GB743857A - Improvements in or relating to aircraft undercarriages - Google Patents

Abstract

743,857. Liquid springs. HUNTING PERCIVAL AIRCRAFT, Ltd., [formerly PERCIVAL AIRCRAFT, Ltd.], FRISE, L. G., and WOTTON, J. May 24, 1954 [Feb. 23, 1953], No. 5053/53. Class 108 (3). [Also in Group XXXIII] A combined shock-absorber and retraction jack is illustrated, comprising a cylinder 10 containing a piston 12 attached to the pistonrod 13. Pressure fluid supply pipes 20 and 21 are fitted, the former having a non-return valve 23, releasable hydraulically when pressure fluid is admitted to pipe 20, by a branch 24. Pipe 21 is provided with a non-return valve. Two passageways are provided in piston 12, with non-return valves, one leading from the outer end of the cylinder to the inner end, its non-return valve being spring-loaded so as not to open until sufficient pressure to effect retraction is reached. The other passageway leads from the inner end to the outer, and contains a restricting orifice. As a shock absorber, the jack is sealed by the non-return valves in pipes 20 and 21, and on compression, the piston-rod 13 enters the cylinder, compressing the liquid, which flows through piston 12 past the spring-loaded non-return valve. On release of compression, the liquid re-expands, and flows back through the restricted passageway. To retract the jack, pressure fluid is admitted to pipe 21, unlocking valve 23, and the jack retracts normally. For extension, pressure fluid is admitted to pipe 20, raising pressure in the cylinder to cause the piston-rod 13 to move outwards, liquid flowing through the piston 12 past the restricted orifice. Specification 743,856, [Group XXXIII], is referred to.