U.S. patent application number 11/923275 was filed with the patent office on 2008-02-21 for container.
Invention is credited to Yashodhan Dhuru, Ares Marasligiller, Jason Phillips, Lawerence John Racana, Anand Ramanujam, Gordon D. Thomas, Edward B. Tucker, Scott Zieker.
Application Number | 20080041850 11/923275 |
Document ID | / |
Family ID | 38086381 |
Filed Date | 2008-02-21 |
United States Patent
Application |
20080041850 |
Kind Code |
A1 |
Tucker; Edward B. ; et
al. |
February 21, 2008 |
Container
Abstract
The container covers stack together in two different ways.
First, the covers can be stacked into an "aligned" stack. The
aligned stack provides structural rigidity for bulk handling during
manufacturing. Second, the covers can be stacked into a "locked"
stack. The locked stack provides even more structural rigidity than
does the aligned stack and is useful when storing unused covers.
The container cover includes a first closure portion, an engagement
portion, and an alignment portion. The base includes a second
closure portion. The first closure portion of the cover is
sealingly engageable with the second closure portion of the base to
define a sealed storage area. 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 the engagement portion of a second cover to form a
locked cover stack.
Inventors: |
Tucker; Edward B.;
(Yorkville, IL) ; Ramanujam; Anand; (Arlington
Heights, IL) ; Racana; Lawerence John; (Willowbrook,
IL) ; Marasligiller; Ares; (Cincinnati, OH) ;
Phillips; Jason; (Cincinnati, OH) ; Dhuru;
Yashodhan; (Cincinnati, OH) ; Thomas; Gordon D.;
(Mason, OH) ; Zieker; Scott; (Cincinnati,
OH) |
Correspondence
Address: |
THE CLOROX COMPANY
P.O. BOX 24305
OAKLAND
CA
94623-1305
US
|
Family ID: |
38086381 |
Appl. No.: |
11/923275 |
Filed: |
October 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11559527 |
Nov 14, 2006 |
|
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|
11923275 |
Oct 24, 2007 |
|
|
|
PCT/US06/06263 |
Feb 22, 2006 |
|
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11559527 |
Nov 14, 2006 |
|
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|
60655830 |
Feb 23, 2005 |
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Current U.S.
Class: |
220/212 ;
220/254.7; 220/326 |
Current CPC
Class: |
B65D 2543/00027
20130101; B65D 21/0222 20130101; B65D 21/0223 20130101; B65D
21/0219 20130101 |
Class at
Publication: |
220/212 ;
220/254.7; 220/326 |
International
Class: |
B65D 51/00 20060101
B65D051/00 |
Claims
1. A container comprising: a first cover comprising a first closure
portion, an engagement portion, and an alignment portion, the first
closure portion being sealingly engageable with a second closure
portion of a base so that when the first and second closure
portions are engaged with each other, the first cover and the base
define a substantially sealed storage area, the engagement portion
being engageable with the engagement portion of a second cover, and
the alignment portion being engageable with the alignment portion
of the second cover; and the base comprising a bottom, a peripheral
sidewall extending from the bottom, an open top, and the second
closure portion.
2. The container of claim 1 wherein the first cover and the base
comprise thermoformed plastic.
3. The container of claim 1 wherein the first and second closure
portions comprise locking rings, the locking rings of the first and
second closure portions each comprising an inner wall, a retention
bead, and an outer wall.
4. The container of claim 1 wherein the first closure portion of
the first cover is engageable with the first closure portion of the
second cover.
5. The container of claim 1 wherein the engagement portion
comprises a rib and a detent groove and wherein the rib of the
engagement portion of the first cover is engageable with the detent
groove of the engagement portion of the second cover.
6. The container of claim 1 wherein the first cover comprises a
gripping tab.
7. The container of claim 1 wherein the bottom, peripheral
sidewall, and open top of the base define a cavity and wherein the
base is partially insertable into the cavity of a second base.
8. The container of claim 1 wherein the alignment portion of the
first cover comprises an element selected from the set consisting
of: a flange, a protrusion, and a locking ring.
