GB1132947A - Anti-sway device for suspended loads - Google Patents

Abstract

1,132,947. Preventing swinging of loads in cranes. PACIFIC COAST ENG. CO. 25 April, 1967 [11 July, 1966], No. 19020/67. Heading B8B. Swinging of a load 17, Fig. 1, is damped by ropes 21 wound on drums on a trolley 11, the arrangement being such that when the ropes are unwound unequally, due to the load swing- ing, a brake opposes the unwinding, whilst no braking occurs when all the ropes are unwinding at the same rate, i.e. when there is no swinging The ropes 21, Fig. 3, are wound on drums 39 and slack is taken up by spring-drums 41. The drums 39 are mounted on shafts 35, 37 which can rotate a central shaft 33 through unidirectional couplings 43. The central shafts on either side of the trolley 11 are connected by chains and sprockets 71 to drive shafts 65, Fig. 5, which are connected to a differential gear 45 through reverse-locking drive couplings 67 and shafts 59. When the load is lowered without swinging, both sets of ropes 21 are paid out at the same rate, thus, both centre shafts 33 rotate at the same speed and this causes drive shafts 65 to rotate. This rotation is transferred to shafts 59 through couplings 67 and their side gears 61, 63, Fig. 5. Because of the way the ropes 21 are wound on drums 39 these gears rotate in opposite directions, so that pinion gears 53 merely rotate without turning the casing 55, 51, on which they are mounted and no braking occurs. When the load swings, two of the ropes 21 will be unwound and therefore only one shaft 59 will be rotated through the driving connections. Since one of gears 61, 63 is moving and the other stationary, the pinions 53 will rotate the casing 51 against the action of the brake 79 and the swinging will be damped. Swinging in the opposite direction will cause rotation in the opposited sense of casing 51. The rope drums 39 may be arranged to damp swinging in two directions at right angles to each other. Two ropes and drums may be used instead of four.