Note: Descriptions are shown in the official language in which they were submitted.
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CONTAINERS WITH INTERLOCKING COVERS
FIELD OF THE INVENTION
[0001] The present invention relates generally to containers, and, more
particularly, to
containers whose covers align together when stacked in a first position and
which
may be locked together in a second position.
BACKGROUND OF THE INVENTION
[0002] Rigid, thermoplastic food containers are generally known. Users often
accumulate a large number of these containers in different sizes and shapes.
When
not in use, the containers are often stored. haphazardly into drawers. In this
case, the
unused containers take up a great deal of room, and finding a matching base
and
cover, which make up a container, in a disarranged drawer may be difficult. To
avoid
this, some users stack the containers in cabinets. While the bases of the
containers
usually nest and therefore take up less room than in a disorganized drawer, it
may still
be difficult to match a base with a cover. In addition, the covers may not
stack and
the covers may tend to topple down. When the containers are in use to store
food, the
containers are often stacked one on top of another in cabinets or in a
refrigerator.
These stacks may be precarious, and their fall may cause food to spill from
the
containers. Many users would find it desirable if the containers, whether
empty or in
use, could be stored in a manner space efficient, less precarious, and more
structurally
rigid.
[0003] During largc-scalc manufacturing, the covers may be transported in bulk
before being separated out for individual packaging. During bulk handling,
manufacturers would find it desirable if the covers would form a stack stable
enough
to resist the vertical and lateral movements caused by forces typically
encountered
during manufacturing operations.
[0004] The present invention has as a general aim to provide containers that
satisfy
both users and manufacturers.
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SUMMARY OF THE INVENTION
[0005] Embodiments according to the principles of the present invention
provide
containers whose covers may be stacked together in two different ways. First,
the
covers may be nested and stacked and configured into an "aligned" stack. The
aligned stack provides enough structural rigidity for bulk handling during
manufacturing. Second, the covers may be stacked, interlocked one to another,
and
configured into a"locked" stack. The locked stack provides even more
structural
rigidity than does the aligned stack and is useful when storing unused covers.
Finally,
once the stack of covers is locked, the top cover of the stack may be easily
released
from the locked stack and removed.
[0006] In some embodiments, the cover includes a first closure portion, an
engagement portion, and an alignment portion. The base of the container
includes a
second closure portion that is sealingly engageable with the first closure
portion of the
cover to define a substantially sealed, leak-proof, and re-sealable storage
area for
items such as food. It is well known to those of ordinary skill in the art,
that the cover
may be sealingly engaged with its base.
[0007] The alignment portion of the cover is engageable with the alignment
portion of
a second cover to form an aligned cover stack. The engagement portion of the
cover
is engageable with a second cover to form a system of covers in a locked cover
stack.
[0008] In one embodiment, once engaged to form a locked stack of covers, the
engagement portion of the top cover of the locked stack is disengageable from
the
cover immediately below the top cover in the cover stack. The top cover is
removable
from the locked stack by a simple lifting action supplied by the thumb or
forefinger of
a user on a gripping tab coupled to the cover.
[0009] In one embodiment, thc engagemcnt portion of the cover is positioned on
a
gripping tab of the cover. The engagement portion is configured as a
downwardly
directed protrusion on the top of the cover of the container. A male cap
component of
the engagement portion, cooperates with a female well component of the
engagement
portion of a second cover aligned immediately below the cover to lock the two
covers
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together in a stack. The male cap component may be nearly vertical and fits
with
minimal clearance inside the female well component so that cover stacking is
provided when the cover stack is not kept in a vertical orientation. In one
embodiment, the male cap component of a cover physically contacts the female
well
component of a second cover and provides a friction fit that locks the covers
stacked
together. The male cap component may have a shape similar to an opened topped
hollow tub having a wedge-shaped outer surface wall. The male cap component
may
further include at least one undercut and at least one lead-in. The lead-in of
the cover
cooperates with the undercut of a second cover to provide a "snap" fit, well
known to
those of ordinary skill in the art, to lock the cover with the second cover.
Thus, The
covers may either nest by sitting on top of each other in a stack that may be
shear de-
nested, or the male cap component may abuttingly engage into the female well
component to lock the covers into one unit for convenient storage.
