GB665527A - Improved hoist - Google Patents

Abstract

665,527. Hoists. WILSON, S. Aug. 29, 1950. [Aug. 29, 1949] No. 22410/49. Classes 78 (iii) and 78 (v). A hoist has a rig adapted to be mounted in an elevated position, the winch being hoistable under its own power from an initial position where it rests on or is supported from the ground without any anchorage to a position in the locality of the rig, and means being provided for securing the winch in such locality. A winch 2 has a winding drum 6 mounted on a shaft 13 operated through gearing driven by a motor 5, Fig. 1. The drum is driven by a clutch which comprises shoes 17 brought into engagement with the flange 16 by pulling a cord 29 attached to a bell crank lever 26 which operates a wedge member 19 through a rod 28, lever 31 and rod 20. The drum is braked by shoes 22 which normally are held in the brake on position by a spring 25 but are released by pulling a cord 35 which operates through a lever 33 and rod 24 to release the brakes from the spring pressure. Pulling the cord 29 puts in the clutch and releases the brake, whereas pulling the cord 35 releases the brake leaving the clutch inoperative. The cable 37 secured to the drum 6 passes upwardly between guide rollers 38 through a tube 40 and conical member 41, through a stop member 48 round sheaves through an angle member 54 and spring 55 to a fall block 56. A latch 59 slides between guide plates 58 and has connected a pair of bell crank levers 62 secured to a spring 65. A pair of finger pieces 70 secured to a lever 66 project into the path of the lever 62. The forked ends of the lever 66 straddle the hook. In operation, the cable 37 is wound until the fall block engages the spring 55 and when the latch 59 is moved to the right further winding hoists the winch past the latch which engages beneath the conical member 41 and holds the winch in the elevated position. To release the winch to ground level, the cord 29 is pulled to raise the lever 66 to move the latch 59 to the inoperative position, then releasing the clutch and releasing the brake by the cord 35, the winch descends under its own weight.