GB984779A - Pneumatic shock-absorber - Google Patents

Abstract

984,779. Pneumatic shock-absorbers. STABILUS INDUSTRIE-UND HANDELGESELLSCHAFT m.b.H. Aug. 22, 1962 [Aug. 24, 19611, No. 32245/62. Heading F2S. In a pneumatic shockabsorber pre-pressurized with a gas at high pressure a piston 2, which divides a damper cylinder 1 into upper and lower working spaces 11, 12 respectively, has low and high pressure ports 14<SP>1</SP>, 13<SP>1</SP> which are controlled by associated weak and strong sets of springs 21, 20. The piston 2, secured on a piston rod 4 between two conical supporting discs 5, 6 by a nut 7, has an inner chamber which accommodates a supporting member 19 with spherically-curved ends which co-operate with the sets of springs 20, 21, the pressure ports 13<SP>1</SP>, 14<SP>1</SP> being distributed in evenlyspaced concentric groups. Corresponding outer groups of ports 13, 14, controlled respectively by valve discs 15, 16, are provided with apertures 17, 18 which correspond with the inner piston ports 13<SP>1</SP>, 14<SP>1</SP> when the piston 2 moves downwardly for low-pressure damping the gas flows through the openings 18 and raises the low-pressure spring plates at a pressure of approximately 150 k.g. and then passes through the outer ports 13 and around the disc valve 15 into the high pressure space 12. High pressure damping, with corresponding upward movement of the piston 2, causes gas to pass through the openings 17<SP>1</SP>, 13 and around the high pressure springs 20, which are biased to about 400 k.g. and through the openings 14 and past the valve discs 16 into the lower space 11. A piston-rod sealing arrangement comprises resilient upper and lower sealing discs 23, 27 which are located between an outer closure plate 22 and a supporting ring 28 secured to the cylinder 8 by means of a snap ring 29, and which are arranged, with the interposition respectively of discs 24, 26 on either side of a central bushing 25 which bounds an oil chamber 30. Conical incisions 31 and 32, 33 are formed respectively in the discs 23, 27 the inner incisions forming lips which wipe the rod 4 and the outer incision 33 forming an outer sealing lip which is urged by the pressure of gas, acting through oblique bores 34 in the ring 28, against the cylinder 8.