Note: Descriptions are shown in the official language in which they were submitted.
CA 02425353 2006-03-07
PLATE CONTAINER WITH DETACHABLE COVER
FIELD OF THE INVENTION
[0002) This invention pertains to sealing containers, and more particularly to
a plate
container with a detachable cover.
BACKGROUND OF THE fNVENTION
[00031 Rigid thermoplastic food containers may be classified into two distinct
categories. The first category of container is the containers that the
consumer acquires
during the purchase of dairy or deli foods at a retail store. This type of
container is often
referred to as an "inexpensive" container since usually the consumer's
intention is to
purchase the food in the container irrespective of the type of container.
Since the consumer
pays the retail price necessary to purchase the food, they often think of the
container as an
inexpensive item which they may save for re-use at a later date.
(0004] With respect to this first type of container, a group includes the
inexpensive
convenience containers which consumers frequently acquire when purchasing deli
foods.
Generally, these "deli" containers need only to perform the function of
providing a highly
visible display and to provide containrnent of solid foods, such as, bakery
items, salads or
fruit at refrigeration temperature to ambient temperature. Often, the material
of choice is a
high clarity grade of APET (amorphous polyethylene terephthalate) or PS
(polystyrene) and
the containers are manufactured into many shapes by a thermofonning process so
as to
provide wall thicknesses of about 0.0 10-0.020 inches. This wall thickness
range represents
the low end of wall thicknesses generally seen in rigid thermoplastic food
containers and as
a consequence the containers can be made very inexpensively. Thus, the
consumer may
deem the container disposable, i.e. discardable without significant monetary
loss that can be
attributed to the cost of acquiring the container. In addition, the weight to
volume ratio (i.e.
the weight of the container over the volume of the container) of these
containers is
approximately 33.8 - 37.2 grams/liter for the total of the top and bottom of
the container.
[0005) Since these deli containers have no elevated temperature requirements
and thus
can be formed from APET or PS, their low heat distortion temperature makes
them highly
unsuitable for microwave cooking applications. Furthermore, because the
containers are not
designed to provide a secure seal for liquid foods, the containers may leak if
inverted while
CA 02425353 2003-04-14
:et No. 492.402
2
attempting to contain such foods during re-use by the consumer. Also, because
the
materials of construction are generally brittle, these containers will
generally crack if
stressed mechanically and thus are not very durable.
[0006] "Dairy" containers also represent another group of thermoplastic
containers that
can be characterized as "inexpensive." These containers are designed to hold
butters, fresh
and processed cheeses, yogurts, and ready-serve sauces at retail. Often a food
producer fills
these containers while the food contents are hot enough to flow freely into
the container. In
these cases, the materials of choice for such containers are generally PP
(polypropylene) or
HDPE (high density polyethylene) owing to their elevated temperature
performance
characteristics. The container bottoms are manufactured by an injection
molding or
thermoforming process. The container bottoms made by injection molding have a
wall
thickness of about 0.020-0.040 inches. The container bottoms made by
thermoforming have
a wall thickness of about 0.010-0.020 inches. Like the "deli" containers, the
"dairy"
containers can be made very inexpensively and as such the consumer may deem
the
container disposable after limited re-use. The weight to volume ratio of the
injection
molded containers is approximately 43.9 - 57.4 grams/liter for the total of
the top and
bottom of the container. The weight to volume ratio of the thermoformed
containers is
approximately 37.2 - 54.1 grams/liter for the total of the top and bottom of
the container.
(0007] Also the dairy containers should prevent moisture loss, oxygen
permeation, and
odor absorption which if not prevented would undesirably alter the food
contents. The food
producer solves these problems by completely enclosing the head space above
the food by
application of a lidding material, such as, foil or thermoplastic barrier film
which is
continuously sealed to the upper lip of the container bottom. The container
generally will
also include a removable rigid thermoplastic lid that is placed over the
continuously sealed
lidding foil or film so that puncture protection is provided. The lid has a
wall thickness of
about 0.010-0.020 inches. The rigid thermoplastic container lid usually
engages the
container bottom so as to provide a crude fit, but it does not have to provide
a secure leak-
proof seal since the lidding material accomplishes this function. Thus when
the consumer
goes to re-use the container, they may find that the container's seal is
unsuitable for rough
transport and handling of liquid foods, since the lidding material has been
peeled off during
consumption of the original contents and only the crude fitting rigid lid
remains.
[0008] The lid is usually made from a softer polyethylene material which often
does not
have the same heat resistance of the container bottom. Thus, when the consumer
goes to re-
use the container, they may find that the lid is easily distorted during
microwave heating.
[0009] Finally, the dairy container materials are usually highly pigmented to
provide
opacity in order to prevent light-induced oxidation of fat-containing dairy
products so as to
extend store shelf life. The consumer may prefer a see-through container which
allows easy
CA 02425353 2003-04-14
et No. 492.402
recognition of food contents during re-use of the container. Thus, dairy
containers would be
unsuitable in this regard.
100101 Although these deli and dairy containers are inexpensive, their lack of
heat
resistance and poor sealing characteristics severally limit their use.
ft10111 For example, many consumers choose to take their lunch to work. While
in
iransit, containers are frequently resting on uneven surfaces or being jostled
from ordinary
movements, and as a result, the contents of an inexpensive container may leak
onto
clothing, upholstery, and/or other food. In addition, the inexpensive
containers may not be
suitable for microwave use, and the food must be removed from the container
and placed on
dishware suitable for microwave cooking before being heated.
10012] The second category of food containers consists of expensive durable
containers
'which may utilize more expensive plastic materials and thick container walls.
These
containers address the shortcomings of the inexpensive containers in that they
may be
suitable for microwave, dishwasher, and freezer use and provide a secure seal
which will
not leak. However, these containers may employ costly materials. In addition,
due to their
sophisticated design elements, these containers generally require heavier
construction to
enable manufacture within the limitations associated with the injection
molding process
from which these containers are made. These containers have wall thicknesses
of about
0.020-0.080 inches. Thus, this second category of containers becomes too
expensive for
disposable use. As a result, a consumer taking his or her lunch to work in an
expensive
durable container must be burdened with also transporting the container from
work to home.
The weight to volume ratio of these containers is approximately 67.6 - 219.6
grarns/liter for
the total of the top and bottom of the container.
[00131 Furthermore, when a food container is used to transport food for
consumption at
another location, for example when a consumer takes his or her lunch to work,
the consumer
is required either to eat the food directly from the container or to make
arrangements for
having a suitable serving dish available at the other location. In the former
case, the
consumer may find the notion of eating the food directly from the container
unappetizing,
thereby reducing the usefulness of the container as a storage device. In the
latter case, the
consumer is subjected to further inconvenience and/or expertse by having to
ensure that a
suitable serving dish is on hand.
