Note: Descriptions are shown in the official language in which they were submitted.
:13S~5949
DISPENSER FOR STRIPED VISCOUS PRQI2UCIS
Technical Field
This invention relates to the field of manually operated pumping
dispensers and, more particularly to improvements in dispensers of the
S type which are especially adapted for handling viscous products such as
striped toothpaste and the like.
BackgrQ,~and
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A dispenser for pasty products of the subject type is illustrated in
U.S. Patent 4,691,847 issued September 8,1987 in the names of John M.B.
Ford, et al., and titled "PASTY PRODUCI DISPENSER HAVING
COMBINAT~ON ACI UATOR AND OUII~T VALVE". While the
principles disclosed and claimed in such prior application are sound and
dispensers constructed in accordance with those teachings have performed
quite well for their intended purposes, further improvements have now
been discovered which make dispensers of that ~pe especially well suited
for striped toothpaste products and the like where preserving the integrity
and clear definition of the stripes within the dispensed bead of toothpaste
is extremely important for aesthetic, user appeal reasons.
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Summary of the Present Invention
Accordingly, one important object of the present invention is to
prov~de a dispenser that is especially, although not exclusively, suited for
dispensing a viscous, axially striped product by virtue of the dispenser's
ability to pump the product under pressure without destroying or otherwise
adversely affecting the integrity and clear definition of the stripes
throughout the product.
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To this end, the reciprocable pumping piston of the dispenser is
provided with a product engaging face that is concave in nature so as to
gently guide the product in a laminar flow into the centrally disposed
outlet passage associated with the piston during the pumpin~ stroke. The
S avoidance of turbulence, agitaffon and sharp directional changes in the
product as is subjected to pumping pressures has been found to be
especially beneficial in preserving the integrity of the stripes. Moreover,
constructing the pumping piston in a manner to achieve such results has
also led to a decrease in the finger pressure required to manually effect a
pumping stroke and to a decrease in any deformation of the piston face
which could otherwise lead to undesirable product blow-by around the
sealing interface between the piston and the walls of the pumping
chamber.
As a result of the concave piston face, it has also been found
desirable to provide the lower takeup piston of the dispenser with a convex
product engaging face complemental to the face of the pumping piston.
This results in several benefits including, for example, maximizing the
degree of evacuation of product from the pump chamber as the convex
face becomes received and nested within the concave face of the pumping
piston upon full depletion of the product, and improved sealing around the
interface between the takeup piston and the walls of the chamber.
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Figure 1 is a vertical cross-sectional view of a dispenser constructed
in accordance with the principles of the present invention with the
actuating lever thereof in its undepressed, standby position and the spout
outlet closed by the valve portion of the lever; and
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Fig. 2 is a vertical cross-sectional view of the dispenser similar to
Fig. ~ but showing the dispenser filled with a striped pro~uct and the
actuating lever depressed.
DeSçrip~ion ~f the Preferred Embodiment
Figs. 1 and 2 show a dispenser 10 having a tubular cylindrical body
12 which is open at its lower end 14 to the atmosphere, except for the
presence of a floating piston 16 which makes sealing engagement with the
interior wall surface of the body 12 and has a downwardly and outwardly
flaring metal skirt 18 or the like on the bottom side thereof which also
engages the interior wall surface of the body 12. The skirt 18 is
sufficiently resilient that it will deflect downwardly to any extent necessary
to permit the piston 16 to move upwardly in the body 12 yet is sufficiently
sti~ as to bite into the wall surface and prevent downward, retrograde
movement of the piston 16 within the body 12. The opposite upper end 20
of the body 12 includes an upright, centrally disposed, reduced-diarneter
sleeve 22 which is supported by transversely extending web means 24.
The sleeve 22 reciprocably receives the tubular stem 26 of a
pumping piston 28 which at its circumferential periphery sealingly engages
the inner wall surface of the body 12. A passage 30 is defined within the
tubular stem 26, and the two pistons 16 and 28 cooperate with the body 12
to form a pumping chamber 32 therebetween.
The sleeve 22 also partially receives the lower end of a tubular
discharge spout 34 which itself receives the upper end of the plunger stem
26 and is securely attached thereto. A passage 36 is defined within the
tubular spout 34, and a discharge outlet 38 is presented at the uppermost
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end thereo A soil spring 40 encircles the piston stem 26 and is trapped
bet~veen the lower extremi~ of the spout 34 and a lower, inturned
terminus 42 of the sleeve 22 for the purpose of yieldably biasing the piston
28 and the spout 34 toward an upper, undepressed position as illustrated in
S Fig. l.
The dispenser 10 is also provided with an actuator 46 in the form of
a lever having a fulcrum 48 associated with the spout 34. The fulcrum 48
takes the form of a pair of pins projecting laterally from opposite sides of
the spout 34, and a pair of legs 50 of the actuator 46 (only one leg S0
being illustrated) straddle the spout 34 and rest at their midpoints on the
respective fulcrum pins 48. Forwardmost ends of the legs S0 are
retainingly hooked beneath overhanging proximal ledges 52 (only one
being shown) on upstanding housing structure 54 at the upper end 20 of
the body 12.
