Note: Descriptions are shown in the official language in which they were submitted.
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A CONTAINER HAVING ADJUSTABLE VENTED COVER
FIELD OF THE INVENTION
[0001] The present invention relates generally to a plastic container having a
cover
and a base, which when sealingly engaged together form a sealed storage area,
and,
more particularly, to container covers that have an adjustable venting
feature. Slots or
holes in the cover are variably exposed by rotating a secondary venting cover
which
attaches to the top of the container cover.
BACKGROUND OF THE INVENTION
[0002] Rigid, thermoplastic food containers are generally known. These
containers
are substantially airtight, which can present a variety of problems during
consumer
use. When the contents of the container are micro-waved, the contents may heat
up
and expand with the evolution of steam causing the cover to violently pop off
the
container and resulting in a potential mess. In other storage applications, it
may be
desirable to adjustably vent the container. For example in the storage of
fruits and
vegetables, it may be desirable to adjustably control the ventilation and
moisture
transmission within the container.
[0003] Prior art examples in U.S. Patent 5,806,703 to Grandi, U.S. Pat. App.
2002/0148845 to Zettle et al, and U.S. Pat. 3,362,565 to Mccormick provide a
level of
venting as a safety valve for packages of products to be cooked. The present
invention has as a general aim to provide containers that solve the problems
of the
current food containers, which lack the ability to controllably adjust venting
of the
container.
SUMMARY OF THE INVENTION
[0004] In view of the foregoing, the present invention provides a container
comprising a cover having a first closure portion, said first closure portion
being
sealingly engageable with a second closure portion of a base so that when said
first
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closure portion and said second closure portion are engaged with each other,
said
cover and said base define a substantially sealed storage area; an engagement
portion;
and a venting cover adjustingly attached to the engagement portion; and the
base
having a bottom; a peripheral sidewall extending from said bottom; an open
top; and
said second closure portion.
[0005] In some embodiments, the container comprises a cover having a first
closure
portion, said first closure portion being sealingly engageable with a second
closure
portion of a base so that when said first closure portion and said second
closure
portion are engaged with each other, said cover and said base define a
substantially
sealed storage area; a central engagement portion; and a circular venting
cover
rotationally attached to the engagement portion; and the base having a bottom;
a
peripheral sidewall extending from said bottom; an open top; and said second
closure
portion.
[0006] The features of the present invention will become apparent to one of
ordinary
skill in the art upon reading the detailed description, in conjunction with
the
accompanying drawings, provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 is an perspective view of a container with a cover and a base
according to an embodiment of the present invention;
[0008] Figure 2 is an perspective view of the base of Figure 1;
[0009] Figure 3 is a partial sectional perspective view with the engagement
portion
of the cover of Figure 1 locking engaged with and engagement portion of a
second
cover;
[0010] Figure 4 is a top plan view of a cover according to an embodiment of
the
present invention;
[0011] Figure 5 is a top plan view of a cover according to an embodiment of
the
present invention;
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[0012] Figure 6 is a top plan view of a cover according to an embodiment of
the
present invention;
[0013] Figure 7 is a top plan view of a cover according to an embodiment of
the
present invention;
[0014] Figure 8 is a top plan view of a cover according to an embodiment of
the
present invention;
[0015] Figure 9 is a top plan view of a venting cover according to an
embodiment of
the present invention;
[0016] Figure 10 is a top plan view of a venting cover according to an
embodiment
of the present invention;
[0017] Figure 11 is a top plan view of a cover with a secondary venting cover
according to an embodiment of the present invention;
[0018] Figure 12 is a top plan view of a cover with a secondary venting cover
according to an embodiment of the present invention;
[0019] Figure 13 is a top plan view of a cover with a secondary venting cover
according to an embodiment of the present invention;
[0020] Figure 14 is a top plan view of a cover according to an embodiment of
the
present invention; and
[0021] Figure 15 is a top plan view of a secondary venting cover according to
an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Reference will now be made to the drawings wherein like numerals refer
to
like parts throughout. For ease of description, the components of this
invention are
described in the normal (upright) operating position, and terms such as upper,
lower,
horizontal, etc., are used with reference to this position. It will be
understood,
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however, that the components embodying this invention may be manufactured,
stored,
transported, used, and sold in an orientation other than the position
described.
[0023] Figures illustrating the components of this invention show some
conventional mechanical elements that are known and that will be recognized by
one
skilled in the art. The detailed descriptions of such elements are not
necessary to an
understanding of the invention, and accordingly, are herein presented only to
the
degree necessary to facilitate an understanding of the novel features of the
present
invention.
