Abstract: Shock absorbing struts for use on aircraft landing gear which include a pair of fluid containing chambers defined by a pair of telescoping cylinders. Fluid flows from one of the chambers to another through a metering orifice proportional to the differential in pressure generated by impact loads created upon landing or taxiing of the aircraft. Upon the differential pressure exceeding a predetermined threshold level an additional flow path positioned in parallel to the metering orifice is opened by an amount proportional to the amount of differential pressure in excess of the threshold to thereby maintain a substantially constant load on the landing gear irrespective of impact loads imparted thereto.

Abstract: A pumping system which converts a source of gas under pressure to hydraulic fluid under pressure. The system includes three free floating pistons coupled through control valves to the pressurized gas source on one side and through appropriate check valves to hydraulic fluid on the other side. The pistons are reciprocated within respective cylinders by application of the pressurized gas to one side thereof and by application of the return pressure of the hydraulic fluid to the other side thereof. Appropriate porting on the gas side of the pistons sequentially applies the gas under pressure to the three pistons to synchronize reciprocation of them so as to provide a continuous flow of fluid under pressure, upon demand, to a load.