GB482985A - Improvements in or relating to shock-absorbing struts for aircraft landing gear - Google Patents

Abstract

482,985. Shook-absorbers. VEREINIGTE DEUTSCHE METALLWERKE AKT.-GES., and FAUDI, F. April 5, 1937, No. 9650. Convention date, April 11, 1936. [Class 108 (iii)] A telescopic strut for aircraft landing-gear comprises a cylinder 1 containing independent pistons 3, 7, the rod 2 of piston 3 being secured at its upper end to the fuselage and the rod 6 of piston 7 carrying at its lower end a landing wheel &c., means being provided to transmit power from one piston to the other so that displacement of one piston causes positive displacement in the opposite direction of the other piston. In the construction shown, when a shock occurs liquid contained inside a tube 9, rigidly secured to the cylinder 1 and projecting through the lower piston 7, is forced through channels 19 in the tube, through an annular space 18 between the cylinder 1 and a lining 4, through apertures 20 in the upper end of the lining, and into a chamber 21 behind the upper piston 3, causing the piston 3 to move downwardly relatively to the cylinder 1. The hollow rod 14 of the piston 3 carries a fork 5 adapted to be pivoted to the aircraft fuselage, and a supporting strut is secured at one end to a sleeve 25 on the cylinder 1 and at its other end is hinged on a pivot beneath the pivot on which the fork 5 is hinged. In order to provide a substantially constant resistance to movement of the piston 3 an oil-restricting aperture 13 therein is gradually closed by a conical pin 17 or a slotted or perforated tube, as the piston descends. Springs 22, 23 in chambers 16, 11 bear the whole or part of the weight of the aircraft during and after landing and restore the pistons 3, 7 to normal position. A spring 24 acts as an additional stop for the piston 3. It is stated that in order to obtain a constant track width of the landing-gear (a) the ratio of the cross-section of the chamber 21 to that of the tube 9 may be equal to the ratio of the length of stroke of the piston 3 to that of the piston 7, or (b) the ratio of the cross-section of the tube 9 to the cross-section of the piston 3 may be equal to the ratio of the forces acting on the two pistons. Alternatively, the proportions may be so selected that a slight widening of the track may result so that the direction of the resultant of the landing force on each side of the longitudinal axis of the aircraft is inclined inwardly instead of being perpendicular to the transverse axis. Each strut may be vertically or obliquely arranged.