Ultra low device volume piston system

Reference Number: N 01-02

Inventors: Rao, V. Durga N.; Yeager, David A.

Owner: NISTAC

USPTO Link:5490445

Invention Summary

A piston and ring assembly operative within a cylindrical bore wall to retain pressurized fluid to one side of the assembly, the piston having a crown and an annular side wall for movement along the bore wall. The assembly comprises a piston having at least on annular groove (the groove having an enlarged height of at least 4 mm) in the side wall of the piston; at least two split compression rings in each such groove effective to each substantially annularly engage the bore wall, the rings having mating superimposed surfaces to facilitate movement of the rings in unison as a result of friction therebetween; a compressed elastomeric ring (constituted of polysilanes, such as silastic with strengtheners) disposed in said groove (having a compression of 10-20% at room temperature), acting between the piston and ring most-remote from said piston crown, to resiliently bias at least the most-remote-ring against the bore wall; a solid film lubricant coating essentially all the sides of said groove; and non-mating surfaces of solid lubricant carried by the rings to effect reduced friction between said rings and groove when being biased by the elastomeric ring.