[0010] In another embodiment, the cover includes a first closure portion at
the outer
peripheral edge of the bottom of the cover. The first closure portion of the
cover
cooperates with a second closure portion on the top perimeter rim edge of the
base of
the container to form a seal. The container uses a rim or perimeter design
that
includes both inside and outside seals. Containers may be embodied with a
variety of
closure portion designs including outer closures and/or inner closures. The
engagement portion is in a position spanning between an inner sealing wall and
an
outer sealing wall at the top of the first closure portion. The engagement
portion of
the cover is configured as a locking lug integral with the first closure
portion.
[0011] The covers and bases of container may be economically constructed from
relatively thin-gauge plastic so that the user may either wash them after use
or dispose
of them with the view that their purchase price allows them to be used as a
consumable good. The container may be readily manufactured, for example, with
conventional thermoforming equipment or thin-walled injection molding. The
cover
may be made from a semi-transparent material to ensure satisfactory visibility
of the
container's contents. The container may be suitable for refrigerator, freezer,
microwave, and machine dishwasher use.
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[0012] 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
[0013] Reference will now be made to the drawings wherein like numerals refer
to
like parts throughout, and wherein:
Figure 1 is an isometric view of a container with a cover and a base according
to an embodiment of the present invention;
Figure 2 is an isometric view of the base of Figure 1;
Figure 3A is an isometric top view of the cover of Figure 1;
Figure 3B is an isometric bottom view of the cover of Figure 1;
Figure 4A is top plan view of the covcr of Figure 1 showing the cngagcment
portion of the cover;
Figure 4B is close-up view of the engagement portion of the cover of Figure
4A as indicated in dotted line;
Figure 4C is front view of the cover of Figure 4A showing the cngagcmcnt
portion of the cover;
Figure 5A is an isometric view of a cross- section of the cover of Figure 3A
taken along a first midline of the cover;
Figure 5B is a close-up view of the engagement portion of the cover of Figure
5A;
Figure 6A is an isometric view similar to Figure 5A showing a cross-section
of the cover and a second aligned with the cover;
Figure 6B is a close-up view similar to Figure 5B showing of the engagement
portion of the cover locked with the engagement portion of a second cover;
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Figure 6C is a close-up view of a the engagement portion of the cover in a
locked configuration with the engagement portion of a second cover;
Figure 7 is an isometric view similar to Figures 5A and 6A showing a cross-
section of a stack of five covers in a locked configuration;
Figure 8 is an isometric view of a container with a cover and a base according
to another embodiment of the present invention;
Figure 9 is an isometric view of the base of Figure 8;
Figure 10A is an isometric top view of the covcr of Figure 8;
Figure 1 OB is an isometric bottom view of the cover of Figure 8;
Figure 11A, is a partial side cross-section view of the container of Figure 8;
Figure 11B is an outline view of the cross-section profile of Figure 11A
schematically depicting the seal formed by the cover and the base;
Figure 12A is a partial side cross-section view similar to the view of Figure
11A showing the cover of Figure 8 and a second cover aligned below but not
locked to the cover;
Figure 12B is a partial side cross-section view similar to the view of Figure
1 lA showing the cover of Figure 8 lockingly engaged with the second cover;
Figure 12C is an outline view of the cross-section profile of Figure 12B
schematically depicting the locking engagement of the cover and the second
cover;
Figure 13A is a partial side cross-section view similar to Figure 1 lA of the
container of Figure 8 having a second cover locked to the cover; and
Figure 13B is an outline view of the cross-section profile of Figure 13A
schematically depicting the seal formed by the cover and the base and the
locking engagement of the cover and the second cover.
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DETAILED DESCRIPTION OF THE INVENTION
[0014] An embodiment according to the principles of the present invention is
illustrated in Figures 1-7. As seen in Figure 1, a container 100 includes a
flexible
cover 102 sealingly engaged to a base 104. The cover 102 includes at least one
gripping tab 106 to facilitate removal of the cover 102 from the base 104. Tn
some
embodiments, the gripping tab 106 includes one or more cross-ribs or a
textured
surface to improve a user's grip and lift on the tab 106. The container 100 is
depicted
as substantially square with rounded corners. In other embodiments of the
present
invention, the container 100 has other shapes such as square, circular, or
elliptical.
