GB1333490A - Permanent magnet grabs - Google Patents

Abstract

1333490 Magnetic grabs VSESOJUZNY PROEKTNO-TEKHNOLOGICHESKY INSTITUT ENERGETICHESKOGO MASCHINOSTBOENIA 14 Dec 1971 87899/71 Heading B8H [Also in Division H1] A magnetic grab comprises a body 1 accommodating a magnetic assembly 2 comprising parallel relatively movable units 6, 7 each of which comprises a flat plate of barium oxide ferrite permanent magnets 8 alternating with non-magnetic elements 9 of similar pitch 10. Unit 6 is fixed in the base of body 1 and unit 7 is reciprocally movable above it on ball bearings with a clearance 11 through pitch 10 to connect and disconnect the magnetic flux; by a horizontal rack 14 on the movable unit engaging a sequential gear 15 held in bearings on mounting plate 13. A linkage 19 connects the gear to a crank 21 on a shaft 22 carrying a fixed ratchet 24 and a free spur gear 25 carrying the ratchet panel 26. In the hook suspension 5, a horizontal apertured base carries a vertical guide (Fig. 3, not shown) concentric with an outer sleeve 30 whose surface carries a vertical rack 27 engaging gear 25. The base has vertical walls connected to the hook suspension ring 28, and the suspension slides on central pin 33 passing through the guide bushing and secured to mounting plate 13 against coil spring 4. In operation, when the lifting cable lightens, suspension 5 rises to compress spring 4, and gear 25 rotates to slide panel 26 over rotated 24; the movable magnetic unit 7 being in ON position indicated at 38 with the magnetic elements 8 collinear, to attract the load which is then lifted. When it is lowered to the ground, spring 4 expands to lower suspension 5 until it rests on mounting plate 13, while gear 25 rotates ratchet 24 anticlockwise and through the linkage and rack shifts movable unit 7 to the OFF position, with the magnetic elements 8 out of line, to release the load. On light lifting, suspension 5 rises, gear 25 turns anticlockwise, and movable unit is in the OFF position, until a new load is gripped.