Impact wrench anvil and method of forming an impact wrench anvil

• US 20060151188A1
• Filed: 01/07/2005
• Published: 07/13/2006
• Est. Priority Date: 01/07/2005
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Bruner, David S., Paris, Alan M., Bodine, Thomas J.
• Granted Patent: US 7,249,638 B2
• Time in Patent Office: Days
• US Class Current: 173/104
• CPC Class Codes: B25B 21/02 with means for imparting impact to screwdriver blade or nut socket
• CPC Class Codes: B25B 23/0035 Connection means between socket or screwdriver bit and tool
• CPC Class Codes: Y10T 29/49 Method of mechanical manufacture

Abstract

An anvil adapted to be received within an impact wrench comprises a round body and a square head. The square head is formed at an end of the round body. A tapered ramp extends from the round body to the square head. A radius is formed in the tapered ramp.

Claims

1. A method for producing an anvil for an impact tool comprising:

providing an anvil comprising steel having less than 0.15% carbon and about 2 to about 4% Ni; and

subjecting the anvil to a plurality of heating and quenching cycles.

2. The method of producing an anvil according to claim 1 wherein the anvil further comprises 0.15-0.3% Si.

3. The method according to claim 1 for producing an anvil wherein subjecting the anvil to a plurality of heat treating and quenching cycles is subjecting the anvil to carburization and quenching and two subsequent reheating and quenching cycles.

4. The method of producing an anvil for heating an impact wrench according to claim 1 wherein subjecting the anvil to a plurality of heat treating cycles at temperatures between about 1450 and 1525°

F. having quenching cycles therebetween.

5. The method for providing an anvil for an impact wrench according to claim 1 wherein providing an anvil having a cylindrical first portion and a square second portion and a transition portion having an exterior radius of 2 mm therebetween.

6. The method of producing an anvil according to claim 5 wherein providing an anvil having a surface texture of less than 1.6 microns R_a regardless of lay.

7. The method of producing an anvil according to claim 5 wherein the second portion has a surface finish of less than 1.6 microns.

8. An anvil for an impact tool comprising:

a body formed of a steel having less than 0.15% carbon and between about 2.95 and about 3.55% Ni, and between about 1.0 and about 1.45% Cr, said body having an exterior layer having a carbon content greater than 0.15% carbon formed by carburization of the body; and

a microstructure having more than 90% tempered martensite formed from a plurality of heat treatment/quenching cycles.

9. The anvil according to claim 8 having a first portion with a circular cross section and a second portion having a square cross section and a transition portion therebetween, said transition portion having an exterior radius of about 2 mm.

10. The anvil according to claim 9 wherein the surface has a surface roughness of less than 1.6 microns

11. The anvil according to claim 9 wherein the first portion and the transition portion have a surface roughness of less than 1.6 microns.

12. The anvil according to claim 8 having greater than about 98% by weight martensite.

13. An impact wrench comprising:

an anvil having a body formed of an alloy steel having less than 0.15% C and between 2.95 and 3.55% Ni, and between 1.0 and 1.45% Cr, said body being formed of more than about 90% tempered martensite which are formed by a plurality of heating and quenching cycles.

14. The impact wrench according to claim 13 wherein the body is subject to a plurality of heat treating cycles at temperatures between about 1450 and 1525°

F. having quenching cycles therebetween.

15. The impact wrench according to claim 14 wherein the body has an outer layer having a carbon content of greater than 0.6% formed by a carburization process.

16. The impact wrench according to claim 15 wherein the anvil body has a first portion with a circular cross section, and a second portion of any square cross section with a first cross-sectional area, and a transition portion therebetween, said transition portion having a second cross-sectional area greater than the first cross-sectional area.

17. The impact wrench according to claim 16 wherein the body has a surface finish of less than 0.8 microns.

18. The impact wrench according to claim 17 wherein the first portion and the transition portion has a surface finish of less than 1.6 microns.