GB743055A - Improvements in and relating to hoists - Google Patents

Abstract

743,055. Builder's hoist; winding and paying out. BRITISH HOIST & CRANE CO., Ltd., and EVANS, P. N. June 15, 1951 [June 5, 1950], No. 13990/50. Classes 78 (3) and 78 (5). A winch-operated hoist such as a builder's hoist with a platform guided on a mast, has a control member for the hoist and a mechanical coupling including a latching member, with a manually-operable member and means for operating the latching member to break the coupling as the result of movement of the platform wherein the pressure tending to hold the latching member in the latching position is derived at least in part from the force applied to the mechanical coupling as shown in Fig. 1, the platform 18 guided on uprights 17 of a mast is operated by a rope 19 from a winch 10. The winch is either brought into engagement with a friction driving pinion or with a brake shoe by the movement of a pair of levers 14 connected to an eccentric mounting for the winch. The levers are counterweighted by weights 15. The levers 14 are connected by a latching member 31 to a manually-operated control rope 25 which exerts a latching pressure and to the loop of a wire rope 34 which is connected to the top and bottom of the mast and has members 46, 50 for engaging indirectly with a projection 43 on the platform. The wire 34 passes round pulleys 37, 39 on the mast and round a pulley 41 on the latch lever 32. The stop members 46, 50 normally engage members 44, 48 pivoted to brackets on the column. The projection 43 on the platform engages the members 44, 48 to shorten the loop and release the latch and apply the brake. As shown in Fig. 3, the levers 14 are interconnected by a cross-bar 55 and have levers 56 pivotally mounted thereto. The levers 56 carry plates 58, the upper ends of which are connected by a cross-bar 59. A sleeve 60 on the cross-bar carries a pair of latches 61, with a detent for engaging the upper crossbar. The sleeve carries a sheave block 64 for the control rope 25 and the lever 32 of the latch device which carries the pulley 41. After the release of the latch the loop of wire 34 is restored and when the operator releases the control rope 25 the upper cross-bar assembly drops and the latch bars automatically relatch. Specifications 627,077 and 743,054 are referred to.