GB356657A - Improvements in or relating to shock absorbers - Google Patents

Abstract

356,657. Hydraulic shock-absorbers. WAHL CO., Chicago, U.S.A. March 3, 1930, No. 6897. Convention date, March 1, 1929. Void [Published under Sect. 91 of the Acts]. [Class 108 (iii).] In a double-acting hydraulic shock-absorber in which an operating lever projects through the side of the cylinder between two opposed pistons which are urged into contact with the lever by springs abutting against the end covers of the cylinder, the ends of the cylinder are connected by a passage having a tapered regulating valve and also provided with means for byepassing some of the liquid. The double-ended cylinder 2, Figs. 2 and 3, is formed with an upstanding central part which carries the bearings for the operating shaft 26 and serves as a reservoir communicating with the space between the pistons 5. The end of the operating lever 25 is rounded to engage the pistons which are forced up by springs 8, 9 bearing against the screwed cylinder caps 6, 7. One-way ball valves 14, 15 ensure the supply of liquid as required from the central reservoir to the ends of the cylinder which are directly connected by the passage 40 having an arrangement of valves shown in the enlarged sectional view, Fig. 4. These valves are designed to prevent hissing of the apparatus by avoiding the passage of liquid past sharp edges while passages controlled by ball-valves may be provided to obtain a differential effect and relief valves controlled by springs also serve to avoid excessive pressure at either end of the cylinder. In a cylindrical cavity arranged at right-angles to the passage 40 is disposed a block 42 having a tapered needle or throttle valve 45 which may be screwed in or out to vary the flow of liquid in either direction. Liquid may also flow through the passages 56, 57 which are controlled by a ball 70. This ball prevents flow in one direction but allows a limited flow in the opposite direction. The ball is very slightly less in diameter than the cylindrical hole in which it is located and a thin film of oil thus leaks through the space between the two in such a way as to avoid hissing. The ball 70 and the loose locating pin 71 are carried in a separate block 64 which is pressed against the block 42 by a spring 68 acting on the closing disc 66. In the event of excessive pressure at either end of the cylinder the block 64 momentarily moves away from the end of the block 42 and allows escape of liquid. Several modifications of the liquid throttling arrangements are illustrated.