[0015] As seen in Figure 3A and 3B, and as described and illustrated more
fully
below, the cover 102, and more particularly the gripping tab 106, includes an
engagement portion 308. Engagement portion 308 allows the cover 102 to engage
with the engagement portion of a second cover.
[0016] The cover 102 further includes a first closure portion 310 at the outer
peripheral edge of the bottom of cover 102. In Figure 2, the base 104 includes
a
second closure portion 212 at the top edge of the base 104. It is well known
to those
of ordinary skill in the art, that the cover 102 may be sealingly engaged with
the base
104. Thus, the first closure portion 310 of the cover 102 is sealingly
engageable with
the second closure portion 212 of the base 104 to define the substantially
sealed, leak-
proof, and re-sealable storage area for items such as food. The container 100
uses a
rim or perimcter design that includcs both inside and outside seals.
Containers may
be embodied with a variety of closure portion designs including outer closures
and/or
inner closures with a variety of undercuts and lead-ins that may affect seal
integrity
[0017] The first 310 and second 212 closure portions may be configured to be
slightly
different in size to form an interference fit therebetween. The interference
between
the closure portions may provide the sealing engagement between the closure
portions. As a result, when the two pieces are engaged, a positive seal may be
formed
between sealing surfaces around the perimeters of the base 104 and of the
cover 102.
The engagement of the first 310 and second 212 closure portions may be
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accompanied by an audible "snap" indicating that the container 100 is securely
closed. .
[00181 As described and illustrated above with reference to Figure 3A and 3B,
the
cover 102, and more particularly the gripping tab 106, includes an engagement
portion 308 that allows the cover 102 to lockingly engage with the engagement
portion of a second cover. The engagement portion of the second cover may
engage
with the engagement portion of yet a third cover, and so on, to form a locked
stack of
any number of covers. This locking feature makes the resultant stack of covers
more
structurally rigid. Thus, the locked stack of covers is less precarious than a
traditional, non-interlocked, stack of covers. Further, as described and
illustrated in
more detail below, the cover 102 accommodates the disengagement of the
engagement portion 308 of the cover 102 from the engagement portion of a
second
cover to release the cover 102 from its locked configuration in the stack of
covers.
[0019] Figures 4A-7 show the utility of an embodiment of the invention when
the
container covers are locked in storage. In one embodiment, the engagement
portion
308 of the cover 102 illustrated in Figures 4A-4C is centered within the
gripping tab
106 at the top surface of the cover 102. As best seen in Figure 4C, the
engagement
portion 308 is depicted as a projection that is directed downwardly from the
top of the
cover 102.
[00201 As shown in Figures 5A and 5B, the projection is in the form of a
hollow, cup-
likc, nested structure. Engagement portion 308 is open at the top and has a
wedge-
shaped outer surface wall defining a male cap component 514 (Figure 5B). The
inner
surface wall of the engagement portion 308 defines a female well component 516
(Figure 5B) adapted to receive the male cap component of another cover. The
male
cap component 514 of the engagement portion 308 of the cover 102 has a shape
complimentary to the female well component 516. In the embodiment of Figures
4A-
7, the walls of the engagement portions taper from top to bottom, being
designed with
a draft angle, to accommodate nesting. Thus, the male cap component 514 of
cover
102 may be receivingly engaged by the female well component of a cover below,
locking the covers into one unit for convenient storage. Engagement portions
of
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different covers may vary in depth to allow locking engagement compatibility
across
a container product family.
[0021] In other embodiments, more than one engagement portion 308 may be
located
on the top surface of the cover 102 to accommodate locking engagement of
multiple
container covers at more than one position on the top surface of the cover
102. In
some embodiments, a standard shape and configuration of the engagement portion
308 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. A standard shaped and configured engagement portion 308 may be used
with,
for example, circular, square, rectangular, and elliptical shaped covers or
with
similarly shaped covers but differently sized covers.
