Note: Descriptions are shown in the official language in which they were submitted.
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
STRUCTURES FOR PROVIDING A REMOVABLE CLOSURE
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Nos.
60/248,026 and
60/248,340, each filed November 13, 2000, and each application entirely
incorporated herein by
reference.
FIELD OF THE INVENTION
The present invention relates to providing closure for a container, and more
particularly,
structures for providing a removable closure.
BACKGROUND OF THE INVENTION
Preshaped snack pieces are typically frangible and might be fragile and easily
broken
during packaging, shipping and/or other handling operations. Conventional
packaging techniques
provide bags and/or boxes that can permit a significant number of the snack
pieces to break or
crush prior to consumption. The well known Pringles~ shaped potato chip snack
pieces, a
product of The Procter & Gamble Company, Cincinnati, Ohio, are individual
snack pieces having
a "saddle" shape and are packaged in a manner which overcomes disadvantages of
the prior art.
The Pringles~ snack pieces have conventionally been packaged as a single
nested stack in a
cylindrical container which provides enhanced protection during packaging,
shipping and/or other
handling. As a result, the Pringles~ snack pieces are typically presented to
the consumer without
breakage.
There is a continuing need for user-friendly, relatively inexpensive
containers for
packaging frangible snack pieces to provide protection during packaging,
shipping and/or other
handling. It is further desired to provide hermetically sealed containers that
provide oxygen and
moisture protection to prevent spoilage of the snack pieces contained therein.
It might also be desirable to provide such inexpensive containers for other
types of
frangible and/or fragile articles to reduce breakage of the articles during
packaging, shipping
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
and/or other handling, to maintain desirable properties of the articles, and
to provide a user-
friendly package.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides various structures for providing a
removable
closure for a container.
In one embodiment, a membrane lid is provided. The membrane lid includes a
surface
with a substantially triangular-shaped perimeter. The perimeter includes
first, second and third
corner portions, wherein each corner portion is bisected by an imaginary Line.
The membrane lid
further includes a projection with a tab and adapted to initially direct a
lifting force to at least one
of the corner portions. The projection either extends outwardly from the
perimeter such that the
projection is non-symmetrically disposed with respect to the imaginary line of
any adjacent corner
portion, or the projection extends non-continuously from an adjacent corner
portion and is
substantially symmetrically disposed with respect to the imaginary line of the
adjacent corner
portion.
In another embodiment, a container is provided with a lip having a
substantially
triangular-shaped horizontal cross-section. The lip includes three corner
portions and three sides,
wherein the sides of the lip are structured differently than the corner
portions of the lip to increase
the relative rigidity of the sides with respect to the corner portions such
that the corner portions
and the sides are adapted to exhibit a substantially uniform reaction pressure
when applying a
membrane lid to the lip of the container.
The membrane lids, container Zips and containers according to the present
invention are
advantageous for packaging articles, such as substantially triangular-shaped
articles to prevent
breakage of the articles. In one example, the stmctures provided herein are.
useful for packaging
tortilla chips and the like to conveniently provide consumers with a product
having minimum
breakage prior to consumption while providing an extended shelf life.
The membrane lids according to the invention allow application of an over-cap
with high
reliability and minimal interference with the membrane lid. The membrane lids
of the invention
may be conveniently removed when desired yet avoid inadvertent removal during
packaging,
shipping or other handling. The container lips according to the invention
further allow the
formation of a reliable and durable hermetic seal with the membrane lid and
contribute to over-
cap retention, even when containers employing the lip are subjected to
pressure differentials, for
example at high altitudes.
Additional objects and advantages of the invention will be more fully apparent
in view of
the following detailed description.
2
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description will be more fully understood in view of
the drawings
in which:
FIG. 1 is a top plan view of one embodiment of a membrane lid according to the
invention;
FIG. 2A is a top plan view of a second embodiment of a membrane lid according
to the
invention;
FIG. 2B is a partial plan view of a third embodiment of a membrane lid
according to the
invention;
FIG. 2C is a partial plan view of a fourth embodiment of a membrane lid
according to the
invention;
FIG. 2D is a partial plan view of a fifth embodiment of a membrane lid
according to the
invention;
FIG. 2E is a partial plan view of a sixth embodiment of a membrane lid
according to the
invention;
FIG. ?F is a partial plan view of a seventh embodiment of a membrane lid
according to
the invention;
FIG. 2G is a partial plan view of an eighth embodiment of a membrane lid
according to
the invention;
FIG. 2H is a partial plan view of a ninth embodiment of a membrane lid
according to the
invention;
FIG. 3 is a cross-section of a stack of membrane lids wherein each membrane
lid includes
at least one bevel portion to assist in alignment;
FIG. 4 is an elevational view of an exemplary container according to the
present
invention;
FIG. 5 is a top plan view of the container of FIG. 4;
FIG. 5A is a partial sectional view along line SA-SA of FIG. 5;
FIG. 5B is a partial sectional view depicting a second embodiment of a lip
structure;
FIG. SC is a partial sectional view illustrating a third embodiment of a lip
structure;
FIG. 6 is an enlarged view of Detail 6 in FIG. 4;
FIG. 7 is an enlarged view Detail 7 in FIG. 4;
FIG. 7A is an enlarged view of the second embodiment of the lip structure;
FIG. 7B is an enlarged view of the third embodiment of the lip structure;
3
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
FIG. 8 is a top plan view of an exemplary over-cap for use with containers
according to
the present invention; and
FIG. 9 is a side elevational view of the over-cap set forth in FIG. 8.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The invention is directed to structures for providing a removable closure to
permit
packaging of one or more pieces (i.e., one or more articles) such as
substantially triangular-shaped
pieces. In one application, one or more snack pieces may be packaged, and in
particular
embodiments, one or more substantially triangular-shaped snack pieces may be
packaged to
present consumers with an accessible product with minimal breakage. It is
contemplated that a
wide variety of snack pieces may be packaged with the structures in accordance
with the present
invention. For example, snack pieces having a substantially triangular,
substantially circular,
substantially elliptical, substantially rectangular, substantially square or
other shaped snack pieces
such as chips (e.g., tortilla chips, potato chips, vegetable chips, fruit
chips, bagel chips), crackers,
biscuits, cookies, candy, or the like. Each of the above mentioned snack piece
shapes could be
packaged, for example, with a variety of containers having various alternative
shapes such as
containers having a substantially circular, substantially elliptical,
substantially rectangular,
substantially square, substantially triangular, or other shape. Exemplary
containers that can be
used with the inventive concepts of the present invention are disclosed in
copending U.S.
Provisional Application No. 60/248,340 of Buisson et al. filed November 13,
2000 entitled "An
Improved Plastic Package for Snack Pieces." Additional containers and
structures relating thereto
that may also be used with the present invention are disclosed in U.S.
Provisional Application No.
60/248,103 of Buisson et al. filed November 13, 2000 and U.S. Patent
Application No.
titled "Container Bottom and Methods" attorney docket No. 8331M filed
herewith, the
entire disclosures of which are incorporated herein by reference. While
exemplary structures of
the present invention are described for use with edible snack pieces, the
structures presented
herein may be useful to store, package and/or ship other piece(s), including,
but not limited to, a
plurality of frangible or fragile pieces (i.e., a plurality of frangible or
fragile articles) in a stacked
relationship.
