GB1177589A - Pneumatically Operable Hydraulic Jack. - Google Patents

Abstract

1,177,589. Hydraulic jacks. YASUI SANGYO CO. Ltd. 22 Nov., 1968, No. 55582/68. Heading B8J. [Also in Division F1] A wheeled hydraulic garage jack driven by compressed air connected from a source (not shown) to the jack body at 11 comprises a lifting arm 5, journalled at a shaft 8, with a load table 7 and a parallel link 9. The compressed air supply is fed from the jack body inlet 11 through a hose 13 to an inlet 12 on the power generating means 3. A spring-loaded ball valve 14 may be opened by operating a lever 17 to feed the compressed air into an air chamber 18 to drive an air piston 20 to the left as shown in Fig. 2, compressing a return spring 22 and driving a plunger.21. When the head of the air piston 20 reaches an exhaust port 24 the compressed air passes through a conduit 26 into a chamber 25 and drives an air exhaust valve member 27 to the left until a groove 28 communicates with the air chamber 18. This connects the chamber 18 to the atmosphere through an opening 29. This reduces the pressure in the chamber 18 so that the spring 22 returns the piston 20 to its original position together with the plunger 21 and valve 27 to restart the cycle. The reciprocation of the plunger 21 draws oil from a tank 31 and forces it into a space 35 in cylinder 36 to force piston 37 to the left. The pressure is transmitted through piston-rod 38 to the lifting arm 5. A needle valve 39 is provided to permit the escape of oil from the cylinder 36 into the tank 31. The valve 39 is operated through a spring-loaded lever 41. The two levers 17, 41 may be selectively operated by rotating an actuator member 53 at the end of a rod 48 passing through outer sleeve 49 of a handle 10. The handle 10 can be set vertically, horizontally or mid-way between, as may be convenient. The rate of lifting is controlled by the controlled rotation of the rod 48.