GB551329A - Improvements in permanent magnetic chuck - Google Patents

Abstract

551,329. Magnetic work-holders. BEECHLYN, J. T. Aug. 15, 1941, No. 10414. [Class 60] A work-holder comprises two insulated pole-elements in connection with a system of permanent magnets, a portion of the system being movable to reverse part of the flux for the purpose of releasing the work held by the poleelements. The workholder shown in Figs. 1 and 2 comprises top and bottom sections 10, 12, and a section 16 having plates 42 arranged between grid-bars 24 on the top section and insulated therefrom by soft metal 46, the plates and grid-bars constituting pole-elements for holding the work. Permanent magnets 20, 22 are arranged between the sections 12, 16, the magnets 20 being fixed, and the magnet 22 consisting of magnets 47, 48 bolted to caps 54 which are rotatably mounted in depressions 32, 40 in the sections 12, 16. The magnet 22 is provided with end-caps having handles attached thereto. The magnet 22 is preferably stronger than the magnets 20, the difference in strength being produced by employing magnets of different sizes, or by arranging their non- magnetic plates across some of the magnetic circuits. When the magnet 22 is so positioned that the upper pole is the same as that of the magnets 20, the fluxes of the magnets are additive, and a powerful work-holding flux passes through the pole-elements and the work. Since the return path of the flux is through the top and bottom sections, there is no tendency for chips to collect. When the magnet 22 is so positioned that the upper pole is different from that of the magnets 20, the flux is considerably reduced, the polarities of the elements 24, 42 are reversed, and the work is released. In a modification, the magnets 20 are arranged to transmit the flux laterally, and the magnet 22 consists of two separately rotatable magnets interconnected by linkage or gearing.