GB1390582A - Handling ferromagnetic loads - Google Patents

Abstract

1390582 Magnetic lifting devices INSTITUT MANIPULACNICH DOPRAVNICH OBALOVYCH A SKLADOVACICH SYSTEMU 23 July 1973 [24 July 1972] 34921/73 Heading B8H [Also in Division H1] A magnetic hoist comprises a member 1 having envelope 2 and magnetic core 3 resting on ledges 4 of the latter, which carries a suspension device 5 having a guide slot 6 therein. Guides 7 engaging pressure pads 8 are also carried by envelope 2, and to the pads are pivoted levers 9 connected to the envelope by rods 10. The levers also carry suspension points 11 for suspension members 12 and terminal suspension points 13 for suspension members 14. A pin 15 moves in guide slot 6 with piston-rod 16, whose upper end carries a suspension head 17 and a piston 18 with a throttle bore 19 and valve 20 moving within oil filled cylinder 21, whose upper end member 22 carries suspension members 12. A further support 23 above the cylinder is movable along rod 16 and has claws 24 engaging latches 25 on frame 26 under control of a control mechanism; the frame having elongate aperture 27 in which suspension head 17 is vertically movable. A ferromagnetic load 28 is engaged by the magnetic core 3, and on lifting frame 26 rod 16 is raised and pin 15 slides in slot 6. Piston 18 rises and compresses the oil in cylinder 21 to raise the latter; thus tensioning suspension members 12 to pivot levers 9 and depress pads 8. This adds to the natural weight of the load; which is raised if the total load is less than the magnet capacity and is left stationary if it exceeds the magnet capacity. During raising (Fig. 2, not shown) piston valve 20 closes and the pressure oil enters the lower part of the cylinder through piston bore 19. Thus piston-rod 16 raises relatively to the magnet until pin 15 abuts the upper end of slot 6, when movement of the piston ceases and the force exerted by suspension members 12 and pads 8 also ceases (Fig. 3, not shown). The magnet then overcomes the true weight of load 28, which is raised. During lowering (Fig. 4, not shown) piston 18 is depressed into cylinder 21 by pressure of support frame 26 on head 17, and valve 20 opens. Subsequently (Fig. 5, not shown) support member 23 is engaged with support frame 26 by claws 24 and latches 25 under central control and on raising the frame syspension 14 is tensioned to pivot levers 9 and apply pressure on the load through pads 8, whereby the magnet is separated from the load. On application to a further load 24 (Fig. 6, not shown) the initial lifting condition is re-established. The hydraulic dashpot piston and cylinder may alternatively be pneumatic, or an equivalent mechanical linkage. The hoist is suspensible directly from a crane hook, or in plurality from a beam suspensible from the hook (Figs. 7 to 10, not shown).