GB650084A - Improvements in or relating to suspension systems for aircraft - Google Patents

Abstract

650,084. Aircraft landing gear. SOC. D'INVENTIONS AERONAUTIQUES ET MECANIQUES S.I.A.M. July 23, 1948, No. 19817. Convention date, July 24, 1947. [Class 4] [Also in Group XXXII] A suspension system for aircraft comprises a piston-and-cylinder type shock absorber operatively connected between a land wheel or equivalent member and the aircraft, in combination with a control device or devices, actuated by the braking system of the aircraft and connected to the absorber to vary the operating characteristic thereof in accordance with variations of the braking effort or the brake torque resulting therefrom. The shock absorber as applied to the nose wheel element of a tricycle undercarriage comprises a cylinder 1 provided with a principal piston 2 connected to a secondary piston 3 by a rod 4 passing freely through a fixed diaphragm 5, the space between the pistons being filled by liquid 6 which, by passing through an orifice 7, absorbs landing shocks transmitted to the piston rod 8. Return movement of the pistons is effected by expansion of the air in chamber 9 which is in communication with an auxiliary air vessel 12 through the medium of a flap valve 15 which is provided with an orifice 16 and which seats on its undersurface on an anular projection so that it permits a free flow of air from cylinder 12 to cylinder 9, while restricting the reverse flow of air to the orifice 16. The vessel 21 is provided with a piston 13 supported by liquid in communication with the feed circuit of the hydraulic brake cylinders through one branch 11a of a pipe 11. Liquid from the other branch 11b operates a spring-loaded piston 18 to which is attached a rod 20, the free end of which is located in the orifice 7 to vary its area. The operation of the brake cylinders causes an application of liquid pressure to the pistons 13 and 18 to increase the air pressure in the cylinder 9 and to reduce the rate of flow through the orifice 7 to enable the shock absorber to resist the increase in loading caused by the forward pitching of the aircraft due to braking action. In an alternative arrangement a normally non-rotating element of the brakes is mounted on a rotatable sleeve and is linked to the aircraft structure by a piston and cylinder unit which is connected to the pipe 11. Specification 535,135 is referred to.