SUMMARY OF THE INVENTION
[0014] The invention provides a container that can be readily manufactured,
for
example, with conventional thermoforming equipment. The container includes a
plate-like
container base having a first closure portion and a plate-like cover having a
second closure
CA 02425353 2007-10-23
4
portion. The closure portions of the cover and the base can be engaged with
each other to
provide a leak-proof, re-sealable closure.
(0015] When the first and second closure portions are occluded, the base and
the cover
define a substantially sealed storage area. The closure portions can be
configured to permit
the venting of the container during occlusion of the cover to the base and
microwave re-
heating of food, for example. The cover can include a raised dome to increase
the capacity
of the storage area. Advantageously, the cover can be removed from the base
and inverted
for use as a plate. The cover can include a gripping tab for facilitating the
removal of the
cover from the container base.
[0016] Each closure portion includes a sealing surface, which can be, for
example,
molded during a thermoforming process such that the sealing surface does not
contact the
mold tool surface during manufacture to facilitate the production thereof.
[0017] The present invention provides a reusable, tight sealing container
available to a
consumer at a price appropriate for disposable use. The cover can be made from
a semi-
transparent material to ensure satisfactory visibility of the container
contents. The container
can be suitable for microwave and machine dishwasher use. The closure portions
can be
configured such that the container maintains its sealing characteristics while
in freezer type
temperatures.
[0018] The cover of the container can be stacked in a nested arrangement with
other
covers. The container base can be stacked in a nested arrangement with other
container
bottoms. The cover can be stacked in a nested arrangement with the container
base wherein
the cover is in an inverted position. A first container can be stacked upon a
second
container.
[0019] Advantageously, the container can function to store materials and also
to act as a
plate or as a pair of plates for serving food, for example.
CA 02425353 2007-10-23
4a
Accordingly, in one aspect the present invention resides in a container
comprising:
a base, the base including a substantially planer bottom wall portion and a
side wall
portion extending upwardly and outwardly from the bottom wall portion and
joined to a
peripheral first closure portion;
the first closure portion including a first sealing surface having a first
inner wall, a first
retention bead, and a first outer wall, the first retention bead between the
first inner wall and the
first outer wall having an inner shoulder and an outer shoulder, respectively,
the first inner wall
defining a first inside cut back portion;
a cover, the cover including a second closure portion; the second closure
portion
including a second sealing surface having a second inner wall, a second
retention bead, and a
second outer wall, the second retention bead between second inner wall and the
second outer
wall, the second inner wall defining a second inside cut back portion;
the second closure portion adapted for sealing occlusion with the first
closure portion so
that when the first and second closure portions are engaged with each other,
the first inside cut
back portion engages the second inside cut back portion;
the first closure portion includes a notch, the notch defining an air
passageway during the
occlusion of the closure portions to permit venting of the storage area;
wherein the first and second closure portions cooperate when engaged together
to close
the air passageway to provide a substantially continuous seal between the
cover and the base;
and
wherein the base includes a third shoulder and a pair of nest lugs including a
first inner
nest lug and a second outer nest lug, the third shoulder is disposed between
the first inner nest
lug and the side wall, the nest lugs being disposed in opposing relation to
each other adjacent the
inner and outer walls of the first closure portion, respectively, the first
inner nest lug extends
upwardly and outwardly from the third shoulder at an oblique angle thereto and
merges into the
inner wall, the second outer nest lug extends outwardly and downwardly from
the outer wall, and
CA 02425353 2007-10-23
4b
the nest lugs engageable with the shoulders of a second base when the first
base is stacked upon
the second base.
[0020] Tluse and other features of the present invention will become apparent
to one of
ordinary ski11 in the art upon reading the detailed description, in
conjunction with the
accompanying drawings, provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a top perspective view of a container for food according to
the present
invention.
[0022] FIG. 2 is a front elevational view of the container of FIG. 1.
[0023] FIG. 3 is a right side elevational view of the container of FIG. 1.
[0024] FIG. 4 is a top plan view of the container of FIG. 1.
[0025] FIG. 5 is a bottom plan view of the container of FIG. 1.
[00261 FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 4.
CA 02425353 2003-04-14
DocKet No_ 492.402
100271 FIG. 7 is a top perspective view of a base of the container of FIG. I.
(0028) FIG. 8 is a front elevational view of the base of FIG. 7.
100291 FIG. 9 is a top plan view of the base of FIG. 7.
[0030] FIG. 10 is a bottom plan view of the base of FIG. 7.
[0031] FIG. 1 I is a cross-sectional view taken along line I 1-11 in FIG. 9.
[0032] FIG. 12 is an enlarged, detail view taken from FIG. 11.
[0033] FIG. 13 is a top perspective view of a cover of the container of FIG.
1.
[0034) FIG. 14 is a front elevational view of the cover of FIG. 13.
(0035] FIG. 15 is a right side elevational view of the cover of FIG. 13.
[0036] FIG. 16 is a top plan view of the cover of FIG. 13.
[0037] FIG. 17 is a bottom plan view of the cover of FIG. 13.
[0038] FIG. 18 is a cross-sectional view taken along line 18-18 in FIG. 17.
[0039] FIG. 19 is an enlarged, cross-sectional view taken along line 19-19 in
FIG. 16.
[0040) FIG. 20 is an enlarged, cross-sectional view taken along the line 20-20
in FIG.
16.
[0041) FIG. 21 is a cross-sectional view of the container of FIG. 1, similar
to the views
in FIGS. 11 and 18, showing the cover and the base in an initial occlusion
position.
[0042] FIG. 22 is an enlarged, detail view taken from FIG. 21.
[0043] FIG. 23 is an enlarged, fragmentary, perspective view, in section of
the container
of FIG. 1 showing the cover and the bottom in an initial occluded position.
[00441 FIG. 24 is a cross-sectional view similar to FIG. 21, showing the cover
and the
bottom in an occluded position.
[00451 FIG. 25 is an enlarged, detail view taken from FIG. 24.
[0046] FIG. 26 is an enlarged cross-sectional view of a pair of bases, as in
FIG. 12,
illustrating the bottoms in a nested configuration.
[0047] FIG. 27 is an enlarged, fragmentary, cross-sectional view of a pair of
covers,
similar to FIG. 18, illustrating the covers in a nested configuration.
[0048) FIG. 28 is a fragmentary, enlarged cross-sectional view of a base and a
cover
similar to the views shown in FIGS. 26 and 27, showing the base and the cover
in a nested
configuration.
[0049] FIG. 29 is an enlarged, fragmentary, cross-sectional view similar to
FIG. 27
except that the bottom is stacked upon the cover.
[0050] FIG. 30 is a cross-sectional view similar to FIG. 21, showing another
embodiment of a container.
[0051] FIG. 31 is an enlarged, detail view taken from FIG. 30.
[0052] FIG. 32 is a cross-sectional view similar to FIG. 30, showing the cover
and the
bottom in an occluded position.
