Dispensing – With discharge assistant – With movable nozzle interconnected therewith
Patent
1994-09-14
1996-01-09
Kaufman, Joseph A.
Dispensing
With discharge assistant
With movable nozzle interconnected therewith
2223214, 2223219, 222341, 222385, G01F 1100
Patent
active
054821886
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns an improved precompression pump particularly intended for spraying or dispensing a fluid, e.g. such as a perfume, a cosmetic or a pharmaceutical. A pump of this kind for a liquid or a semi-liquid is usually operated by a finger.
One specific type of manual precompression pump is described in document FR-2 403 465. That type of pump includes a cylindrical pump housing containing a slidable annular plunger controlled by a push rod which slides in said plunger and includes an outlet channel leading to the pump housing via a side opening, the plunger including a substantially axial annular lip that interacts with the push rod to block or clear said side opening, the push rod being connected to the plunger by a first resilient member which pushes the plunger back into a position in which said side opening is blocked, said first resilient member urging said plunger towards an annular ram which urges said lip radially towards the push rod by wedging it.
In that type of pump the radial force exerted on said lip of the plunger is not accurately controlled. This can eventually lead to deformation of the lip as the result of creep, to jamming of the lip into the side opening of the push rod, and possibly to tearing of the lip.
SUMMARY OF THE INVENTION
An object of the present invention is to solve this technical problem.
The present invention consists in a pump of the above type wherein the ram is further designed to abut the plunger outside said lip, thereby limiting the movement of the ram and the plunger towards each other, and thus limiting the radial force applied to said plunger lip.
In a first embodiment, corresponding to the pump described in above-mentioned document FR-2 403 465, the invention consists in a precompression pump including at least:
a cylindrical pump housing having first and second ends,
an annular plunger slidable axially in said pump housing,
a push rod slidable in said plunger and passing through said second end of the pump housing, said push rod extending axially between a first end outside the pump housing and a second end inside the pump housing, said push rod having a blind passage extending axially from the first end of the push rod to a side opening inside the pump housing, the plunger including an annular central lip extending partway towards the first end of the pump housing, said central lip being adapted to slide in sealed contact with at least one part of the push rod between said side opening and the second end of the push rod, said central lip being adapted to clear the side opening of the push rod when the plunger is displaced sufficiently far towards the first end of the push rod,
a first resilient member mounted between the push rod and the plunger and urging said plunger towards the second end of the push rod,
an annular ram disposed between the plunger and said first end of the pump housing, slidable in said pump housing and axially movable relative to the push rod, and
a second resilient member urging the ram towards the second end of the pump housing so that the ram is pressed against the central lip of the plunger, said ram and said central lip having shapes such that the ram applies an inward radial clamping force to the central lip, by wedging it, whilst urging said central lip axially towards the second end of the pump housing, wherein the ram is further adapted to abut against the plunger outside the central lip, which limits movement of the ram and the plunger towards each other and thereby limits the radial clamping force applied to the central lip of the plunger.
The first end of the pump can include an inlet valve and the pump can further include a second resilient member which urges the push rod towards said second end of the pump housing.
In a second embodiment the invention consists in a precompression pump including at least:
a cylindrical pump housing having a first end fitted with an inlet valve and a second end,
an annular plunger slidable axially in said pump housing,
a push rod slidable in s
REFERENCES:
patent: 3463093 (1969-08-01), Pfeiffer et al.
patent: 4087025 (1978-05-01), Steiman
patent: 4228931 (1980-10-01), Ruscitti et al.
patent: 5046644 (1991-09-01), Cater
patent: 5147073 (1992-09-01), Cater
Kaufman Joseph A.
Valois S.A.
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