9. The container of claim 1 wherein the alignment portion of the
first cover is located on the first closure portion.
10. The container of claim 1 wherein the alignment portion of the
first cover is located on the engagement portion.
11. The container of claim 1 wherein the alignment portion of the
first cover is engageable with a second alignment portion of the
base.
12. A first cover for a container, the first cover comprising: a
first closure portion; an engagement portion; and an alignment
portion, wherein the first closure portion is sealingly engageable
with a second closure portion of a base so that when the first and
second closure portions are engaged with each other, the first
cover and the base define a substantially sealed storage area,
wherein the engagement portion is engageable with the engagement
portion of a second cover, and wherein the alignment portion is
engageable with the alignment portion of the second cover.
13. The first cover of claim 12 wherein the first cover comprises
thermoformed plastic.
14. The first cover of claim 12 wherein the first closure portion
comprises a locking ring, the locking ring of the first closure
portion comprising an inner wall, a retention bead, and an outer
wall.
15. The first cover of claim 12 wherein the first closure portion
of the first cover is engageable with the first closure portion of
the second cover.
16. The first cover of claim 12 wherein the engagement portion
comprises a rib and a detent groove and wherein the rib of the
engagement portion of the first cover is engageable with the detent
groove of the engagement portion of the second cover.
17. The first cover of claim 12 wherein the first cover comprises a
gripping tab.
18. The first cover of claim 12 wherein the alignment portion of
the first cover comprises an element selected from the set
consisting of: a flange, a protrusion, and a locking ring.
19. The first cover of claim 12 wherein the alignment portion of
the first cover is located on the first closure portion.
20. The first cover of claim 12 wherein the alignment portion of
the first cover is located on the engagement portion.
21. The first cover of claim 12 wherein the alignment portion of
the first cover is engageable with a second alignment portion of
the base.
22. A system of container covers, the system comprising: a first
cover comprising a first closure portion, an engagement portion,
and an alignment portion, wherein the first closure portion is
sealingly engageable with a second closure portion of a base so
that when the first and second closure portions are engaged with
each other, the first cover and the base define a substantially
sealed storage area, and wherein the engagement portion is
engageable with the engagement portion of a second cover; and a
second cover comprising a first closure portion, an engagement
portion, and an alignment portion, wherein the alignment portion of
the first cover is engageable with the alignment portion of the
second cover.
23. The system of claim 22 wherein the first cover and the second
cover each comprises thermoformed plastic.
24. The system of claim 22 wherein the first closure portion
comprises a locking ring, the locking ring of the first closure
portion comprising an inner wall, a retention bead, and an outer
wall.
25. The system of claim 22 wherein the first closure portion of the
first cover is engageable with the first closure portion of the
second cover.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 11/559,527, filed Nov. 14, 2006, which is a continuation in
part of International Application No, PCT/US 06/06263, filed Feb.
22, 2006, which claims benefit of U.S. Provisional Application No.
60/655,830, filed Feb. 23, 2005.
FIELD OF THE INVENTION
[0002] The present invention relates generally to containers, and,
more particularly, to containers whose covers align together when
stacked in a first position and which can be locked together in a
second position.
BACKGROUND OF THE INVENTION
[0003] 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 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.
[0004] During large-scale 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.
[0005] The present invention has as a general aim to provide
containers that satisfy both users and manufacturers.
SUMMARY OF THE INVENTION
[0006] In view of the foregoing, the present invention provides
containers whose covers can be stacked together in two different
ways. First, the covers can be stacked into an "aligned" stack. The
aligned stack provides enough structural rigidity for bulk handling
during manufacturing. Second, the covers can be stacked into a
"locked" stack. The locked stack provides even more structural
rigidity than does the aligned stack and is useful when storing
unused covers.
[0007] In some embodiments, the container cover includes a first
closure portion, an engagement portion, and an alignment portion.
The base includes a second closure portion. The first closure
portion of the cover is sealingly engageable with the second
closure portion of the base to define a substantially sealed,
leak-proof, and re-sealable storage area for items such as food.
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 the engagement
portion of a second cover to form a locked cover stack.