CA 02425353 2003-04-14
a i et No. 492.402
6
(0053] FIG. 33 is an enlarged, detail view taken from FIG. 32.
100541 FIG. 34 is a cross-sectional view similar to FIG. 21, showing yet
another
embodiment of a container.
[0055] FIG. 35 is an enlarged, detail view taken from FIG. 34.
100561 FIG. 36 is a cross-sectional view similar to FIG. 34, showing the cover
and the
bottom in an occluded position.
[0057] FIG. 37 is an enlarged, detail view taken from FIG. 36.
[0058] FIG. 38 is a cross-sectional view similar to FIG. 21, showing another
embodiment of the container.
[0059] FIG. 39 is an enlarged, detail view taken from FIG. 38.
[0060] FIG. 40 is a fragmentary, perspective view, in section, of the
container of FIG.
38.
[0061] FIG. 41 is an enlarged, detail view taken from FIG. 40.
[0062] FIG. 42 is a cross-sectional view similar to FIG. 38, showing the cover
and the
bottom in an occluded position.
[0063] FIG. 43 is an enlarged, detail view taken from FIG. 42.
[0064] FIG. 44 is a fragmentary, perspective view, in section, of the
container of FIG.
42.
[0065] FIG. 45 is an enlarged, detail view taken from FIG. 44.
[00661 FIG. 46 is a top plan view of another embodiment of a base suitable for
use with
the cover of FIG. 13.
[0067] FIG. 47 is a partial, cross-sectional view of the container of FIG. 1,
showing the
manufacture thereof.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0068] Turning now to the drawings, there is shown in FIG. 1 an illustrative
container
100 constructed in accordance with the present invention. Referring to FIGS. 1-
6, in this
embodiment, the container 100 includes a flexible plastic base 102 which is
sealingly closed
by a flexible plastic cover 104 to define a storage area 106.
[0069] The base 102 has a plate-like configuration, and the cover 104 has a
similar
shape. The cover 104 can be removed from the base 102 and inverted for use as
a serving
dish. Advantageously, the container 100 can function to store materials and
also to act as a
plate or as a pair of plates for serving food, for example. The cover also
conveniently can
act to prevent splatter of contents during microwave re-heating of food.
[0070] Referring to FIG. 6, the base 102 includes a first closure portion 110
in the form
of a raised locking ring. The cover 104 includes a second closure portion 111
in the form of
a raised locking ring. The first and second closure portions 110, 111 can be
engaged with
CA 02425353 2003-04-14
L et No. 492.402
7
each other to provide a leak-resistant, re-sealable closure to occlude the
base 102 and the
cover 104. The first and second closure portions I 10, 111 can be occluded to
seal the
container 100 by pinching the first and second locking rings between a user's
fingers, for
example. The container can be reusable.
[0071] Referring to FIGS. 7-12, the base 102 is shown. The base 102 is a
relatively
shallow, flat-bottomed receptacle suitable for holding and serving food. The
base 102
includes a generally planar bottom portion 120 and a curved sidewall portion
122 extending
around the bottom. The sidewall 122 is generally curved and extends upwardly
and
outwardly from the periphery of the bottom 120. In other embodiments, the
sidewall 122
may have a constant wall draft or may include a combination of arcs and linear
segments
with or without points of inflection.
[0072] Referring to FIG. 7, the bottom 120 and the sidewall 122 define an
interior
cavity 124. Referring to FIGS. 9 and 10, the bottom 120 is substantially
circular, having a
perimeter 126 in the form of a circumference. In other embodiments, the bottom
120 can
have other shapes, such as, rectangular, for example. The bottom 120 can
include an
embossed area or receive a label, a sticker, or other display means for
bearing indicia. The
base 102 includes a first stacking element 130 in the form of a ring which
coincides with the
circumference 126 of the bottom 120 and extends from an exterior surface 132
of the base
102, as shown in FIG. 12.
[0073] Referring to FIG. 7, the first closure portion I 10 is in the form of a
raised
locking ring that extends around an upper edge 134 of the sidewall 122. The
base 102
includes a flange 140 which extends outwardly from the first closure portion
110, extending
therearound, as also shown in FIGS. 8 and 9.
[0074] Referring to FIG. 12, the base 102 can include a pair of nest lugs 142,
143 which
are disposed in opposing relation to each other, flanking the first closure
portion i 10. The
nest lugs 142, 143 can facilitate the nesting of a plurality of bases to form
a vertical stack
convenient for the commercial handling and packaging thereof.
[0075] The base includes a shoulder 146 which is disposed between the first
nest lug
142 and the upper edge 134 of the sidewall 122. The shoulder 146 is
substantially parallel
to the bottom portion 120 of the base 102. The shoulder 146 can extend around
the entire
sidewall at the upper edge 134. The first nest lug 142 extends from the
shoulder 146 at an
oblique angle thereto. The first nest lug 142 merges into the first closure
portion 110. The
second nest lug 143 can extend outwardly from the first closure portion 110,
extending
between the first closure portion and the flange 140.
[0076] The flange 140 can provide a convenient gripping surface to facilitate
the
occlusion of the cover and the bottom and the removal of the cover from the
bottom. The
flange can further enhance the plate-like appearance of the bottom. The flange
140 can
CA 02425353 2003-04-14
i :et No. 492.402
8
include a raised ring 150 extending from an interior surface 152 of the base
102, as also
shown in FIGS. 7 and 9. The raised ring 150 adds rigidity to the flange 140.
The raised
ring 150 also provides a frictional gripping surface to reduce slippage when
grasping the
flange 140. In other embodiments, rigidifying and gripping structures can be
provided to
the surface of the flange 140 that are continuous or intermittent rib pattems,
or other
decorative shapes.
[00771 Referring to FIG. 12, the first closure portion 110 includes an inner
wall 160, a
retention bead 162, and an outer wall 164. The inner wall 160, the retention
bead 162 and
the outer wall 164 define a first sealing surface 166, which is part of the
interior surface 152
of the base 102. The inner wall 160 extends from the first nest lug 142 and
merges into the
retention bead 162. The retention bead 162 can include a pair of rounded
shoulders 170,
171 and a crown surface 174. The outer wall 164 joins the retention bead 162
and the
second nest lug 143. The inner and outer walls 160, 164 converge toward each
other from
the retention bead 162 toward the first and the second nest lugs 142, 143,
respectively, and
in doing so provide inside and outside cut back portions.
[0078] One of the first and the second closure portions can include at least
one notch
that defines an air passageway between the base and the cover when the closure
portions of
the base and the cover undergo an occlusion sequence. In this embodiment, the
first
rounded shoulder 170 of the retention bead 162 includes a pair of notches 176
and 177, also
shown in FIGS. 7 and 11. For ease of description, only one notch 176 will be
described
herein. It will be understood that the description of the one notch 176 is
applicable to the
other notch 177, as well. The notch 176 can define an air passageway during
the occlusion
of the first and second closure portions to permit venting of the container.