[0024] All publications, patents and patent applications cited herein, whether
supra
or infra, are hereby incorporated by reference in their entirety to the same
extent as if
each individual publication, patent or patent application was specifically and
individually indicated to be incorporated by reference.
[0025] As used herein and in the claims, the term "comprising" is inclusive or
open-
ended and does not exclude additional unrecited elements, compositional
components,
or method steps. Accordingly, the term "comprising" encompasses the more
restrictive terms "consisting essentially of' and "consisting of'.
[0026] It must be noted that, as used in this specification and the appended
claims,
the singular forms "a," "an" and "the" include plural referents unless the
content
clearly dictates otherwise. Thus, for example, reference to a "surfactant"
includes two
or more such surfactants.
[0027] Unless define otherwise, all technical and scientific terms used herein
have
the same meaning as commonly understood by one of ordinary skill in the art to
which the invention pertains. Although a number of methods and materials
similar or
equivalent to those described herein can be used in the practice of the
present
invention, the preferred materials and methods are described herein.
Recitation of
ranges of values herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the range, unless
otherwise
indicated herein, and each separate value is incorporated into the
specification as if it
were individually recited herein. All methods described herein can be
performed in
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any suitable order unless otherwise indicated herein or otherwise clearly
contradicted
by context. The use of any and all examples, or exemplary language (e.g.,
"such as")
provided herein, is intended merely to better illuminate the invention and
does not
pose a limitation on the scope of the invention unless otherwise indicated.
[0028] The term "container", as used herein, is meant to mean and include any
storage container for storing food in a refrigerator. A container may be made
of any
suitable material, depending upon the product therein. For example, a
container may
be made of plastic.
[0029] An embodiment of the present invention is illustrated in Figures 1 and
2. A
container 100 includes a flexible cover 102 sealingly engaged to a base 104.
In the
example of Figures 1 and 2, the container 100 is depicted as substantially
circular in
top plan view. In other embodiments of the present invention, the container
100 has
other shapes such as rectangular, square, or elliptical.
[0030] The cover 102 includes a central engagement portion 106 that is
lockingly
engageable with the central engagement portion of a second cover (shown in
Figure
3). Circumscribing the engagement portion 106 of the cover 102 can be at least
one
articulation element 108. The engagement portion 106 of the Figures is
depicted as
circular but, as with the shape of the container 100 itself, other shapes are
possible. In
some embodiments, a standard shape and configuration of the engagement portion
106 is used with covers 102 of various shapes and sizes. This enhances storage
flexibility by allowing different types of covers 102 to be stored together in
a locked
stack.
[0031] The cover 102 includes a first closure portion 110 on the outer portion
of the
base. The first closure portion 110 is sealingly engageable with a second
closure
portion 210 of the base 104. The first closure portion 110 of the cover 102
can be
sealingly engaged with a second closure portion 210 of the base 104 to provide
a leak-
resistant, re-sealable closure. When the first closure portion 110 of the
cover 102 and
the second closure portion 210 of the base 104 are abutted and sealingly
engaged with
each other, the cover 102 and the base 104 define a substantially sealed
storage area
within container 100 (Figure 1).
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[0032] As shown in Figure 2, the base 104 of the container 100 includes a
bottom
202 and a peripheral sidewall 204 extending upwardly from the peripheral edge
of the
bottom 202. The top of the base 104 is open. The second closure portion 210 of
the
base 104, which, as noted above, is adapted to sealingly engage with the first
closure
portion 110 of the cover 102, is positioned at the open end of the peripheral
sidewall
204 of the base 104. In one embodiment, the second closure portion 210 of the
base
104 is a raised locking ring that extends from an upper edge of the peripheral
sidewall
204 of the base 104.
[0033] More particularly with reference to the engagement portion 106, the
cover
102 illustrated in Figures 1 and 3 includes the engagement portion 106 that
allows the
cover 102 to lockingly engage with the engagement portion 306 of a second
cover 302
to form a locked stack of covers (Figure 3). This locking feature makes the
resultant
stack of covers more structurally rigid and thus less precarious than a
traditional, non-
interlocked, stack of covers.
