Patent ID: 6764286
Filing Date: 2004-07-20
Classification: B60T,F04B,F16K

Abstract:
A piston pump comprising:a pump housing defining a cavity therein; a cylinder having open first and second ends, said cylinder being attached to said pump housing and disposed in said cavity within said housing, a longitudinal bore being defined through said cylinder, said longitudinal bore having an inlet at said first end and an outlet at said second end, said cylinder defining an outlet check valve seat about the outlet of said second end; a piston slidably received in said open first end of said cylinder, said piston having a first passageway formed therein, said first passageway having an inlet end and an outlet end, the inlet end of said first passageway of said piston being in fluid communication with said cavity of said pump housing; a first spring member fixed with a snap fit to an exterior portion of said piston and fixed with a snap fit to said cylinder; a piston valve seat being defined about said outlet end of said piston; a cylinder head attached to said cylinder and to said pump housing, said cylinder head enclosing said open second end of said cylinder, a second passageway being formed within said cylinder head, said second passageway having an inlet and an outlet, the outlet of said second passageway being in fluid communication with an aperture in said pump housing; a first check valve member disposed in the outlet end of said first passageway of said piston, said first check valve member cooperating with said piston valve seat to allow fluid to flow only from the inlet end of said first passageway of said piston to the outlet end of said first passageway of said piston; a retaining element for limiting the range of movement of said first check valve member, said retaining element having an aperture for the passage of fluid; a second check valve member disposed between said cylinder head and said second end of said cylinder, said second check valve member allowing fluid to flow only from the inlet to the outlet of said second passageway; a second spring member extending between said cylinder head and said second check valve member, said second spring member biasing said second check valve member toward said outlet check valve seat of said second end of said cylinder; and a drive arrangement selectively reciprocating said piston in said cylinder, whereby fluid is introduced into said first passageway of said piston, passes into said longitudinal bore of said cylinder via said first check valve member, is urged from said longitudinal bore by the reciprocating motion of said piston, and is delivered to said second passageway via said second check valve member.