Mechanical accumulator

Claim 1

A mechanical accumulator for holding and supplying a volume of fluid under pressure comprising: a cylindrical hollow casing closed at one end with a fixed end wall and having an inwardly extending annular end wall adjacent an opposite end forming an open end of said casing; a variable volume fluid pressure chamber formed by a cylindrical piston in coaxial alignment in said casing fixedly secured to said fixed end wall and an annular outer cylinder slidably mounted on said piston for reciprocal movement toward and away from said fixed end wall and closed adjacent an end opposite said fixed end wall, said cylinder including a plurality of longitudinally extending recesses of substantially circular transverse cross-section positioned adjacent an outer wall surface in parallel, equilaterally spaced relation with respect to a central longitudinal axis of said piston, each of said recesses having a transverse end wall adjacent said fixed end wall of said casing; a pair of coaxial coil springs mounted in each of said recesses acting in compression between said annular end wall of said casing and the end wall of the recess for biasing said cylinder toward said fixed end wall of said casing to minimize the volume of said pressure chamber; a fluid conduit in said piston for directing pressurized fluid into and out of said chamber; and switch means externally of said fluid chamber actuated by movement of said cylinder in response to volume changes of said chamber for controlling the operation of a fluid device in fluid communication with said chamber.