GB191500568A - Improvements in or relating to the Landing Devices of Aeroplanes and Hydro-Aeroplanes. - Google Patents

Abstract

568. Vickers, Ltd., and Duncan, T. S. Jan. 13. [Cognate Application, 11,664/15.] Pneumatic and hydraulic springs; dashpots.-A device fitted between the wheels, skids, or floats and the framework of an aeroplane in order to absorb the shock of landing comprises two telescopic members enclosing compressed air and oil, the shock being dissipated by further compressing the air and by causing the oil to be forced from one part of the apparatus to the other through gradually diminishing passages. The recoil is also damped and the parts brought gently to rest by fluid friction. Fig. 1 shows one form of the device laid on its side, the left-hand end being normally the lower end. A lower cylinder A containing oil works in an upper compressed-air cylinder C having a plunger B adapted to displace oil from the lower cylinder. The plunger B is tapered so that the annular space through which the oil flows diminishes as the cylinder A rises. An inner casing A<1>, perforated for the passage of oil through it into the cylinder C, guides the cylinder A. The plunger B is hollow and in communication through a hole B<1> with the air space, and a piston D carried by a rod D<1> in the cylinder A works within the plunger B. The rod D<1> is a loose fit in the hole in the plunger, or the plunger may have separate perforations, so that there is always some oil at its lower end which retards the descent of the piston D. Fig. 3 shows a modification in which the plunger B acts as a guide for the upper end of the cylinder A. The plunger is square in crosssection, parallel-sided, and fits a hole in the end of the cylinder A, but tapered flats b<x>, Fig. 5, are cut at the corners so as to leave ports a<x> in the top of the cylinder A. Inclined slots b<1> forming continuations of the flats b<x> are cut in the plunger to allow free flow of the oil at the beginning of the stroke. The piston D, in this case, is formed as an enlargement of the head of the cylinder A and works in a reduced part of the cylinder C. One or more passages d<1> in the piston D ensure a supply of oil beneath the piston. A tube b<2> communicating with the air cylinder through a chamber b<4> and passage B<1> ensures that any oil in the plunger will be blown out on the return stroke. The plunger may be triangular or polygonal, or it may be cylindrical with tapered flats or keyways formed upon it. Instead of forming the fluid passages on the outside of the plunger, they may be formed on a rod projecting into the open lower end of the ram from the base of the cylinder A.