The air
passageway can permit the container to be vented during the occlusion of the
closure
portions for sealing the cover 104 to the base 102. The venting feature can be
advantageous
since it is desirable to expel air upon closing the container to prevent
untoward bulging of
the container by trapped air and to reduce the amount of air in the headspace
of the
container since this air may negatively affect the quality of the stored food
contents. The air
passageway can be sealed to prevent air from passing therethrough when the
closure
portions are fully occluded. A seal can be formed between the first and second
closure
portions such that the container is substantially leak resistant.
[0079] In this embodiment, as shown in FIG. 12, the notch 176 is located at
the first
shoulder 170 adjacent the top of the inner wall 160. The notch 176 is disposed
between the
inner walls 160 and the outer wall 164 of the closure portion 110. The notch
176 is in the
form of a discrete, depression-like channel that extends over at least a
portion of the total
width of the first closure portion 110, measured from the inner wall 160 to
the outer wall
164.
CA 02425353 2003-04-14
D :t No. 492.402
9
[0080] The base 102 has a sufficient thickness to withstand the heat of
microwave
cooking and remain sturdy during lifting while laden with hot food and also
withstand the
heat of top-shelf dishwashing without deforming.
[0081] Referring to FIGS. 13-20, the cover 104 is shown. The cover 104
includes an
interior surface 190 and an exterior surface 191. The cover 104 can include a
raised dome
194 to increase the size of the storage area and/or to allow the user to
create a vacuum in the
container upon sealing. For example, in order to create a vacuum, the user can
depress the
dome during the closing of the container. A return force imparted upon the
dome generated
by the inherent resiliency of the material of the cover will urge: the dome to
return to its
normal position, creating a vacuum.
[0082] Referring to FIG. 13, the dome 194 includes a central, field portion
196 that is
generally circular. In other embodiments, the field portion 196 can be other
shapes, for
example rectangular or elliptical. The central field portion 196 is configured
such that it can
include an embossed area or receive a label, a sticker, or other display means
for bearing
indicia.
[0083] The second closure portion 111 can extend from the exterior surface
191,
extending around a perimeter 198 of the dome. A generally planar flange 200,
also shown
in FIGS. 14 and 15 can extend from the second closure portion 111. A second
stacking
element 210 extends around the periphery of the central field portion 196.
Referring to FIG.
18, the second stacking element 210 extends from the interior surface 190 of
the cover 104
to define a groove 212 in the exterior surface 191.
[0084] Referring to FIG. 19, the cover 104 can include a pair of nest lugs,
216, 217
flanking the second closure portion 111. The nest lugs 216, 217 are disposed
in opposing
relationship to each other and can be configured to allow the nesting of a
plurality of covers
in a vertical stack convenient for the commercial handling and packaging
thereof
[0085] The second closure portion 11 I is similar to the first closure
portion. 'The second
closure portion 111 includes an inner wall 220, a retention bead 222, and an
outer wall 224.
The inner wall 220, the retention bead 222, and the outer wall 224 define a
second sealing
surface 226, which is a part of the interior surface 190 of the cover 104. The
inner wall 220
extends from the first nest lug 216 and merges into the retention bead 222.
The retention
bead 222 can include a pair of shoulders 230, 231 and a crown surface 234. The
outer wall
224 joins the retention bead 222 and the second nest lug 217. The inner and
outer walls
220, 224 converge toward each other from the retention bead 222 toward the
first and the
second nest lugs 216, 217, respectively, and in doing so provide inside and
outside cut back
portions.
CA 02425353 2003-04-14
E ;t No. 492.402
[0086] The second nest lug 217 can extend outwardly from the outer wall 224 of
the
second closure portion 111, extending between the second closure portion 111
and the
flange 200.
[0087] Referring to FIG. 19, to facilitate the manufacture of the cover, the
flange 200
can extend a distance 240 at least equal to one-half of a height 242 of the
second closure
portion I 1 l, measured from the top surface 243 adjacent to the trim edge 244
to the crown
surface 234, to promote proper pilot configuration for a punch-and-die
trimming operation,
for example.
[0088] Referring to FIG. 20, the second closure portion 111 and the raised
dome 194
define a channel 250 therebetween. The channel 250 includes an open mouth 252
and a
closed end 254. The mouth 252 is aligned with the crown surface 234 of the
second closure
portion 111. The channel 250 can have a width 258, measured between the dome
194 and
the second closure portion 111 along the mouth 252. The channel 250 can have a
predetermined depth 260, measured between the open mouth 258 and the closed
end 254.
In one embodiment, the width 258 can be less than twice the depth 260 of the
channel 250.
In other embodiments, the width 258 of the channel 250 can be less than the
depth 260 of
the channel 250.
[0089] The closed end 254 of the channel 250 is substantially parallel to the
field
portion 196 of the cover 104, as shown in FIG. 18. The channel 250 can extend
around the
entire perimeter of the dome 194. The first nest lug 216 extends from the
closed end 254 of
the channel 250 at an oblique angle thereto.
[0090] Referring to FIG. 13, the cover 104 can include at least one gripping
tab adjacent
the second closure portion 111 to facilitate removal of the cover from the
base. The cover
104 includes a pair of gripping tabs 270, 271. The gripping tabs 270, 271 are
disposed in
opposing relationship to each other, extending from the second closure portion
111 and the
flange 200. The gripping tabs 270, 271 are integral with the flange 200.
Referring to FIG.
14, the gripping tabs 270, 271 extend outwardly from the flange 200.
[0091] Referring to FIG. 16, each gripping tab 270, 271 includes a curved
outer edge
274 and a shoulder portion 276 that defines a notch 278. Each gripping tab
270, 271
includes a raised rib 280 that generally conforms to the periphery of the
flange 200. The rib
280 extends outwardly from the second closure portion 111. The rib 280 defines
an
indented portion 284 that is contained within the rib 280. The indented
portion 284 has a
closure portion side 290, an outer side 292, and a shoulder side 294, which,
seen from a top
plan view, substantially correspond to the shape of the second closure portion
111, the outer
edge 274 of the gripping tab, and the shoulder 276 of the gripping tab,
respectively. In
other embodiments, the gripping tabs 270, 271 may have other shapes as seen
from a top
plan view. For example, the shape can be elliptical, oblong, ovate, or dog-
eared, or the
CA 02425353 2003-04-14
1 et No. 492.402
11
shape can be composed of longitudinal edges that are concentric with the shape
of the
cover.
[0092] The rib 280 and indented portion 284 have a reinforcing and stiffening
effect
which provide a means of leverage in separating the cover from the base. The
rib 280 and
the indented portion 284 can further provide a frictional gripping surface to
minimize
slippage when grasping the respective tab 270, 271.
[0093] In other embodiments, the gripping tab may also include one or more
cross-ribs
or a textured surface to improve the grip on the tab.
