GB1335741A - Magnetic chuck - Google Patents

Abstract

1335741 Magnetic holding devices W MAURER 19 April 1971 [16 Feb 1970] 20186/71 Heading H1P A magnetic chuck (Figs. 1, 2) comprises baseplate 1 overlain by rectangular steel frame 2 whose upper face is covered by a non-magnetic layer 19 of, e.g. brass, aluminium, white metal or plastic on which is disposed a ferromagnetic head plate 3 supporting the workpiece 5, which is slotted to receive high permeability pole shoes 6 surrounded by a gap filled with securing non-magnetic material, e.g. brass, aluminium, white metal or plastic. A homopolar pack of permanent bar magnets 10, enclosed within a ferromagnetic grid 12, 13 by non-magnetic material 15, e.g. brass, aluminium, white metal or plastic is laterally displaceable by lever 8 relatively to the frame 2 and the base-plate and gap is left between the grid and the headplate on which the magnet poles abut. Lever 8 operates an eccentric pin and lever (Fig. 3, not shown) to laterally move the pack which in the position shown generates flux 14 engaging and attracting the workpiece to surface 4, while the bars 12 of the grid and pole shoes 6 coincide to complete the magnetic circuit. In the displaced position, magnets 10 are aligned in the pole shoes 6 and the cross-bars 12 are out of alignment with them so that the magnetic circuit is completed through the cross-bars, the polepieces, and the headplate to release the workpiece. A magnetic plate 16 underlying base-plate 1 is magnetized with poles at the top and bottom faces to oppose the polarity of magnets 10 and suppress undesired flux therefrom through the machine table and the tool operating on the workpiece. Plate 16 may be laminated and spaced.