Magnetorheological reconfigurable clamp for a flexible manufacturing system

• US 20050269758A1
• Filed: 06/03/2005
• Published: 12/08/2005
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Menassa, Roland J., Sears, Ivan G., Stevenson, Robin
• Granted Patent: US 7,204,481 B2
• Time in Patent Office: Days
• US Class Current: 269/266
• CPC Class Codes: B23K 11/11 Spot welding
• CPC Class Codes: B23K 37/0435 Clamps
• CPC Class Codes: B23K 37/0443 Jigs
• CPC Class Codes: B23K 37/047 moving work to adjust its position between soldering, welding or cutting steps B23K37/053 takes precedence
• CPC Class Codes: B23Q 1/035 with an array of longitudinally movable rods defining a reconfigurable support surface
• CPC Class Codes: B25B 1/2421 the parts having a linear movement

Abstract

A reconfigurable clamp for a flexible manufacturing system comprises a body portion, a plurality of pins slidably engaged within sleeves formed in the body portion, a compression spring attached to each shaft of the plurality of pins, a reservoir comprising a magnetorheological fluid in operative communication with the plurality of pins, and an electromagnet in operative communication with the magnetorheological fluid, wherein the electromagnet selectively increases a yield stress property of the magnetorheological fluid; and a matching pressure foot.

Claims

1. A reconfigurable clamp, comprising:

a body comprising a plurality of sleeves and a reservoir in fluid communication with the plurality of sleeves;

a plurality of pins, wherein each one of the plurality of pins is disposed in sliding engagement with a corresponding one of the plurality of sleeves, wherein each one of the plurality of pins comprises a head, a shaft extending from the head, and a compression spring in operative communication with the shaft;

a magnetorheological fluid disposed in the reservoir and the plurality of sleeves; and

an electromagnet in operative communication with the magnetorheological fluid.

2. The reconfigurable clamp of claim 1, further comprising a stop in operative communication with each one of the plurality of pins and the plurality of sleeves.

3. The reconfigurable clamp of claim 2, wherein the stop comprises a protrusion extending from each one of the plurality of pins and a recess disposed in a sidewall of the corresponding one of the plurality of sleeves.

4. The reconfigurable clamp of claim 1, wherein the magnetorheological fluid comprises ferromagnetic or paramagnetic particles or particulates dispersed in a carrier fluid.

5. The reconfigurable clamp of claim 4, wherein the particles or the particulates are in an amount of about 5 to about 75 percent by volume of the magnetorheological fluid.

6. The reconfigurable clamp of claim 1, wherein the body has at least one gimbaled surface.

7. The reconfigurable clamp of claim 1, wherein each one of the plurality of pins further comprises a seal in sealing communication with the shaft and the corresponding one of the plurality of sleeves.

8. The reconfigurable clamp of claim 1, wherein the magnetorheological fluid is disposed in a bladder.

9. A reconfigurable clamp system, comprising:

a clamp comprising a body portion, a plurality of pins slidably engaged within sleeves formed in the body portion, a compression spring attached to each shaft of the plurality of pins, a reservoir comprising a magnetorheological fluid in operative communication with the plurality of pins, and an electromagnet in operative communication with the magnetorheological fluid, wherein the electromagnet selectively increases a yield stress property of the magnetorheological fluid; and

a matching pressure foot.

10. The reconfigurable clamp system of claim 9, further comprising a stop in operative communication with each one of the plurality of pins and sleeves.

11. The reconfigurable clamp system of claim 10, wherein the stop comprises a protrusion extending from each one of the plurality of pins and a recess portion disposed in a sidewall of the sleeves.

12. The reconfigurable clamp system of claim 9, wherein the magnetorheological fluid comprises ferromagnetic or paramagnetic particles or particulates dispersed in a carrier fluid.

13. The reconfigurable clamp system of claim 12, wherein the particles are in an amount of about 5 to about 75 percent by volume of the magnetorheological fluid.

14. The reconfigurable clamp system of claim 9, wherein the body portion has at least one gimbaled surface.

15. The reconfigurable clamp system of claim 9, wherein each one of the plurality of pins further comprises a seal in sealing communication with the shaft and the sleeves.

16. The reconfigurable clamp system of claim 9, wherein the magnetorheological fluid is disposed in a bladder.

17. A process for clamping a workpiece, the process comprising:

loading a first workpiece onto a reconfigurable clamp, wherein the reconfigurable clamp comprises a clamp comprising a body portion, a plurality of pins slidably engaged within sleeves formed in the body portion, a compression spring attached to each shaft of the plurality of pins, a reservoir comprising a magnetorheological fluid in operative communication with the plurality of pins, and an electromagnet in operative communication with the magnetorheological fluid, wherein the electromagnet selectively increases a yield stress property of the magnetorheological fluid;

compressing the plurality of pins to conform substantially to a surface contour of the first workpiece;

applying a magnetic field with the electromagnet to the magnetorheological fluid to alter a shear force of a sliding engagement between the plurality of pins and the sleeves; and

applying a member to a backside of the first workpiece.

18. The process of claim 17, wherein applying the magnetic field comprises changing a current to a coil in proximity to the magnetorheological fluid.

19. The process of claim 17, further comprising discontinuing the magnetic field;

removing the member; and

removing the first workpiece from the reconfigurable clamp.

20. The process of claim 17, further comprising loading a second workpiece onto the reconfigurable clamp, wherein the second workpiece has a different surface contour than the first workpiece;

compressing the plurality of pins to conform substantially to a surface contour of the second workpiece;

applying a magnetic field with the electromagnet to the magnetorheological fluid to alter the shear force of the sliding engagement between the plurality of pins and the sleeves; and

applying a member to a backside of the surface of the second.