Structures for providing closure may comprise membrane lids, container lips
and/or
containers which are particularly suitable for packaging articles, such as
substantially triangular-
shaped articles. The membrane lids, container lips and containers according to
the present
invention provide improvements which facilitate packaging, contribute to
reduced breakage
during packaging, shipping and/or handling, and/or contribute to maintaining
the hermetic seal of
the container while presenting a user-friendly membrane lid to a consumer for
removal at will. In
4
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
particular embodiments of the present invention, exemplary membrane lids,
container lips and
containers are substantially triangular-shaped and may be used, for example,
to package
substantially triangular-shaped articles. Within the context of the present
invention, "substantially
triangular-shaped" includes a generally three-side polygon shape wherein the
sides are connected
with one another at respective corner portions and can comprise a sharp angle
or a more rounded
configuration. In the exemplary membrane lids (e.g., see FIG. 1), the rounded
corner portions
connect straight or substantially straight sides. Within the present
invention, "straight" may
include a distance between the corner portions, rather than requiring any
surface or cross-sectional
configuration of the sides.
One aspect of the present invention includes membrane lid structures for
providing
closure to a container. For example, the membrane lid may have a substantially
triangular shape
to connect with a substantially triangular-shaped opening of a container.
In exemplary embodiments, the substantially triangular-shaped membrane can
have three
sides and three corner portions that are each bisected by an imaginary line.
Exemplary membrane
lids include one or more projections that extend outwardly from a
substantially triangular-shaped
perimeter without intersecting the imaginary line of any adjacent corner
portion. Embodiments of
membrane lids also include one or more projections that are non-symmetrically
disposed with
respect to the imaginary line of any adjacent corner portion or one or more
projections that
extends non-continuously from an adjacent corner portion and are substantially
symmetrically
disposed with respect to the imaginary line of the adjacent corner portion.
For example, the
membrane lids can include one or more projections that are interrupted along
the imaginary line
of an adjacent corner portion. Each of the exemplary projections in accordance
with the present
invention are structured to direct a lifting force to at Ieast one corner
portion regardless of the
location along the perimeter of the membrane.
Providing one or more projections with one or more of the above-mentioned
structures
may reduce or prevent interference of the membrane lid projections) with the
container lip and/or
inner extensions of the over-cap corner portions. After a membrane lid is
sealed to a container, an
over-cap is typically applied over the membrane lid for protecting the
membrane lid and/or to
permit selective closure of the container once the membrane lid is at least
partially removed.
Exemplary over-caps that may be used with the inventive concepts of the
present invention are
disclosed in U.S. Provisional Application No. 60/248,089, filed November 13,
2000, and also
U.S. Patent Application No. , titled "Substantially Triangular-Shaped
Over-Cap" attorney docket No. 8329M filed herewith, the entire disclosures of
which are
incorporated herein by reference.
5
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
Any interference between the membrane lid projection and the over-cap tends to
reduce
the reliability of the connection between the over-cap and the membrane sealed
container. For
example, interference between the membrane lid projection and over-cap may
present a
significant obstacle when applying the over-cap to the container on a high-
speed assembly line.
Moreover, after application of the over-cap, any interference between the
projection and over-cap
may cause inadvertent disengagement of the over-cap from the container. For
instance, the
above-mentioned interference can present a problem with changes in atmospheric
or external air
pressure resulting in changes in the interior chamber pressure of the
container. If the outside air
pressure decreases (e.g., that might develop in high altitude locations), the
over-cap may
disconnect as the container expands in response to increased interior chamber
pressure.
Referring now to the drawing figures in detail, wherein like numerals indicate
the same
elements throughout the views, FIG. 1 depicts one exemplary embodiment of a
membrane lid 10
comprising a generally planar surface 12 having a substantially triangular-
shaped perimeter 14.
The perimeter of the membrane includes three sides 16 wherein at least one of
the sides (e.g.,
"16a") can be represented by a hidden line. The hidden lines illustrated
throughout the figures
demonstrate the substantially triangular shape of the perimeter adjacent the
one or more
projections and is not intended to denote perforations or any other type of
alteration to the
generally planar surface 12. In one embodiment, the membrane lid 10 has a
substantially
equilateral triangular-shaped perimeter, wherein the sides 16 of the
triangular shape are of equal
or substantially equal length.
The membrane lid 10 also includes corner portions 20a, 20b, 20c which are
shown as
rounded but may be more or less angled as desired and each include an
imaginary center line 18a,
18b, 18c that bisects each corresponding corner portions 20a, 20b, 20c. The
membrane lid 10 is
sized and dimensioned to cover a similarly substantially triangular-shaped
container, such as a
perimeter of a container opening. In one exemplary embodiment, the membrane
lid 10 may be
used to connect to a container lip 54 located adjacent one end of a container
body 52 (see FIG. 4
and FIG. 5). The lengths of the sides 16 of the membrane lid 10 will be
designed to cover the
perimeter of the opening and may be sealed to the container lip, if provided.
In exemplary
embodiments, as shown in FIG. 1, the membrane lid has side lengths "L" that
can be from about 4
cm to about 14 cm, for example from about 6 cm to about 9 cm. In particular
exemplary
embodiments, the side length "L" is from about 7.5 cm to about 8.5 cm. The
above lengths,
however, are for exemplary purposes only; therefore, the sides may be provided
with other
lengths depending on the particular application.
6
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
As indicated in FIG. 1, the membrane lid 10 can include a projection 24
extending
outwardly from the perimeter 14 of the membrane lid 10 without intersecting
the imaginary line
18a, 18b of any adjacent corner portion 20a, 20b. Although not shown, the
membrane lid could
be provided with a plurality of projections, for example, comprising any
combination of the
exemplary projections described throughout this application or their
equivalents. When the
perimeter of the membrane lid is adhered to a surface, each of the membrane
lid projections
described herein is dimensioned and located to initially direct a lifting
force toward at least one of
the corner portions.
As illustrated in FIG. 1, for example, the projection 24 extends generally
outwardly from
at least one side 16a of the perimeter 14 such that the projection 24 is non-
symmetrically disposed
with respect to the imaginary lines I8a, 18b of adjacent corner portions 20a,
ZOb. The projection
may also include two tabs 26a and 26b that can be arranged to symmetrically
disposed along the
perimeter with respect to the imaginary line 18c of a distal corner portion
20c. Providing dual
tabs permit easy access from a left-handed or right-handed individual and may
assist in removing
residual portions of a ripped membrane lid that might remain after a first
attempt to remove the
lid. Alternatively or in addition, the one or more projections described above
can include one or
more tabs to extend from two or more sides of the substantially triangular-
shaped membrane lid,
thereby facilitating tab access at different positions of the container
relative to the consumer.
Moreover, although not shown, the projections described herein may comprise
three or more tabs
extending from the perimeter in accordance with the present invention. Each
tab 26a, 26b can be
gripped by a consumer at lifting point 28a or 28b to apply a lifting force to
the projection 24 to
facilitate removal of the membrane lid 10 from the container lip or other
surface to which the
membrane lid is adhered.
