Patent ID: 6622706
Filing Date: 2003-09-23
Classification: F02M,F04B,F05C

Abstract:
A pump comprising, a body; a crank chamber in the body; a crankshaft rotatably mounted on the body and including a drive end located outwardly of the body and a cylindrical eccentric in the crank chamber; a piston bore in the body, the bore extending from one side of the body to the crank chamber adjacent the eccentric; a closure sealing the bore at the side of the body; an outlet check valve located in the piston bore inwardly from said closure; a high pressure outlet passage in the body opening into the bore between the check valve and the closure; a hollow, cylindrical piston moveably mounted in the piston bore between the crank chamber and the check valve, the piston having a convex inner end adjacent the crank chamber and an inlet opening extending through said end, said piston and bore defining a variable volume pumping chamber; a spring in the pumping chamber, said spring including a spring end engaging said piston end; a slipper located between the piston end and the eccentric, the slipper including a partial cylindrical surface engaging the eccentric and a concave surface engaging the convex surface of the end of the piston to permit rotation of the slipper about the piston, the spring biasing the end of the piston against the slipper and the slipper against the eccentric; the slipper including a slipper opening communicating with the piston opening during return strokes of the piston, a recess in the eccentric, said recess communicating with the slipper opening during return strokes of the piston; a source of fluid to be pumped, and an inlet passage extending from the source of fluid, through the body, the crank chamber, the recess, the slipper opening and the piston opening to the pumping chamber, said inlet passage unobstructed during return strokes of the piston.