GB618260A - Improvements in beam type hoisting apparatus - Google Patents

Abstract

618,260. Cranes. MALBESIN, E. E. June 13, 1946, No. 17760. Convention date, March 1. [Class 78 (iv)] In a hoisting apparatus of the kind having a vertical support carrying at its top a beam which is movable about a horizontal axis, and one arm of which has a movable grab supporting carriage thereon, the other arm carries a pulley over which the hoisting cable passes, and also co-operates with a rear support comprising locking means for limiting the angular displacement of the beam and locking said beam in either of its limiting positions. The beam 3, pivoted at 2, can be locked in either of its limiting positions by catches 21, 20 and has a pulley 10 slidable thereon, which pulley is attached to a winch 12 by a rope 11 and has a cable 6 passing therearound, said cable also passing over a fixed pulley 9 and pulleys 7, 8 on the carriage 4, and having its ends anchored to the grab 5. Attached to the winch 12 is another cable 13 which passes over a pair of tensioning pulleys, around a brake 17, and is attached to a jawactuating mechanism on the grab. A winch 22 controls both brake 17 and a brake 19 around which latter passes an endless cable 18 which also passes over a fixed pulley 30 and is attached to the ends of the carriage 4. Assuming the beam is engaged by catch 20 and the grab is open and lowered over the spoil, winding of ropes 11, 13 on winch 12 separates pulleys 9, 10 and lifts the grab to the end of the beam and at the same time the jaws 16 are closed by the cable 13 and the release of catch 20 allows the beam to be pulled into engagement with catch 21 by the rope 11. On the release of brake 19 the cable 18 is freed and the carriage and grab slide towards the pivot 2, the slack in cable 13 being taken up by the tensioning loop. Disengagement of winch 12 allows the grab to be lowered over the discharge point and actuation of brake 17 causes the jaws to open and the load to fall. On release of catch 21 the carriage and empty grab tilt the beam back into engagement with catch 21, and operation of the winch 12 lifts the grab and closes the jaws, and on release of brake 19 the carriage is free to return to its endmost position without lengthening ropes 11, 13. Release of winch 12 and actuation of brake 17 allows the grab to drop and the jaws to open ready for another cycle of operation.