The projections of the present invention are structured to discourage tearing
of the
membrane when a consumer applies a lifting force to at least one tab to remove
the membrane lid
from the attached surface (e.g., a lip of a container). In one embodiment,
proper distribution of
the lifting force can be accomplished by a projection which substantially
covers a lifting area
defined by two imaginary lines that extend from an outer tangential point at
each of the two
adjacent corner portions to a lifting point which is used to grip the membrane
lid for application of
the lifting force. The lifting point should be position a sufficient distance
from the perimeter of
the membrane lid such that a consumer may sufficiently grip the projection to
remove the
membrane lid from the container. For example, in exemplary embodiments, the
lifting point is
located at least about 4 mm from the perimeter of the membrane lid. In other
embodiments, the
lifting point is located at least about 8 mm from the perimeter of the
membrane lid. Other lifting
7
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
point distances could also be used in accordance with the present invention
without departing
from the scope of the claims.
As depicted in FIG. l, for example, a first lifting area 34a is at least
partially or entirely
defined by the perimeter 14 and a first outer imaginary line 30a extending
from the first lifting
point 28a to an outer tangential point of the first corner portion 20a and a
first inner imaginary
line 32a extending from the first lifting point 28a to an outer tangential
point of the second corner
portion 20b. A second lifting area 34b is at least partially or entirely
defined by the perimeter 14
and a second outer imaginary line 30b extending from the second lifting point
28b to an outer
tangential point of the second corner portion 20b and a second inner imaginary
line 32b extending
from the second lifting point 28b to an outer tangential point of the first
corner portion 20a. Thus,
with reference to FIG. l, tab 26a of the projection 24 substantially or
entirely covers at least the
lifting area 34a at least partially or entirely deftned by the perimeter 14
and lines 30a and 32a
while tab 26b of the projection 24 substantially or entirely covers at least a
lifting area 34b at least
partially or entirely defined by the perimeter 14 and lines 30b and 32b. The
projection 24 is
therefore dimensioned to substantially or entirely cover each of the lifting
areas 34a, 34b to
distribute force over the lifting areas while initially directing the lifting
force to at least one of the
adjacent corner portions 20a, 20b, thereby reducing the probability of stress
tears by minimizing
stress concentrations.
The projection 24 may also be structured such that the lifting areas 34a, 34b
define an
overlap area 36 to provide additional support to further discourage tearing of
the membrane, for
example, when the entire lifting force is applied to a single tab (e.g.,
either 26a or 26b). This
arrangement removes acute forces in the membrane from a point close to the
middle of the
corresponding side and therefore reduces the probability of undesired tearing
of the membrane.
FIG. 2A discloses portions of an alternative membrane lid 110 with a surface
112 and a
substantially triangular-shaped perimeter 114. The perimeter 114 includes
sides 116 wherein at
least one side (e.g., "116a") can be represented by a hidden line. The
membrane lid 110 further
includes corner portions 120a, 120b, 120c that are bisected by imaginary lines
118a, 118b, 118c.
The exemplary membrane lid 110 includes a projection 124 including a single
tab 126. The
projection 124 is non-symmetrically disposed with respect to the imaginary
lines 118a, 118b of
adjacent corner portions 120a, 120b. As described above, embodiments of the
present invention
including a single or multiple tabs extending outwardly from a side (e.g.,
from side "116a") may
be symmetrically disposed along the perimeter with respect to the imaginary
line 118c of a distal
corner portion 120c. Optional dual tabs can be provided to distribute a
lifting force and/or to
permit easy access from a left-handed or right-handed individual.
8
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
Tabs in accordance with each of the exemplary embodiments of the present
invention
described throughout this application may be located closer to one corner
portion or the other such
that the tabs are not syrmnetrically disposed along the perimeter with respect
to any imaginary
line.
As illustrated in FIG. 2A, the projection 124 includes a single tab 126 which
is sized to
accommodate gripping by a consumer to apply a lifting force to the projection
124 at a lifting
point 128 to remove the membrane lid 110 from the container lip ox other
surface to which it is
adhered. The membrane lid 110 is sized and structured to discourage tearing of
the membrane
when a consumer is lifting the tab 126 to remove the membrane lid 110 from the
container or
other surface to which the membrane lid 110 is attached. Redirection of the
lifting force to reduce
tearing incidents can be accomplished by structuring the projection 124 to
substantially or entirely
cover a lifting area 134. The lifting area 134 is at least partially or
entirely defined by the
perimeter 114 and a first imaginary line 130 extending from the lifting point
128 to an outer
tangential point of the first corner portion 120a and a second imaginary line
132 extending from
the lifting point 128 to an outer tangential point of the second corner
portion 120b. The projection
124 is therefore dimensioned to at least substantially or entirely cover the
lifting area 134 to
distribute force over the lifting area while initially directing the lifting
force to at least one of the
corresponding corner portions 120a, 120b.
As further shown in FIG. 2A, the outer perimeter 127 of the tab 126 may be
curved
inwardly such that the tab 126 includes less material. Reducing the amount of
material may be
desirable to reduce material costs while also preventing the tab from
obscuring an advertising or
other informational display disposed on the exterior surface of the container
to which the
membrane lid may be attached. However, the outer perimeter 127 should have a
sufficient size to
permit the tab 126 to at least substantially or entirely cover the lifting
area 134 at least
substantially or entirely defined by the perimeter 114 and lines 130, 132.
FIG. 2B includes a membrane lid 210 similar to the membrane lid 110 described
above.
In fact, unless otherwise noted, the membrane lid 210 can be identical to the
membrane lid 110.
However, unlike the membrane lid 110, the membrane lid 210 includes a
projection 224 having an
outer perimeter 227 that does not have a reduced portion and does not curve
inwardly. In fact, as
shown in FIG. 2B, the outer perimeter 227 has straight line portions and,
although not shown,
may even curve outwardly. Structuring with outer perimeter such that the
projection does not
have a reduced portion (e.g., with straight line segments as illustrated) or
includes augmented
portions (e.g., with outwardly curved portions) will increase the structural
strength of the
projections 224, thereby reducing stress concentrations and corresponding
tearing incidents.
9
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
FIGS. 2C-2H illustrate alternative embodiments of a projection that extends
non-
continuously from an adjacent corner portion and is substantially
symmetrically disposed with
respect to the imaginary line bisecting the adjacent corner portion. A
substantially symmetrical
projection will include projections that are symmetrical with respect to the
imaginary line when
viewed without the features that provide the non-continuous extension. Non-
continuous
extension of the projection can result from alternate projection material
configuration,
construction, composition, interruption, or the like when viewing the outer
surface of the
projection and/or through a cross-section of the projection. For example, the
non-continuous
extension can result from a weakened area of the projection. The weakened area
can include
portions of the projection, or the entire projection, that defines apertures,
perforations, slits,
scores, crimps, cuts, channels, or other irregularities. For example, the
weakened area could
include the entire projection or a portion less than the entire projection.
The weakened areas in
accordance with the present invention are designed to reduce or prevent
interference between the
inner extension of the over-cap and the container lip and may also reduce or
prevent puckering or
wrinkling of the projection as it is bent down to conform to the outer surface
of the container after
application of the over-cap.