[0008] The covers and bases can be economically constructed from
relatively thin-gauge plastic so that the user can 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
can be readily manufactured, for example, with conventional
thermoforming equipment. The cover can be made from a
semi-transparent material to ensure satisfactory visibility of the
container's contents. The container can be suitable for
refrigerator, freezer, microwave, and machine dishwasher use.
[0009] 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
[0010] FIG. 1 is an isometric view of a container with a cover and
a base according to an embodiment of the present invention;
[0011] FIG. 2 is an isometric view of the container cover of FIG.
1;
[0012] FIG. 3 is a top plan view of the container cover of FIG.
1;
[0013] FIG. 4 is an isometric view of the container base of FIG.
1;
[0014] FIG. 5 is a top plan view of the container base of FIG.
1;
[0015] FIG. 6 is a side sectional view of the container of FIG.
1;
[0016] FIG. 7 is an enlarged, detail view of a portion of FIG.
6;
[0017] FIG. 8 is side sectional view of another embodiment of the
container shown in FIG. 7;
[0018] FIG. 9 is a side sectional view of another embodiment of the
container shown in FIG. 7;
[0019] FIG. 10 is a side sectional view of a stack of two sealed
containers;
[0020] FIG. 11 is a side sectional view of a stack of two nested
container bases with two locked container covers;
[0021] FIG. 12 is a side sectional view of another embodiment of
the stack of FIG. 11;
[0022] FIG. 13 is a side sectional view of a stack of two nested
container bases with one locked container cover and with one
aligned cover;
[0023] FIG. 14 is a side sectional view of another embodiment of
the stack of FIG. 13;
[0024] FIG. 15 is a side sectional view of an aligned stack of a
container cover and a base;
[0025] FIG. 16 is a side sectional view of a stack of two nested
container bases with two aligned container covers;
[0026] FIG. 17 is a side sectional view of a stack of two nested
container bases with one aligned container cover and with one
locked container cover;
[0027] FIG. 18 is a side sectional view of a locked stack of two
container covers;
[0028] FIG. 19 is an enlarged, detail view of a portion of FIG.
18;
[0029] FIG. 20 is a side sectional view of an aligned stack of two
container covers;
[0030] FIG. 21 is an enlarged, detail view of a portion of FIG.
20;
[0031] FIG. 22 is a process flow diagram of an exemplary
manufacturing process for making containers according to the
present invention; and
[0032] FIG. 23 is a process flow diagram of another exemplary
manufacturing process for making containers according to the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Turning to the drawings, wherein like reference numerals
refer to like elements, a first embodiment of the present invention
is illustrated in FIGS. 1 through 5. A container 100 includes a
flexible cover 102 sealingly engaged to a base 104. In the example
of FIGS. 1 through 5, 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
rectangular, circular, or elliptical.
[0034] The container cover 102 can include at least one gripping
tab 106 to facilitate removal of the cover 102 from the container
base 104. In some embodiments, the gripping tab 106 includes one or
more cross-ribs or a textured surface to improve a user's grip on
the tab 106.
[0035] The container cover 102 illustrated in FIGS. 2 and 3
includes an engagement portion 200 that allows the cover 102 to
engage with the engagement portion 200 of a second cover 102 to
form a locked stack of covers 102. This locking feature makes the
resultant stack of covers more structurally rigid and thus less
precarious than a traditional, non-interlocked, stack of
covers.
[0036] The engagement portion 200 of FIGS. 2 and 3 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 200 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. The engagement portion 200 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 where rotation
is defined about an axis normal to the point 302 at which midlines
304 and 306 of the cover 102 intersect as shown in FIG. 3. 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.
[0037] The container cover 102 may have a central field 300, shown
in FIG. 3 on the top of the engagement portion 200. The central
field 300 may include an embossed symbol such as a manufacturer's
mark or may allow a user to attach a label or to write information,
such as the date or user's name. When the central field 300
includes a writeable area, that area could be of an opaque color
which would receive a contrasting color from a writing instrument.
The writeable area could be incorporated into the material for the
container cover 102 or could be applied to that material by
printing.
