GB903213A - Improvements in or relating to shock absorbers - Google Patents

Abstract

903,213. Hydraulic shock absorbers. ARMSTRONG PATENTS CO. Ltd. Feb. 1, 1961 [June 9, 1960], No. 20313/60. Class 108(3). A telescopic hydraulic shock absorber comprises a piston 22 which works in a pressure cylinder 10 and one-way valve arrangements 14, 24 in a plug 12 for the cylinder 10 and the piston 22 respectively which cause the hydraulic fluid to flow unidirectionally, in a continuous closed circuit, through the piston 22 and the cylinder 10 and a concentric reservoir 16, defined by an outer cylinder 18 and the cylinder 10, and from the reservoir 16 back into the cylinder 10 the fluid circuit also including a flow-restricting or metering valve 38. During a compression stroke, with the valve 14 closed and the valve 24 open fluid, equivalent to the piston rod displacement, passes through - a passage 34 in a. sealing gland 28, which closes the piston rod end of the cylinders 10, 18 and sealingly accommodates the rod 26, and into a tube 36 which discharges into the adjustable metering valve 38 mounted in the cylinder 18. The valve 38 has an axial passage 40 provided with a valve seat 42 for a needle-type valve 44 which is axially displaceable by a screw-cap 46 detent means 48 on which define multiple positions. The tube 36 is provided with a filter 37. The adjustable valve 38 may be replaced by a fixed orifice or by a spring-loaded plate valve. Alternatively a metering valve 38 may be used in conjunction with another tube similar to the tube 36 and having a spring loaded plate valve or a fixed orifice at its free end. The cross-sectional-area of the piston rod is chosen to be one half of the area of the bore of the cylinder 10. When the shock absorber is to be used in a horizontal position the outer cylinder 18 may carry an auxiliary reservoir 58 to prevent cavitation in the reservoir 16 and guard against losses past the gland 28.