FIG. 2C illustrates an exemplary membrane lid 310 wherein the perimeter
includes sides
316 wherein at least one of the sides (e.g., "316a") can be represented by a
hidden line. At least
one corner portion 320 is bisected by an imaginary line 318 wherein a
projection 324 extending
outwardly from the perimeter 314 adjacent corner portion 320 is substantially
symmetrically
disposed with respect to the imaginary line 318 bisecting an adjacent corner
portion 320. The
projection 324 includes a single tab 326 presenting a lifting point 328 for a
consumer. The
projection 324 extends non-continuously from the adjacent corner portion 320
and includes a
weakened area that comprises portions of the projection that define one or
more apertures 338
with a closed perimeter 340. The aperture 338 may be adapted to prevent
interference between
the over-cap and portions of the container opening. Fox example, providing an
aperture 338 may
facilitate the connection between the inner extensions 78 of the over-cap 70
and the lip 54 of the
container 50 by limiting or preventing the projection from interfering with
the connection between
the over-cap and the lip. Indeed, the aperture 338 can be located on the
projection so° that the
inner extensions 78 at least partially extends through the aperture 338 to
engage the lip 54 when
the over-cap 70 is installed on the container 50.
The symmetrical location of the aperture 338 along the imaginary line 318
causes the
aperture 338 to interrupt the projection 324 along the imaginary line 318. In
alternative
embodiments, the aperture 338 may be offset from the imaginary line 318 and/or
a plurality of
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
apertures may be provided such that the projection 324 is not interrupted
along the imaginary line
318. For example, although not shown, exemplary embodiments include a
plurality of apertures
symmetrically offset about the imaginary line 318 without intersecting with
the imaginary line
318 such that the projection 324 is not interrupted along the imaginary line
318.
As illustrated in FIG. 2C, the aperture 338 can have a half moon or "D" shape
to further
prevent interference between the projection 324 and the container 50. The
projection 324 may
need to be reinforced or structured with increased tearing resistance to
prevent failure or ripping at
the relatively sharp corner portions 342 of the aperture 338.
FIG. 2D illustrates another embodiment of a membrane lid 410 similar to the
membrane
lid 310 described above and can be identical unless otherwise noted. For
example, the membrane
lid 410 also includes a substantially triangular-shaped perimeter 414 with
sides 416 wherein at
least one of the sides (e.g., "416a") can be represented by a hidden line. At
least one corner
portion 420 is bisected by an imaginary line 418. A projection 424 extends
outwardly from the
perimeter 414 adjacent corner portion 420 and is substantially symmetrically
disposed with
respect to the imaginary line 418 bisecting the adjacent corner portion 420.
The projection 424
includes at least one tab 426 and extends non-continuously from the adjacent
corner portion 420
and includes a weakened area that comprises portions of the projection that
define one or more
apertures 438 with a closed perimeter 440. However, unlike the membrane lid
310 illustrated in
FIG. 2C, the aperture 438 of the membrane lid 410 includes a perimeter 440
with rounded or
smooth corner portions 442 designed to reduce stress concentrations in the
membrane when
applying a lifting force at lifting point 428 to thereby reduce or prevent
tearing incidents.
The aperture 438 in FIG. 2D, as well as apertures in projections of any of the
embodiments of the present invention, may have a substantially circular shape.
The apertures, if
provided in any of the projections, could also have an oblong shape or other
shape to simplify the
manufacturing process and/or enhancing the functional characteristic of the
aperture to prevent
interference between the over-cap and the container.
As with the aperture 338, the symmetrical location of the aperture 438 along
the
imaginary line 418 causes the aperture 438 to interrupt the projection 424
along the imaginary line
418. In alternative embodiments, the aperture 438 may be offset from the
imaginary line 418
and/or a plurality of apertures may be provided such that the projection 424
is not interrupted
along the imaginary line 418. For example, although not shown, exemplary
embodiments include
a plurality of apertures symmetrically offset about the imaginary line 418
without intersecting
with the imaginary line 418 such that the projection 424 is not interrupted
along the imaginary
line 418.
11
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
FIG. 2E illustrates yet another embodiment of a membrane lid 510 in accordance
with the
present invention. The membrane lid 510 can be identical to the membrane lid
described in FIGS.
2C or 2D or other embodiments described throughout this application including
a projection with
an aperture, unless otherwise noted. For example, the membrane lid 510
includes a substantially
triangular-shaped perimeter 514 with sides 516 wherein at least one of the
sides (e.g., "516a") can
be represented by a hidden line. At least one corner portion 520 is bisected
by an imaginary line
518. A projection 524 extends outwardly from the perimeter 514 of an adjacent
corner portion
520 and is substantially symmetrically disposed with respect to the imaginary
line 518 bisecting
the adjacent corner portion 520. The projection 524 includes at least one tab
526 presenting at
least one lifting point 528a, 528b. The projection 524 extends non-
continuously from the adjacent
corner portion 520 and includes a weakened area that comprises portions of the
projection that
define one or more apertures 538 to facilitate connection between the over-cap
and the container
as described above.
As with the apertures 338 and 438 described above, the symmetrical location of
the
aperture 538 along the imaginary line 518 causes the aperture 538 to interrupt
the projection 524
along the imaginary line 518. In alternative embodiments, the aperture 538 may
be offset from
the imaginary line 518 and/or a plurality of apertures may be provided such
that the projection
524 is not interrupted along the imaginary line 518. For example, although not
shown, exemplary
embodiments include a plurality of apertures symmetrically offset about the
imaginary line 518
without intersecting with the imaginary line 518 such that the projection 524
is not interrupted
along the imaginary line 518.
As illustrated in FIG. 2E, the aperture 538, as well as each of the apertures
described
throughout this application, may include an opening 541 providing the aperture
538 with an open
perimeter 540. The open perimeter allows the membrane lid to be formed with a
single perimeter
comprising an outermost perimeter rather than an inner aperture perimeter
distinct from an
outermost perimeter. Providing a single outermost perimeter may reduce
manufacturing steps
and/or otherwise reduce the manufacturing costs for producing the membrane
lid. The opening
541 may be a narrow or wide slit or the like. In one embodiment, the opening
541 extends along
the imaginary line 518 that bisects the corner portion 520 to provide
symmetrical division of
lifting force when simultaneously lifting the tab at lifting points 528a,
528b.
FIG. 2F illustrates another embodiment of a membrane lid 610 in accordance
with the
present invention. The membrane lid 610 can be identical to the membrane lid
described in FIGS.
2C-2E or other embodiments described throughout the present invention unless
otherwise noted.
For example, the membrane lid 610 includes a substantially triangular-shaped
perimeter 614 with
12
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
sides 616 wherein at least one of the sides (e.g., "616a") can be represented
by a hidden line. At
least one corner portion 620 is bisected by an imaginary line 618. A
projection 624 extends
outwardly from the perimeter 614 of an adjacent corner portion 620 and is
substantially
symmetrically disposed with respect to the imaginary line 618 bisecting the
adjacent corner
portion 620. The projection 624 extends non-continuously from the adjacent
corner portion 620.
A weakened area of the projection 624 includes a scored portion wherein the
projection includes
one or more slits 638. The one or more slits can be formed as cuts that extend
entirely through the
thickness of the projection. In other examples, the slit can be formed as cuts
that extend only
partially through the thickness of the projection.
