Miniature shock absorber

Abstract

A miniature shock absorber including an outer tubular housing, an inner tubular housing positioned within the outer tubular housing to define a pressure chamber within the inner housing and an annular accumulator chamber between the housings, a piston mounted for movement in the inner tubular housing, and a piston rod extending out of the front end of the tubular housings for impact by an object to be decelerated. A needle valve is positioned in the rear end of the shock absorber for coaction with an axial passage defined at the rear end of the pressure chamber. The needle valve is threadably received in the rear end wall of the shock absorber and includes an external knob to threadably move the needle valve relative to the axial passage to thereby vary the resistance offered to an impacting object. Return flow of fluid from the accumulator chamber to the pressure chamber occurs through a radial metering port in the inner tubular housing coating with an annular axial passage defined between the piston and a reduced diameter valving portion of the piston rod with the piston shuttling back and forth relative to the piston rod to selectively preclude and allow communication between the pressure chamber and the accumulator chamber. Also disclosed is a stop arrangement, including a stop collar formed as an integral front end portion of the outer tubular housing, to preclude bottoming of the piston against the end wall and to provide precise predetermined end limit positioning for the impacting object.