Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02638287 2008-07-25
COATED LIFT-TAB FOR RESEALING POP-TOP CONTAINERS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0001] The present invention relates to resealable containers, particularly re-
closable
seals for pop-top aluminum cans.
DESCRIPTION OF THE PRIOR ART
[0002] The term "lift-tab" is used herein to refer to that family of finger-
operated lever
components used to prize open an access hole in pop-top-type containers and
that
remain attached to the container after the container is opened. "Lift-tab"
includes, by way
of example, finger-tabs, pop-top tabs, pull-tabs, and the like, as are well
known opening
devices used for soda cans, beer cans, juice cans, and the like. Such lift-tab
based pop-
top cans have been a commercial success for a number of years. Their primary
advantage is that they obviate the need for a separate can opener, or "church
key," in
order to open a beverage can and they reduce unsightly pop-top litter because
the lift-tab
is permanently connected to the container.
[0003] FIG 1 shows a typical prior art lift-tab as used in a pop-top beverage
container,
namely a can 101 having a generally planar top 201 that has an upper surface
surrounded by and contiguous with a rim 401. An access hole, generally oval,
in the top
is defined by an edge. While the beverage container is closed, the access hole
is
occluded by a sealing plate 301 that is connected to the edge by an inscribed
break-line
1001, thereby providing a frangible waterproof seal. A lift-tab 501 is
connected to the top
by means of a connector 901, normally a simple rivet. The lift-tab has a
finger-end 701
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and a swivel-end 801. A ventral surface of the lift-tab is defined as the
lower or bottom
surface of the lift-tab when the lift-tab is pressed down against the top of
the container as
shown in FIG 1. In other words, the ventral surface of the lift-tab is the
surface facing the
upper surface of the top of the container when the lift-tab is in the closed
position prior to
opening the container. Near the finger-end of the lift-tab is normally a
finger aperture 601.
[0004] The swivel-end 801 of the lift-tab the lift-tab is rotatably connected
to the top
201 by a connector 901, allowing the lift-tab to rotate 360 degrees about the
rivet. In
addition to a pivot point, the rivet-connection also provides a fulcrum
whereby raising the
finger-end 701 forces the swivel-end 801 to move downward against the sealing
plate
301, prizing the sealing plate loose from the top.
[0005] But for a hinge just under the aforesaid fulcrum, the access hole is
circumscribed by the inscribed break-line. Because the swivel-end 801 of the
lift-tab
extends beyond the fulcrum, when the finger-end 701 of the lift-tab is lifted,
the swivel-end
is forced downward against the sealing plate, which, in turn, is pushed
downward by
means of the upward finger pressure on the finger-end, augmented by the
mechanical
advantage gained by the fulcrum, thereby forcing break-line 1001 to shear,
whereby the
access hole opens as the sealing plate is pushed into the container. The lift-
tab is then
conveniently pressed back down flat against the top of the container, leaving
the access
hole open and unobstructed so that the contents of the container can be poured
out or
accessed either by drinking directly from the access hole or by inserting a
drinking straw
into the access hole.
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[0006] Currently existing pop-top containers, such as described above, are not
resealable. Once the sealing plate is pushed into the interior of the can the
sealing plate
cannot be accessed to be pulled back into it's original position. This
detracts significantly
from the usefulness of such cans.
[0007] U.S. Pat. 4,681,238 to Sanchez is an example of attempts to provide
resealable
pop-top devices. Sanchez provides two sealing plates, both of which are
attached to the
under-surface of the top, in the interior of the can. In the un-opened
configuration, a first
sealing plate is disposed against the access hole from underneath the top. The
sealing
plate has a pliable layer on its upper, or dorsal, surface that provides a
watertight seal.
When the can is opened, this first sealing plate is pushed downwards in the
same manner
described above. In order to reseal the can, the lift-tab is twisted and a
second internal
sealing plate is rotated into position under the access hole. This second
sealing plate
also has a resilient layer that seals the hole from below. This approach to
providing a
resealable beverage container has never attained widespread use. The device,
particularly the rivet connection, is complex and difficult to produce and
requires
significant re-tooling by the manufacturer. Furthermore, it is difficult to
position the
internal second sealing plate accurately under the access hole in order to
make a
watertight seal.
[0008] What is needed is a resealable pop-top container that is simple and
effective in
its use, inexpensive to produce without the need of re-tooling or extensive
design
modifications of the existing art .
