Patent ID: 8360286
Filing Date: 2013-01-29
Classification: A47K,B05B

Abstract:
1. A pump for dispensing liquid from a reservoir comprising: piston chamber-forming member having a chamber disposed about an axis, the chamber having a diameter, a chamber wall, an inner end and an outer end, the inner end of the chamber in fluid communication with the reservoir, a one-way valve mechanism between the reservoir and the chamber permitting fluid flow through the inner end of said chamber, only from the reservoir to the chamber; a piston-forming element received in the piston chamber-forming member axially slidable inwardly and outwardly therein, said piston-forming element having an axially extending hollow stem having a central passageway closed at an inner end and having an outlet proximate an outer end, an inner disc on the stem extending radially outwardly from the stem circumferentially thereabout, an outer disc on the stem spaced axially outwardly from the inner disc and extending radially outwardly from the stem circumferentially thereabout, an inlet located on the stem between the inner disc and the outer disc in communication with the passageway, the piston-forming element slidably received in the piston chamber-forming member for reciprocal axial inward and outward movement therein in a stroke of movement between an extended and a retracted position, the chamber having an axially inner chamber portion and an axially outer chamber portion, the inner chamber portion opening outwardly into the outer chamber portion, in movement between the extended position and the retracted position, the outer disc is maintained within the outer chamber portion, in movement between the extended position and the retracted position, the inner disc is within the inner chamber portion in an inwardmost portion of the stroke and within the outer chamber portion in an outwardmost portion of the stroke, in the outer chamber portion the chamber wall being cylindrical, when the outer disc is in the outer chamber portion the outer disc substantially preventing fluid flow in the outer chamber portion past the outer disc in an outward direction, when the inner disc is in the outer chamber portion the inner disc engaging the chamber wall to substantially prevent fluid flow in the outer chamber portion past the inner disc in an inward direction but the inner flexing disc elastically deforming away from the chamber wall of the outer chamber portion to permit fluid flow in the outer chamber portion past the inner disc in an outward direction, the inner chamber portion further comprising a spacing means for spacing the inner disk from the chamber wall, such that when the inner disc is in the inner chamber portion at least portions of the inner disc and the chamber wall are spaced radially to permit fluid flow in the inner chamber portion in both an inward direction and an outward direction past the inner disc.