GB1449145A - Permanent magnets - Google Patents

Abstract

1449145 Permanent magnets; magnetic holding devices DEFENCE SECRETARY OF STATE FOR 16 July 1974 [6 July 1973] 32271/73 Heading H1P A limpet magnet (Fig. 1, not shown) comprises a permanently magnetized strontium ferrite poled cuboid with adjacent parallel steel polepieces whose end surfaces contact a ferromagnetic surface over spacing strips of iron loaded rubber. In a modification (Fig. 2) plural permanent limpet magnets 21 each comprising a poled strontium ferrite cuboid 22 with adjacent parallel steel polepieces 23 are all embedded in a rubber slab 24 presenting a flat contact surface 26 to a ferromagnetic surface 27 to support a load 25. In a further modification (Fig. 3) plural permanent limpet magnets comprises a continuous flexible strip 31 adherent to a load 35, and the strip has plural composite ceramic ferromagnetic cuboids permanently magnetized and arranged in oppositely poled pairs separated by iron loaded rubber polepieces 33, the cuboids being composite of rubber and strontium ferrite. The surfaces 36 of the strip contacting ferromagnetic surface 37 comprise iron or ferrite loaded rubber. The ferrous loaded rubber elements may be heat moulded in a high magnetic field, and strip 31 may be fabricated from adherent single blanks. Barium ferrite may be used alternatively and the magnet may be of horseshoe form.