The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 05, 1987
Filed:
Apr. 03, 1986
Dominic F Pignataro, Shrewsbury, MA (US);
Walker Magnetics Group, Inc., Worcester, MA (US);
Abstract
The magnetic chuck disclosed herein is of the permanent magnet type in which both a top plate and a shiftable pack comprise alternating major pole pieces and magnets, the pack being shiftable so that its magnets either aid or oppose the magnets in the top plate, thereby to change between holding and release states. Improved holding for thin workpieces is obtained by providing a central region in the top plate in which the major pole pieces are thinner than the magnets and in which a plurality of floating minor pole pieces are positioned in the gaps between the major poles. While less flux is available through the thinner major pole pieces, the floating pole pieces provide an increased number of transitions for flux between top plate and workpiece so the total holding force for thin workpieces is improved. Increased flux available at the outer regions to either side of the central region provides good holding force for larger workpieces so that the chuck is well-adapted for a wide range of applications such as may be found in machine shop tool rooms.