GB1178606A - Improvements relating to Hydraulic Telescopic Shock Absorbers - Google Patents

Abstract

1,178,606. Hydro-pneumatic shock-absorbers. WOODHEAD MFG. CO. Ltd. 23 March, 1967, No. 13782/67. Heading F2S. In an hydraulic telescopic shock-absorber, particularly intended for "soft" suspension systems, comprising a working piston 18 which is slidable in a cylinder 10, has a rod 12 which extends through an upper seal, not shown, in the cylinder 10 and a two-way valve damping system 19-23, excessive rebound, normally associated e.g. with rubber rebound stops, is overcome by fitting, to the lower end of the rod 12, an auxiliary piston 30 which is of a size to allow almost unrestricted flow of fluid between it and the cylinder 10 during movement therein and which, as it approaches the end of a contraction stroke, enters a downwardly tapered auxiliary cylinder 41 to provide a progressively increasing hydraulic resistance, the auxiliary cylinder 41, being unitary with the main cylinder 10, and preferably having a constant-diameter extension portion 42 to provide a final stop, or a "dead length". An end cap 44 carries a mounting member 44. The auxiliary piston 30, which is secured to the piston-rod 12 by means of a spacer sleeve 28 and swaging 32, has through ports 40 which are controlled by a plate spring 36 and a disc valve 37 so that, on movement of the auxiliary piston out of the auxiliary cylinder, liquid can flow relatively easily into the auxiliary cylinder 41. Bleed notches 38 in disc valve 37 allow a very small amount of upward flow of liquid through the ports 40 as the auxiliary piston travels downwards in the cylinder 41.