[0038] The container cover 102 of FIGS. 1 through 3 can be
constructed with a wall thickness thinner than that of a container
base 104. The cover 102 can be made from any suitable plastic and
can be made by any suitable technique, such as thermoforming. In
one embodiment, the cover 102 can be formed from polypropylene. Due
to the thermoforming process, the wall thickness of the cover 102
can vary. A thinner container cover 102 reduces material costs and
increases flexibility to more easily accommodate its removal from,
and engagement with, a container base 104. The cover 102 can
maintain adequate flexibility for proper sealing even during
typical freezer temperatures.
[0039] The container base 104 of FIGS. 4 and 5 includes a bottom
400 and a sidewall 402 extending from the periphery of the bottom
400. The bottom 400 includes a raised lower section 404 to
accommodate the engagement portion 200 of a container cover 102
when containers 100 are stacked together. This feature is further
discussed and illustrated below. Just as the engagement portion 200
of FIG. 3 can include a central field 300, a similar field for a
manufacturer's mark or for user information could be included in
the raised portion 404 of the base 104.
[0040] The container base 104 of FIGS. 1, 4, and 5 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, thermoforming, or
overmolding. In one embodiment, the container base 104 is formed
from polypropylene. The wall thickness of the container base 104
can vary due to the manufacturing process.
[0041] FIGS. 6 through 9 present embodiments of a container 100
whose cover 102 is sealingly engaged with its base 104. FIG. 6
shows the cover 102 cooperating with the base 104 to define a
sealed storage compartment 600. The cover 102 can be sufficiently
flexible to allow a user to create a vacuum in the container 100
upon sealing. In order to create a vacuum, the user could, for
example, depress the cover 102 during the closing of the container
100. A return force imparted upon the cover 102 by the resiliency
of the material of the cover 102 will urge the cover 102 to return
to its normal position, thereby creating a vacuum. To facilitate
convenient sealing engagement of the cover 102 with its base 104,
the users can, at their discretion, apply downward force to only
the engagement portion 200 of the container cover 102. The
engagement portion 200 is located to accept and distribute the
force to the first closure portion 700 of the cover 102 during
sealing to the base 104. The engagement portion 200 may also act as
a convenient handle for grasping the cover 102.
[0042] In the embodiments of FIGS. 6 through 9, the container 100
uses a locking rim design that includes both inside and outside
seals as will be described. The present invention can be embodied
with a variety of closure designs including outer closures and/or
inner closures.
[0043] FIG. 7 depicts an embodiment of the closure portions used to
engage the cover 102 with the base 104 of the container 100. The
cover 102 includes a first closure portion 700 in the form of a
raised locking ring. The first closure portion 700 of the cover 102
can be engaged with a second closure portion 702 of the base 104 to
provide a leak-resistant, re-sealable closure.
[0044] The first closure portion 700 includes an inner wall 704, a
retention bead 706, and an outer wall 708. The inner wall 704, the
retention bead 706, and the outer wall 708 define a first sealing
surface, which is part of the lower surface of the cover 102. The
first closure portion 700 can include one or more locking ridges
710. The outer wall 708 extends between the retention bead 706 and
a flange 712. The flange 712 can provide a convenient gripping
surface to facilitate the removal of the cover 102 from the base
104.
[0045] As illustrated in FIG. 7, the second closure portion 702 of
the base 104 is a raised locking ring that extends from an upper
edge of the sidewall of the base 104. The second closure portion
702 includes an inner wall 714, a retention bead 716, and an outer
wall 718. The inner wall 714, the retention bead 716, and the outer
wall 718 define a second sealing surface, which is part of the
upper surface of the base 104. The second closure portion 702 can
include one or more locking ridges 720. The outer wall 718 extends
between the retention bead 716 and a flange 722. The flange 722 can
provide a convenient gripping surface to facilitate the removal of
the cover 102 from the base 104.