[0022] The engagement portion 308 may also be chosen to have a shape or
otherwise
include alignment portion elements that provide rotational alignment of a
stack of
covers 102. Rotation is defined about an axis normal to the plane formed by
orthogonal midlines, i.e., first midline 318 and second midline 320, of the
cover 102
(Figure 3A). The origin of the rotational axis is at the center point 322
where the
orthogonal midlines 318 and 320 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. The
cngagcmcnt portion 308 dcpictcd in Figures 4-6, which has a wcdgc-shapcd outer
surface defining the male cap component 514 of the cover 102, is an engagement
portion shape that inherently requires rotational alignment before locking
with
engagement portions of other covers. Alternately, cover 102 may have elements
that
self-aligning during the process of locking connection of the engagement
portions.
[0023] Referring again to Figure 5B, the male cap component 514 includes an
undercut 524 configured as a lengthwise bead along at least a part of the
bottom edge
of the male cap component 514. In the embodiment of Figures 4A-7, undercut 524
is
positioned around the entire outer surface wall of the engagement portion 308
making
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up the male cap component 514. The undercut 524 projects outwardly from the
engagement portion 308 of the cover 102.
[0024] The female well component 516 of the engagement portion 308 of the
cover
102 includes a lead-in 526. Lead-in 526 is configured as a groove or
indentation
along at least a portion of the top edge of the female well component 516. In
this
embodiment, lead-in 526 is indented around the entire inner surface wall of
the
engagement portion 308 making up the female well component 516.
[0025] Referring to Figures 6A-6C, to lock a second cover 602 to the cover 102
the
cover 102 is first rotationally aligned with the second cover 602. As noted
above, the
cover 102 inherently requires rotational alignment with the second cover 602
before
locking. To align the cover 102 with the second cover 602, the cover 102 is
rotated
about its center point 322 (Figure 3A) until the engagement portion 308 of the
cover
102 is directly above an engagement portion 608 of the second cover 602.
[0026] The engagement portion 608 of a second cover 602 is configured as
described
above for the cover 102. More particularly, the engagement portion 608 of the
second
cover 602 includes a male cap component 614. The male cap component 614 of the
second cover 602 includes an undercut 624 configured as a lengthwise bead
along the
entire bottom edge of the male cap component 614 of the second cover 602_
Further,
in this embodiment, the engagement portion 608 of the second cover 602
includes a
female well component 616 defined by the inner surface wall of the engagement
portion 608. The fcmale wcll component 616 of the engagement portion 608 of
the
second cover 602 includes a lead-in 626. Lead-in 626 of the second cover 602
is
configured as a groove or indentation along at least a portion of the top edge
of the
female well component 616 of the engagement portion 626 of the second cover
602.
In this embodiment, lead-in 626 is indented around the entire inner surface
wall of the
engagement portion 608 making up the female well component 616 of the second
cover 602.
[0027] As best seen in Figure 6C, when in a locked configuration, the outer
surface
wall of the engagement portion 308 defining the male cap component 514 of the
cover
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102 engages and. interacts with a female well component 616 defined by the
inner
surface wall of the engagement portion 608 of the second cover 602 stacked
immediately below the cover 102. More particularly, the undercut 524 of the
cover
102 is adapted to engage and cooperate with the lead-in 626 of the engagement
portion 608 of the second cover 602 to form a locked relationship between
cover 102
and second cover 602.
[00281 In locking the second cover 602 with the cover 102, engagement portion
308
of the cover 102 is rotationally aligned above the engagement portion 608 of
the
second cover 602 (Figure 6A). As shown in Figure 6B, the cover 102 is next
pressed
down onto and contacted with the second cover 602 such that male cap component
514 of the cover 102 is receivingly engaged by the female well component 616
of the
second cover 602, to form a locking relationship between cover 102 and second
cover
602. More particularly, when the cover 102 is pressed down on the second cover
602,
the undercut 524 of the engagement portion 308 of the cover 102 forms a snap
or
friction fit with lead-in 626 of the engagement portion 608 of the second
cover 602,
which locks the cover 102 and the second cover 602 together into one unit for
convenient storage.
[0029] Referring to Figure 7, similarly, in this embodiment, a third cover
702A,
includes an engagement portion 708A. The engagement portion 708A of the third
cover 702A is configured as described above for the cover 102 and the second
cover
602. The engagement portion 708A of the third cover 702A may be lockcd with
the
engagement portion 608 of the second cover 602 in a manner similar to that
described
above for locking the cover 102 with the second cover 602. Likewise, an
engagement
portion 708B of a fourth cover 702B may be locked with the engagement portion
708A of the third cover 702A and an engagement portion 708C of a fifth cover
702C
may be locked with the engagement portion 708B of the fourth cover 702B to
form a
locked stack 728 of five covers as shown in Figure 7.