The symmetrical location of the slit 638 along the imaginary line 618 causes
the slit 638
to interrupt the projection 624 along the imaginary line 618. In alternative
embodiments, the slit
638 may be offset from the imaginary line 618 and/or a plurality of slits may
be provided such
that the projection 624 is not interrupted along the imaginary line 618. For
example, although not
shown, exemplary embodiments include a plurality of slits symmetrically offset
about the
imaginary line 618 without intersecting with the imaginary line 618 such that
the projection 624 is
not interrupted along the imaginary line 618.
The one or more slits 638 can be shaped in a variety of patterns, such as
waved,
sinusoidal, arcuate or other shape. Moreover, a plurality of slits may be
provided to further
weaken the projection. As illustrated in FIG. 2F for example, one slit can be
intersected with a
plurality of cross slits. The arcuate shape of the larger slit is designed to
substantially match the
contact area between the inner extension of the over-cap and the lip to reduce
or prevent
interference therebetween. A single slit, rather than multiple slits, may be
provided to weaken the
projection to reduce interference without weakening the projection to the
point that it rips or tears
when applying a lifting force to the projection. In alternative embodiments, a
plurality of slits
may be provided to further weaken the area to further minimize interference.
In one example, the
slit may be formed as a cross (i.e., two intersecting slits).
The slit 638 may be narrow (as illustrated in FIG. 2F) or wide to facilitate
functionality
while reducing manufacturing costs. Providing a thin cut slit, rather than a
wide slit or slot, may
be easier to manufacture and prevent accumulation of scrap material. However,
a wider slit or
slot may be provided to further reduce interference. A wide slit can take the
form of a channel
(i.e., wherein the slit does not extend entirely through the thickness of the
membrane lid) or an
open slot (i.e., wherein the slit extends entirely through the thickness of
the membrane lid).
FIG. 2G illustrates another embodiment of a membrane lid 710 in accordance
with the
present invention. The membrane lid 710 can be identical to the membrane lid
described in FIGS.
13
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
2C-2F or other embodiments described throughout the present invention unless
otherwise noted.
For example, the membrane lid 710 includes a substantially triangular-shaped
perimeter 714 with
sides 716 wherein at least one of the sides (e.g., "716a") can be represented
by a hidden line. At
least one corner portion 720 is bisected by an imaginary line 718. A
projection 724 extends
outwardly from the perimeter 714 of an adjacent corner portion 720 and is
substantially
symmetrically disposed with respect to the imaginary line 718 bisecting the
adjacent corner
portion 720. The projection 724 extends non-continuously from the adjacent
corner portion 720.
A weakened area of the projection 724 includes a scored portion wherein the
projection includes a
plurality of perforations or slits 738. The one or more perforations or slits
738 can be formed as
pinpoint pricks or cuts that extend partially or entirely through the
thickness of the projection.
The perforations or slits 738 can by symmetrically or non-symmetrically
disposed about
the imaginary line 718. In one example, one or more of the slits intersect the
imaginary line to
cause an interruption in the projection 724 along the imaginary line 718. In
alternative
embodiments, each of the perforations or cuts 738 may be offset from the
imaginary line 718 such
that the projection 724 is not interrupted along the imaginary line 718. For
example, although not
shown, exemplary embodiments include a plurality of perforations or cuts 738
symmetrically
disposed about the imaginary line 718 without intersecting with the imaginary
line 718 such that
the projection 724 is not interrupted along the imaginary line 718.
The perforations or cuts 738 may be arranged in a variety of patterns along
the projection
724. In one embodiment, the perforations or cuts 738 axe arranged in an
arcuate pattern to
substantially match the inner extension 78 from the over-cap 70, thereby
minimizing interference
between the over-cap and container lip.
FIG. 2H illustrates another embodiment of a membrane lid 810 in accordance
with the
present invention. The membrane lid 810 can be identical to the membrane lid
described in FIGS.
2C-2G or other embodiments described throughout the present invention unless
otherwise noted.
For example, the membrane lid 810 includes a substantially triangular-shaped
perimeter 814 with
sides 816 wherein at least one of the sides (e.g., "816a") can be represented
by a hidden line. At
least one corner portion 820 is bisected by an imaginary line 818. A
projection 824 extends
outwardly from the perimeter 814 of an adjacent corner portion 820 and is
substantially
symmetrically disposed with respect to the imaginary line 818 bisecting the
adjacent corner
portion 820. The projection 824 extends non-continuously from the adjacent
corner portion 820.
A weakened area of the projection 824 includes a scored portion wherein the
projection includes
one or more crimps 838.
14
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
The crimps 838 can by symmetrically or non-symmetrically disposed about the
imaginary
line 818. In one example, one or more of the crimps intersect the imaginary
line 818 to cause an
interruption in the projection 824 along the imaginary line 818. In
alternative embodiments, each
of the crimps 838 may be offset from the imaginary line 818 such that the
projection 824 is not
interrupted along the imaginary line 818. For example, although not shown,
exemplary
embodiments include a plurality of crimps 838 offset from the imaginary line
718 without
intersecting with the imaginary line 818 such that the projection 824 is not
interrupted along the
imaginary line 818.
The crimps 838 may be arranged in a variety of patterns along the projection
824. In one
embodiment, the crimps 838 are arranged in an arcuate pattern to substantially
match the inner
extension 78 from the over-cap 70, thereby minimizing interference between the
over-cap and
container lip.
The above-described embodiments are exemplary in nature and may include other
embodiments in accordance with the concepts of the present invention. For
example, any
combination of the above features, or their equivalents, could be incorporated
to provide the non-
continuous extension. In addition, while the non-continuous extension of
exemplary
embodiments described above have related to projections that are substantially
symmetrically
disposed with respect to the imaginary line of the adjacent corner portion,
the projection can also
extend non-continuously from the perimeter of other embodiments to further
limit or prevent
portions of the projection from interfering with the connection between the
over-cap and the lip.
For example, the projection can extend non-continuously from the perimeter
while also being
non-symmetrically disposed with respect to the imaginary line of any adjacent
corner portion. In
addition, exemplary membrane lids in accordance with the present invention can
include a
plurality of projections including one or more of the projections described
throughout the
application or their equivalents (e.g., one or more of the projections
illustrated in FIGS. 1, 2A-2E,
and 3 for example).
In any of the embodiments described above including a projection with a
plurality of tabs,
the tabs may be joined together with membrane portions having an outer
perimeter with a curved
perimeter and/or a perimeter without sharp angles that might otherwise provide
potential stress
concentration points for membrane tear.
As described above, providing a projection with a plurality of tabs may assist
in left or
right handed removal of the membrane lid from the container. The additional
tabs may also
facilitate removal of residual membrane lid portions if the membrane lid rips
during the process of
removing the membrane lid from the container. For example, a first tab might
be gripped to
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
remove the lid. After applying a lifting force, the membrane may inadvertently
tear into two
portions wherein only a first portion is removed by the consumer. The second
tab could then be
used to remove the remaining portions of the lid.
It is also desirable to minimize the amount of material used for the membrane
lids
described above to reduce material expenses and minimize the projection hang-
over that might
otherwise be unsightly and/or cover portions of the container display surface.
