Landing gear mechanism including bypass valve assembly for reducing damping loads during taxiing

A landing gear mechanism for high performance aircraft comprising a main cylinder, a main strut piston axially movable within said main cylinder, a restrictor member contained within said cylinder and defining with said cylinder and piston upper and lower chambers, said restrictor member having orifice means therethrough for controlling the rate of flow of hydraulic fluid from said lower chamber to said upper chamber during landing, and bypass valve means providing for increased flow of hydraulic fluid from said lower chamber to said upper chamber whenever said landing gear mechanism engages a bump during taxiing to reduce the damping loads that would otherwise occur if all of such hydraulic fluid were required to flow through said orifice means, said bypass valve means comprising bypass passage means around said orifice means, a slide member mounted for axial movement relative to said restrictor member between open and closed positions for respectively opening and closing said bypass passage means, and means for keeping said slide member in the closed position until after landing has taken place and the pressure in said upper chamber has risen to a predetermined level, said means for keeping said slide member in the closed position until after landing has taken place comprising a secondary piston having a first surface area which is continually acted upon by a secondary pressure source of a predetermined magnitude urging said secondary piston toward said slide member.