GB546706A - Improvements in or relating to undercarriages for aircraft - Google Patents

Abstract

546,706. Aircraft landing gear. AERONAUTICAL & MECHANICAL INVENTIONS, Ltd. (Soc. d'Inventions Aeronautiques et Mecaniques S.I.A.M.). Jan. 23, 1941, No. 941. [Class 4] A retractable undercarriage operable by a hydraulic jack is provided with a compensating jack, associated with an accumulator, which resists retraction and stores up energy during the first portion of the retraction and afterwards operates with increasing effect to assist retraction. In one form a leg 11 braced by a jointed strut 14, 114 is retracted by a jack 15 acting between lugs on the struts 14, 114. A lever 20 on the leg occupies the position shown with respect to a compensating jack 18 when the leg is entended, but as the leg is retracted the jack 18 is at first compressed and afterwards becomes increasingly effective to assist the retraction of the leg. The jack 18 is oil filled and connected to an accumulator 116 with a compressed air chamber. The jack 15 is connected at its lower end alternatively to a pump or to exhaust and its upper end is connected to the accumulator 116. In another form the jack 18 occupies the position of the jack 15 in the arrangement just described, the main jack, which need not have an accumulator, acting between a fixed point and the strut 114. The upper end of the jack 18 may, alternatively, be connected to a fixed point. Specifications 503,789 and 518,414 are referred to. According to the Provisional Specification the compensating jack may be fully compressed when the undercarriage is down and assists retraction of the leg throughout the greater part of its movement.