[0094] Referring to FIG. 20, the tab 271 includes a relieved portion 300
adjacent the
outer wall 224 of the second closure portion 111. As a result, the relieved
portion provides
less interference contact with the base during the removal or engagement of
the cover 104
while still providing an adequate closure portion to maintain proper sealing
of the closure
device. The raised rib 280 defines the relieved portion 300.
[0095] Referring to FIGS. 17 and 20, by extending along the periphery of the
flange
200, the rib 280 of the tab 271 defines an arc-shaped, elongated relieved
portion 300. The
configuration of the rib 280 defines the relieved portion 300 such that it
extends over a
relatively large arc of the second closure portion 111, thereby facilitating
removal of the
cover 104 from the base and providing the cover 104 with an outer periphery
310 that does
not extend outwardly beyond the flange 140 of the base 102 when the cover is
occluded
thereto, as shown in FIG. 4. In other embodiments, the outer periphery 310 of
the cover 104
can extend outwardly beyond the flange 140 of the base 102.
[0096] The relieved portion of the tab permits container venting by allowing a
portion
of the cover 104 to be removed from the base 102 while still maintaining a
seal around the
remaining perimeter of the container. This feature is useful iin microwave
cooking where
the cover 104 prevents food from splattering onto the inside surface of the
microwave while
still allowing the container to vent.
[0097] By utilizing at least one of the tabs, less force is required to remove
the cover
104 from the base 102. The lower opening force also reduces the possibility
for 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
to reduce the possibility of spilling the contents stored in the container
during removal of
the cover from the base.
[0098] In addition, the lower opening force may be beneficial when the
container is
used in a freezer. Some materials which may be used to make the container may
become
brittle at or near freezer temperatures. Consequently, if the container is
removed from the
freezer and immediately opened, the material for the container (and thus the
container) are
subject to the failure if the opening force is too high. Therefore, the lower
opening force
CA 02425353 2003-04-14
~ -t No. 492.402
12
reduces the possibility of failure when the container is removed from the
freezer and
immediately opened.
(0099] Referring to FIG. 20, the gripping tab 271 can be configured such that
the
respective gripping tab extends outwardly from the raised rib 280 a
predetermined distance
320, measured between an outer end 322 of the raised rib 280 and the tool side
trim edge
244. The distance 320 that the gripping tab extends from the rib 280 can be at
least equal to
one-half of a height 326 of the raised rib 280, measured from the top surface
243 adjacent to
the trim edge 244 to a top 330 of the raised rib 280, thereby facilitating
proper pilot design
during a punch-and-die trinuning operation, for example.
(00100] The thinner container cover reduces material costs and increases
flexibility to
more easily acconunodate its removal from, and engagement onto, the base. The
cover 104
can maintain adequate flexibility for proper sealing even during typical
freezer
temperatures. Furthermore, the lack of surface detail on the container
material provides for
easy washing.
[001011 Referring to FIGS. 21-25, an occlusion sequence for the container 100
is shown
wherein the cover 104 is sealingly secured to the base 102. Referring to FIG.
21, the cover
104 is resting upon the base 102 with the second closure portion 111 aligned
with the first
closure portion 110. Referring to FIG. 22, the nest lugs 216, 217 of the
second closure
portion 111 are in respective contact with the shoulders 170, 171 of the first
closure portion
110. The second sealing surface 226 of the second closure portion is disposed
over the first
sealing surface 166 of the first closure portion. Referring to FIG. 23, the
notch 176 adjacent
the inner wall 160 of the first closure portion 110 cooperates with the second
closure portion
111 to define an air passageway 350 for venting the storage ar=ea 106 of the
container 100
during the occlusion of the cover 104 and the base 102.
1001021 Referring to FIG. 21, the container 100 can be closed, for example, by
placing
the base 102 on a supporting surface 352 and placing the cover 104 upon the
base 102. The
cover 104 can be pushed toward the base 102 with the supporting surface 352
holding the
base in place to allow the closure portions 110, 111 to engage each other to
seal the
container 100. To occlude the cover and the base, a sealing force is applied
to the cover 104
in a sealing direction 354 such that the sealing force moves the cover 104 and
the base 102
relatively toward each other. The cover 104 and the base 102 are between the
application of
the sealing force and the supporting surface 352 to overcome the interference
between the
closure portions 110, 111. The cover 104 and the base 102 can be occluded by
aligning the
first closure portion 110 with the second closure portion 111 and applying a
force from
underneath the first closure portion 110 and an oppositely directed force from
above the
second closure portion 111 as would be accomplished by pinching, and then
applying this
force all the way around the closure perimeters so as to completely occlude
the container.
CA 02425353 2003-04-14
Do.._.:t No. 492.402
13
[00103] Referring to FIG. 22, the inner and outer walls 220, 224 of the second
closure
portion 111 deflect away from each other while passing over the shoulders 170,
171 of the
first closure portion 110. Once beyond the shoulders 170, 171 of the base 102,
the inner
and outer walls 220, 224 of the cover 104 move toward each other toward their
normal
position, respectively acting against the inner and outer walls 160, 164 of
the first closure
portion 110 of the base 102. The retracting of the inner and outer walls 220,
224 of the
cover 104 causes the cover 104 to move toward the base 102 until the sealing
surface 226 of
the cover 104 rests against the sealing surface 166 of the base 102, as shown
in FIGS. 22, 24
and 25. In addition, the engagement of the first and second closure portions
110, 111 in an
occluded position can be accompanied by an audible "snap," indicating that the
container is
securely closed.
1001041 In the occluded position, as shown in FIGS. 24 and 25, the inner and
outer walls
220, 224 of the cover 104 can be displaced from their normal position to an
intermediate
engaged position. The inner wall 220 of the cover 104 can exert a force
against the inner
wall 160 of the base 102 to form a seal 353. Referring to FIG. 25, the first
sealing surface
166 of the first closure portion 110 is in sealing engagement with the second
sealing surface
226 of the second closure portion. The first and second closure portions 110,
111 cooperate
when in the occluded position to close the air passageway 350 to provide a
substantially
continuous seal between the cover 104 and the base 102.
1001051 The first and second closure portions 110, 111 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 110, 111 can provide the sealing engagement
between the
closure portions to occlude the cover 104 and the base 102. As a result, when
the two
pieces are engaged, a positive seal can be formed around the inside perimeter
of the
container at the point where the inner wall 160 of the base 102 contacts the
inner wal1220
of the cover 104. In one embodiment, the range of interference fit between the
inner walls
160, 220 is about 0.005 to about 0.020 inches.
[001061 The closure portions can have several other sealing areas when the
cover
engages the base. For example, an interference fit can be accomplished between
the first
and second closure portions 110, 111 to provide the sealing engagement between
the
closure portions to occlude the cover 104 and the base 102 whereby when the
two pieces are
engaged, a positive seal can be formed around the outside perimeter of the
container at the
point where the outer wall 164 of the base 102 contacts the outer wall 224 of
the cover 104.
