Patent ID: 6390457
Filing Date: 2002-05-21
Classification: C08F,C08L,F16F

Abstract:
A soft-start, soft-return gas spring, comprising:a base plate; a head plate defining a central opening; an inner tube mounted to extend between said head plate and base plate; a main piston mounted to reciprocate in said inner tube; a piston rod having an inboard end connected to said main piston and having an outboard end extending up through the central opening, said main piston and piston rod together comprising a piston/rod assembly that moves as a unit between an extended, rest position and a retracted, compressed position; a primary gas chamber defined within said inner tube between said main piston and said base plate; a relief chamber defined between said inner tube and said piston rod and between said head plate and said main piston; seals for preventing fluid flow from the primary and relief chambers; passageway means for providing communication between said primary and relief chambers; and, valve means for regulating fluid flow in said passageway means between an open position and a closed position, said valve means including a valve ring coaxially mounted around said piston rod between said main piston and said head plate, and wherein the closed position includes no fluid flow between said primary and relief chambers.