GB1173051A - Aircraft Undercarriages - Google Patents

Abstract

1,173,051. Aircraft undercarriages. ELECTRO-HYDRAULICS Ltd. 22 March 1968. [30 March 1967] No. 14576/67. Headings B7G. [Also in Division F2] An aircraft undercarriage comprises a cylinder 1 adapted at one end 2 for connection to an aircraft (e.g. a helicopter), a tube 4 carrying a ground engaging element (e.g. a wheel on a stub-axle 52) at one end 33, and having a piston 16 slidable in the cylinder, there being bearing means 5, 6 on the cylinder to engage the tube and to define with the cylinder and the tube two liquid containing chambers 19, 20 one each side of the piston 16, the tube 4 having a diaphragm 21, the space within the tube between the diaphragm and the end 33 being divided in another liquid containing chamber 24 and a chamber 34 filled with compressible fluid, by a further piston 22 having a hollow piston-rod 23 extending towards the diaphragm, the rod 23 having slidable therein another piston 31 connected by another piston passing through the piston 22 to the end 33 and defining with the rod 23 and piston 22 a further chamber 37 into which fluid may be introduced (e.g. via a valve 35 and a passage 36) to compress the fluid in the chamber 34 and cause transfer of liquid between the chambers 19, 20 and 24 which are interconnected (e.g. via passages 25, 29) to bring the end 33 nearer the cylinder 1. Fluid may pass between chambers 19 and 20 past the seal 18. Compressible fluid (e.g. air) may be pumped into the chamber 34 via an inlet 40, and liquid may be supplied to chamber 19 via an inlet 1A. The flow of liquid through some of the passages 25 may be controlled by a one-way valve 28, and through some of the passages 29 by a one-way valve 30. On the cylinder 1 there may be a rotary fluid connector comprising a sleeve 42 keyed to the cylinder having three inlets 43 each connected to an axial passage having an opening 43A leading to one of three circumferential passages 44A, 44B, 44C in another sleeve 44 rotatable about sleeve 42, each passage 44A, 44B, 44C having an outlet 46, these supplying fluidto inlet 40, and to wheelbrakes. The tube 4 is prevented by arms 48 from rotating relative to the sleeve 44 which is locked rotatively relative to the cylinder 1 by a spring key 50 engaging a selected one of a series of notches (12A . . . 12D), Fig. 3 (not shown), in a ring 12 keyed to the cylinder. An aircraft (e.g. a helicopter) on which the undercarriage is fitted if lashed down, may have its shock absorber partially closed while the lashings are applied or removed, the shock absorbers being opened between while to tension the lashings.