GB605775A - Improvements in counterweight control systems for lifting device crabs - Google Patents

Abstract

605,775. Counterweight systems for lifting crabs. SOC. FRANCAISE DE CONSTRUCTION DE BENNES AUTOMATIQUES. March 25, 1942, No. 3975. Convention date, March 11, 1941. [Classes 78 (ii) and 78 (iv)] In a lifting device of the kind where a crab 4 carrying a grab 1 travels along a guideway 6 under the action of a counterweight 14, an adjustable stop means 15 is interposed in the path of the counterweight so that the crab is stopped at the desired discharge point. In Fig. 1, crab 4 runs on wheels 5 along guideway 6. To the crab 4 is pivoted arm 8 biassed by spring 10 so that brake 36 on the arm presses against the guideway; and to pivoted arm 8 is suspended opening ring 7 by. cable, not shown. Grab 1 is hauled by rope 2 towards stop 11 at the loading position, and by rope 12 under counterweight 14 to the discharging position, at which position the counterweight is held by an adjustable stop. Stops. On rod 15 is fixed counterweight stops 16, 17, 18 which are angularly displaced and the rod is rotatable by handle 19 so that the counterweight 14 may be arrested at different heights and the crab arrested at differing positions: of discharge. Alternatively (Fig. 2), a stop 21 may be set at each such position, the stop being pivoted at 23 and being under the opposing actions of spring 24 and solenoid 25 so that making the circuit swings the stop into the path of the counterweight. Again (Fig. 3), the stop 29 may be varied in position by being fixed on screw 30 to which translatory movement is given by rotation of nut 31, the nut being held so as to have no movement in a vertical plane and rod 32 serving as vertical guide. In the modification of Fig. 4, stop 29 reciprocates between points 33, 33a which are the contacts of reversing switch 34 controlling electric motor 35 which drives the nut 31 and the motion may be regular or irregular so that the discharge of the grab occurs at points between corresponding limits. Specification 543,969 is referred to.