Inverted piloted collet chuck and applications thereof

Patent metadata

Field	Value
Publication number	US-9849520-B2
Application number	US-201514825461-A
Country	US
Kind code	B2
Filing date	Aug 13, 2015
Priority date	Aug 13, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Collet chucks are described herein having design and architecture for minimizing and/or mitigating collet misalignment during rotary tool coupling operations. For example, a collet chuck comprises a housing for connection and rotation with a spindle about an axis of rotation, wherein the housing defines a socket for receiving a collet. The collet comprises a nose end engaging the socket and a second tapered end engaging a locknut assembly.

First claim

The invention claimed is:

1. A collet chuck comprising: a housing for connection and rotation with a spindle about an axis of rotation, the housing defining a socket; and a collet comprising a nose end engaging the socket and a second tapered end engaging a locknut assembly comprising a locknut; wherein the nose end of the collet has a tapered portion which decreases in diameter in the direction of the nose end; and wherein the socket has an interior tapered portion which engages the tapered portion of the nose end of the collet, the interior tapered portion having a complementary taper angle to the tapered portion of the nose end of the collet; wherein the locknut assembly further comprises a pilot clamping ring positioned within a bore of the locknut at a first radial clearance, wherein the pilot clamping ring engages the second tapered end of the collet and is positioned within a cylindrical inner surface of the housing at a second radial clearance.

2. The collet chuck of claim 1 , wherein the locknut assembly comprises a locknut threadingly engaging the housing.

3. The collet chuck of claim 1 , wherein compressive force applied by a collar of the locknut is transmitted through the pilot clamping ring collapsing the collet.

4. The collet chuck of claim 1 , wherein the pilot clamping ring freely rotates in the locknut bore.

5. The collet chuck of claim 1 , wherein the collet is selected from the group consisting of an ER-style collet and TG-style collet.

6. The collet chuck of claim 5 providing a runout error of less than 0.010 mm according to DIN6499.

7. The collet chuck of claim 5 providing a runout error of less than 0.005 mm according to DIN6499.

8. The collet chuck of claim 1 , wherein the locknut assembly further comprises a snap ring positioned between the locknut and pilot clamping ring.

9. The collet chuck of claim 1 , wherein the collet is an ER-style collet, the collet chuck having a grip strength greater than 1800 in/lb at an applied torque of 100 ft/lb.

10. A method of clamping a tool comprising: providing a collet chuck including a housing for connection and rotation with a spindle about an axis of rotation, the housing defining a socket and a collet having a nose end engaging the socket and a second tapered end for receiving a shank of a cutting tool in a central bore of the collet; positioning the cutting tool shank in the collet central bore; and collapsing the central bore by tightening a locknut assembly comprising a locknut engaging the housing, wherein the nose end of the collet has a tapered portion which decreases in diameter in the direction of the nose end; wherein the socket has an interior tapered portion which engages the tapered portion of the nose end of the collet, the interior tapered portion having a complementary taper angle to the tapered portion of the nose end of the collet: and wherein the locknut assembly further comprises a pilot clamping ring positioned within a bore of the locknut at a first radial clearance, wherein the pilot clamping ring engages the second tapered end of the collet and is positioned within a cylindrical inner surface of the housing at a second radial clearance.

11. The method of claim 10 , wherein the locknut threadingly engages the housing.

12. The method of claim 10 , wherein the pilot clamping ring freely rotates in the locknut bore.

13. The method of claim 10 , wherein the collet is selected from the group consisting of an ER-style collet and TG-style collet.

14. The method of claim 10 , wherein the locknut assembly further comprises a snap ring positioned between the locknut and pilot clamping ring.

15. The method of claim 10 , wherein the collet is an ER-style collet, the collet chuck having a grip strength greater than 1800 in/lb at an applied torque of 100 ft/lb.

16. The method of claim 10 , wherein the cutting tool is a drill or an endmill.

Assignees

• Kennametal Inc

Inventors

• Mccormick Michael R

Classifications

• Y10T279/17495

  Threaded sleeve and wedge · CPC title

• B23B31/20 Primary

  Longitudinally-split sleeves, e.g. collet chucks · CPC title

• Y10T409/303752

  Process · CPC title

• B23B2231/2078

  Jaw carriers, i.e. components retaining the collet itself · CPC title

• B23B31/02

  Chucks · CPC title