The amount of
overhang or amount of excess membrane material around the remainder of the lid
which will
extend past the point of sealing along a container lip is typically
proportional to the removal
functionality of the membrane lid. The amount of overhang can vary from 0 mm,
where the seal
is at the very edge of the membrane lid, and in other examples can extend to
about 3 mm from the
seal between the container and the membrane lid. In another example, the
overhang of the
membrane lid past the seal is from about 0 mm to about 1 mm, or in another
exemplary
embodiment from 0 mm to about 0.5 mm. In still another embodiment, the
overhang can be
wrapped under the lip to which the membrane lid is applied.
A variety of materials may be used to fabricate the membrane lid. The membrane
lid can
be formed of a single piece of monolayer or multilayer material. Typical
multilayer material
comprises at least one layer of an oxygen and moisture barrier material, for
example foil, and one
layer of sealant, for example a thermoplastic polymer which will seal to a
container lip. The layer
of sealant can be a coating or continuous or non-continuous layer (e.g.,
coating) to seal with the
appropriate surface. For example, the sealant can be applied as a non-
continuous layer to the
membrane or on the container lip prior to sealing to minimize the amount of
sealant, thereby
avoiding excess waste of unused material. In other applications, it can be
desired to provide the
layer as a continuous layer to one of the remaining layers of the membrane lid
in order to simplify
formation of the membrane lid from a continuous sheet of material.
In one embodiment, the membrane lid is formed of a multilayer laminate
comprising an
acrylic primer, a foil layer of about 0.0015 inch thickness, and an ethylene
vinyl acetate sealant
layer of about 0.00125 inch thickness. An adhesive layer may be provided
between the foil layer
and the ethylene vinyl acetate layer, if desired. The lid membrane structure
presented herein can
be used with other membrane materials without departing from inventive
concepts of the present
invention.
FIG. 3 illustrates a stack of membrane lids 1000 where each membrane lid 1010
can
includes at least one bevel portion 1011 to assist in stacking and aligning a
plurality of membrane
lids prior to applying the membrane lid to the container. In one example, a
6.4 rnm horizontal
distance "b1" could be provided, with an end bevel offset "b2" of about 1.5
mm. Accordingly,
16
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
each of the embodiments described herein may include a membrane lid with at
least one bevel
portion to facilitate stacking and aligning of a plurality of membrane lids.
Moreover, the bevel
portion rnay be provided on the proj ection or other areas of the membrane lid
and can extend
about the entire periphery of the membrane lid in additional embodiments.'
The membrane lids in accordance with the present invention may be applied to
the
container, adjacent the container opening, with a variety of attachment
techniques. In exemplary
embodiments, the membrane lids are structured to be attached to the container
with a heat sealing
process. In one embodiment, the membrane lid may be applied to a container lid
by a sealing
element at a temperature of greater than about 300°F, for example, from
about 350°F to about
450°F for a time and with a force sufficient to seal the membrane lid
to the container lip. In one
embodiment, the sealing element applies the membrane lid for about 0.5 seconds
to about 1
second and with a pressure of about 80 to about 100 psi. The sealing process
and corresponding
structure is designed to provide a hermetically sealed container while
providing a removable lid
having an acceptably low lifting force requirement for a consumer to remove
the membrane lid
from the container.
FIG. 4 sets forth a container which may be used together with a membrane lid
according
to the present invention. A suitable container is disclosed in U.S.
Provisional Application No.
60/248,340 filed November 13, 2000, to Buisson et al entitled "An Improved
Plastic Package for
Snack Pieces," Attorney Docket 8332P. The container may optionally include a
container and/or
a container bottom design as disclosed in U.S. Provisional Application No.
60/248,103, filed
November 13, 2000, and U.S. Application No. filed on even date to Buisson et
al,
entitled "Container Bottom And Methods," Attorney Docket 8331M.
As shown in FIGS. 4 and 5, the container 50 comprises a substantially
triangular-shaped
container body 52 and an outwardly extending lip 54 adjacent an upper end of
the body 52. FIG.
5 shows a top view of the container 50 which demonstrates that both the lip 54
and the container
body 52 have a substantially triangular-shaped horizontal cross-section.
It is desirable to structure a container with an opening adapted to receive a
membrane lid,
such as one of the membrane lids described above, to provide a hermetic seal
while also
presenting a removable closure that can easily be removed by a consumer at
will. A stronger seal
typically requires increased pressure, heat and/or adhesive between the
membrane and container
opening to provide a seal strength sufficient to provide the desired hermetic
condition. However,
increasing the seal strength results in increased effort by the consumer to
remove the membrane
lid. Moreover, undue seal strength may also result in ripping or tearing of
the membrane as the
consumer applies the required lifting force to break the seal and remove the
membrane from the
17
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
container. Therefore, it is desirable to provide a seal sufficient to achieve
a hermetic condition
while further presenting a user-friendly membrane lid that may be easily
removed when desired.
As described above, the seal strength is often a function of pressure,
temperature and/or
adhesive between the membrane lid and the container during the sealing
process. The inherent
properties of a non-circular container lip shape may cause uneven vertical
rigidity. Uneven
rigidity typically causes varying reaction pressures at various locations
around the lip. To ensure
a sufficient hermetic seal at all locations of the lip, the membrane lid
application force must be
increased to provide the minimum required reaction pressure at all locations
around the lip.
Accordingly, areas having the lowest rigidity will have the required minimum
reaction pressure
necessary to achieve the hermetic seal, however, the points along the lip
having a higher reaction
pressure will provide an excessive seal strength that may prove difficult for
a consumer to
overcome.
To provide a seal that is within the desired strength range, it is beneficial
to provide a seal
having a substantially constant strength about the container opening to
thereby avoid sealing areas
having excessive sealing strength. Accordingly, a substantially uniform
reaction pressure may be
desired at each point of the seal along the lip when pressing the membrane lid
against the
container during the sealing process. Providing a substantially uniform
reaction pressure will
permit application of sealing force sufficient to meet the minimum
requirements of a hermetic
seal without having mmecessarily strong sealing areas that are more difficult
to overcome.
The structure of circular containers having a circular horizontal cross-
section generally
provide a uniform lip having a uniform reaction pressure when sealing a
membrane lid to the
container. Accordingly, applying a sealing force to a membrane lid against a
conventional
circular container will typically result in a constant reaction pressure at
all contact locations
between the container lip and the membrane lid. However, container lips having
a substantially
triangular-shaped horizontal cross section may not have an inherently uniform
reaction pressure
when forcing the membrane lid against the container lip. Rather, attempting to
seal a membrane
lid to the substantially triangular-shaped container lip by applying a sealing
force to the
membrane lid may result in an uneven reaction pressure at different points of
the container lip and
therefore varying degrees of sealing strength between the container lip and
the membrane lid.
Typically, the lip of a substantially triangular-shaped container inherently
has a greater degree of
vertical rigidity at the corner portions than at the sides between the corner
portions, thereby
resulting in a higher degree of flexing of the sides than the corner portions
upon application of a
sealing force to the membrane lid. Accordingly, by the inherent nature of a
substantially
triangular-shaped lip, the reaction force and corresponding reaction pressure
will typically be
18
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
greater at the corner portions resulting in a higher seal strength at the
corner portions than at the
sides between the corner portions. To ensure a sufficient hermetic seal
strength at the sides, an
increased application force must be administered to the membrane lid that will
also cause
excessive reaction pressure and a correspondingly excessive seal strength at
the corner portions.