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BRIEF SUMMARY OF THE INVENTION
[0009] The invention is a resealable beverage container comprising an improved
pop-
top opening device of the type that is operated by pulling a lift-tab attached
by one end to
a fulcrum, thereby forcing a sealing plate to shear and bend downwards from
the top to
expose an access hole in the top of the container, the access hole being
defined by an
edge. The improvement comprises modifying the lift-tab by depositing or
annealing a
pliable pull-tab coat to at least the ventral surface of the finger-end of the
lift-tab such that
the coated lift-tab can be used to repeatedly to reseal the access hole
Resealing the
container is accomplished by rotating or swivelling the lift-tab so that the
pliable pull-tab
coat is adjacent the open access hole and then pressing the pull-tab down
against the top
of the container, wherein the pliable material on the ventral side of the pull-
tab engages
the edges of the opening to form a watertight seal. In order to unseal the
resealed
container, the coated portion of the lift-tab is lifted away from the access
hole and rotated
or swivelled out of the way, preferably back to its original position opposite
the access
hole. The preferred material of the pliable seal is medical-grade vinyl. The
coated pull-
tab optionally includes a straw-orifice with an orifice-closure comprising
frangible break-
lines that can be forced open to accommodate a drinking straw when the pull-
tab is
sealing the access hole.
[0010] The invention also comprises an improved lift-tab of the type used in
pop-top
beverage containers, the lift-tab having a finger-end, a swivel-end, and a
ventral surface in
which a pull-tab coat of resilient material is deposited on or annealed to the
ventral
surface of the finger-end.
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[0011] The invention also comprises a resealable beverage container
comprising: a
top having an upper surface; an access hole in the top for accessing the
contents of the
container, the access hole defined by an edge; a rotatable swivel connector; a
sealing
plate connected to a substantial portion of the edge by a frangible break-line
when the
container is closed; and a pull-tab attached to the upper surface of the top
by means of
the swivel connector. The pull-tab comprises a ventral surface; a finger-end;
a swivel-end
opposite the finger-end; and a pull-tab coat comprising a resilient material
deposited on or
annealed to the ventral surface of the finger-end of the pull-tab. The
rotatable connector
connects the swivel-end of the pull tab to the upper surface of the top such
that the pull-
tab coat on the ventral surface of the finger-end of the pull-tab can be
aligned over the
access hole by rotating the pull-tab about the connector.
[0012] The invention also comprises a method of producing a resealable pop-top
beverage container comprising the steps of depositing on or annealing a
resilient pull-tab
coat to the ventral surface of a pull-tab; attaching the pull-tab to the upper
surface of the
top by means of a rotatable connection between the pull-tab swivel-end and the
top
wherein the rotatable connection acts as a fulcrum whereby by raising the
finger-end of
the pull tab shears the connection between the sealing plate and the edge of
the access
hole and the sealing plate is forced into the lumen of the container, and
wherein the pull-
tab is rotatable about the rotation connection and configured such that the
pull-tab coat on
the ventral side of the pull-tab can be juxtaposed against the access hole for
sealing the
hole.
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[0013] The method of producing the coated lift-tabs comprises the steps of
treating
vinyl or other material used to produce the seal with a standard aluminum to
vinyl
adhesive promoter, placing a lift-tab in a mold, injecting the vinyl or other
material into the
mold, placing the mold in an oven, baking the vinyl sufficiently long and at a
sufficient
temperature to cause the vinyl or other suitable material to become a
resilient, solid state
rubber, removing the coated lift-tab from the mold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the drawings identical reference numbers are employed to identify
identical
elements. The sizes and relative positions of the elements in the drawings are
not
necessarily to scale. For example, thicknesses are generally not drawn to
scale and are
enlarged to insure comprehension of the drawings.
[0015] FIG. 1 is a perspective view of a prior art pop-top container prior to
being
opened, as discussed above.
[0016] FIG. 2 is a perspective view of a pop-top container in a closed
configuration
with its lift-tab modified according to the invention.
[0017] FIG 3 is a perspective view of a pop-top container in a resealed
configuration
with its modified lift-tab serving to reseal the access hole.
[0018] FIG 4 is a top view of a lift-tab modified according to the invention.
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[0019] FIG 5 is a cross-sectional drawing through a lift-tab coated according
to the
invention and in a configuration for resealing a can.