[0046] The first and second closure portions 700 and 702 can be
configured to be slightly different in size to form an interference
fit therebetween. The interference fit between the first and second
closure portions 700 and 702 can provide a sealing engagement
between the closure portions. As a result, when the two pieces are
engaged, a positive seal can be formed between the first and second
sealing surfaces around the perimeters of the base 104 and of the
cover 102.
[0047] The engagement of the first and second closure portions 700
and 702 can be accompanied by an audible "snap" indicating that the
container is securely closed.
[0048] In the example of FIG. 7, the inner wall 704 of the first
closure portion 700 of the cover 102 extends to the engagement
portion 200. This engagement portion 200 includes an upper
protrusion 724 and a lower protrusion 726.
[0049] In the embodiment of FIG. 7, the cover 102 includes a ridge
728 on the outer wall 708 of the first closure portion 700. FIG. 8
presents another embodiment without this ridge. In general, the
first and second closure portions 700 and 702 and the engagement
portion 200 shown in FIGS. 6 through 9 are examples only, and many
other types of closure and engagement portions could be used with
the present invention. For example, the engagement portion 200
could include complementary locking rings. As these and many other
types of closure and engagement portions are well known in the art,
they need not be discussed at length here.
[0050] FIG. 9 shows another embodiment of the cover. The cover 102
of FIG. 9 includes an alignment ridge 900 located on the outer wall
708 of the first closure portion 700. This alignment ridge 900 is
discussed in detail below.
[0051] In FIG. 10, the sealed container 100 rests on top of a
second sealed container 1000. The raised lower section 404 of the
base 104 of the upper container 100 accommodates the engagement
portion 200 of the cover 1002 of the lower container 1000.
[0052] FIGS. 11 and 12 show the utility of an embodiment of the
invention when the containers are in storage. In the Figures, a
stack of two nested container bases 104 and 1100 is joined to a
locked stack of covers 102 and 1102. The lower cover 102 is
sealingly engaged with the upper base 104 to form a structurally
rigid stack.
[0053] In the embodiment of FIGS. 11 and 12, the two covers 102 and
1102 are locked together by their engagement portions 200. As
described in relation to FIG. 7, the engagement portions 200 can
each include an upper protrusion 724 and a lower protrusion 726.
Each protrusion 724, 726 is convex on one side and concave on the
other. The lower protrusion 726 of the upper cover 1102 fits over
and receives the upper protrusion 724 of the lower cover 102, thus
locking the covers 102 and 1102 together. In this manner, the
covers 102 and 1102 are held together and form a structurally
stable cover stack. 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 portion or discretely segmented
about the engagement portion. 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 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
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.
[0054] The container bases 104 and 1100 are shown nested in FIGS.
11 and 12 but are not locked together. In many applications,
nesting the container bases without locking them together provides
sufficient structural rigidity to a stack of bases. It is possible,
however, to apply the techniques of the present invention to the
bases themselves and to thus provide a mechanism for locking the
bases together. The same types of closure and engagement portions
available for locking the covers together or for locking the covers
to the bases can be adapted to locking the bases together.
[0055] The container covers 102 and 1102 of FIG. 11 include the
ridge 728 described in relation to FIG. 7, while the covers in FIG.
12 do not include this feature. The ridge 728 provides a
rigidifying function to the outer wall 708 and also provides a
retaining ledge to assist de-nesting of covers during
manufacture.
[0056] FIGS. 13 and 14 present another position for the stack of
covers in FIGS. 11 and 12. The container bases 104 and 1100 are
nested together and the lower cover 102 is locked onto the upper
base 104. However, the upper cover 1102 is not locked to the lower
cover 102. Instead, the upper cover 1102 is resting on, and aligned
with, the lower cover 102. In this configuration, the two covers
102 and 1102 are said to form an "aligned" stack to distinguish it
from the locked stack of FIGS. 11 and 12. The ability to form an
aligned, but not locked, stack is important in manufacturing
because it allows the covers to be transported in bulk before being
separated out for individual packaging. The aligned stack is stable
enough to resist the vertical, lateral, or rotational movements
caused by forces typically encountered during manufacturing
operations, but the covers are not so strongly connected that they
hinder de-nesting when necessary.