[0030] A stack of locked covers, each with at least one undercut on the male
cap
component of its engagement portion and at least one cooperating lead-in on
the
female well component, may be unlocked by pulling upwardly on the tab of the
top
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cover while holding the stack of locked. covers below the top cover and so on
until the
entire stack of covers is unlocked. The unlock covers may nest on top of each
other in
a stack that may be shear de-nested as is well know to those of ordinary skill
in the
art. Advantageously, in this embodiment, the engagement portions may be nearly
vertical and accordingly the male cap components of the engagement portions
fit with
minimal clearance inside the cooperating female well components. Cover locking
is
provided without excessively increasing the height of a stack of locked covers
over
the height of a stack of unlocked covers that have no engagement portions.
[00311 As with the shape of the container 100 itself, the engagement portions
of the
covers may assume a variety of shapes, locations, and matingly engageable
surface
configurations. Another embodiment in accordance with he principles of the
present,
for example, is described and illustrated more fully below with reference to
Figures 8-
13B. Referring to Figure 8, a container 800 includes a flexible cover 802
sealingly
engaged to a base 804. As seen in Figure l OB, 1 lA and 11B, the cover 802
further
includes a first closure portion 1010 at the outer peripheral edge of the
bottom of
cover 802. The cover 802 includes at least one gripping tab 806 to facilitate
removal
of the cover 802 from the base 804. The container 800 is depicted as
substantially
square with rounded corners. In other embodiments of the present invention,
the
container 800 has other shapes such as square, circular, or elliptical.
[0032] In Figure 9, 11A, and 11B, the base 804 includes a second closure
portion 912
at the top perimeter edge of the sidewall 911 of the base 804 that is integral
with the
bottom 909 of the base 804. It is well known to those of ordinary skill in the
art, that
the cover 802 may be sealingly engaged with the base 804 to define the
substantially
sealed, leak-proof, and re-sealable storage area for items such as food shown
in Figure
8. The container 800 uses a rim or perimeter design that includes both inside
and
outside seals. Containers may be embodied with a variety of closure portion
designs
including outer closures and/or inner closures.
[0033] Referring to Figures 10A-11B, the cover 802 includes an engagement
portion
1008. As best seen in Figure 11B, engagement portion 1008 is integrally
forrned with
the first closure portion 1010 of the cover 802 and is not formed. at the tab
806 as in
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the embodiment described above with reference to Figures 1-7. As described.
and
illustrated more fully below with reference to Figures 12A and 12B, the
engagement
portion 1008 allows the cover 802 to lockingly engage with the first closure
portion
of a second cover.
[0034] Figure 11A, is a partial side cross-section view of the container 800
of Figure
8. Figure 11B is an outline view of the cross-section profile of Figure 1 1A
schematically depicting the seal formed by the first closure portion 1010 of
the cover
802 and the second closure portion 912 of the base 804. The first closure
portion
1010 of the cover 802 cooperates with the second closure portion 912 of the
base 804
to defme a sealed storage compartment. Referring to Figures 1 1A and 11B
together,
the first closure portion 1010 includes an inner sealing wall 1130 and an
outer sealing
wall 1132. The inner sealing wall 1130 defines a first sealing surface and the
outer
sealing wall 1132 defines a second sealing surface, both of which are part of
the lower
surface of the cover 802 (See also Figure l OB). In the embodiment shown, the
inner
sealing wall 1130 includes a first inner lead-in 1133A at the bottom of the
first sealing
portion 1010 where it joins the top of the cover 802. Likewise, the outer
sealing wall
1132 includes a first outer lead-in 1133B at the bottom of the first sealing
portion
1010. Further, in this embodiment, the inner sealing wall 1130 includes a
second
inner lead-in 1134A at the top of the first sealing portion 1010 of the cover
802.
Likewise, the outer sealing wall 1132 includes a second outer lead-in 11 34B
at the top
of the first sealing portion 1010 of the cover 802. In other embodiments,
first sealing
portion 1010 may contain more than one inner and. outer lead.-ins of the cover
802.
