GB1128249A - Improvements in or relating to shock absorbers - Google Patents

Abstract

1,128,249. Hydraulic shock-absorbers. AUGUST BILSTEIN K.G. 2 Dec., 1966 [3 Dec., 1965], No. 54148/66. Heading F2S. A steplessly adjustable shock-absorber, especially for vehicles, comprises a piston 4 having two sets of ports 4<SP>1</SP> controlled by sets of spring plates 3, 5 and a hollow piston-rod 1 through which extends a tension rod 11 having its upper end connected by nuts 15, 16 to a diaphragm and support ring 13, 14 and its lower end extending through a support piston 8 which is secured thereon by a nut 10 the rim 8<SP>1</SP> of the piston 8 bearing against the rim of the largest plate of the spring set 5 with a force which depends upon the tension of the rod 11. The diaphragm 13, clamped between two housing parts 18, 20 carried by the upper end of the rod 1, divides a space in the housing 18, 20 into an upper chamber 17 which is connected to atmosphere through a port 19 and a lower chamber 22 which is connected by a bore 23 to a duct 24 leading, e.g. to an air spring bellows on the vehicle. An increase in the pressure in the chamber 22 causes the support piston 8 to increase its pressure on the corresponding plate of the spring set 5 so that the rebound stroke damping is increased. In a modification, Fig. 2, not shown, pressure control fluid is fed through a bore (42) and a port (41) in the rod (26) and through a groove (40) and bore (39) in the flange (32) of a support disc (31) which is sealed to the rod (26) by means of gaskets (44, 45), the support disc (31) guiding a domed support piston (35) which has its rim (37) in engagement with the outer edge of a spring unit (33) secured to the rod (26) by a nut (34). An annular projection (36) on the upper face of the support piston (35) bears against the lower face of a valve spring unit (30) which controls bores (29<SP>1</SP>) through the piston (29) during extension of the unit. A fluid-tight chamber (38) in the support piston (35) is ensured by seals (43, 43<SP>1</SP>) the pressure of fluid supplied through the bore (42) in the piston-rod (26) controlling the stiffness of the valve unit (30) and thus the damping factor of the unit during its expansion strokes. The shock absorber valves could consist of valve plates loaded with coil springs. A support piston could also be mounted on the piston-rod side of the working piston so that the damping factor of the shock-absorber is adjustable on the compression stroke. If the two valve sets on opposite sides of the working piston are to work independently of each other they should be supplied through separate flow passages in the piston-rod. A pressure-equalizing opening (48) is formed in the rim 37 of the piston (35). A port 9 is also formed for the same purpose in the piston 8 as shown.