[0057] The tab 106 (see FIG. 1) can be designed so that the tabs
nest in an interdigitating fashion when in a stack of covers so
that the covers are kept in an aligned configuration. In one
embodiment, the design of the tab 106 permits stable cover-to-cover
stacking in the immediate vicinity of the tab 106 in the locked
state, such that a portion of the tab 106 comes to rest on a
portion of the cover below it in the stack to provide resistance to
further stack compression.
[0058] In the embodiment of FIG. 13, the covers 102 and 1102 align
by touching in two areas. First, the engagement portions 200 of the
covers 102 and 1102 each includes a lower shoulder 1300 and an
upper shoulder 1302. The lower shoulder 1300 of the upper cover
1102 rests on the upper shoulder 1302 of the lower cover 102.
Second, the flange 712 of the upper cover 1102 rests on the outer
wall 708 of the lower cover 102. These two contact areas serve to
align the covers 102 and 1102 into a stack less structurally rigid
than a locked stack, but sufficiently rigid for many purposes.
Comparing FIGS. 11 and 13 shows how an aligned stack can be
converted into a locked and rotationally aligned stack by an
application of pressure upon the stacked items. FIG. 11 shows that
when force is applied to the aligned stack of FIG. 13 to create a
locked stack, the flange 712 of the upper cover 1102 is pushed
farther down the outer wall 708 of the lower cover 102. Cover
alignment is further rigidified by the touching of covers 102 and
1102 at the inside wall of the closure portions. In the embodiment
of FIG. 11, the cover inner wall 704 includes an upper shoulder
1104 located just above the uppermost locking ridge 710 and a lower
shoulder 1106 located just below the lowermost locking ridge 710.
Thus, in this pair of locked covers, the lower shoulder 1106 of the
cover 1102 rests on the upper shoulder 1104 of the cover 102.
Considering both FIGS. 11 and 13, the flange 712 that creates an
aligned condition can be continuous along the perimetric path of
the first closure portion 700 or discreetly segmented along the
perimetric path of the first closure portion 700. Considering FIG.
12, the contacting shoulders 1104 and 1106 of the inside wall 704
that create an aligned condition between locked covers can be
continuous along the perimetric path of the first closure portion
700 or discreetly segmented along the perimetric path of the first
closure portion 700. In some embodiments, this alignment feature
may be desirable to ensure that the connected covers are aligned
rotationally about an axis normal to the center of the covers,
especially when the covers include engagement portions that permit
rotation between the covers. In some embodiments, if the alignment
feature were absent, then the covers would be free to rotate. Free
rotation could have undesirable consequences because the cover
stack may be inadequately organized to facilitate manufacturing or
may inadequately provide an organizational benefit to the user.
[0059] The embodiment of FIG. 14 differs from that of FIG. 13 in
that the flange 712 of the upper cover 1102 does not come down far
enough to touch the lower cover 102 when the covers 102 and 1102
are in an aligned stack. Variations such as those between the
embodiments of FIGS. 13 and 14 can be chosen to alter the amount of
rigidity present in an aligned stack. Even though the flange 712 of
the upper cover 1102 does not come down far enough to touch the
lower cover 102 in this less rigid aligned stack, the contact
between the lower shoulder 1300 of the engagement portion 200 of
the upper cover 1102 and the upper shoulder 1302 of the lower cover
102 can provide concentric or rotational alignment to assist the
user in aligning the engagement portions 200 during the process of
connecting covers. Comparing FIGS. 12 and 14 shows how an aligned
stack can be converted into a locked and rotationally aligned stack
by an application of pressure upon the stacked items. FIG. 12 shows
that when force is applied to the aligned stack of FIG. 14 to
create a locked stack, the cover alignment is further rigidified by
the touching of covers 102 and 1102 in two areas. First, the flange
712 of the upper cover 1102 rests on the outer wall 708 of the
lower cover 102. Second, the lower shoulder 1106 of the upper cover
1102 rests on the upper shoulder 1104 of the lower cover 102. In
some embodiments, this alignment feature may be desirable to ensure
that the connected covers are aligned rotationally about an axis
normal to the center of the covers, especially when the covers may
include engagement portions that permit rotation between the
covers.