In one embodiment, the range of interference fit is about 0.005 to about 0.020
inches.
1001071 Referring to FIG. 25, when the first and second closure portions 110,
111 are
sealingly engaged with each other, the flange 140 of the base 102 is closely
adjacent the
flange 200 of the cover 104. The flange 140 of the base can be resiliently
flexible such that
CA 02425353 2003-04-14
D. ::t No. 492.402
14
the flange 140 can be flexed away from the cover 104 in an opening direction
355 to
provide a separation between the flanges 140, 200 for facilitating the removal
of the cover
104 from the base 102.
(00108] Referring to FIGS. 26-29, a plurality of containers, and a plurality
of container
components, can be stacked together. The components of the container can be
nested, and
several containers can be nested together. A plurality of containers can be
stacked
vertically.
[001091 Referring to FIG. 26, a plurality of bases 402, 403 can be stacked
together in a
nested arrangement. When the bases 402, 403 are nested, the nest lugs 142, 143
of the
upper container base 403 rest on the retention bead 162 of the first closure
portion 110 of
the lower container base 402. The nest lugs 142, 143 of the upper container
base 403 are in
respective contact with the shoulders 170, 171 of the retention bead 162 of
the lower
container base 402. The nest lugs 142, 143 of the lower container base 402 are
configured
such that the lower container base 402 can be stacked upon yet another
container base with
the lower container base 402 contacting that container base in the same manner
as the upper
container base 403 contacts the lower container base 402. The inner wall 160
of the lower
container base 402 can be designed to be a predetermined length to maintain an
air space
405 between the sidewall 122 of the lower container base 402 and the sidewall
122 of the
upper container base 403 such that the unintentional interlocking of container
bases 402,
403 is avoided. Each container base 102 can be configured to provide a low
stacking height
when nested together to facilitate packaging and minimize storage space.
[001101 Referring to FIG. 27, a plurality of container covers 504, 505 is
stacked together
in a nested arrangement. When the container covers 504, 505 are stacked
together in a
nested formation, the retention bead 222 of the second closure portion 111 of
the upper
container cover 505 rests upon the nest lugs 216, 217 of the lower container
cover 504. The
portions of the container covers 504, 505 in contact with each other prevent
the container
covers 504, 505 from interlocking as well as provide support for retaining the
nested stack
in a secure position. The inner wall 220 of the lower container cover 504 can
be configured
to be a predetermined length to maintain an air space 507 between the raised
dome 194 of
the upper container cover 505 and the raised dome 194 of the lower container
cover 504.
(00111) The nest lugs 216, 217 of the upper container cover 505 are disposed
such that
they can receive the retention bead of yet another container cover to add to
the nested stack.
(00112] Referring to FIG. 28, the base 102 can be nested within the cover 104
when the
cover 104 is in an inverted position. The base 102 and the cover 104 can be
nested such
that the base 102 rests upon the cover 104 with the first stacking element 130
contacting the
second stacking element 210 and the side wall 122 of the base 102 contacting
the perimeter
198 of the dome 194 of the cover 104. The second stacking element 210 of the
cover 104
CA 02425353 2003-04-14
~:t No. 492.402
acts as a standoff to position the base 102 with respect to the cover 104 such
that a cavity
515 is defined, thereby preventing the interlocking of the base 102 and the
cover 104 in this
position.
[00113) The nested arrangement shown in FIG. 28 provides a convenient storage
position
for the cover 104 when the base 102 is used as a serving dish. The cover 104
can be
conveniently stored in an inverted position below the base 102 during use. In
such a stored
position, the cover 104 can be kept with the base 102, thereby reducing the
likelihood of
misplacing the cover.
[001141 A stack of bottoms can be nested with a stack of covers such that the
stack of
bottoms are uninterrupted and the stack of covers are uninterrupted with the
lowermost
bottom being in contact with the uppermost cover, as shown in FIG. 28. This
configuration
provides for an efficient stacking arrangement for packaging a set of bases
and covers for
display at the point of retail in that it reduces the size of the overall
package as compared to
an arrangement where the cover 104 was not inverted. If the cover 104 were not
inverted,
the overall height occupied by one container wouid be preserved, resulting in
a greater
overall package size.
1001151 Referring to FIG. 29, the occluded container can be stacked
vertically. The first
stacking element 130 and the second stacking element 210 have complementary
configurations such that the second stacking element 210 of a first container
600 can engage
the first stacking element 130 of a second container 601 to facilitate the
alignment of the
containers 600, 601 and to assist in stacking the containers 600, 601.
1001161 The groove 212 defined by the second stacking element 210 of the cover
is
configured to accept the first stacking element 130 of the base. The groove
212 can act to
secure the first stacking element 130 to reduce relative transverse movement
between the
first and second containers 600, 601. The stacking elements 130, 210 can
maintain the
closed containers in vertical alignment when placed in a stacked position,
thereby
minimizing shelf space within a cabinet, refrigerator, or freezer, for
example, while
providing for a stable stacking arrangement.
[00117] Referring to FIGS. 30-33, another embodiment of the container 700 is
shown.
The container 700 undergoes an occlusion sequence in FIGS. 30-33. The
container 700
includes a base 702 and a cover 704, which include a first and a second
closure portion 710,
711, respectively. Referring to FIG. 31, the first closure portion 710
includes an inner wall
760, a retention bead 762 and an outer wall 764. The first closure portion 710
includes a
notch 776 adjacent the outer wall 764. The notch 776 is disposed at a second
shoulder 771
of the retention bead 762. The notch 776 can cooperate with the second closure
portion 711
to define an air passageway 781 for venting a storage area 706 of the
container 700.
CA 02425353 2003-04-14
Do..net No. 492.402
16
[00118] Referring to FIG. 33, the first and second closure portions 710, 711
are occluded
to seal the container 700. The first and second closure portions 710, 711
cooperate in the
occluded position to close the air passageway 781. Respective sealing surfaces
766, 767 of
the first and second closure portions 710, 711 are in sealing engagement with
each other.
The outer wall 764 of the first closure portion 710 and an outer wall 765 of
the second
closure potion 711 cooperate to provide a substantially continuous seal 767
between the
cover 704 and the base 702.
[00119] The container 700 is similar in other respects to the container 100
shown in FIG.
l.
[00120] Referring to FIGS. 34-37, another embodiment of the container 800 is
shown.
The container 800 undergoes an occlusion sequence in FIGS. 34-37. The
container 800
includes a base 802 and a cover 804, which includes a first and second closure
portion 810,
811, respectively. Referring to FIG. 35, the first closure portion 810
includes an inner wall
860, a retention bead 862, and an outer wall 864. The retention bead 862
includes first and
second shoulders 870, 871. Each shoulder 870, 871 includes a notch 876, 877,
respectively.
