Clamping device for tool holder

Patent metadata

Field	Value
Publication number	US-12194545-B2
Application number	US-202017786215-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 20, 2019
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A clamping device for releasably holding a tool holder shank includes a housing, a drawbar axially moveable in a bore in the housing between an advanced releasing position and a retracted locking position, engagement members moveable under the effect of the drawbar into locking engagement with the tool holder shank, and a sleeve arranged around a wall of the housing and axially moveable in relation to it. A first wedge is received in a first aperture in the wall and configured to move the drawbar rearwards in the bore when pressed radially inwards in the aperture by movement of the sleeve in a first axial direction. A second wedge is received in a second aperture in the wall and configured to move the drawbar forwards in the bore when pressed radially inwards in the aperture by movement of said sleeve in an opposite axial direction.

First claim

The invention claimed is:

1. A clamping device for releasably holding a tool holder shank, the clamping device comprising:
a housing having a front end, a rear end and a bore which intersects the front end and extends rearwardly therefrom, wherein a mounting portion for receiving the tool holder shank is provided at a front end of the bore;
a drawbar slidably mounted inside the bore so as to be reciprocally moveable in the bore along a longitudinal axis thereof between an advanced releasing position and a retracted locking position;
engagement members arranged around the drawbar at a front end thereof, wherein the engagement members, under the effect of a movement of the drawbar from the advanced releasing position to the retracted locking position, are moveable from a first position, in which the engagement members allow the tool holder shank to move into and out of said mounting portion, to a second position, in which the engagement members are in locking engagement with the tool holder shank and keep it secured to the housing; and
a first wedge having a wedge surface facing towards the rear end of the housing and a first pressure receiving surface, wherein the first wedge is slidably received in a first aperture that extends radially through a peripheral wall of the housing, wherein the first pressure receiving surface on the first wedge faces outwards from the housing and the wedge surface on the first wedge is in contact with a first slide surface on the drawbar facing towards the front end of the housing, the first wedge being configured to press the drawbar towards the retracted locking position when it is pressed radially inwards in the first aperture; that, the clamping device including a second wedge slidably received in a second aperture that extends radially through the peripheral wall, wherein the second wedge includes a second wedge surface, which faces towards the front end of the housing and is in contact with a second slide surface on the drawbar facing towards the rear end of the housing, and a second pressure receiving surface, which faces outwards from the housing, the second wedge being configured to press the drawbar towards the advanced releasing position when it is pressed radially inwards in the second aperture, wherein the clamping device includes an actuating sleeve arranged around the peripheral wall and slidably mounted to it so as to be axially moveable in relation to the housing in a first axial direction in order to effect a movement of the drawbar from the advanced releasing position to the retracted locking position and in an opposite second axial direction in order to effect a movement of the drawbar from the retracted locking position to the advanced releasing position, wherein the actuating sleeve on its inner side is provided with a first pressure applying surface, which faces inwards for contacting the first pressure receiving surface and has a radial distance to the longitudinal axis that increases as seen in said first axial direction, and a second pressure applying surface, which faces inwards for contacting the second pressure receiving surface and has a radial distance to the longitudinal axis that increases as seen in said second axial direction, wherein the first pressure applying surface is configured to press the first wedge radially inwards in the first aperture by pressing against the first pressure receiving surface when the actuating sleeve is moved in said first axial direction, and wherein the second pressure applying surface is configured to press the second wedge radially inwards in the second aperture by pressing against the second pressure receiving surface when the actuating sleeve is moved in said second axial direction.

2. The clamping device according to claim 1 , wherein the actuating sleeve is configured to assume a self-locking axial position on the peripheral wall when the drawbar has been forced into the retracted locking position under the effect of the actuating sleeve and the first wedge, so as to thereby keep the drawbar in the retracted locking position.

3. The clamping device according to claim 2 , wherein the first pressure applying surface and the first pressure receiving surface are inclined in relation to the longitudinal axis by such an angle α that the first wedge will keep the actuating sleeve in a self-locking axial position on the peripheral wall when the drawbar has been forced into the retracted locking position under the effect of the actuating sleeve and the first wedge.

4. The clamping device according to claim 3 , wherein the first wedge includes a third pressure receiving surface which faces outwards from the housing, wherein the actuating sleeve on its inner side is provided with a third pressure applying surface, which faces inwards for contacting the third pressure receiving surface, the third pressure applying surface having a radial distance to the longitudinal axis that increases as seen in said first axial direction; that, wherein the third pressure applying surface and the third pressure receiving surface are inclined in relation to the longitudinal axis by an angle β, which is larger than the angle α, and wherein the first and third pressure applying surfaces and the first and third pressure receiving surfaces are arranged consecutively on the actuating sleeve and on the first wedge, respectively, such that, upon a movement of the actuating sleeve in the first axial direction, the third pressure applying surface is configured to slide and press against the third pressure receiving surface during a first phase of the movement and the first pressure applying surface is configured to slide and press against the first pressure receiving surface during a subsequent second phase of the movement.

5. The clamping device according to claim 4 , wherein the first and third pressure applying surfaces and the first and third pressure receiving surfaces are curved as seen in a cross-sectional plane perpendicular to the longitudinal axis.

6. The clamping device according to claim 1 , wherein the first pressure applying surface and the second pressure applying surface partly overlap each other in the axial direction of the actuating sleeve and are spaced apart from each other in the circumferential direction of the actuating sleeve.

7. The clamping device according to claim 6 , wherein the second pressure applying surface is provided in a recess formed in a rotationally symmetric inner wall surface of the actuating sleeve.

8. The clamping device according to claim 1 , wherein the clamping device includes two or more such first wedges spaced apart in the circumferential direction of the peripheral wall, each first wedge being received in a respective first aperture that extends radially through the peripheral wall.

9. The clamping device according to claim 8 , wherein the first wedges are three in number.

10. The clamping device according to claim 8 , wherein the first wedges are evenly distributed in the circumferential direction of the peripheral wall.

11. The clamping device according to claim 8 , wherein the clamping device includes two or more such second wedges spaced apart in the circumferential direction of the peripheral wall, each second wedge being received in a respective second aperture that extends radially through the peripheral wall.

12. The clamping device according to claim 11 , wherein the second wedges are three in number.

13. The clamping device according to claim 11 , wherein the second wedges are evenly distributed in the circumferential direction of the peripheral wall.

14. The clamping device according to claim 11 , wherein the first wedges and the secon

Assignees

• Sandvik Coromant Ab

Inventors

• Matlik Gunnar

Classifications

• B23B2260/146

  Wedges · CPC title

• B23B2231/12

  Chucks having means to amplify the force produced by the actuating means to increase the clamping force · CPC title

• B23B31/265 Primary

  by means of collets · CPC title