Spray pump

Claim 1

A spray pump for spraying fluid comprising: a container cap for securement in an opening of a container partly filled with liquid; said container cap having an annular end wall with a central opening; a tubular cylinder extending down from the underside of the container cap; said tubular cylinder including an upper, smaller diameter cylindrical portion and a lower, larger diameter portion and an intermediate, tapering portion extending between the lower extent of the upper portion and the upper extent of the lower portion, said tapering portion having means defining an annular internal, downwardly and radially inwardly facing, tapered surface; means defining a suction opening through the tapering portion intermediate the axial extent thereof; a suction tube communicating with the tubular cylinder adjacent the lower end of the tubular cylinder and adapted to depend into a body of liquid in the container; means defining a one-way check valve between said tubular cylinder and said suction tube, oriented to permit fluid flow from said suction tube to said tubular cylinder; a tubular piston slidably received in said tubular cylinder; said tubular piston having means defining an upwardly and radially outwardly facing tapered surface configured to engage the tapered surface on the tubular cylinder intermediate portion in sealing engagement therewith at the upper extent of the sliding of said tubular piston, said tapered surface on the tubular piston surrounding means defining a throughbore of the tubular piston; a tubular plunger slidably received in the throughbore of the tubular piston and extending axially beyond said tubular piston in both directions; said plunger, above said tubular piston, including means defining a radially enlarged portion having a downwardly facing shoulder positioned to engage the tubular piston; said plunger, below said tubular piston, including means defining a radially enlarged poRtion having an upwardly facing shoulder positioned to engage the tubular piston; the vertical distance between said downwardly facing shoulder and said upwardly facing shoulder being greater than the thickness of the tubular piston where it is engaged by the two shoulders, thereby providing for limited axial movement between the tubular plunger and the tubular piston and alternative engagement of the tubular piston by the two shoulders; means defining an opening through said tubular plunger communicating between the throughbore thereof and the exterior thereof intermediate the two shoulders, this opening being so positioned that when the upwardly facing shoulder is in engagement with the tubular piston, the opening is closed by contact with the wall of the throughbore of the tubular piston and that when the downwardly facing shoulder is in engagement with the tubular piston, the opening communicates between the throughbore of the plunger and the interior of the tubular cylinder, under the tubular piston; said plunger proceeding upwardly through said central opening in the container cap; a combined spray head and pushbutton means mounted upon the valve rod above said central opening, and having means defining a fluid outlet passageway therein in communication with the throughbore of said plunger; means blocking the throughbore of the plunger below said opening thereof; a compression coil spring received and mounted, within the tubular cylinder, and arranged to obtain purchase against the tubular cylinder to resiliently force the plunger and the tubular piston upwardly to the upper positions thereof wherein the upwardly facing shoulder engages the tubular piston and forces the piston upwardly so that the recited sealing achievement is achieved, and so that, when the pushbutton means is depressed, the plunger moves downwardly further resiliently compressing the coil spring, thus establishing communication through the opening in the plunger and then permitting communication between the exterior of the cap and the exterior of the intermediate, tapered portion of the tubular cylinder through said opening in said intermediate, tapered portion.