US 4,059,175 AGranted

Linear force shock absorber

OwnerRichard G. Dressell, Jr., Robert J. Heidemaninventors

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Abstract

A shock absorber for providing a linear decelerating force to a machine part by means of a piston which forces fluid through a series of orifices formed by the coaction of holes in the piston cylinder and grooves formed on the internal diameter of a sleeve which fits over the cylinder. One form of groove is disclosed which varies in depth about the perimeter of the sleeve and has an inclined sidewall which varies the width of the groove on the internal diameter of the sleeve as a function of its depth. An alternative form of groove has a constant depth and is formed spirally on the sleeve with a pitch that is an integral divisor of the hole spacings. A series of orifices having a low ratio of length to width are formed by the coaction of the holes and the grooves and are adjustable by rotating the cylinder relative to the sleeve. The absorber is constructed in such a manner as to allow the insertion of the piston into the cylinder without any special inserting tools and to eliminate the possibility of an improper assembly.

Claims8

Dependent claims

A device for absorbing the kinetic energy of a moving member so as to decelerate the member, comprising:

a tubular cylinder having a plurality of holes formed in its wall which are spaced relative to one another along the longitudinal axis of the cylinder;
a piston slidable within the cylinder;
a sleeve having an interior wall surrounding the cylinder and having a number of holes formed in it equal to the number of holes formed through the cylinder and spaced relative to one another longitudinally along the length of the sleeve at the same spacing as the holes in the cylinder, and further having a plurality of annular grooves formed in the interior wall of the sleeve, each groove being in substantial alignment with one of the holes in the sleeve, and, having a width at the surface of the interior wall of the sleeve which varies over the length of the groove;
a volume exterior to said sleeve, the holes in said sleeve providing fluid communication with the grooves and the exterior volume;
means for positioning the sleeve over the cylinder so that the grooves overlie the holes in the cylinder and a fluid orifice is formed by the interface of each of the holes in the cylinder and a respective overlying surface of the overlying groove;
each of the grooves being of such configuration that at any point along the length of the groove, the cross-sectional area of the groove is greater than the area of the fluid orifice formable by the interface of the hole and groove at that point, where the area of the orifice so formed is a function of the rotational position of the sleeve relative to the cylinder, whereby said grooves are at relatively low pressure relative to the pressure in said cylinder to thereby minimize leakage flow between said cylinder and said sleeve.

3 more elements

Dependencies are inferred from the claim text.