[0020] FIG 6 is a flow chart of the process of coating and attaching a lift-
tab according
to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The inventive concepts, utility, and novel features of the invention
are described
here with reference to specific embodiments. These embodiments represent the
best
mode known to us for practicing and making the invention. Although the steps,
elements,
and limitations of the invention, as well as their structural and functional
relationships, may
be easily comprehended with respect to the preferred embodiments as disclosed
herein, it
is to be noted that these disclosures are representative of many possible
embodiments
that incorporate the inventive concepts of our invention .
STRUCTURALFEATURES
[0022] The improved pop-top beverage container of the present invention
provides a
lift-tab that is modified to function as both a lift-tab and a resealing
device. FIG. 2 shows
the pop-top container 101 of FIG 1, including access hole 301, rim 401, lift-
tab 501, and
rivet connector 901. The lift-tab shown in FIG 2 has been modified according
to the
invention by depositing on or annealing to the pull-tab a pull-tab coat 102
made of resilient
material. The lift-tab need not be otherwise modified, thereby minimizing
additional
production costs. The pull-tab is mounted on the upper surface of top 201, as
described
above with respect to the prior art, such that the ventral surface of the
finger-end of the
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pull tab faces the upper surface of the top, and when the pull-tab is rotated
about the
connector 901 the ventral surface of the finger-end faces the access hole.
Although our
invention achieves its objective of resealing the container as long as the
ventral portion of
the finger-end of the pull-tab is coated, in our preferred embodiment the
coating covers
the entire pull-tab. It will be obvious from this disclosure that as long as
the ventral
surface of that part of the pull-tab that is juxtaposed against the access
hole is coated, the
access hole can be resealed. It is not necessary to coat the entire tab.
[0023] The pull-tab coat is made of a resilient material capable of conforming
to the
edge of the access hole, forming a frictional, watertight seal when the lift-
tab is pressed
against the hole. A vinyl material is preferred, and, more specifically,
commonly known
and easily obtainable medical-grade vinyl. This lift-tab coat thereby seals
the access hole
when the lift-tab is rotated 180 degrees about the rivet connector and pressed
down onto
the hole, as shown in FIG 3.
[0024] FIG 3 shows the pop-top container 101 of FIG. 2 with lift-tab 501
rotated 180
degrees about the rivet connection 901 and pressed down onto the access hole.
Because the pull-tab coat 102 is resilient, it makes a water-tight frictional
seal when the
lift-tab is pressed against the access hole. However, it can be lifted free
from the access
hole by slight to moderate upward pressure on the finger-end 701 of the lift-
tab. The lift-
tab can then be rotated 180 degrees about the rivet connector and back into
its original
position so that the contents of the container can be easily accessed. This
process of
resealing and reopening the container can be repeated as many times as
desired.
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[0025] FIG. 4 shows a lift-tab 304 that has been modified according to the
invention by
the application of pull-tab coat 104. The geometrical shape of the lift-tab is
characteristically triangular with rounded corners, but the invention is not
limited to any
particular shape of lift-tab. As indicated in FIG 4, the coat may extend
beyond the edges
of the lift-tab. The extent by which the coat extends beyond the lift-tab will
depend on the
geometry and size of the lift-tab vis-a-vis the geometry and size of the
access hole.
[0026] Lift-tabs also characteristically include a finger aperture 504 to make
it easier
for a user's finger-tip to engage the tab. The invention exploits such finger
apertures by
providing an straw orifice 604 through the pull-tab coat for inserting a
drinking straw
through the coating, through the finger aperture, and into the lumen of the
container. The
straw orifice 604 is preferably fashioned in the pull-tab coat by inscribing
frangible break-
lines 704 converging in a circular pattern. Thus, the straw orifice is
watertight until a straw
is forced through it.
[0027] There is also provided in the lift-tab, as is common in the existing
art, a rivet
aperture 204 for receiving the rivet that rotatably connects the lift-tab to
the top. Except
for applying the pull-tab coat, the means of producing the pop-top beverage
container
need not be modified at all, thereby avoiding expensive re-tooling costs that
are required
by other approaches.
