Dispenser pump

Claim 2

A fluid dispenser pump having a piston extending from one end of a cylinder with resilient means urging the piston from the cylinder to its extended position for manual movement into the cylinder to its retracted position, said piston and cylinder being elastomeric plastic members with complementary cylindrical walls forming a sequence of chambers, which include: a. an inlet chamber to communicate with a fluid supply; b. an auxiliary pressure chamber normally sealed from the inlet chamber but communicating with the inlet chamber whenever the piston is at its fully extended position; c. an operating chamber communicating with the auxiliary pressure chamber and a first check valve means between the operating and auxiliary pressure chambers which permits flow from the auxiliary pressure chamber to the operating chamber but prevents a reversal of such flow; d. a discharge chamber communicating with the operating chamber and a second check valve means between the discharge and operating chambers which permits flow from the operating chamber to the discharge chamber but prevents a reversal of such flow; and e. an outlet from the discharge chamber; wherein f. said auxiliary pressure chamber and said operating chamber increase in volume when the piston is being extended and decrease in volume when the piston is being retracted whereby reciprocation of the piston into the cylinder pumps fluid past the check valve means and through the pump; and g. said check valve means are formed as thinwall sleeve members embracing stem portions, said sleeve members expanding responsive to fluid pressure, to move away from the stem portions to permit fluid flow therepast.

Claim 3

The dispenser defined in claim 1, wherein: a. said piston includes an auxiliary stem which lies within the auxiliary pressure chamber when the piston is extended; b. the inlet chamber adjacent to the auxiliary pressure chamber slidably receives the auxiliary stem with a substantially fluid-tight fit, and said stem is adapted to move into the inlet chamber as the piston commences to retract into the cylinder to cut off communication between the inlet and auxiliary pressure chambers to normally seal the auxiliary pressure chamber from the inlet chamber and to force fluid from the auxiliary pressure chamber, past the said first check valve means and into the operating chamber.

Claim 4

The dispenser defined in claim 1, wherein the complementary cylindrical walls of the cylinder and piston include: a. a central axial stem depending from the piston and a smaller auxiliary stem extending therefrom; b. a cylindrical axial wall within the cylinder to receive said auxiliary stem and define said auxiliary pressure chamber; c. a tubular extension from the cylinder having a cylindrical intake passageway connecting with the auxiliary pressure chamber to define said intake passageway; wherein said auxiliary stem lies in the auxiliary pressure chamber when the piston is fully extended from the cylinder but moves into the intake passageway as the piston commences to retract into the cylinder with the auxiliary stem being proportioned to provide a sliding, fluid-tight fit in the intake passageway.

Claim 5

The dispenser defined in claim 3, wherein: said central axial stem fits in said cylindrical wall with a loose fit to permit flow between the two; and said first check valve means is at the end of the cylindrical axial wall and comprises a slightly converging portion, feathered to a thin edge and reduced in diameter to normally embrace and grip said stem but to flex away from the stem responsive to pressure in the auxiliary pressure chamber.

Claim 6

The dispenser defined in claim 4, wherein: an axial wall on the piston embraces the aforesaid cylindrical axial wall with the space between the two and said central axial stem constituting said operating chamber; and said second check valve means at the extended end of the cylindrical axial wall of the piston comprises a slightly converging portion, feathered to a thin edge and reduced in diameter to normally embrace and grip said cylindrical axial wall but to flex away from the wall responsive to pressure in the operating chamber.

Claim 7

The dispenser defined in claim 5, wherein: said piston is formed with an outer wall embracing, but being spaced from, the aforesaid axial wall on the piston; and said cylinder includes an outer wall embracing the outer wall of the piston with the space between these outer walls and the adjacent inward walls of the piston and cylinder forming said discharge chamber; and a spout means at the upper end of the piston having a passageway communicating with said discharge chamber.

Claim 8

A fluid dispenser pump of resilient plastic material and of the type which includes an uprightly oriented cylinder having the top open and the bottom closed by a floor adapted to be mounted in the mouth of a container, a piston extending from the top of the cylinder to reciprocate therein and a spring means urging the piston to an extended position from the cylinder for manual operation of the same by depressing the piston to a retracted position within the cylinder, wherein the cylinder includes: a. an intake tube depending from the floor of the cylinder; b. a cylindrical sleeve within the cylinder upstanding from the floor of the cylinder to define a central section and an outer annular section with the passageway from the intake tube communicating with the central section, with the diameter of the central section being greater than the diameter of the intake tube, and the piston includes: c. a head section at the top thereof; d. a stem depending from the head section and being fittable within the cylindrical sleeve with a clearance fit to permit fluid to move between the stem and cylinder sleeve; e. an auxiliary stem depending from the stem and fittable into said intake tube with a fluid tight fit; f. a piston sleeve depending from the head section to fit over the cylindrical sleeve with a clearance fit to permit fluid to move between the cylindrical sleeve and piston sleeve, and wherein: g. the upper end of said cylindrical sleeve is feathered and tapered inwardly to embrace and engage said stem to form a resilient check valve; and h. the lower end of said piston sleeve is feathered and tapered inwardly to embrace and engage the outer wall of said cylindrical sleeve to form a resilient check valve.

Claim 9

A fluid dispenser pump of resilient plastic material and of the type which includes an uprightly oriented cylinder having the top open and the bottom closed by a floor adapted to be mounted in the mouth of a container, a piston extending from the top of the cylinder to reciprocate therein and a spring means urging the piston to an extended position from the cylinder for manual operation of the same by depressing the piston to a retracted position within the cylinder, wherein the cylinder includes: a. an intake tube depending from the floor of the cylinder; b. a cylindrical sleeve within the cylinder upstanding from the floor of the cylinder to define a central section and an outer annular section with the passageway from the intake tube communicating with the central section, with the diameter of the central section being greater than the diameter of the intake tube, and the piston includes: c. a head section at the top thereof; d. a stem depending from the head section and being fittable within the cylindrical sleeve with a clearance fit to permit fluid to move between the stem and cylinder sleeve; e. an auxiliary stem depending from the stem and fittable into said intake tube with a fluid tight fit; f. a piston sleeve depending from the head section to fit over the cylindrical sleeve with a clearance fit to permit fluid to move between the cylindrical sleeve and piston sleeve, and wherein: g. the upper end of said cylindrical sleeve is feathered and tapered inwardly to embrace and engage said stem to form a resilient check valve; and h. the lower end of said piston sleeve is feathered and tapered inwardly to embrace and engage the outer wall of said cylindrical sleeve to form a resilient check valve.

Claim 10

The pump defined in claim 7, wherein: a piston wall depends from the head section about and spaced from said piston sleeve; and a cylinder wall upstands from the floor to lie about the piston wall with a fluid tight fit.