The increased seal strength at the corner portions may be difficult to
overcome by a consumer
attempting to remove the membrane lid or may also result in membrane lid
tears.
In accordance with inventive concepts of the present invention, the lip of the
substantially
triangular-shaped container has sides that are structured differently than the
corner portions to
increase the relative rigidity of the sides with respect to the corner
portions. In fact, the different
structure reduces or substantially prevents differences in vertical rigidity
between the corner
portions and sides and can result in a substantially constant reaction
pressure in response to a
sealing force. Accordingly, with the inventive concepts of the present
invention, a membrane lid
may be sealed to a substantially triangular-shaped lip with a substantially
constant strength seal
about the opening of the container.
For example, FIGS. 5, SA, 6 and 7 depict exemplary embodiments of a container
50
including a lip 54 adjacent an opening of a container body 52 wherein the lip
54 has sides 58
structured differently than the corner portions 56 to increase the relative
rigidity of the sides 58
with respect to the corner portions 56. Indeed, the different structure of the
sides 58 and corner
portions 56 provides a lip that exhibits a substantially uniform reaction
pressure when applying a
membrane lid to the lip 54 of the container 50.
FIG. 6 depicts an enlarged side view of an exemplary corner portion 56 of the
Iip 54 from
Detail 6 in FIG. 4, while FIG. 7 illustrates an enlarged side view of the side
58 of the lip 54 from
Detail 7 in FIG. 4. Moreover, FIG. 5A depicts a cross-sectional view of the
corner portion 56 and
side 58 of the lip 54. The lip 54 has a top surface 60, an outer wall surface
62, 63 and a bottom
surface 64. In addition, the outer wall surface 62 of the corner portion 56
has an outwardly
protruding substantially U-shaped configuration with a rounded apex 68. This
configuration
provides the corner portions 56 with sufficient structural integrity to
receive the membrane lid. In
contrast, the sides 58 of the lip 54 are structured differently with a
substantially flat outer wall
surface 63 when compared to the U-shape of the outer wall surface 62 of the
lip corner portions
56. With this configuration, the desired corner portion and side rigidity can
be obtained while
maintaining a uniform vertical height H, from the top surface 60 to the bottom
surface 64 of the
lip 54. As illustrated in FIG. 7, while the substantially flat outer wall 63
can have a minor degree
of curvature, the outer wall 63 is substantially flat when compared to the U-
shaped profile of the
outer wall surface 62 at the corner portions 56. Modifying the outer wall 63
such that it is
19
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
substantially flat, rather than having a U-shaped profile, increases the
relative rigidity to the sides
58 with respect to the corner portions 56. Accordingly, the combination of the
U-shaped outer
wall surface 62 of the corner portions 56 and the substantially flat outer
wall surface 63 of the
sides 58 provides a substantially triangular-shaped container lip 54 which
exhibits a substantially
uniform reaction pressure when applying a membrane lid to the lip of the
container when
compared to the reaction pressure exhibited when applying a membrane lid to a
substantially
triangular-shaped container lip with a substantially uniform lip structure at
the corners and sides.
While a wide range of protrusion distances may achieve the desired lip
structure, FIG. 6
depicts one embodiment where the distance Li which the lip protrudes beyond
the container body,
may be from about 0.03 to about 0.10 inch. In one particular example, LI is
about 0.08 inch.
With reference to FIG. 7, the distance LZ which the lip protrudes beyond the
container body, may
be from about 0.01 to about 0.10 inch. In one particular example, Lz is about
0.06 inch.
The container may be formed with a variety of lip structures to provide the
lip with a
substantially uniform reaction pressure when applying the membrane lid to the
container opening.
FIGS. 5B and 7A depict an alternative embodiment of a container lip 154 in
accordance with
additional exemplary embodiments of the present invention. As illustrated in
FIG. 5B, the corner
portion 156 is structured similar to the corner portion 56 of FIGS. 5A and 6
and can be identical.
The container lip 154 includes a top surface 160, a bottom surface 164, and an
outer wall surface
162 with an outwardly protruding substantially U-shaped configuration with a
rounded apex 168.
With reference to FIGS. 5B and 7A, the container lip 154 further includes
sides 158 structured
differently than the corner portions 156 of the lip 154 to increase the
relative rigidity of the sides
158 with respect to the corner portions 156. The exemplary sides 158 are
structured with an
outwardly protruding substantially W-shaped outer wall surface 163 wherein
apex areas 167 of
the W-shaped surface 163 extend outwardly from the container body and are
disposed on opposite
sides of a recessed central portion 169. The W-shaped sides 158 have a
horizontal thickness Tl at
the apex areas 167 and has a greater horizontal thickness than the horizontal
thickness T3 of the
recessed central portion 169 or the horizontal thickness TZ of the corner
portion 156. Such extra
horizontal lip thickness at the apex areas 167 may be obtained by creating the
W-shaped sides
using a blow-molding process. Providing the container lip 154, as illustrated
in FIGS. 5B and 7A,
with W-shaped sides 158 having increased horizontal thickness T~ at the apex
areas 167 increases
the relative rigidity of the sides 158 with respect to the corner portions
such that the corner
portions 156 and sides 158 are adapted to exhibit a substantially uniform
reaction pressure when
applying a membrane lid to the lip of the container when compared to the
reaction pressure
exhibited when applying a membrane lid to a substantially triangular-shaped
container lip with a
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
substantially uniform lip structure at the corners and sides. Moreover, as
with the embodiment of
FIG. 7, the structural properties of the lip 154 may be achieved with the
corner portions and the
sides having a wall surface with the same vertical height between the top
surface 160 to the
bottom surface 164.
FIGS. SC and 7B illustrate additional embodiments of a container lip 254
includes having
corner portions 256 with an outer wall surface 262 having a substantially U-
shaped configuration
with a rounded apex 268 and sides 258 with an outer wall surface 263 with
rounded apex 267 that
is similar or identical to the outer wall surface 262. As further illustrated
in FIG. SC, the
horizontal Iip thickness Tl of the sides 258 is larger than the horizontal
thickness TZ of the corner
portions 256 to increase the relative rigidity of the sides 258 with respect
to the corner portions
256 such that the corner portions 256 and sides 258 are adapted to exhibit a
substantially uniform
reaction pressure when applying a membrane lid to the lip of the container
when compared to the
reaction pressure exhibited when applying a membrane lid to a substantially
triangular-shaped
container lip with a substantially uniform lip structure at the corners and
sides. Moreover, as with
the embodiment of FIGS. 7 and 7A, the structural properties of the lip 254 may
be achieved with
the corner portions and the sides having a wall surface with the same vertical
height between the
top surface 260 to the bottom surface 264.
The above embodiments are exemplary in nature. Additional structural
differences
between the sides and corner portions are intended to be encompassed by the
present invention as
long as the sides are adapted to exhibit a substantially uniform reaction
pressure when applying a
membrane lid to the lip of the container. Moreover, the term "substantially
uniform reaction
pressure" is intended to include reaction pressures that are uniform at the
corner portions and
sides as well as "substantially uniform" when compared to the differences in
reaction pressure
between the corner portions and sides when applying a membrane lid to a
substantially triangular-
shaped container lip with a substantially uniform lip structure at the corners
and sides.