[0034] As shown in Figure 3 the cover 102 is locked together with the second
cover
302 by their central engagement portions 106 and 306 respectively. In the
example of
Figure 3, the engagement portion 106 of the cover 102 includes an upper
protrusion
118 (see also Figure 1) and a lower protrusion 120. Further, the engagement
portion
of the second cover 302 likewise includes an upper protrusion 318 and a lower
protrusion 320. Each protrusion 118, 318, 120, and 320 is convex on one side
and
concave on the other. The lower protrusion 120 of the cover 102 fits over and
receives the upper protrusion 318 of the second cover 302, thus locking the
covers
102 and 302 together. In this manner, the covers 102 and 302 are held together
and
form a structurally stable cover stack. A third cover (not shown) may be
lockingly
engaged with the second cover 302, a fourth cover with the third and so on to
form a
stack of any number of covers.
[0035] The engagement portion 106 can also be chosen to have a shape or
otherwise
include elements that provide an aligned or locked stack of covers 102 with
rotational
alignment. Rotation, as used herein, is defined about an axis A (Figure 1)
normal to
the plane formed by orthogonal midlines, i.e., first midline 405A and second
midline
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405B at the top surface of the cover 102 as shown in Figure 4. The origin of
the
rotational axis is at the center point 407 at which the orthogonal midlines
intersect.
For instance, shapes that inherently require alignment prior to engagement or
that may
be self-aligning during the process of connecting engagement portions would be
shapes with linear or curvilinear sides, vertices or lobes such as triangular,
square,
rectangular, or multi-petal shapes. Additionally, the cover may have one or
more
elements on or about the engagement portion that require alignment prior to
connection of engagement portions or elements that may be self-aligning during
the
process of connecting engagement portions.
[0036] Other embodiments of the engagement portion may include one or more of
the following features to enable engagement: convex portions or ribs, concave
portions or ribs, linear or curvilinear undercuts, discrete snap elements or
buttons,
interference fits, textured surfaces, or elements that modify surface friction
or
tackiness at or around the point of engagement. The engaging areas that create
a
locking condition can be continuous about the engagement portions or
discretely
segmented about the engagement portions. In some embodiments, the force
required
to connect the cover and the second cover may differ substantially from the
force
required to disengage the covers. For instance, it may be beneficial during
manufacturing that the force needed to connect the covers is less than the
force
required to separate the covers. As a result, the covers are relatively easy
to connect
during manufacturing, yet they will lock securely and not undesirably separate
during
the manufacturing process. To accomplish this, the protrusions on the
engagement
portion may be designed where, for a given protrusion, the upper protrusion
edge
comprises a gradual taper whereas the lower protrusion edge comprises a more
abrupt
shape. For example, in one embodiment, the shape of the protrusion may be
similar
to a barbed hook with gradual taper on the upper edge of the barb that would
impart
little resistance during engagement and with an abrupt shape on the lower edge
of the
barb that would impart relatively high resistance during disengagement.
Conversely,
it may be beneficial to design the engagement portion so that the force that
needs to
be applied to connect the covers is more than the force required to separate
the covers,
since the user may perceive that a high connecting force equates to
satisfactory
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locking integrity, whereas a weak connecting force may lead the user to
perceive that
the cover stack lacks the integrity required to insure the expected
organizational
benefit. Thus, the high connecting force provides the perceived benefit, yet a
lower
disengagement force does not require that the user untowardly struggle during
separation of covers. To accomplish this, the protrusions on the engagement
portion
may be designed where, for a given protrusion, the upper protrusion edge
comprises
an abrupt shape whereas the lower protrusion edge comprises a more gradual
taper.
For example, in one embodiment, the shape of the protrusion may be a reversed
barb
with an abrupt shape on the upper edge of the barb that would impart
relatively high
resistance during engagement and with a gradual taper on the lower edge of the
barb
that would impart little resistance during disengagement. Furthermore, during
the
process where the user applies force to aligned covers in a direction normal
to the
general cover plane so as to lock the covers together, the engagement portion
can
provide tactile or audible feedback upon locking. In this way, the user would
sense
that the covers are connected and that no further force need be applied.
[0037] More particularly, the first closure portion 410 and the second closure
portion 210 forms the sealing engagement of the cover 102 and the base 104. As
would be apparent to one of ordinary skill in the art, the present invention
can be
embodied with a variety of closure designs including outer closures and/or
inner
closures. Related U.S. Patent Application 2009/0166369, co-owned with the
present
invention and incorporated in its entirety herein by reference, further
describes the
closure portions. However, the closure portions described therein are examples
only,
and many other types of closure portions could be used with the present
invention.
