Patent ID: 9587655
Date: 2017-03-07
CPC Classifications: B05B,F15B

Claim:
1. A pump for dispensing fluids from a reservoir, comprising: a piston chamber-forming member having an elongate chamber, said chamber having a chamber wall, an outer open end and an inner end in communication with the reservoir; a one-way valve between the reservoir and the chamber permitting fluid flow through the inner end of the chamber from the reservoir to the chamber; a piston-forming element slidably received in the chamber extending outwardly from the open end thereof; the piston-forming element having an inner head portion, an outer base portion and a variable length portion intermediate the head portion and the base portion joining the head portion and the base portion, the base portion having a central axially extending hollow stem having a central passageway open at an outer end of the passageway forming an outlet, a head disc extending radially outwardly from the head portion engaging the chamber wall circumferentially thereabout to prevent fluid flow in the chamber past the head disc in an inward direction, the head disc elastically deforming away from the chamber wall to permit fluid flow in the chamber past the head disc in an outward direction, a base disc extending radially outwardly from the stem of the base portion axially outwardly from the head disc engaging the chamber wall circumferentially thereabout to prevent fluid flow in the chamber past the base disc in an inward direction, the base portion having a central axially extending hollow stem having a central passageway open at an outer end forming an outlet, the passageway extending from the outlet inwardly to an inner end of the passageway open to the chamber between the head disc and the base disc, the piston-forming element received in the piston chamber-forming member reciprocally coaxially slidable inwardly and outwardly by movement of the base portion in the chamber between a retracted position and an extended position in a cycle of operation to draw fluid from the reservoir and dispense it from the outlet, the piston-forming element and the chamber coaxially disposed about a central axis, the variable length portion comprising a tubular member coupled at an outer end of the tubular member to the base portion and at an inner end of the tubular member to the head portion, the tubular member transmitting axially directed tension force applied thereto by the base portion from the base portion to the head portion, the tubular member reducing in length axially between the base portion and the head portion when axially directed compression forces are applied to the tubular member by the base portion, the tubular member having a wall member extending between inner end of the tubular member and the outer end of the tubular member, the wall member having the shape of a solid of revolution rotated about the central axis, the wall member having a radially outwardly directed outer wall surface and a radially inwardly directed inner wall surface, at least one wall opening radially through the wall member from the outer wall surface to the inner wall surface, the tubular member being resilient having an inherent bias to assume an initial unbiased configuration of an unbiased length measured along the central axis, the tubular member resiliently deflectable to biased configurations each having a length measured along the central axis less than the unbiased length, the inherent bias of the resilient member biasing the tubular member to return towards the unbiased configuration from any one of the biased configurations, a reduction in the length of the tubular member as measured along the central axis corresponds to the outer wall surface increasing in convexity as seen in cross-sectional side view in flat planes including the central axis extending radially from the central axis.