Accordingly, a "substantially uniform pressure" may include pressures that are
different but more
uniform than would otherwise be exhibited by corner portions and sides having
substantially the
same lip structure.
In addition, a combination of the embodiments described above can be applied
to arrive at
the desired rigidity for the sides and corner portions. For example, the
horizontal thickness of the
lip could vary (e.g., as illustrated in FIG. SC) as well as the profile of the
outer wall surface (e.g.,
as illustrated in FIGS. 5A and SB). '
In exemplary embodiments of the lip structure, the top surface of the lip can
extend
horizontally from the top of the outer wall surface or at an upward angle with
respect to the
21
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
horizontal. Thus, angle "c" (e.g., see FIGS. 6, 7, 7A and 7B) can be from
about 0° to about 20°,
for example from about S° to about 18°, and in one example from
about 8° to about 12°. By
arranging the top surface horizontally or at an angle greater than 0°,
the container lip exhibits a
spring-like motion when a membrane lid is applied thereto and therefore
provides resistance to the
S membrane sealing force to result in a better membrane lid seal. The upward
angle of the top
surface also assists in providing a substantially uniform reaction pressure
along the lip upon
application of the membrane and alleviates the impact of imperfections in the
lip resulting from
trimming, mold parting lines and the like. While the top surface is
illustrated as being directed
upwardly and inwardly, the top surface could alternatively be oriented to
extend upwardly and
outwardly.
In one embodiment, a uniformly angled top surface is obtained by using a mold
with a
greater top surface angle "c" at the sides than the top surface angle "c" at
the corner portions of
the lip. For example, a mold may be provided with a top surface corner portion
angle "c" of about
1S° with respect to the horizontal and a top surface side angle "c" of
about 20° with respect to the
horizontal.
While the membrane lid and lip structure described above are useful
individually, they
may be used in combination. For example, a combination of any of the membrane
lids with any
of the lip structures described herein can be used to provide a substantially
uniform reaction
pressure along the perimeter of the lip upon application of the membrane lid
to obtain and
maintain a hermetic seal while providing a membrane lid that can be easily
removed by a
consumer at will. As described above the hermetic seal provided by the
membrane lid will create
an effective barrier against oxygen and moisture
The containers SO in accordance with the present invention may be formed by a
variety of
methods. For example, the container 50 may be formed from a thermoplastic
material and can be
2S blow molded, although other production methods may be employed. Suitable
thermoplastic
materials include, but are not limited to, polyolefms, such as polyethylene
and polypropylene,
vinyl polymers such as ethyl vinyl alcohol (EVOH), or the like. These
materials may be
monolayered and some of the materials may be combined. For example, a
multilayer material
may include both a polyolefm layer and an EVOH layer. In a specific
embodiment, the container
SO is blow molded from a multilayer material comprising a layer of EVOH
sandwiched between
two layers of high density polyethylene (HDPE).
One particular embodiment of the blow-molded, multiple-layer plastic structure
of the
container is as follows: a virgin polyolefin layer, a tie layer, a layer of
EVOH, another tie layer,
and another virgin polyolefin layer. Typically, container SO will also have
one or more layers of
22
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
regrind material in-between the tie layer and the virgin polyolefin Iayer. The
layer of EVOH
might be no less than 0.00005 inches thick and no thicker than 0.006 inches,
for example no less
than 0.00005 inches and no greater than 0.003 inches and in another example no
less than 0.0001
inches and no greater than 0.0012 inches.
An even more particular example of this multilayer plastic structure comprises
a six-layer
structure including the following layers (from the outside layer to the inside
layer): about 9.31
grams (g) or about 19.4% by weight of HDPE; about 18.91 g or about 39.4% by
weight of Plant
Regrind and HDPE; about 0.62 g or about 1.3% by weight of a tie layer; about
2.02 g or about
4.2% by weight of EVOH; about 0.62 g or about 1.3% of a tie layer; and about
16.51 g or about
34.4% of Plant Regrind and HDPE.
Another example of this six-layer structure can comprise (from outside layer
to inside
layer): about 10.7 grams (g) or about 19.4% by weight of HDPE; about 21.66 g
or about 39.4% by
weight of Plant Regrind and HDPE; about 0.69 g or about 1.3% by weight of a
tie layer; about
2.33 g or about 4.2% by weight of EVOH; about 0.69 g or about 1.3% of a tie
layer; and about
18.94 g or about 34.4% of Plant Regrind and HDPE.
Yet another example of this six-layer structure can comprise (from the outside
layer to the
inside layer): about 15.0% by weight of HDPE homopolymer and color; about
63.6% by weight
of Plant Regrind (60% by weight) and HDPE homopolymer and color (40% by
weight); about
1.4% by weight of a tie layer; about 3.6% by weight of EVOH; about 1.4% of a
tie layer; and
about 15.0% of Plant Regrind and HDPE homopolymer and color.
The container will typically have a thickness of from about 0.005 to about
0.055 inches,
for example from about 0.010 to about 0.045 inches. The container body 52 and
the lip 54 are
integrally formed, for example, by a blow molding process. Advantageously, the
lip structure
described herein is self supportive on the underside of the top surface of the
lip. Thus, the lip
structure may be formed by blow molding while overcoming the disadvantages of
many
conventional lip designs which require mechanical support for application of
the membrane.
In another embodiment of the containers according to the invention, the
containers can
further include an over-cap 70, an example of which is set forth in FIGS. 8
and 9. For example,
the over-cap 70 could comprise one of the over-caps described in U.S.
Provisional Application
No. 60/248,089, filed on November 13, 2000, entitled "Substantially Triangular-
Shaped Over-
Cap," and U.S. Application No. filed on even date, entitled "Substantially
Triangular-
Shaped Over-Cap," to Buisson et al., Attorney Docket 8329M, which are
incorporated herein by
reference.
23
CA 02424582 2003-04-O1
WO 02/38462 PCT/USO1/47051
The exemplary over-cap 70 of FIGS. 8 and 9 comprises a substantially
triangular-shaped
top surface 72 and a skirt 74 extending substantially downwardly from the
perimeter 76 of the top
surface 72. As is further shown in FIGS. 8 and 9, the skirt 74 includes
substantially rounded
corner portions and substantially straight sides extending around the
perimeter. 76 of the top
surface 72. The skirt corner portions include inner extensions 78 while the
skirt sides are
substantially free of inner extensions. As used herein, "substantially free of
inner extensions"
includes instances wherein the skirt sides have a sufficiently small
percentage of such inner
extensions such that the corner portion inner extensions are not prevented
from moving inward
when an outward pressure is exerted on the underside of the over-cap. In one
embodiment, the
skirt sides are free of inner extensions. The skirt including corner portions
having inner
extensions and skirt sides substantially free of inner extensions provides the
over-cap with the
ability to securely attach to the lip 54 of the container 50 described herein
and resist pressure
differentials between inner and outer sides of such a container.
Advantageously, this structure
also allows easy removal of the over-cap from such a container when desired by
a consumer.
The specific embodiments and examples set forth above are provided for
illustrative
purposes only and are not intended to limit the scope of the following claims.
Additional
embodiments of the invention and advantages provided thereby will be apparent
to one of
ordinary skill in the art and are within the scope of the claims.
24