The notches 876, 877 are disposed adjacent the inner and outer walls 860, 864,
respectively.
The notches 876, 877 are substantially aligned with each other and in opposing
relation with
each other. The notches 876, 871 cooperate with the second closure portion 811
to define a
pair of air passageways 881, 883 for venting the storage area of the container
800 during the
occlusion of the cover 804 and the base 802.
[00121] Referring to FIG. 37, first and second closure portions 810, 811 are
in the
occluded position, forming a seal therebetween. The air passageways 881, 883
are closed.
The inner and outer walls 860, 864 of the first closure portion 810
respectively cooperate
with inner and outer walls 861, 865 of the second closure portion 811 to
provide a pair of
seals 885, 887 therebetween.
[00122] The container 800 is similar in other respects to the container 100
shown in FIG.
1.
[00123] Referring to FIGS. 38-45, another embodiment of a container 900 is
shown. The
container 900 includes a base 902 and a cover 904, which liave a first and
second closure
portion 910, 911, respectively. Referring to FIG. 39, the first closure
portion includes an
inner wal1960, a retention bead 962 and an outer wall 964. The first closure
portion 910
includes a notch 976 in the form of a groove that extends from the inner wall
960 to the
outer wall 964. Referring to FIG. 41, the notch 976 of the first closure
portion 910
cooperates with the second closure portion 911 to define an air passageway 981
for venting
the storage area of the container 900 during the occlusion of the cover 904
and the base 902.
[00124] Referring to FIG. 43, the first and second closure portions 910, 911
are occluded
to seal the container 900. The air passageway 981 is closed. The inner wall
960 of the first
CA 02425353 2003-04-14
D. -;t No. 492.402
17
closure portion 910 cooperates with an inner wall 961 of the second closure
portion 911 to
provide a seal 985.
1001251 The container,'900 is similar in other respects to the container 100
shown in FIG.
[00126] 'Referring to FIG. 46, another embodiment of a base 1002 is shown. The
base
1002 can be used with any suitable cover, such as the cover 104 shown in FIG.
1, to provide
an enclosed storage area. The base 1002 includes a first closure portion 1010
in the form of
a raised locking ring. The first closure portion 1010 includes an inner wall
1060, a retention
bead 1062, and an outer wall 1064. The retention bead 1062 includes first and
second
shoulders l a70, 1071. The first closure portion 1010 includes first and
second notches
1076, 1077 that define air passageways between the base 1002 and the cover
while the
closure portions of the base and the cover undergo an occlusion sequence. The
first and
second notches 1076, 1077 are disposed on the shoulders 1070, 1071,
respectively, adjacent
the inner and outer walls 1060, 1064, respectively. The first and second
notches 1076, 1077
are substantially aligned with, and in opposing relation to, each other. The
base 1002
includes a third and a fourth notch 1078, 1079 which are disposed in opposing
relation to
the first and second notches 1076, 1077 on the closure portion 1010. The third
and fourth
notches 1078, 1079 are disposed 180 apart from the first and second notches
1076, 1077
along the first closure portion 1010. The third and fourth notches 1078, 1079
are disposed
on the first and second shoulders 1070, 1071 adjacent the inner and the outer
walls 1060,
1064, respectively. The third and fourth notches 1078, 1079 are substantially
aligned with,
and in opposing relation to, each other. The third and fourth notches 1078,
1079 can
cooperate with the closure portion of the cover to define a pair of
passageways for venting
the storage area defined by the base and the cover during the occlusion
sequence thereof.
[00127] Referring to FIG. 47, both the container base 102 and the container
cover 104
can be made of a plastic material. .The cover and the base can be made by a
thermoforming
process, for example, such that the first and second sealing surfaces 166, 226
are molded
without contacting the respective mold tool surface during rnanufacture
thereof.
[00128] In one method for making the container 100, a base mold 1101 can be
provided.
By way of illustration, the space which the base mold 1101 can occupy during
manufacture
of the base 102 is shown by a cross-hatch region 1101 in FIG. 46. The base
mold 1101
includes a base mold tool surface 1105 configured to define the base 102. The
base mold
tool surface 1105 is configured such that the exterior surface 132 of the base
102 is in
contact with the base mold tool surface 1105. The first sealing surface 166 of
the first
closure portion I 10 can be made without contacting the base mold tool surface
1105 during
the manufacture thereof. The base 102 can be molded by conventional
thermoforming
techniques.
CA 02425353 2006-03-07
18
[00129] A cover mold 1111 can be provided. By way of illustration, the space
which the
cover mold IIII can occupy during manufacture of the cover 104 is shown by a
second
cross-hatch region 1111 in FIG. 46. The cover mold 1111 has a cover mold tool
surface
1115 configured to define the cover 104. The cover mold tool surface 1115 can
be
configured such that the exterior surface 191 of the cover 104 is in contact
with the cover
mold tool surface 1115. The second sealing surface 226 of the second closure
portion 111
can be molded without contacting the cover mold tool surface 1115 during the
manufacture
thereof. The cover 104 can be molded using conventional thermoforming
techniques.
[001301 The selection of mold surfaces permits manufacture of the cover which
otherwise may be impractical due to thermoforining considerations. In this
instance, the
cover mold 1111 is commonly referred to as a "female" mold owing to the dome
106
portion of the cover 104 being formed into a concavity on the tool surface.
Use of a female
mold is, advantageous as compared to a "male" mold having a convexity in order
to avoid
overly-deep draw formation that may result in webbing. For instance, the
channel 250 in
FIG. 20 may be impractical to form with use of male tooling because of the
high likelihood
that webbing would occur due to the overly-deep draw in this area. With female
tool
manufacture, this concern is avoided. It is very advantageous to utilize a
domed cover
whereby the width 258 defined by the channel 250 in FIG. 20 is narrow. This is
because the
headspace of the container defined by the interior surface 190 is
deleteriously reduced as the
width 258 is made wider, assuming dimensions of the closure 111 remain
constant. If a
male tool were chosen to manufacture the cover 104, the width 258 would
necessarily be
wider to avoid webbing. As such, not only is container headspace compromised
but also the
cover's dual function of being inverted and itself used as a serving plate
would be
compromised owing to the coincident reduction in serving area defined by the
interior
surface 190. Furthermore, selection of a female tool to manufacture the cover
104 also
permits use of reverse trim station configurations which are commonly employed
on state-
of-the-art thermoforming equipment.
[00131] The container can be made with conventional thermoforming equipment.
The
tools can be run on an in-line extrusion/forrning process or on a roll-fed
thermoforming
process, for example.
[00132] The base and the cover can be fabricated by thermoforming a clarified
polypropylene homopolymer material, such as the clarified polyprohomo with the
trade
name 3289M and sold by Fina Oil and Chemical Co. In another embodiment, the
container
may be fabricated by thermoforming a clarified random copolymer polypropylene
material,
such as Pro-fax SR-256M from Montell North America Inc., Wilmington, DE.
