Clamp assembly including permanent magnets and coils for selectively magnetizing and demagnetizing the magnets

Patent metadata

Field	Value
Publication number	US-9281108-B2
Application number	US-201414515614-A
Country	US
Kind code	B2
Filing date	Oct 16, 2014
Priority date	Apr 30, 2012
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

A clamp assembly comprises a first clamp including a plurality of magnet devices. Each magnet device includes a permanent magnet and a coil surrounding the permanent magnet. The clamp assembly further comprises a controller for pulsing the coils to selectively magnetize and demagnetize the permanent magnets.

First claim

That which is claimed is:

1. A method of clamping a stack, the method comprising:
positioning permanent magnets against a first surface of the stack;
placing a flux-conducting structure against a second surface of the stack; and
applying external magnetic field pulses to the permanent magnets to magnetize and demagnetize the permanent magnets,
wherein applying external magnetic field pulses to the permanent magnets to magnetize the permanent magnets comprises promoting magnetic domain alignment within the permanent magnets sufficient to clamp the stack between the permanent magnets and the flux conducting structure;
wherein applying external magnetic field pulses to the permanent magnets to demagnetize the permanent magnets comprises demoting magnetic domain alignment within the permanent magnets sufficient to reduce a clamping force applied to the stack by the flux-conducting structure and the permanent magnets;
wherein applying external magnetic field pulses is performed in a first direction for magnetizing the permanent magnets; and
wherein applying external magnetic field pulses is performed in a second direction for demagnetizing the permanent magnets, the second direction being opposite the first direction.

2. The method of claim 1 , wherein the permanent magnets are positioned about a process axis.

3. The method of claim 1 , wherein pulse duration is on the order of milliseconds, and clamping cycle is at least ten seconds.

4. The method of claim 1 , wherein the flux-conducting structure includes a plate for providing a flux path.

5. The method of claim 1 , wherein the flux-conducting structure includes a plurality of second magnet devices aligned with the permanent magnets.

6. The method of claim 1 , wherein the permanent magnets are disposed in a robot end effector.

7. The method of claim 6 , wherein applying external magnetic field pulses to the permanent magnets is performed selectively by a controller.

8. The method of claim 6 , wherein positioning permanent magnets against a first surface of the stack is performed by at least one robot.

9. The method of claim 1 , wherein applying external magnetic field pulses comprises applying a single external magnetic field pulse.

10. The method of claim 1 , wherein applying external magnetic field pulses comprises applying at least two external magnetic field pulses.

11. The method of claim 1 further comprising modulating either magnitude or duration of the external magnetic field pulses during magnetization to alter a peak current attained by the pulse.

12. The method of claim 1 , wherein applying external magnetic field pulses to the permanent magnet comprises applying external magnetic field pulses to less than all of the permanent magnets.

13. The method of claim 1 , wherein applying external magnetic field pulses is performed simultaneously for all of the permanent magnets.

14. The method of claim 1 , wherein the permanent magnets are demagnetized prior to being positioned against a first surface of the stack.

Assignees

• Boeing Co

Inventors

• Sarh Branko
• Rus Daniela Lucia
• Marchese Andrew Dominic

Classifications

• B25B11/002 Primary

  Magnetic work holders · CPC title

• H01F7/1805

  Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current (for holding relay armature in attracted position with reduced energising current H01H47/04; quick energising of electro-dynamic machines H02P9/08; for quickly de-energising of dynamo-electric generators H02P9/123) · CPC title

• H01F7/18

  Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings · CPC title

• H01F7/04

  Means for releasing the attractive force · CPC title

• B25J15/0608

  with magnetic holding means · CPC title