GB899111A - Landing gears on aircraft - Google Patents

Abstract

899,111. Aircraft undercarriages. CLEVELAND PNEUMATIC INDUSTRIES Inc. March 3, 1960, No. 7622/60. Class 4. [Also in Group XXXIV] A retractable leg 10 for an aircraft undercarriage carries lugs 12, 13 to which are pivotally attached beams 14, 17 each provided at its outer extremity with an axle 19 for a pair of landing wheels 21. The beams are connected to the leg 10 by spring loaded plunger units 22 and 23 respectively which permit upward pivotal movement of the beams but limit downward movement beyond a predetermined amount. Beam 14 carries a pair of lugs 42 and beam 17 a pair of lugs 36 and a rod 34 is pivotally attached at 37 to lugs 36 and at its other end passes through a one-way clamping device 38 pivotally attached at 41 to lugs 42. Device 38 comprises a housing 39 having a frusto-conical bore 44 into which frusto-conical clamping elements 46 are urged by a spring 51 so that rod 34 may move freely into the device but is prevented from being drawn out of it. A metallic spring 26 is connected at 27 to beam 14 and at 29 to a plunger 28 having a head 33 which slides within a bore 32 in beam 17 so that it permits free downward pivotal movement of the beams but limits upward movement to that resisted by spring 26. In operation light loads are resisted by spring 26 and extension of rod 34 operating within its elastic limit but high-impact loads are resisted by permanent tensile deformation of rod 34, which has to be renewed after each landing. An embodiment, Fig. 8 (not shown), is described for a leg having a pair of wheels on a single beam with plunger 28 operating within the base of leg 10 and rod 34 arranged vertically between the leg and a cantilever extension of the beam. A plurality of deformable tension elements may be provided to permit repeated landings, manually or automatically operated means being provided to render the clamping means to be sequentially rendered operative. The invention is particularly applicable to undercarriages on highspeed aircraft subject to kinetic heating liable to adversely affect hydraulic shock absorbers.