Gas spring booster arrangement

Claim 1

A gas spring comprising, an elongated cylinder defining an elongated cavity, a piston received within the cylinder and slidable between the opposite ends of the cavity to provide a pair of chambers whose volumes vary during this piston movement, the piston defining a restricted passage for communicating the chambers and allowing pressure equalization therebetween, sealing means defining an aperture at one end of the cylinder, an elongated connecting rod sealingly slidable within the aperture of the sealing means for movement between retracted and extended positions relative to the cylinder and having its inner end attached to the piston, the attachment between the connecting rod and the piston reducing the area of the piston facing the sealing means to provide a differential area between the opposite sides of the piston, a pressurized gas received within the cylinder and flowing through the passage in the piston to provide equal stages of pressure within the chambers, the gas normally urging the piston toward the sealing means as a result of the differential area between the opposite sides of the piston to normally bias the connecting rod toward the extended position, a booster including a helical spring encircling the connecting rod and mounted on the cylinder extending outwardly from the end thereof including the sealing means, the helicAl spring being engaged by the outer end of the connecting rod during a limited range of movement thereof adjacent the retracted position and being compressed during retraction of the connecting rod during this limited range of movement to provide a bias aiding the gas in urging the connecting rod toward extended position, and an elongated hollow cover for the helical spring, the cover being composed of a rigid material and having one end thereof seating the outer end of the helical spring and the other end thereof slidable on the outer side of the cylinder to thus enclose the helical spring while allowing sliding movement of the cover along the cylinder axially of the longitudinal axis thereof during compression and extension of the helical spring under the impetus of the connecting rod moving within the limited range of movement adjacent its retracted position.