GB622663A - Improvements in or relating to shock absorbers - Google Patents

Abstract

622,663. Hydro-pneumatic shock-absorbers ELECTRO-HYDRAULICS., (formerly ELECTRO - HYDRAULICS (MESSIER), Ltd. ORLOFF, G., and NEILSON, C. B. V. July 16, 1946, No. 21318. [Class 108 (iii)] The invention relates to shock-absorbers of the type in which fluid is contained in a deformable chamber permanently in communication with a second chamber through an orifice or orifices which may be valved, and the space in which is spring-controlled, the chambers being in the form of tubes which constitute the whole shock-absorber. According to the invention a third chamber within the two tubes and spring- controlled, is in valved-communication with the deformable chamber, the arrangement being such that in the event of fluidpressure in the deformable chamber rising to a pre-determined level, further damping is automatically effected by open communication between the deformable and third chambers. A cylinder 1 is divided into two chambers 1, 2 by a fixed diaphragm 7. A piston 18 slidable in the chamber 1, has an extension 14 which passes through the diaphragm 7 and carries a counter-piston 15 slidable in the chamber 2. The chamber 1 is filled with liquid which extends through orifices 8, 9 in the diaphragm 7, controlled by valves 10, to partially fill the chamber 2. The remainder of the chamber 2 contains compressed air which may, however, be replaced by resilience of the liquid or by coiled or rubber springs separated from the liquid by a floating piston. The piston 18 is carried by a hollow rod 11 which constitutes a third chamber 3 defined by a floating piston 24 beneath which is compressed air. The chambers 1, 3, are in communication by a relief valve 21 and a non-return valve 22. A port 16 is provided in the counter-piston 15 and a groove 17 in the extension 14 modifies the damping action of the ports 8, 9, in the diaphragm 7. In a second construction, the counter-piston may be connected to the floating piston by a rod 14 which passes through, instead of being secured to, the piston 18. In operation the resilience of the compressed air in chamber 2 serves to cushion normal loads, damping occurring due to flow through the orifice 9; while under excess loads the relief valve 21 releases liquid from the chamber 1 to chamber 3, with additional damping taking place due to flow through the valve 21. On extension or relief of load, liquid passes back from chamber 3 to chamber 1 through the non- return valve 22.