[0035] As described and illustrated more fully below with reference to Figures
12A
and 12B, integral with first closure portion 1010 at the second inner lead-in
1134A
and second outer lead-in 1134B lead-ins is the engagement portion 1008 of the
cover
802. The engagement portion 1008 is configured as a locking lug spanning
between
the second inner 1134A and second outer 1 134B lead-ins of the first closure
portion
1010.
[0036] The second closure portion 912 of the base 804 is a raised ring that
extends
from an upper edge of the sidewal1911 of the base 804 (See also Figure 9). The
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second. closure portion 912 includes an inner sealing wall 1138, an outer
sealing wall
1140 and a retention bead 1141 integral with and spanning between the inner
sealing
wall 1138 and outer sealing wall 1140 of the second closure portion 912 of the
base
804. The inner sealing wall 1138 defines a third sealing surface and the outer
sealing
wall 1140 defines a fourth sealing surface. The second closure portion 912 may
include one or more lead-ins. In the embodiment shown, the inner sealing wall
1138
of the second closure portion 912 includes an inner lead-in 1142A. The outer
sealing
wall 1140 of the second closure portion 912 includes an outer lead-in 1142B.
[0037] The first closure portion 1010 and the second closure portion 912 may
be
configured to be slightly different in size to form an interference fit
therebetween.
The interference fit between the first closure portions 1010 and the second
closure
portion 912 may provide a sealing engagement between the closure portions.
More
particularly, the first sealing surface of the inner sealing wall 1130 of the
first closure
portion 1010 abuttingly contacts the third sealing surface of the inner
sealing wall
1138 of the second closure portion 912 to provide an inner sealing engagement;
and
the second sealing surface of the outer sealing wall 1132 of the first closure
portion
1010 abuttingly contacts the fourth sealing surface of the outer sealing wall
1140 of
the second closure portion 912 to provide an outer sealing engagement.
[0038] The second inner lead-in 1134A of the first closure portion 1010
cooperates
with the inner lead-in 1142A of the second closure portion 912 to enhance and
maintain the inner sealing engagement between the cover 802 and the basc 804.
In a
similar manner, the second outer lead-in 1134B of the first closure portion
1010
cooperates with the outer lead-in 1 142B of the second closure portion 912 to
enhance
and maintain the outer sealing engagement between the cover 802 and the base
804.
As a result, when the cover 102 and the base 104 are abuttingly engaged, a
compound
positive seal is formed between the sealing surfaces around the perimeters of
the
cover 802 and the base 804.
[0039] The abutting engagement of the first closure portion 1010 and second
closure
portion 912 may be accompanied by an audible "snap" indicating that the
container is
securely closed. and sealed. To facilitate sealing engagement of the cover 802
with its
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base 804, a user applies a downward force on the cover 802, or, more
conveniently,
only to the top of the engagement portion 1008 of the cover 802, while the
first
closure portion 1010 of the cover 802 is aligned with the second closure
portion 912
of the base 804.
[0040] Figure 12A is a partial side cross-section view similar to the view of
Figure
11A showing the cover 802 of Figure 8 and a second cover 1202 aligned below
but
not locked to the cover 802. Figure 12B is a partial side cross-section view
similar to
the view of Figure 11A showing the cover 802 of Figure 8 lockingly engaged
with the
second cover 1202. Figure 12C is an outline view of the cross-section profile
of
Figure 12B schematically depicting the locking engagement of the cover 802 and
the
second cover 1202. As best seen in Figure 12C, integral with the first closure
portion
1010 of the cover 802 is the engagement portion 1008 spanning between the
second
inner lead-in 1134A and the second outer lead-in 1134B of the first closure
portion
1010. The engagement portion 1008 of the cover 802 is configured as a locking
lug
integral with the first closure portion 1010.
[0041] The engagement portion 1208 of the second cover 1202 includes an inner
undercut portion 1244A above and integral with an inner lead-in 1234A of the
engagement portion 1208 of the second cover 1202. Likewise, the engagement
portion 1208 of the second cover 1202 includes an outer undercut portion 1244B
above and integral with an outer lead-inl234B at the engagement portion 1208
of the
second cover 1202. A retention bead 1241 of the cngagement portion 1208 of the
second cover 1204 is integral with and spans between the inner lead-in1234A
and the
outer lead-in 1234B of the engagement portion 1208 of the second cover 1204.
