Pump dispenser for delivering a predetermined dosage regardless of method of actuation

A finger actuated pump dispenser mounted on a fluid containing vessel which when actuated will discharge fluid at a predetermined pressure and will deliver a predetermined dosage regardless of the method of actuation, the dispenser comprising:

• a vertical hollow elongated body having an upper section defining a first hollow vertical cylinder with a first diameter and open upper end and an integral lower section defining a second hollow vertical cylinder with a second and smaller diameter and a closed lower end with a central opening, the lower end of the first cylinder being joined to an open upper end of the second cylinder, the body having a first vertical bore extending through both cylinders;
• a collar having a central opening aligned with the first bore and enclosing the upper end of the first cylinder;
• a sleeve open at upper and lower ends and having a first enlargement intermediate these ends, the sleeve having a second vertical bore aligned with the first bore, the portion of the sleeve intermediate the upper end and the first enlargement extending upwardly through the collar opening with the first enlargement being disposed below the collar, the first enlargement and the remaining portion of the sleeve being disposed within the first cylinder;
• a first hollow vertical piston having an upper open end and a lower closed end having a central opening which is aligned with the first bore, the first piston being disposed and vertically slidable along the sleeve within the first cylinder;
• a vertical stem having an upper vertical section with relatively small cross sectional area which extends upwardly through the first piston and through the second bore, the upper section being spaced inwardly from the second bore, the space between the upper section and the inner wall of the second bore defining a fluid discharge path, the stem having an integral lower vertical section with a cross sectional area which is larger than that of the upper section and smaller than that of the second cylinder, the upper end of the lower section being adjacent the lower end of the first piston;
• a second vertical piston vertically slidable in the second cylinder with an upper end adjacent and engagable with the lower end of the lower section, the second piston having a second enlargement intermediate its ends which engages the inner wall of the second cylinder;
• first spring means disposed within the first cylinder between the lower end of the first piston and the first enlargement;
• second spring means disposed within the second cylinder between the lower end of the second cylinder and the second enlargement;
• and means associated with the second piston and the second cylinder and actuated during at a selected position of the second piston with respect to the second cylinder during an upstroke to establish a fluid transfer path between the fluid in the container and a pump chamber formed by the space subtended by the inner wall of the first cylinder, the stem and the two pistons, said means associated with the second piston and cylinder including an enlarged recess disposed in the inner wall of the second cylinder at its upper end, said fluid transfer path being established when the second enlargement is aligned with and spaced from said recess;
• and actuator means connected to the upper end of the upper stem section and the upper end of the sleeve.