Alterrnative
plastic materials which would be suitable for fabricating the container by
themzoforming
include PS (polystyrene), CPET (crystalline polyethylene terephthalate), APET
(amorphous
CA 02425353 2006-03-07
19
polyethylene terephthalate), HDPE (high density polyethylene), PVC polyvinyl
chloride),
and PC (polycarbonate), for example.
1001331 The base and the cover can be made from a generally transparent
material to
allow a user to view the inside of the container to view its contents. The
container can be
constructed from a material that is suitable for use in conventional freezers
and microwave
ovens and that is dishwasher-safe.
1001341 The cover can be configured such that it is different from the base to
facilitate
the ready identification of the two components from each other. The base of
the container
can be made from a homopolymer polypropylene material, for example with a
color tinting
added thereto, such as blue, for example. The cover can be made from a
homopolymer
polypropylene, for exampie, which can be untinted to facilitate
differentiation between the
base and the cover.
[00135], The container may include only one notch for venting or may include a
plurality
of notches in spaced relationship to each other around the perimeter. The
container from a
top plan view may be circular, elliptic, or generally rectangular.
[001361 The container may include additional features. For example, the
container top
and/or the container bottom may have an area which allows the user to write
information,
such as, the date. The write-on area could be an opaque color, such as, an
opaque white,
which would receive a contrasting color from a writing instrurnent, such as, a
marker with
black ink. The write-on area could be incorporated into the material for the
container or
could be applied to the material, such as, by printing.
[00137] The container may also include a visual indication of closure between
the
container top and the container bottom. The visual indication may be a color
change in the
area where the container top engages the container bottom. In one embodiment,
the closure
device on the container top may be a first color, such as, a translucent blue
and the closure
device on the container bottom may be a second color, such as, an opaque
yellow. When
the closure devices are occluded, the first and second colors produce a third
color, such as, a
green which is visible to the user to indicate that the container is sealed.
Alternatively, the
color change can result from the appearance or loss of a color as a result of
hindrance by the
closure portions. Examples of color change closures and techniques for forming
a color
change seal are shown in U.S. Patents Nos. 4,186,786, 4,285,105, 4,829,641,
4,907,321,
5,248,201, 5,356,222, 5,252,281 and 5,427,266.
[00138) The colors may be incorporated into the material for the container or
a portion of
the container, such as in the closure area, or the colors may be applied to
the material, such
as, by printing. The actual inclusion of a color change closure or visual
indication closure
can be effected by use of established commercially available techniques. For
example, if
the lid and tub are to have a different color at the interface where the lid
attaches to the tub
CA 02425353 2006-03-07
the two respective surfaces can be fashioned with a color or design by use of
screen printing
(also known as silk-screen printing), pad printing (also known as transfer pad
printing) or
ink jet printing. The printing may be performed on the unformed material or
the printing
may be performed on the formed container. In addition, other approaches for
forming a
color or pattern on the lid and tub surfaces where such mate includes the use
of co-extruded
sheet material which is then thermoformed. The aforementioned techniques are
well known
for use in providing decorative surfaces to plastic surfaces.
[00139] Furthermore, the colors may be incorporated into the material by using
in-mold
labeling during the thermoforming process. The process for in-mold labeling
for
thermoforming involves the following steps. The label, such as an opaque
yellow label, is
positioned in a predetermined location on the thermoforming cavity for the
part. The plastic
is then positioned over the label and over the thermoforming cavity. The part
is then
formed and the label is embedded into the part. As an example, the closure
device on the
container top may include a translucent blue in-mold label and the closure
device on the
container bottom may be an opaque yellow in-mold label. When the closure
devices are
occluded, the in-mold labels produce green which is visible to the user to
indicate that the
container is sealed.
[00140] The container may also include an audible indication of closure or a
tactile
indication of closure. In one embodiment, the closure device on the container
top includes
interior protrusions which engage exterior detents on the closure device on
the container
bottom. When the closure devices are engaging, the closure devices will make a
clicking
sound and cause a vibration in the container which is perceptible to the user
to indicate that
the container is sealed. Examples of audible closures and/or tactile closures
disclosing
techniques to provide this functionality are shown in U.S. Patents 4,944,072,
5,070,584,
5,138,750, 5,140,727, 5,154,086, 5,363,540, 5,403,094.
[00141] The container may also include a rough exterior surface to reduce
slipping and
improve grasping by the user. For example, the exterior of the container
bottom may have a
textured surface, as opposed to a smooth surface, to improve handling by the
user,
especially if the user's hands are wet or greasy.
1001421 In addition, 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 top may include a self-venting mechanism
which
opens when the pressure in the container exceeds a predetennined value.
[00143] The container bottom may include a peelable lid with a super seal.
Specifically,
in a commercial use, the container bottom may include an interior peelable lid
which is
glued to the closure device.
CA 02425353 2006-03-07
21
[00144] In another embodiment, the peelable lid would release or vent when the
sealed
container and contents are heated in a microwave oven. Specifically, the heat
would
weaken the glue and allow the pressure to escape and /or the glue would be the
weakest
point of the container and allow the pressure to escape.
1001451 The container may be divided to separate various foods in the
container. The
divider would permit the user to store one food in one compartment and another
food in
another compartment. The divider may be integral with the container or a
separate
component. In addition, only the container bottom may include a divider or
both the
container bottom and the container top may each include a divider. The divider
located in
the container top may only partially engage the divider in the bottom of the
container so as
to provide splash protection or may fully engage the divider in the bottom of
the container
so as to provide varying degrees of inter-compartmental leak resistance. The
container may
be compartmented by use of a separate smaller container that can be disposed
within the
main container such that the smaller container is securedly maintained by a
locating means
or fastening means. The smaller container may be lidded or may utilize the
container cover
as a lid.
[00146] The container may also include a temperature-indicating strip which
would
indicate the temperature of the container and contents. In one embodiment, the
temperature
strip could indicate the approximate temperature of the container and
contents. In another
embodiment, the temperature strip could indicate whether the container and
content are
within one of several temperature ranges. In a third embodiment, the
temperature strip
could indicate whether the container and contents are either hot or cold.
[00148] The use of the terms "a" and "an" and "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 claimed.
No language
CA 02425353 2003-04-14
D. ~t No. 492.402
22
in the specification should be construed as indicating any non-claimed element
as essential
to the practice of the invention.
[q 1491 Preferred embodiments of this invention are described herein,
including the best
mode known to the inventors for carrying out the invention. Of course,
variations of those
preferred embodiments would become apparent to those of ordinary skill in the
art upon
reading the foregoing description. The inventors expect skilled artisans to
employ such
variations as appropriate, and the inventors intend for the invention to be
practiced
otherwise than as specifically described herein. Accordingly, this invention
includes all
modifications and equivalents of the subject matter recited in the claims
appended hereto as
permitted by applicable law. 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.
