Clamping device for tool holder

Patent metadata

Field	Value
Publication number	US-12325077-B2
Application number	US-202117800091-A
Country	US
Kind code	B2
Filing date	Feb 2, 2021
Priority date	Feb 17, 2020
Publication date	Jun 10, 2025
Grant date	Jun 10, 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, engagement members moveable under the effect of the drawbar into locking engagement with the tool holder shank, and an actuating member rotatably arranged in the bore. Upon rotation of the actuating member, a contact surface on a motion transferring element fixedly connected to the actuating member achieves an axial movement of the drawbar by pressing against a contact surface on another motion transferring element fixedly connected to the drawbar. At least one of the contact surfaces includes two sections with mutually different pitch, such that the same angular displacement of the actuating member, when rotated in a first rotary direction, results in a longer axial movement of the drawbar in a first phase of the rotary movement than in a final phase thereof.

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; and
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 of the bore, 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;
an actuating member rotatably arranged in the bore so as to be rotatable about the longitudinal axis, wherein the actuating member is axially fixed in relation to the housing so as to be prevented from moving along the longitudinal axis; and
a motion transferring mechanism arranged inside the housing, wherein the motion transferring mechanism is configured to transfer a rotary movement of the actuating member in a first rotary direction in relation to the housing into an axial movement of the drawbar from the advanced releasing position to the retracted locking position, wherein the motion transferring mechanism comprises:
a first motion transferring element, which is fixed to or fixedly connected to the drawbar so as to be moveable along the longitudinal axis together with the drawbar and which is provided with a first pressure receiving contact surface facing towards the front end of the housing; and
a second motion transferring element, which is fixed to the actuating member so as to be rotatable in relation to the housing and the drawbar together with the actuating member and which is provided with a first pressure applying contact surface facing towards the rear end of the housing for contacting the first pressure receiving contact surface, wherein the first pressure applying contact surface is configured to press the drawbar from the advanced releasing position to the retracted locking position by sliding and pressing against the first pressure receiving contact surface when the actuating member is rotated in the first rotary direction; and wherein at least one of said contact surfaces includes a first contact surface section and a second contact surface section arranged at different positions along an associated motion transferring element, such that, upon a movement of the actuating member in the first rotary direction, the first contact surface section is configured to slide against the other contact surface during a first phase of the movement and the second contact surface section is configured to slide against the other contact surface during a final phase of the movement, wherein the first contact surface section has a larger pitch than the second contact surface section such that the same angular displacement of the actuating member in connection with a rotation thereof in the first rotary direction in relation to the housing results in a longer axial movement of the drawbar in said first phase than in said final phase.

2. The clamping device according to claim 1 , wherein the pitch is constant along said second contact surface section.

3. The clamping device according to claim 1 , wherein the pitch is constant along said first contact surface section.

4. The clamping device according to claim 3 , wherein the second contact surface section is positioned on the associated motion transferring element adjacent to said first contact surface section, such that the second contact surface section follows directly after the first contact surface section.

5. The clamping device according to claim 1 , wherein the second contact surface section has a pitch such that the first and second motion transferring elements will keep the actuating member in a self-locking rotary position in relation to the drawbar when the drawbar has been forced into the retracted locking position under the effect of the actuating member and the first and second motion transferring elements.

6. The clamping device according to claim 1 , wherein the first pressure receiving contact surface includes the first and second contact surface sections.

7. The clamping device according to claim 6 , wherein the first contact surface section of the first pressure applying contact surface is configured to slide and press against the first contact surface section of the first pressure receiving contact surface during said first phase of the rotary movement of the actuating member in the first rotary direction, and wherein the second contact surface section of the first pressure applying contact surface is configured to slide and press against the second contact surface section of the first pressure receiving contact surface during the final phase of this rotary movement.

8. The clamping device according to claim 7 , wherein the first contact surface section of the first pressure applying contact surface has the same pitch as the first contact surface section of the first pressure receiving contact surface, and the second contact surface section of the first pressure applying contact surface has the same pitch as the second contact surface section of the first pressure receiving contact surface.

9. The clamping device according to claim 1 , wherein the first pressure applying contact surface includes the first and second contact surface sections.

10. The clamping device according to claim 1 , wherein the first and second motion transferring elements form part of two threads, which are arranged in threaded engagement with each other, wherein said contact surfaces have the form of thread surfaces.

11. The clamping device according to claim 1 , wherein the first motion transferring element has a form of an external projection on an envelope surface of a shaft which is fixed to the drawbar, and wherein the actuating member is sleeve-shaped and surrounds said shaft, wherein the second motion transferring element has a form of an internal projection on the actuating member.

12. The clamping device according to claim 1 , wherein the motion transferring mechanism is configured to transfer a rotary movement of the actuating member in a second rotary direction, opposite to the first rotary direction, into an axial movement of the drawbar from the retracted locking position to the advanced releasing position.

13. The clamping device according to claim 12 , wherein the first motion transferring element is provided with a second pressure receiving contact surface facing towards the rear end of the housing, and wherein the motion transferring mechanism includes a third motion transferring element, which is fixed to the actuating member so as to be rotatable in relation to the housing together with the actuating member and which is provided with a second pressure applying contact surface facing towards the front end of the housing for contacting the second pressure receiving contact surface, wherein the second pressure applying contact surface is configured to press the drawbar from the retracted locking position to the advanced releasing position by sliding and pressing against the second pressure receiving contact surface when the actuating member is rotated in the second rotary d

Assignees

• Sandvik Coromant Ab

Inventors

• Wasterlund Jonas
• Matlik Gunnar

Classifications

• Y10T409/309464

  and draw bar · CPC title

• B23B2260/02

  Cams · CPC title

• B23B2260/034

  Drawbars · CPC title

• B23B31/12

  Chucks with simultaneously-acting jaws, whether or not also individually adjustable · CPC title

• B23B31/28

  using electric or magnetic means in the chuck · CPC title