Patent ID: 6170809
Filing Date: 2001-01-09
Classification: F16F

Abstract:
A gas spring, comprising:a body having a bore;a piston rod assembly having a piston and a piston rod slidably received in the bore for reciprocation between retracted and extended positions and defining a first gas chamber and a second gas chamber both constructed to receive a gas under pressure;a first passage communicating the first gas chamber with the second gas chamber and having at least a portion sized to provide a restricted flow rate of gas therethrough;a second passage communicating the first gas chamber with the second gas chamber; anda valve in the second passage to control the flow of gas through the second passage and constructed and arranged so that upon movement of the piston rod assembly toward its retracted position, the volume of the second gas chamber is decreased and the valve permits gas in the second gas chamber to flow through the second passage and into the first gas chamber and upon movement of the piston rod assembly toward its extended position, the volume of the first gas chamber is decreased, the valve at least substantially prevents gas flow through the second passage and the flow rate of gas from the first gas chamber to the second gas chamber through the first passage is controlled by the portion that restricts flow to control the flow rate of gas out of the first gas chamber and thereby control the rate at which the piston rod assembly moves towards its extended position.