Patent ID: 8944294
Filing Date: 2015-02-03
Classification: A47K,B05B

Abstract:
1. A fluid pump comprising: a piston chamber-forming member defining a chamber about a chamber axis, the chamber having a radially inwardly directed chamber wall, an inner inlet end and an outer open outlet end, the inlet end of the chamber providing for communication with a source of fluid, the piston chamber-forming member including a center post member extending along the axis coaxially of the chamber outwardly from an inner end of the post member to a distal outer end of the post member whereby an annular compartment is defined within the chamber between the chamber wall and the post member, the piston chamber-forming member including the chamber and the post member formed as a unitary element by injection molding with the inner end of the post member fixedly integrally attached to the piston chamber-forming member proximate the inlet end of the piston chamber-forming member against relative movement, an inlet one-way valve across the inlet end of the chamber permitting fluid flow outwardly but preventing fluid flow inwardly, an annular piston-forming element coaxially slidably received in the annular compartment for reciprocal movement between a retracted position and an extended position with the post member received in a central passageway through the piston-forming element and the chamber wall radially outwardly of the piston-forming element, engagement between the piston-forming element and the chamber wall preventing fluid flow therebetween outwardly, an outlet one-way valve provided by engagement between the post member and the passageway preventing fluid flow inwardly therepast but permitting fluid flow outwardly therepast, wherein sliding of the piston-forming element inwardly relative the piston chamber-forming member reduces the volume of the compartment between the inlet one-way valve and the outlet one-way valve such that fluid is forced to pass outwardly in the passageway past the outlet one-way valve annularly about the post member, and wherein sliding of the piston-forming element outwardly relative the piston chamber-forming member draws fluid past the one-way valve outwardly into the compartment.