Safety clamp

• US 5,937,687 A
• Filed: 07/17/1998
• Issued: 08/17/1999
• Est. Priority Date: 05/16/1997
• Status: Expired due to Fees

• Current Assignee: Pines Manufacturing, Inc. (Park-Ohio Holdings Corporation)
• Original Assignee: Pines Manufacturing, Inc. (Park-Ohio Holdings Corporation)
• Inventors: Glissman, Thomas W., Bhandari, Ajay K., Kreja, Tim, Bossert, Clayton E.
• Primary Examiner(s): Butler, Rodney
• Application Number:
  US09/118,632
• Time in Patent Office: 396 Days
• Field of Search: 72/155, 72/157, 72/158, 72/159, 72/149, 72/420, 72/422, 72/459, 72/460, 72/426, 72/457, 269/329, 269/277, 269/74, 269/43, 269/254 CS, 192/130, 192/129 A
• US Class Current: 72/155
• CPC Class Codes: B21D 7/02 over a stationary forming member; by use of a swinging forming member or abutment
• CPC Class Codes: B21D 7/024 by a swinging forming member
• CPC Class Codes: B25B 5/08 using cams

Abstract

A tube bending machine having a rotatable bend die, a pressure die, a clamp die, an actuator and a controller. A clamp assembly holds the clamp die and includes a base, a clamp die holder which is spring biased away from and slideably engageable with the base. A spacer is also attached to the base and is moveable between positions. A gear rotatably mounted to the base is attached to a first and second cam by a shaft and the gear moves on a rack. The first cam is followed by a cam follower which moves to allow the spacer to change positions. The clamp die holder may move toward the housing in case the clamp die engages an obstruction, thus avoiding damage or injury to the obstruction. A second position of the spacer substantially blocks the space between the clamp die holder and the base, thus making a substantially rigid connection between them. The second position is used during the tube bending process. A first microswitch senses the clamp die holder position and stops or opens the clamp die holder assembly if an obstruction is present. A set up mode is also provided by disengaging the gear from the rack and moving the spacer to the second position.

Claims

1. In a tube bending machine for bending a tube and having a rotatable bend die, a pressure die, a clamp die, an actuator and a controller, the improvement comprising:

a clamp assembly for holding the clamp die, comprising;

a base;

a clamp die holder spaced from and movably attached to the base;

a spacer operatively attached to move between the clamp die holder and the base, the spacer moveable between positions, a first position of the spacer allowing the clamp die holder to move relative to the base if the clamp die engages an obstruction thus avoiding damage or injury to the obstruction;

a second position of the spacer substantially blocking a space between the clamp die holder and the base thus making a substantially rigid connection between the clamp die holder and the base so that the tube is firmly engaged for bending; and

a mechanism which moves the spacer between the first position and the second position in response to a position of the clamp die holder.

2. The tube bending machine of claim 1, wherein the clamp assembly further includes the clamp die holder which is resiliently mounted to the base.

3. The tube bending machine of claim 1, wherein the clamp assembly further includes the spacer which is spring biased to the second position.

4. The tube bending machine of claim 1, wherein the clamp assembly further includes the clamp die holder which is spring biased away from the base.

5. The tube bending machine of claim 1, wherein the clamp assembly further includes slideable rods holding the clamp die holder so that the clamp die holder may move to engage the spacer to prevent movement from the first position if the clamp die meets an obstruction and moves toward said base.

6. The tube bending machine of claim 1, wherein the clamp assembly further includes a first microswitch which senses the position of the spacer and stops operation of the tube bender if the spacer is in the first position.

7. The tube bending machine of claim 2, wherein the mechanism in the clamp assembly includes a cam follower and a first cam which are operatively mounted on the base, the cam follower follows the first cam in order to permit movement of the spacer between the first and second positions.

8. The tube bending machine of claim 7, wherein the clamp assembly further includes a gear which is operatively mounted to the base on a shaft with the cam, a rack is mounted near the gear and is engageable by the gear so that as the clamp assembly moves toward the tube, the gear turns the first cam, the cam follower follows the first cam and permits the spacer to move from the first to the second position if there is no obstruction but remains in the first position if there is an obstruction.

9. The tube bending machine of claim 8, wherein said gear is moveable to a position which does not engage the rack so that the clamp assembly is moved readily during setting up of the tube to be bent.

10. The tube bending machine of claim 9, wherein a microswitch senses the position of the gear when it is not engaging the rack and allows a spring to rotate a second cam to move the spacer to the second position, said microswitch also sensing when the gear reengages the rack.