[0038] As shown in Figure 5, the central engagement portion 106 of the cover
502
may contain one or more openings 504 of various shapes, for example slits,
allantoids,
rounded openings, etc that are useful for venting. Figure 6 shows cover having
a
central engagement portion 106 having several smaller openings 504 and one
large
opening 506. Figure 7 shows an embodiment of the cover 502 having circular
openings 508 that fan out from the center. Figure 8 shows an embodiment of the
cover 502 having allantoid openings 510 that fan out from the center.
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[0039] Figure 9 shows a venting cover 902 that can fit over a central
engagement
portion 106 of a cover 502 of Figures 5, 6, 7, and 8. The venting cover 902
has
curved slits 904. Figure 10 shows a venting cover 1002 having one large
opening
1004. In Figure 11, the venting cover 902 is rotationally attached over the
central
engagement portion (not shown) of the cover 502. In the configuration of
Figure 11,
the curved slits 904 are not ventingly connected to openings (not shown) on
the cover
502. Figure 12 shows the cover 502 with the venting cover 902 rotated to
expose the
openings 504. Figure 13 shows the venting cover 1002 rotationally attached
over the
central engagement portion (not shown) of the cover 502 of Figure 6 so that
the large
opening 1004 of the venting cover 1002 exposes the large opening 506 of the
cover
502. Figure 14 shows an example of a cover 1402 having a rectangular central
engagement portion 1406 with venting openings 1404. Figure 15 shows a venting
cover 1410 slideably attached to the central engagement portion 1406 and
partially
exposing the venting openings 1404 of the cover 1402.
[0040] The base 104 can be made from any suitable plastic with sufficient
thickness
to withstand without deforming the heat of microwave cooking and of top-shelf
dishwashing. It should also remain sturdy during lifting while laden with hot
food.
The base 104 can be made from any suitable plastic and can be made by any
suitable
technique, such as co-extrusion, lamination, injection molding, vacuum
thermoforming, or overmolding. In one embodiment, the base 104 is formed from
polypropylene. As with the cover 102, the nominal wall thickness of the base
104 can
vary somewhat due to the manufacturing process.
[0041] The cover 102 can be constructed with a wall thickness thinner than
that of a
base 104. The cover 102 can be made from any suitable plastic and can be made
by
any suitable technique, such as vacuum thermoforming processes described
herein. In
one embodiment, the cover 102 can be formed from polypropylene. Due to the
vacuum thermoforming process, the wall thickness of the cover 102 can vary
slightly
over its nominal thickness. A cover 102 with a nominal thickness less than the
nominal thickness of the base 104, however, reduces the cost of material for
the
container 100. Further, with a thinner cover 102, increased cover flexibility
more
easily accommodates the removal of the cover 102 from, and the sealing
engagement
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with, the base 104. The cover 102 can maintain adequate flexibility for proper
sealing
even during typical freezer temperatures.
[0042] The cover 102 can be made by various plastic molding processes,
including
but not limited to vacuum thermoforming and injection molding. Vacuum
thermoforming of the cover 102 is typically the most economical means for
forming
the cover 102. As is well know in the art, vacuum thermoforming involves
heating a
suitable plastic sheet of material to a temperature at which the sheet becomes
formable into a shape that is set as the plastic sheet cools. As used herein,
a suitable
plastic sheet is a plastic sheet that may be readily used by the vacuum
thermoforming
process. The heated plastic sheet is made to conform to the surface features
of a
single surface "male" tool by drawing the heated sheet of plastic to the
surface of the
tool by the force of a vacuum applied to the tool. In vacuum thermoforming,
the
sealed air space between the heated plastic and mold is evacuated to draw the
heated
plastic to contact the single male surface of the mold.
[0043] Typically, however, in vacuum thermoforming, the thickness of the
finished
article formed by the process is nominally uniform. A side cross-section view
through the vacuum thermoformed article reveals a substantially uniform
thickness
profile. The "bottom" surface of the heated plastic sheet that contacts the
tool surface
conforms to its shape. The "top" surface of the plastic element formed in the
vacuum
thermoforming process does not contact a tool surface and generally resides at
a
uniform distance from the bottom surface of the plastic article. Only nominal
thinning of the plastic material occurs when it bends and stretches around
curved
mold features to conform to the path of the curved surfaces of these features.
As used
herein, a substantially uniform thicknesses in side cross-sectional profile is
a thickness
in a plastic article that is not sufficiently variable to preclude its
manufacture with
typical prior art single male surface vacuum thermoforming techniques.
