GB290828A - Improvements in or relating to fluid operated devices particularly hydraulic lifts - Google Patents

Abstract

290,828. Express Lift Co., Ltd., and Turner, V..R. May 18, 1927. Presses, cylinder-and-piston; pressure-producing apparatus; governing and controlling. - In a hydraulic press or lift two mechanically unconnected rams are arranged to move simultaneously and to maintain a predetermined value of the ratio of the velocity of the one to the other. In one construction cage lifts 1, 2, Fig. 1, are mounted on a piston rod 9 and ram 14, respectively, which work in cylinders 4, 10 connected by a pipe 12. When a valve 3 is actuated so that the pipe 5 is put into communication with the supply pipe 6, fluid is admitted to the bottom of cylinder 4, the piston 8 moves upwards and fluid from the part of the cylinder 4 above the piston is forced through the pipe 12 into the cylinder 10, thereby raising the ram 14. In order to compensate for leakage which may occur at the glands 11, 13, the bottom of the cylinder 10 is connected through a non-return valve 18 and pipe 17 to a supply tank 19, and through a pipe 41 and a normally closed valve 20 to the pipe 5. In another construction, cage lifts 1, 2, Fig. 2, are mounted on rams 34, 14 working in cylinders 32, 10 which are connected by pipes 31, 30 to cylinders 29, 28. Rams 25, 24 working in these cylinders are connected by a crosshead 23 which is attached to the ram 21 of a cylinder 4. Fluid is admitted to the cylinder 4 by a pipe 5. The cylinders 28, 29 are connected to the pipe 5 by pipes 37, 39 provided with valves 38, 40 which may be actuated automatically or by hand. The pipes 30, 31 are connected by non-return valves 35, 36 to a pipe 17 leading to a supply tank 19.