The actuator lever 46 includes a finger-engaging portion 56 on one
side of the fulcrum pins 48, as well as a valve flap portion 58 on the
opposite side of the fulcrum pins 48. The valve portion 58 is integrally
connected with the finger-engaging portion 56 by an intermediate web
portion 60, and it will be noted that the valve portion 58 is of such a
dimension as to completely cover and thereby close the outlet 38 when the
actuator 46 is in its Fig. 1 position. If desired, the spout 34 may have an
angled upper end as shown in order to best accommodate the valve
portion 58 and a web portion 60 of actuating lever 46.
The pumping piston 28 has a lower, product-engaging face 44 which
is of smoothly arcuate, concave configuration. It is to be noted that
although the face 44 is arcuate in the illustrated embodiment, it is also
within the concepts of the present invention to provide such face 44 with
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sloping flat surfaces that converge toward the passage 30. The number of
such sloping surfaces is largely discretionar~.
The lower takeup piston 16 is provided w~th an upper, product
engaging face 17 that is of smoothly arcuate, convex configuration
S complemental to that of the face 44 of pumping piston 28. Once again,
although face 17 has been disclosed herein as being smoothly arcuate, it is
within the scope of the present invention to achieve its convex
configuration through sloping flat surfaces or the like, although it is
preferred that, in any event, the face 17 be configured in a corresponding
and complemental way with respect to the face 44.
Operation of the Preferred Embodiment
The return spring 40 normally maintains the pumping piston 28, the
spout 34, and the actuator 46 in the position of Fig. 1 in which the valve
flap 58 tightly covers and seals the outlet 38. Upon the application of
downwardly directed finger pressure to the operating portion ~6 of the
actuator 46, the latter rocks downwardly about the fulcrum pins 48 in a
clockwise direction so that the valve flap 58 is lifted off the outlet 38 in
substantially the same manner as illustrated in Fig. 2. At the same time,
because the legs 50 are retained beneath the ledges 52, depression of the
operating portion 56 also causes the spout 34 and hence the pumping
piston 28 to be shifted downwardly a short distance. This exerts a positive
pumping pressure on the product contained within the chamber 32, forcing
the same upwardly through the passages 30 and 36 and out the outlet 38.
When pressure on the operating portion 56 is released, the spring
40 returns the spout 34 to its original raised position of Fig. 1 and likewise
forces the pumping piston 28 back to its original position. By virtue of the
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fulcrum pins 48 moving upwardly at this time and the legs 50 being
trapped beneath the ledges 52, the actuator 46 is rocked in a
counterclocL~vise direction about fulcrum pins 48 to thereby return the
operating portion 56 to its original undepressed position and to lower the
S flap 58 once again into covering relationship with the outlet 38. In view of
the evacuatior. of product within the chamber 32 and the closing of the
outlet 38 by valve flap 58, the floating piston 16 is caused to be moved
upwardly within the chamber 32 by a corresponding amount as
atmospheric pressure is applied against the bottom of the piston 16 by the
operl lower end 14 of the body 12.
The gently arcuate, concave face 44 of the pumping piston 28 has
the effect of easing the transfer of product from within the pumping
chamber 32 to the spout 34. In this respect, whereas in prior dispensers
the pumping face of the piston is normal to the path of travel of product
therethrough and the product must therefore be converged centrally and
turned sharply and abruptly at right angles, in the present invention
downward movement of the pumping piston 28 tends to deflect or guide
the product gently inwardly while at the same time pressing downwardly to
force the product up through the passage 30.
This is quite significant when the product being dispensed has a
number of axial stripes of sharply contrasting colors as illustrated in Fig. 2
where, for example, the stripes 62, 64, and 66 may be white, the stripe 68
red, and stripe 70 aqua. By converging the outer portions of the product
inwardly toward the passage 30 at an oblique angle to the latter during the
pumping stroke, it has been found that the stripes are much more prone to
maintain their sharp, contrasting definition so that the bead of
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product ultimately dispensed will be aesthetically pleasing.
It has also been found that the concave configuration of the piston
face 44 yields improved structural integrity as compared to prior pumping
pistons having thin faces disposed normal to the path of product flow. In
S this respect it has been observed that the pressures developed during a
pumping stroke had a tendency to deflect and deform such prior piston
faces, thus also tending to pull the sealing peripheries thereof away from
their interface with the pumping chamber. This could result in product
blow by and leakage around the pumping piston under some conditions.
Furthermore, it has been noted that the concave configuration of
the piston face 44 reduces the finger pressure required to depress the
piston 28. Helpful in this regard is the lack of turbulence and agitation
involved during the pumping action, all of which enhances the ease with
which the piston 28 may be depressed.
On the other hand, the convex configuration of the takeup piston 16
assures that as the latter approaches the upper limits of its travel, the face
17 thereof will be complementally received by the concavity of the pumping
piston 28. Consequently, evacuation of the product within chamber 32is
maximized, there being no remaining space for entrapment of product
residue between the complemental faces 44 and 17 once the takeup piston
16 has fully risen into engagement with the piston 28.
Furthermore, it is believed that as a result of the convex
configuration applied to the takeup piston face 17, an enhanced peripheral
sealing action is obtained between takeup piston 16 and the walls of the
chamber 32, perhaps as a result of product forces being directed
downwardly along the domed face 17 and generally outwardly toward the
sealing periphery of the piston 16.
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It will of course be understood that the foregoing sets forth but one
exemplary embodiment of the present invention. Various modifications
within the spirit and scope of this invention will be apparent to ~hose
skilled in the art, and such modifications can obviously be made without
S departing from the underlying principles of the invention.