Conversely,
a non-uniform thickness is a profile thickness in an article that varies
enough to
preclude the manufacture of the article with standard prior art vacuum
thermoforming
techniques requiring instead other plastic molding techniques such as
injection
molding.
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[0044] Injection molding of a plastic article involves heating suitable
plastic
material in the form of pellets or granules until a melt is obtained. The melt
is next
forced into a split-die mold, sometimes referred to as a split-die tool, where
it is
allowed to "cool" into the desired shape. Both the bottom surface and the top
surface
of the plastic article are formable by the split-die mold. Thus, articles may
by formed
by the injection molding process that have side cross-sectional profiles of
varying
non-uniform thickness. After the plastic melt cools, the split-die mold is
opened and
the article is ejected. Since, the mold is separable, undercut surface on the
plastic
article may be relieved from the split-die mold when it is opened. Injection
molding,
well know in the art, is typically used to form plastic articles that have
large undercuts
and substantially varying thicknesses in side cross-sectional profile. As used
herein
undercuts are said to be large if a molded plastic article having undercut
features is
difficult or impossible to remove from a single-surface vacuum thermoforming
mold
after it is formed and cooled.
[0045] Since cover 102 as described, contains significant undercuts, such as
included in upper protrusion 118 and lower protrusion 120 (Figures 1 and 3) on
the
engagement portion 106 of the coverl02, injection molding would typically be
required to form cover 102. Further, injection molding would typically be
required to
form articulation elements 108 that are significantly thinner than the rest of
cover 102.
[0046] The container 100 can be reusable, but it can also be constructed
cheaply
enough that consumers see it as a disposable item, with replacement covers 102
and
bases 104 available separately for retail sale. The base 104 and the cover 102
can be
fabricated by vacuum thermoforming a clarified polypropylene homopolymer
material. In another embodiment, the container 100 may be fabricated by vacuum
thermoforming a clarified random copolymer polypropylene material. Other
plastic
materials which would be suitable for fabricating the cover 102 and the base
104 of
the container 100 by vacuum thermoforming include PS (polystyrene), CPET
(crystalline polyethylene terephthalate), APET (amorphous polyethylene
terephthalate), HDPE (high density polyethylene), PVC (polyvinyl chloride), PC
(polycarbonate), and foamed polypropylene. The material used can be generally
transparent to allow a user to view the contents of the container.
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[0047] The container 100 may include a visual indication of closure between
the
cover 1102 and the base 104. The visual indication may be a color change in
the area
where the cover 102 engages the base 104. In one embodiment, the first closure
portion 310 on the cover 102 may be a first color and the second closure
portion 416
on the base 104 may be a second color. When the closure portions are engaged,
the
first and second colors produce a third color which is visible to the user to
indicate
that the container 100 is sealed.
[0048] The container 100 may include a rough exterior surface to reduce
slipping
and to improve grasping by the user, especially if the user's hands are wet or
greasy.
[0049] The container 100 may be divided to separate foods in the container. A
divider may be integral with the container 100 or may be a separate component.
Either the base 104 only may include a divider or both the base 104 and the
cover 102
may each include a divider. The divider located in the cover 102 may only
partially
engage the divider in the base 104 so as to provide splash protection, or it
may fully
engage the divider in the base 104 to provide varying degrees of inter-
compartmental
leak resistance. The container 100 may include a strip indicating the
temperature of
the container 100 and its contents.
[0050] The venting cover could be injection molded or thermoformed. The
venting
cover could be made of a number of plastic materials as indicated above, for
example
polypropylene. The venting cover can be removably attached to the central
engagement portion. An interference fit between the venting cover and the
central
engagement portion can provide a sealing engagement when the venting cover is
in
the closed position. If the cover or venting cover is made from a softer
durometer
material, the venting could be more easily closed off in the closed position.
Suitable
materials are impact copolymer polypropylene, polyolefin plastomer, polyolefin
elastomer and styrene butadiene rubber.
[0051] This invention has been described herein in detail to provide those
skilled in
the art with information relevant to apply the novel principles and to
construct and use
such specialized components as are required. However, it is to be understood
that the
invention can be carried out by different equipment, materials and devices,
and that
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various modifications, both as to the equipment and operating procedures, can
be
accomplished without departing from the scope of the invention itself.
Moreover, any
combination of the above described elements in all possible variations thereof
is
encompassed by the invention unless otherwise indicated herein or otherwise
clearly
contradicted by context. While the invention is described herein in connection
with
certain preferred embodiments, there is no intent to limit the present
invention to
those embodiments.
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