housing, and a rod joined to the striking element and guided by the bearing.

17. The striking mechanism as recited in claim 16 wherein the rod has projection, the spring element being a spiral spring surrounding the rod and engaging the projection.

18. The striking mechanism as recited in claim 1 further comprising a guide and a recovery element, the anvil being mounted in the guide, the recovery element pressing the anvil opposite the striking direction.

19. The striking mechanism as recited in claim 18 wherein the recovery element is a damping ring.

20. The striking mechanism as recited in claim 18 wherein the guide has a stop opposite to the striking direction, the recovery element pressing the anvil opposite the striking direction against the stop.

Assignees

• Schad Hanspeter
• Hakenholt Christoph
• Khandozhko Sherhey
• Kuntner Jochen
• Sanchen Guenther
• Abu Antoun Chafic
• Dorfmeister Johann
• Hilti Ag

Inventors

• Schad Hanspeter
• Hakenholt Christoph
• Khandozhko Sherhey
• Kuntner Jochen
• Sanchen Guenther
• Abu Antoun Chafic
• Dorfmeister Johann

Classifications

• B25D11/064 Primary

  using an electromagnetic drive · CPC title

• B25D2250/371

  Use of springs · CPC title

• B25D2250/345

  Use of o-rings · CPC title