Dual piston seal

Claim 1

A dual resilient integral piston seal ring for a piston and cylinder assembly wherein, a. said piston having a ring seal receiving channel with bottom and sidewalls extending thereabout and a narrow rib extending radially outwardly substantially medially of said sidewalls from the bottom of the channel and terminating substantially medially of the height of said sidewalls; b. said seal ring having a body of generally rectangular formation in cross section and a top, bottom and sidewalls and an annular groove in its bottom wall and concentric outermost and innermost flanges; c. the outermost flange being adjacent the top of the body and with outwardly tapered similar extensions at both sides of the body, with each extension tapering to a rather thin edge portion for sealing engagement with an adjacent cylinder wall when the ring is in the piston channel; d. the innermost flange being concentric with and spaced inwardly from the outermost flange and of greater axial width than the outermost flange and adjacent the bottom of the body and extends outwardly on each side thereof opposite the annular groove in the bottom portion of the body; e. each extension of the innermost flange having a rounded marginal edge portion thereof for engagement with adjacent opposite sidewalls of the channel and adjacent spaced portions of the bottom wall of the channel in the piston; f. the narrow rib in the channel fitting into the annular groove in the bottom wall of the body, and g. an intermediate wide cylindrical plane surface on the body between the extensions on either side of the body and the plane surface being slightly below the end tapered marginal edges of each of said outermost flange extensions thus providing a slight space between said plane surface and the adjacent inner surface of the cylinder wall to allow for a lubricating oil film in said space.