GB551684A - Improvements relating to retractable landing gear for aircraft - Google Patents

Abstract

551,684. Hydraulic machines. BRISTOL AEROPLANE CO. Ltd., FRISE, L. G., and PONTING, R. March 24, 1939, No. 9354. [Class 69 (ii)] [Also in Group XXXIII] A retractable landing-gear for aircraft comprises a hydraulic accumulator connected to an operating jack through a control valve and a large bore pipe, the accumulator being kept charged by a continuously working pump through a small bore pipe and an air vessel being associated with the outlet from the jack. A pump 48, which may be' driven by the aero-engine. delivers oil at low pressure through a pipe 47 to a booster 43, described in Specification 551,683, from which oil at high pressure passes through pipes 44, 45, 46 and a non-return valve 42 to the hydraulic accumulator 37. Air under pressure is introduced into the upper end of the accumulator above a floating piston 38. Should the pressure become too great a piston 52 is depressed to open a by-pass valve 5'6 in the pump circuit. A pressure-relief valve 54 also is provided in the pump circuit. A valve 35 controls the operation of a jack 32 connected to the undercarriage, oil from the exhaust side passing to a closed chamber 53 from which it more slowly escapes through a filter 60 to the oil reservoir 50. The booster 43 may be omitted. The accumulator, jack, valve 35, and chamber 53 may be arranged in a wing remote from the pump circuit, to actuate through short large bore pipes an undercarriage similar to that described in Specification 463,807, [Group XXXIII].