GB563466A - Improvements in or relating to hydraulic controls for aircraft undercarriages - Google Patents

Abstract

563,466. Aircraft undercarriages. RUBERY OWEN MESSIER, Ltd., and ORLOFF, G. Dec. 26, 1941, No. 16686. [Class 4] A wheel-carrying member pivoted to a deformable frame incorporating a shock absorber connected to the airframe is retractable by a hydraulic jack against the resistance of spring returning means, the pressure fluid for the jack first releasing a locking device, for holding the parts in their extended position, and then opening a valve to permit the fluid to flow to the jack. A telescopic oleo-pneumatic shock absorber 11 is pivoted to the airframe at 12 and a casting 19 at the lower end is connected to the airframe by a radius link 13 which is roughly trapezoidal in plan. A swivelling wheel fork 25 is mounted in another casting 26 pivoted to the casting 19 at 27 and is normally locked in the extended position by a catch 48 pivoted to the casting 19 and engaging a transverse pin 50 on the casting 26. Rubber cables 39 urge the parts into the extended position. A jack 31 passing through a hole in the link 13 is connected between a bracket 44 on the shock-absorber and an eye 30 on the casting 26. Pressure fluid from a pump is supplied through a single pipe 53 and entering a small cylinder 45 depresses a piston 46, Fig. 4, having a piston rod 47 connected to the latch 48. Towards the end of the piston stroke a valve 58 on the piston is unseated as its stem 60 comes into contact with a cross-pin 62 and fluid can flow through the valve to a pipe 54 leading to the jack. A pipe 56 enables the undercarriage to be positively extended in an emergency but normally the cables 39 extend the under carriage when the pressure in the pipe 53 is released. The swivelling motion of the wheel is controlled by a shimmy-damper 29 as described in Specification 549,772, [Group XXXII].