GB1221970A - Hydraulic shock-absorbers - Google Patents

Abstract

1,221,970. Springs. WOODHEAD MFG. CO. Ltd. 1 Oct., 1968, No. 46585/68. Heading F2S. An hydraulic shock absorber has a piston 4, Figs. 1 and 2, which is mounted on a piston rod 13, is reciprocable in a cylinder 1, and has passages 5, 6 therein which connect a chamber X of the cylinder with a chamber Y of the cylinder. An annular reservoir is formed between the cylinder 1 and an outer coaxial member 2, the reservoir being connected to the chamber Y through a valve 23 and passages 30, and being separated into chambers 32, 33 by means of a part annular wall 34 which extends around an arc of 220 degrees. A gap of 140 degrees in the wall 34 forms a connection between the reservoir chambers 32, 33. The passages 5 in the piston 4 are closed by a valve-plate 7 being urged by a spring 8 and the passages 6 are closed by a valveplate 10 being urged by a spring 11 and a nut 12. The piston-rod 13 passes through an end closure disc 14 and a seal 15 which carries a cover 16. The valve 23 is mounted in the cylinder 1, has a bore 24 closed by a disc 25 urged by a spring 26, the disc 25 carrying a valve member 27 which is urged by a spring 27a to close a passage 28 which extends through the valve member 27. In operation rebound loads are provided by the valve 10 whilst compression loads are provided partly by the valve 7 and partly by the valve 27. As the length of the shock absorber is reduced under compression loads, oil passes through the valve 7 and oil displaced by the piston-rod entering the cylinder passes to the reservoir 31, via passages 28, 30. The chamber 33 is maintained full of oil to prevent ingress of air therein and excess oil is passed through the gap in the part-annular wall 34 and into the chamber 32. On return of the piston rod, its volume is recuperated by oil from the reservoir 33 which passes through the valve 25 against the force of the spring 26, oil also passes through the valve 10 on the piston 4. In a modification a shock absorber is of the one-way type and comprises a piston 50, Fig. 3 (not shown), having bores 60 closed by a one-way valve 63; a closure member 56, having passages 61 closed by a one-way valve 64; and a closure member 55, having bores 62 closed by a one-way valve 65.