Shock absorber

Abstract

A shock absorber for providing a decelerating force employs a piston disposed in a cylinder acting to displace the hydraulic fluid through a programmed series of orifices disposed along the length of the cylinder, with turbulent flow of the hydraulic fluid through the orifices. An adjustment in the shock absorber characteristics is achieved by a sleeve slidably fit over the cylinder, the cylinder having a series of ports with the sleeve being formed with a corresponding series of encircling straight-sided grooves which extend transversely with respect to the radial planes of the cylinder, such that each groove defines a variable area orifice depending on the rotative position of the sleeve over the cylinder by the overlying of the groove and cylinder ports. In a first version, the grooves are shaped as rings, tilted with respect to the cylinder axis so as to form ellipses; and, in a second version, the encircling grooves are formed in a partial spiral with a connecting return leg to provide a greater than 180.degree. metering range. Both configurations have groove areas greater than the orifice area to insure a low pressure condition in the groove such that the primary resistance to flow is defined by turbulent flow through the orifice.