Pneumatically actuated magnetic workpiece holder

Abstract

A pneumatically actuated magnetic workpiece holder comprising a housing having a contact surface for contacting a workpiece to be held, and a magnet assembly translationally disposed in the housing, the magnet assembly comprising a plurality of permanent magnets arranged so that adjacent magnets are of opposite polarities. The housing is adapted for fluid communication with a pneumatic supply. The magnet assembly is biased towards an operative position, according to which the magnet assembly is sufficiently near the contact surface to exert on a workpiece an attractive force sufficient for holding the workpiece in contact with the workpiece holder, and is translationally positionable by pneumatic pressure towards an inoperative position, according to which the magnet assembly is sufficiently distant from the contact surface so as to be unable to exert on the workpiece an attractive force sufficient for holding the workpiece in contact with the workpiece holder. The invention is adapted for replacing suction-cup workpiece holders in conventional vacuum lifting devices, and a method of utilizing the present invention in this fashion is taught to comprise providing the workpiece holder with a coupling complimentary to the coupling for such conventional suction-cup workpiece holders, so that the magnetic workpiece holder may be substituted for the conventional suction-cup holder in the vacuum lifting device. According to this method, the vacuum supply of the conventional vacuum lifting device is adapted to provide such positive air pressure for employing the magnetic workpiece holder of this invention.