[0060] FIG. 15 shows that a container cover 102 can be aligned,
without locking, onto the top of a container base 104. FIG. 16
shows an aligned stack of two covers 102 and 1102 on top of a
nested stack of bases 104 and 1100. FIG. 17 differs from FIG. 16 in
that the upper cover 1102 is locked onto the lower cover 102.
Comparing FIGS. 16 and 17 shows how an aligned stack can be
converted into a locked stack by an application of pressure upon
the stacked items.
[0061] FIG. 16 also shows another embodiment of the alignment
portion of the container covers 102 and 1102. An alignment ridge
900 is located on the outer wall 708 of the covers 102 and 1102.
When in an aligned stack, the flange 712 of the upper cover 1102
rests on the alignment ridge 900 of the lower cover 102 increasing
the rigidity of the stack. FIG. 17 shows that when pressure is
applied to the aligned stack to create a locked stack, the flange
712 of the upper cover 1102 is pushed past the alignment ridge 900
of the lower cover 102.
[0062] FIGS. 18 and 19 emphasize the compactness of a locked stack
of container covers 102 and 1102, while FIGS. 20 and 21 emphasize
the compactness of an aligned stack of container covers. While the
aligned stack is not quite as compact as the locked stack, the
compactness of either stack is a significant benefit of the present
invention when covers are stored for future use.
[0063] A high-level abstraction of an exemplary manufacturing
process usable for making containers according to the present
invention is shown in FIG. 22. Extruded sheets of plastic (step
2200) are thermoformed into rough bases (step 2202). The extra
plastic is trimmed from the rough bases (step 2204), and the
completed bases are then nested into a stack (step 2206) for
further handling.
[0064] In parallel with the above steps, covers are made in a
similar process (steps 2212 through 2218). In steps 2216 and 2218,
the completed covers need not be locked together because an aligned
cover stack is sufficiently rigid for bulk handing.
[0065] For packaging the completed bases and covers, an appropriate
number of bases (steps 2208 and 2210) and covers (steps 2220 and
2222) are removed from their respective stacks. The bases and
covers are stacked and combined with packaging materials (steps
2224 through 2228) to create an individual retail unit 2230 (which
may include a number of bases and covers). The individual retail
units are then packed together in bulk (step 2232) for shipment to
retail outlets.
[0066] FIG. 23 presents a variation on the manufacturing process of
FIG. 22. In the embodiment of FIG. 23, the bases are processed
through the same steps 2200 through 2210. However, in step 2316 of
FIG. 23, the covers are locked together in a stack rather than
forming the aligned stack of FIG. 22's step 2216. In some
manufacturing environments, increased structural rigidity makes the
locked cover stack more appropriate than the aligned cover stack.
The locked stack of covers is processed through steps 2318, 2220,
and 2322. In step 2224 of FIG. 23, an appropriate number of locked
covers are combined with bases and packaging materials to create an
individual retail unit 2330.
[0067] The container can be reusable, but it can 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 can be fabricated by
thermoforming a clarified polypropylene homopolymer material. In
another embodiment, the container may be fabricated by
thermoforming a clarified random copolymer polypropylene material.
Other plastic materials which would be suitable for fabricating the
container by 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.
[0068] The container may include a visual indication of closure
between the container cover and the container base. The visual
indication may be a color change in the area where the cover
engages the base. In one embodiment, the closure portion on the
cover may be a first color and the closure portion on the base 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 is sealed.
[0069] 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.
[0070] 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
container cover may include a self-venting mechanism which opens
when the pressure in the container exceeds a predetermined
value.
[0071] The container may be divided 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 fully engage the
divider in the base to provide varying degrees of
inter-compartmental leak resistance.
[0072] The container may include a strip indicating the temperature
of the container and its contents.
[0073] The gripping tab can 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
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.
This 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 cover from the
base. This lower opening force also reduces the possibility of
container failure from stress and fatigue. The lower opening force
can 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.
[0074] 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 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
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.
[0075] 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.
* * * * *