[0042] The engagement portion 1208 of the second cover 1202 is adapted to
cooperate with the first closure portion 1010 of the cover 802 to lockingly
engage the
second cover 1202 with the cover 802. Thus, the configuration of the
engagement
portion 1208 of the second cover 1202 mimics a part of the second closure
portion
912 of the base 804 (Figure 11C). More particularly, the inner undercut
portion
1244A and outer undercut portion 1244B of the engagement portion 1208 of the
second cover 1202 correspond to inner sealing wall 1130, and outer sealing
wall
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1132, respectively, of the second closure portion 912 of the base 804 (see
Figures 11B
and 11 C).
[0043] To lockingly engage the second cover 1202 with the cover 802, the first
sealing portion 1010 of the cover 802 is aligned above the engagement portion
1208
of the second, cover 1202 as shown in Figure 12A. In a manner similar to that
described above for the first and second closure portions, a user applies a
downward
force on the first cover 802 while the first closure portion of the cover 102
is aligned
above the engagement portion 1208 of the second cover 1202. The first closure
portion 1010 of the cover 802 abuttingly engages the engagement portion 1208
of the
second cover 1202 to lock the second cover 1202 to the cover 802 as shown in
Figure
12B and 12C. More particularly, when lockingly engaged, inner sealing wall
1130
and first inner lead-in 11 33A of the cover 802 engages, respectively, with
inner lead-
in 1234A and inner undercut portion 1244A of the second cover 1202; and outer
sealing wall 1132 and first outer lead-in 1133B of the cover 802 engages,
respectively, with outer lead-in 1234B and outer undercut portion 1244B of the
second cover 1202 to lock the cover 802 with the second cover 1202.
[00441 In a similar manner, a third cover may be locked to the second cover
1202, a
fourth cover may be locked to the third cover and so on to form a stack of
locked
covers. In this embodiment, the stack of locked covers, each with a first
closure
portion and a cooperating engagement portion as described above, may be
unlocked
by pulling upwardly on the tab of the top cover while holding the stack of
lockcd
covers below the top cover and so on until the entire stack of covers is
unlocked. The
untock covers may nest on top of each other in a stack that may be shear de-
nested as
described in related U.S. Provisional Patent Application # 60/655830.
[0045] Figure 13A is a partial side cross-section view similar to Figure 11A
of the
container 800 of Figure 8 having a second cover 1302 locked to the cover 802
of the
base 804 of the container 800. Figure 13B is an outline view of the cross-
section
profile of Figure 13A schematically depicting the seal formed by the cover and
the
base and the locking engagement of the cover and the second cover. As shown in
the
Figures container 800 may be sealed by engaging cover 802 to the base 804 as
CA 02637145 2008-07-14
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d.escribed, above with reference to Figures 11A and 11B while at the same time
a
second cover 1302 is locking engaged with the cover 802 as described above
with
reference to Figures 12A-12C. The engagement portion of the second cover 1302
may engage with the engagement portion of yet a third cover, and so on, to
form a
locked stack of any number of covers above the base 804 of the container 800.
[0046] In the embodiment shown in Figures 8-13B, the engagement portion of the
cover is formed above the first closure portion the cover around the entire
perimeter
edge of the cover. In other embodiments, the engagement portion of the cover
is
formed as one of more discrete segments above the first closure portion of the
cover
that cooperate with the first closure portion of a second cover.
[0047] The covers described above may be constructed with a wall thickness
thinner
than that of its base. The covers may be made from any suitable plastic and
may be
integrally made by any suitable technique, such as thermoforrning. Tn one
embodiment, the covers may be formed from polypropylene. Due to the
thermoforming process, the wall thickness of the covers may vary. Thinner
covers
reduce material costs and increase flexibility to more easily accommodate
their
removal from, and engagement with, their bases. The covers may maintain
adequate
flexibility for proper sealing even during typical freezer temperatures.
[0048] The covers may be sufficiently flexible to allow a user to create a
vacuum in
containers upon sealing. In order to create a vacuum, the user could for
example
depress a cover during the closing of the container. A return force imparted
upon the
cover by the resiliency of the material of the cover will urge the cover to
return to its
normal position, thereby creating a vacuum.
