Rotary pumps and motors and thrust plates therefor

Claim 1

In a rotary gear pump or motor having a case, a pair of meshing rotary gears in said case, said gears having axial stub shafts journaled in said case, the improvement comprising a unitary thrust plate for the corresponding ends of the pair of rotary gears adapted to lie between the case and the ends of the gears, said thrust plate being of a metal softer than the gears and having a front face adapted to abut the gear ends and a rear face abutting the case, a pair of spaced openings extending through said thrust plate to receive the gear stub shafts, a pair of connected at least half annular grooves in the rear face spaced from and surrounding each of said openings at least on one side, a groove in the rear face connecting said annular grooves at their closest points, at least one groove in the rear face extending radially from each said annular groove to the periphery of the body generally opposite the groove connecting the at least half annular grooves defining at least two substantially identical areas on opposite sides of the body, a generally U-shaped elastomer gasket having the contour of the combined grooves on the rear face of the body and fitting sealingly into said grooves with the opening of the U-shaped gasket opening downwardly in the groove resilient means normally urging said gasket partially out of said grooves into sealing contact with the case and fluid delivery means connecting said groove in the rear face between said annular grooves with said meshing gears intermediate the top and bottom of the U-shaped gasket whereby high pressure fluid passes along said fluid delivery means to said groove intermediate the top and bottom of the U-shaped gasket, down between the U-shaped gasket and groove and through beneath said gasket into the interior thereof to pressurize the gasket to the maximum pressure of the pump and said gasket acts as a check valve between the groove and fluid delivery means.