Patent ID: 6286726
Filing Date: 2001-09-11
Classification: B05B

Abstract:
A manually operated pump for dispensing liquids under pressure, comprising:a cup-shaped body formed from a lateral wall defining a cylindrical inner surface and a base wall having a hole therein;a hollow stem, of which one end is shaped as a piston sealedly slidable along said cylindrical surface of said cup-shaped body and the other end projects from said cup-shaped body;a pump operating head mounted on the end of said stem projecting from said cup-shaped body and having a discharge hole communicating with the bore of said stem;a mounting element for securing said cup-shaped body to the mouth of a container containing the liquid to be dispensed;a first spring housed in said cup-shaped body and acting on said stem to urge it away from the base wall of said cup-shaped body;a tubular appendix projecting from said base wall of said cup-shaped body about said hole provided in said base wall and extending into the interior of said cup-shaped body;a seat provided at said hole in said base wall of said cup-shaped body to house one end of a liquid intake tube;a profiled seat provided at the free end of said tubular appendix;a floating ball positioned in said profiled seat to sealedly close the bore of said tubular appendix when said pump is operated to dispense said liquid;and a valving element housed in said stem bore and movable between a rest position in which a profiled portion thereof seals against a corresponding profiled seat provided in said stem bore in proximity to that end thereof facing said cup-shaped body and a delivery position in which the profiled end of said valving element is raised away from said seat in said stem;a second spring inserted into said stem bore and acting on said valving element to urge it into its rest position;said end of said valving element facing said cup-shaped body making contact with said ball to press said ball into said profiled seat in said tubular appendix before said stem reaches its end-of-travel position when said stem is pressed into said cup-shaped body to compress said liquid contained in said cup shaped-body, wherein the diameter of said cup-shaped body is at least equal to the length of travel of said stem between a rest position thereof and a position of maximum lowering thereof within said cup-shaped body;said length of said tubular appendix within said cup-shaped body being less than said diameter of said cup-shaped body;the profile portion of said valving element and said profiled seat in said stem bore being defined by substantially conical, mutually complementary surfaces; andwherein said profiled portion of said valving element is defined by a first and second consecutive adjacent conical surfaces, said first conical surface closer to the free end of said valving element having cross-sections smaller than those of said second conical surface adjacent to said first conical surface.