[0049] The base may be integrally made from any suitable plastic with
sufficient
thickncss 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 may be made from any suitable plastic and may be made by any
suitable technique, such as co-extrusion, lamination, injection molding,
thermoforming, or overmolding. As is well known in the art, the same forming
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process is typically u.sed to form both the base and. the cover of the
container. In one
embodiment, the base is formed from polypropylene. The wall thickness of the
base
may vary due to the manufacturing process.
[0050] Other embodiments of the engagement portion may include one or more of
the
following features to enable locking 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 points of engagement.
[0051] In some embodiments, the force required. to connect the covers 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 discngagcmcnt. Conversely, it may be beneficial to design the
cngagcmcnt
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 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
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WO 2007/084892 PCT/US2007/060570
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 may 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.
[0052] in accordance with embodiments of the present invention, the container
may
be reusable, but it may also be constructed cheaply enough that consumers see
it as a
disposable item, with replacement covers and bases available separately for
retail sale.
The base and the cover may be fabricated by thennoforming a plastic such as
clarified
polypropylene homopolymer material. In another embodiment, the container may
be
fabricated by thermoforming a clarified random copolymer polypropylene
material.
Other plastic materials that would be suitable for fabricating the container
by
thermoforming include opposing 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 may be generally transparent to allow a user
to
view the contents of the container.
[0053] The containcr may include a visual indication of closure between the
cover
and the base. The visual indication may be a color change in the area where
the cover
engages the base. In one embodiment, the first closure portion on the cover
may be a
first color and the second closure portion on the base may be a second color.
When
the closure portions are sealingly engaged, the first and second colors
produce a third
color which is visible to the user to indicate that the container is sealed..
[00541 The container 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. In
addition, the pinching bar may all have a rough exterior to aid in application
of the
pinching force supplied by a user to disengage locked. covers.
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[0055] The container may include a self-venting feature. The pressure in the
sealed.
container may increase when the sealed container and contents are heated in a
microwave oven. Thus, the cover may include a self-venting mechanism that
opens
when the pressure in the container exceeds a predetermined value.
[0056] The container may be divid.ed to separate foods in the container. A
divider
may be integral with the container or may be a separate component. Either the
base
only may include a divider or both the base and the cover may each include a
divider.
The divider located in the cover may only partially engage the divider in the
base so
as to provide splash protection, or it may f-ully engage the divider in the
base to
provide varying degrees of inter-compartmental leak resistance.
[0057] The container may include a strip indicating the temperature of the
container
and its contents.
[0058] The gripping tab may include a relieved portion that provides less
interference
contact with the base during the removal or engagement of the cover while
still
providing an adequate first closure portion to maintain proper sealing of the
container.
The relieved portions of the gripping tab permit venting by allowing a portion
of the
cover to be unsealed from the base while still maintaining a seal around the
remaining
perimeter of the container. Tlus feature is useful in microwave cooking where
the
cover prevents food from splattering onto the inside surface of the microwave
while
still allowing the container to vent. By using the gripping tab, less force is
required to
remove the covcr from the base. This lowcr opcning force also reduces the
possibility
of container failure from stress and fatigue. The lower opening force may
improve
the ability of the user to maintain control over the container components
while
removing the cover from the base and thus to reduce the possibility of
spilling the
contents stored in the container.
[0059] The use of the terms "a," "an," "the," and similar referents in the
context of
describing the invention (especially in the context of the following claims)
are to be
construed to cover both the singular and the plural, unless otherwise
indicated herein
or clearly contradicted by context. Recitation of ranges of values herein are
merely
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intended. to serve as a shorthand method of referring ind.ivid.ually 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 may be performed in 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.
[0060] While the invention is described herein in connection with certain
preferred
embodiments, there is no intent to limit the present invention to those
embodiments.
On the contrary, it is recognized that various changes and modifications to
the
described embodiments will be apparent to those skilled in the art upon
reading the
foregoing description, and that such changes and modifications may be made
without
departing from the spirit and scope of the present invention. Skilled artisans
may
employ such variations as appropriate, and the invention may be practiced
otherwise
than as specifically described herein. Accordingly, the intent is to cover all
alternatives, modifications, and equivalents included within the spirit and
scope of the
invention. 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.
