Patent ID: 8907754
Filing Date: 2014-12-09
Classification: B23Q,B25B

Abstract:
1. A magnetic holding device, comprising: an array of a plurality of switchable permanent magnets; a carrier that holds the array of switchable permanent magnets to form at least a portion of a working surface; each switchable permanent magnet in the array having a coil of wire surrounding a magnetizable core element; the array arranged in a plurality of at least first and second groups of one or more switchable permanent magnets in each group; the at least first and second groups having alternating switchable permanent magnets on the carrier, where each switchable permanent magnet in the first group has at least one closest neighbor switchable permanent magnet that is in the second group, and where each switchable permanent magnet in the second group has at least one closest neighbor switchable permanent magnet that is in the first group; and a magnetizing and demagnetizing circuit coupled to the coils and configured to selectively carry out magnetizing and demagnetizing actions on each group of switchable permanent magnets so as to selectively and independently place each group of switchable permanent magnets in the array into a selected one of the following states: