Magnetic gripping apparatus having circuit for eliminating residual flux

Patent 4956625 Issued on September 11, 1990. Estimated Expiration Date:

May 26, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

675323

2213007

2445459

3740683

Permanent magnet holding system
Patent #: 3978441
Issued on: 08/31/1976
Inventor: Sobottka , et al.

Devices for magnetic control with permanent magnets
Patent #: 4015174
Issued on: 03/29/1977
Inventor: Cotton de Bennetot

Magnetic control closure system
Patent #: 4141547
Issued on: 02/27/1979
Inventor: Duquenne , et al.

Magnetic gripping apparatus Patent #: 4847582
Issued on: 07/11/1989
Inventor: Cardone , et al.

Inventors

Assignee

Tecnomagnete S.p.A

Application

No. 357342 filed on 05/26/1989

US Classes:

335/290, With circuit control means335/295With magnetic-hold control means (e.g., means to control the hold strength)

Examiners

Primary: Harris, George

Attorney, Agent or Firm

Beveridge, DeGrandi & Weilacher

International Class

H01F 007/20

Foreign Application Priority Data

1988-06-10 IT

Abstract

A magnetic gripping apparatus, of the permanent magnet type, comprising a base plate and peripheral walls, at least a first and a second pole units, each pole unit comprising a main pole piece having an outer face defining a gripping surface, main permanent magnets arranged between said main pole pieces and said base plate, an intermediate pole member between said first and second pole units, said intermediate pole member extending from the base plate to the gripping surface and secondary magnets between the pole members and the pole pieces; a first electrical windings encircles each main magnet, said electrical winding being operatively conected to a control unit, and a residual flux eliminating circuit comprising a second electrical winding encircling said intermediate pole member, said second winding being operatively connected to a demagnetizing control unit.