Dispensing – Processes of dispensing
Reexamination Certificate
2000-11-15
2001-11-13
Kaufman, Joseph A. (Department: 3754)
Dispensing
Processes of dispensing
C222S321900, C222S385000
Reexamination Certificate
active
06315162
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a pump dispenser in which a plunger having an actuator top reciprocates inside a hollow cylindrical body. More specifically, this invention relates to such a dispenser in which, at the bottom of the plunger stroke and in a lockdown condition, a seal closes off a vent hole.
BACKGROUND OF THE INVENTION
The U.S. patent application Ser. No. 09/079,481 filed May 15, 1998, now U.S. Pat. No. 6,053,371, assigned to our assignee, discloses a meritorious liquid dispenser comprising a hollow body and a one-piece plunger including an actuator portion and piston portion. The disclosure of this patent is incorporated hereinto by reference. The plunger includes a stem and an enlarged piston head at its lower end. Between the stem and head is formed an upwardly facing shoulder. Inlet and outlet check valves are provided and a spring urges the plunger upward. The body has near the upper end an internal inward and downward flap which, when engaged by the shoulder, stops upward movement of the plunger. A vent hole is formed in the body. The flap, being above the vent hole is in position to seal venting. While the arrangement of the patent application is indeed meritorious, there has been a need for an improved vent seal particularly in lockdown position.
SUMMARY OF THE INVENTION
The invention is, of course, described in the claim language appended hereto. In summary, under the present invention, the stem of the plunger is formed with a tapered zone enlarging in an upward direction to a wider diameter portion. For the majority of travel of the plunger inside the pump body, the flap barely contacts the stem. As the plunger approaches lockdown position, near the end of the stroke, however, the flap engages the taper and then the wider diameter in an interference fit and achieves a seal.
The flap thus does double duty: as a stop as described in said patent and as a seal. As a stop the flap protrudes enough toward the stem to serve as a wiper and to engage the shoulder as described to limit upward movement of the plunger and, incidentally, to effect a seal between flap and shoulder in top position. In the lockdown position the flap firmly engages the wider diameter to effect a seal.
REFERENCES:
patent: 2362080 (1944-11-01), Martin
patent: 3128018 (1964-04-01), Corsette et al.
patent: 3191814 (1965-06-01), Corsette et al.
patent: 3248021 (1966-04-01), Corsette et al.
patent: 3362344 (1968-01-01), Duda
patent: 3949906 (1976-04-01), Pettersen et al.
patent: 5158211 (1992-10-01), Meshberg
patent: 5392962 (1995-02-01), Meshberg
patent: 5549223 (1996-08-01), Hori
patent: 5725128 (1998-03-01), Foster
patent: 5775547 (1998-07-01), Foster et al.
patent: 5850948 (1998-12-01), Garcia et al.
patent: 6053371 (2000-04-01), Durliat et al.
patent: 6082593 (2000-07-01), Borcherds
patent: 6173863 (2001-01-01), Brozell et al.
Brozell Leonora M.
DiVitto Anthony M.
Sayers Richard C.
Kaufman Joseph A.
Owens-Illinois Closure Inc.
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