[0028] FIG 5 shows the modified lift-tab in cross-section as it appears when
it is
sealing the access hole. The figure shows a relevant portion of the top 105 of
container
505. The top extends over the edge of the container to form the rim 705. Lift-
tab 205 is
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coated with the pull-tab coat 305 and pressed against the top 105 in order to
seal the
access hole from leakage of the contents from the lumen 605 of the container.
The
modified lift-tab is pivotally connected to the top by means of rivet
connection 405.
Because the pull-tab coat is resilient, it protrudes into the lumen of the
container as
indicated by the bulge 305 to provide a watertight seal.
MANNER OF USING
[0029] By providing the foregoing coated pull-tab, one is able to easily
produce a
resealable pop-top beverage container. Having produced such a container with a
coated
pull-tab, the manner of using our invention is simple, straight-forward, and
almost intuitive
for anyone who has opened a conventional pop-top can. The initial step of
opening the
container is no different than that of opening a standard pop-top container.
The finger-end
701 of the lift-tab 501 is prized upwards, forcing the swivel-end 801 downward
against the
sealing plate 301 and breaking the frangible watertight seal between the
sealing plate and
the edge of the access hole, thus opening the access hole. The sealing plate
is thusly
bent downwards and into the interior of the container. As is commonly done in
the
existing art, the lift-tab can then be pressed back down against the top to
get it out of the
way while the beverage is being accessed.
[0030] When the user desires to reseal the container, the lift-tab is rotated
about the
rotatable connector 901, until the ventral surface of the finger-end is
juxtaposed against
the access hole. In the preferred embodiment, the lift tab must be rotated
approximately
180 degrees about the rivet connector in order to align the lift tab with the
access hole for
sealing. When the lift-tab is positioned over the access hole, the lift-tab is
pressed down
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and the resilient coating seals the access hole by frictional forces between
the pull-tab
coat and the edge of the hole.
[0031] When the user wishes to re-open the container, she lifts up on the
leading
edge of the lift-tab, pulling the pull-tab coat free of the edge. She then
rotates the tab
enough to reveal the open access hole.
[0032] Once the lift-tab is pressed down on the access hole to reseal the
container, if
the embodiment of the invention being used includes an optional straw orifice
604 as
shown in FIG 4, a straw can be forced through the orifice by breaking the
frangible break-
lines 704.
[0033] The rotations of the lift-tab of 180 degrees disclosed above are
preferred;
however, a rotation of any angle that accommodates the needs of the user and
the
geometry of the lift-tab and access hole are sufficient and anticipated by
this disclosure.
MANNER OF MAKING
[0034] One of the advantages of our invention over the existing art is that
our invention
is produced easily and economically. The coating can be applied to any lift-
tab without
the need to re-tool the entire can-producing process. A preferred process for
applying the
coating to the lift-tab is as follows.
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[0035] Depending on the materials employed to produce the lift-tab, the lift-
tab is
optionally coated with a vinyl adhesion promoter specific for that material
106. The lift-tab
is placed in a two part mold 206, which is closed and sealed. Liquid vinyl is
injected 306
and a mold-heater is positioned adjacent the mold 406, or the mold is placed
in an oven.
The mold is heated 506 for a sufficient length of time and to a sufficient
temperature to
allow the liquid vinyl to solidify to a rubberized state having enough
resiliency to properly
seal the access hole when pressed into position. These parameters, of course,
depend
upon the materials being employed. With respect to a medical grade vinyl
applied to
aluminum pull-tabs, we have found that approximately 350 C. for 30 seconds is
effective.
After baking, the mold-heater is removed 606 and the mold is refrigerated 706.
The mold
is then broken 806 to extract the coated lift-tab, which is then attached to
the can 906
using existing and well-known techniques.
[0036] On the basis of the present disclosure, those skilled in the art will
be able to
determine, without undue experimentation, the optimum type of vinyl or other
resilient
substance to employ and the optimum conditions for coating the lift-tabs with
the vinyl or
other resilient substance, depending on various considerations such as the
material the
tab is made of, expected ambient temperatures in which the invention will be
used, and
the like. While the foregoing process produces good results, those skilled in
the art will
realize from this disclosure that other processes for coating a lift-tab with
resilient coating
are obvious alternatives.
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SUMMARY
[0037] From the foregoing description, the novelty, utility, and means of
making and
using our invention will be readily apprehended. It is to be understood that
our invention
is not limited to the embodiments disclosed above but encompasses any and all
embodiments lying within the scope of the disclosure and claims.
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