GB983394A - Improvements in or relating to shock absorbers - Google Patents

Abstract

983,394. Shock absorbers; seals. DES ETABLISSEMENT REPUSSEAU S.A. June 9, 1961 [June 9, 1960; April 13, 1961], No. 20951/61. Headings F2B and F2S. [Also in Division B7] A railway vehicle buffer, Figs. 1 and 2 (see Division B7), comprises a telescopic plunger B which when pushed inwardly under load compresses an hydraulic shock absorber unit E in parallel with rubber/ metal springs in Fig. 1, and a metal spring in Fig. 2. The unit E, Figs. 3, 4, comprises an oil-filled cylinder a, and a partly filled piston c provided with a head having an orifice j 1 which may be closed or throttled by a slidable stem j which on no load is pressed into the Fig. 4 position by springs 8 and u. In operation, as the buffing load increases the slider j is forced back against spring s until the gap x is closed. In this position, Fig. 7 (not shown), the orifice j 1 is closed by the head j 3 of the slider and oil can no longer pass from the space a 1 through the orifice and ducts q 1 , and pipe m to the reservoir c 1 . Increased load then causes the slider head j 3 to be pressed even further back to compress the heavier spring u, in which position, Fig. 8 (not shown), the slider head is clear of the other side of the orifice and oil can once again pass from a 1 to c 1 . The reservoir c 1 is vented to atmosphere through a passage i in the piston base and a pipe n which reaches above the oil in c 1 so that on recoil the oil returns from c 1 to a 1 . The seals f and g are subjected only to low pressures, as the piston when telescoping draws oil from c 1 at low pressure into the space behind its head. Oil forced past the seals is collected by a cup v, Fig. 9 (not shown), and returned to c 1 , or is collected in a bellows h and forced back into the reservoir during the next compression via tube n. The resilient low-pressure ring seals f of trapezoidal section are complemented by one or more of the seals g, Fig. 5, which are of rubber and are fixed by screws to the cylinder a. The seals g have thick lip portions which bear tightly on the piston c, and are retained against longitudinal displacement by a member p.