GB981915A - Improvements in and relating to telescopic hydraulic shock absorbers - Google Patents

Abstract

981,915. Hydraulic shock absorbers. ARMSTRONG PATENTS CO. Ltd. April 19, 1963 [March 20, 1962], No. 10569/62. Heading F2S. A telescopic hydraulic shock-absorber has a cylinder 10 with a valve-plate 36 in the foot valve 30 which admits fluid from a reservoir into the cylinder and a piston 16 with a valveplate 40 which permits flow through the piston towards the foot valve 30, each valveplate being associated with a leak-notch which permits flow in a direction opposite to that through the valves. In Fig. 1 the leak-notches for the two valves are indicated at 46 and 48. That at 48 may be replaced by an axial channel in the piston-rod 20 opening in front of the piston-head and venting through a short radial channel into the space behind the piston (Fig. 2, not shown). Figs. 3 and 4 show alternative foot-valves 60 and 70 in which, in addition to the leak-notches respectively at 70 and 80, means are provided to relieve excess pressures on the valve-plates 66 and 86. In valve 60 any excess pressure will cause the centre of the valve-plate 66 to depress so that fluid can escape through the central aperture 67 into a recess 63 having an outlet 72. In valve 70 the valve-plate 86 has holes 88 which are normally masked by an inner plate 82 having ports 84. In the latter instance excess pressure depresses the plate 82 so that fluid can escape through to a radial groove 78 in the valve.