GB191016309A - Improvements in or relating to Hydraulic Lifts, Cranes and the like. - Google Patents

Abstract

16,309. Carey, R., and Waygood & Co., R. July 8. [Cognate Applications, 22,492/10 and 22,493/10.] Fluid-pressure, ram, and like apparatus; electric equipment.-Relates to hydraulic lifts, cranes, &c. of the kind in which the lift and balance cylinders are connected in a closed hydraulic circuit to a rotary pump with reversible delivery, and comprises means for controlling the pump and for compensating leakage in the circuit. The hoist cylinder 10, with its ram 11 connected directly or through ropes with the load, is in communication by a pipe 18 with one port of a rotary pump 17 operated by an electric motor 16. The pump is preferably of the kind described in Specification 12,574/09, [Class 102 (i), Pumps &c.], having reversible delivery and supply ports, connected respectively to the lift and balance cylinders 10, 13. The pump 17 is reversed and controlled by a rod 20, Fig. 4, carrying a roller 26 engaging a curved slot in a plate 24 controlled by the hand-rope 23. Liquid escaping by leakage is led to a pit 34, and is returned to the system by a small pump 35 driven by an electromotor which is started automatically by a float or ball valve. When a double-acting hoist cylinder is used, the leakage returns from the pit by atmospheric pressure through non-return valves. The control rod 20 may be actuated by a spirally-slotted disk rotated by a hand-rope or by a relay electromotor 45 operating similarly to that described in Specification 8576/02. The control motor 45 has forward and reverse coils 47, 48 coupled to a series of switches actuated by the motor 45 through a wheel 51, and also to switches controlled by up-and-down solenoids 52, 53, energized by the movement of a hand switch 54 in the cage. The rotary disk operating the rod 20 may also be arranged to close valves in the connecting-pipes, and to cut out the driving-motor 16 when it is in the neutral position.