Note: Descriptions are shown in the official language in which they were submitted.
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CONTAINER AND LID ASSEMBLY
FIELD OF THE INVENTION
The technical field relates generally to container and lid assemblies, for
instance
container and lid assemblies that can be used in the commercial food
processing industry.
BACKGROUND OF THE INVENTION
Various kinds of containers have been suggested over the years. Many
containers
designed for holding food include a main bottom section forming a tray, a
dish, a bowl, a
receptacle or the like, and each container is hermetically sealed around or
near its top edges
by a wrapping and/or a lid to protect the contents during the transportation,
storage and
handling. Some containers are sold to customers without any contents therein
but others are
sold together with food items, for instance as prepackaged meals or the like.
Designing food containers for the commercial food processing industry can be
challenging. For instance, since most of these containers are only designed to
hold food
items until eaten by the customers, it is desirable that the quantity of
materials required for
making them and the manufacturing costs be minimized. Unfortunately, this is
not always
easy to achieve since the containers and their lids must also meet other
requirements, such as
resisting shipping, storage and handling, including handling at the stores or
the restaurants
where they are sold. The containers must remain intact and constantly sealed,
between the
packaging process and the moment customers open them, to avoid contamination
and
spoilage. On the other hand, adding too many packaging layers or features,
such as a
protective box made of cardboard or the like, or additional layers of
wrapping, to mention
just a few, increases the volume of waste material to be recycled and/or
discarded after their
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use. This situation is not desirable and it will likely dissatisfy many actual
or potential
customers.
Further difficulties and challenges in the design of food containers are
created when
these food containers must also be used for heating/cooking food items
directly therein, for
instance in a microwave oven. In a microwave oven, the heat generated inside
the food items
is transferred to the container itself and the temperature of the container
can eventually
become very high. Containers must still remain sufficiently rigid even when
heated at high
temperatures.
Even more challenging is the design of food containers used for
heating/cooking food
items directly therein and that can be reclosed after the initial opening by
the customer.
These food containers are used with lids that can be reclosed during
heating/cooking and/or
afterwards for transportation and storage. For example, some prepackaged meals
require
separate ingredients to be mixed and/or added before heating/cooling them,
such as a meal
where water must be added before heating/cooking. Some meals can also be
packaged with
ingredients that must be mixed together by the customer inside the container
but where not
all ingredients are mixed at the same time. An example is a stir-fry meal
where a sauce or
the like is added only after some cooking/heating time. Still, physical
interventions by the
customer during the heating/cooking process, for instance to stir the content,
may be another
reason to have a reclosable lid. Other situations exist as well.
Containers must perform well in the hands of customers but they must also be
easy to
handle at the packaging end, for instance, by the packaging equipment. Some
designs can be
adequate for transportation, storage and handling but far less for the
packaging process.
Difficulties in handling containers and sealing their lids can increase costs
and complexity of
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the packaging equipment and/or decrease the production rate.
Still, some container designs can create difficulties for the customers when
they
attempt to remove the sealed lid. Containers with rectilinear sides and
relatively sharp
corners are often difficult to handle when the lids are very light and
flexible.
Unfortunately, none of the previously-suggested containers has proven entirely
satisfactory to address many of the challenges encountered in the design of
containers,
particularly in the design of containers intended for the commercial food
processing
industry.
It is therefore clear that improvements in the related technical field are
still and
always be needed.
SUMMARY OF THE INVENTION
There is provided an assembly that includes a container and a lid. The
container
includes a main body and a container rim surrounding the main body. The
container rim
has an outer peripheral horizontal top surface and an inner peripheral
horizontal top
surface. The outer peripheral horizontal top surface surrounds the inner
peripheral
horizontal top surface and is vertically below the inner peripheral horizontal
top surface.
The lid includes a ring-shaped lid frame and a membrane that is attached over
a top
surface of the lid frame. The lid frame includes a flat strip portion having a
continuous
flat top surface and a continuous flat bottom surface, which
bottom surface engages the outer peripheral horizontal top surface when the
lid is in a
closed position. The lid frame also includes at least one latching tab that is
made integral
with an outer edge of the flat strip portion.
Although the container and lid assembly may be used for retaining many
different
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products, the present invention is directed primarily to containers suitable
for the food
industry. Thus, the assembly includes a container and a corresponding lid
therefore.
Many different shapes may be utilized as will be understood by those skilled
in the
art.
The materials conventionally are plastic materials and in one embodiment of
the
present invention, a thermoforming process is utilized to form the container.
On the other
hand, the lid frame may be injection molded.
The lid frame is utilized with a membrane which seats over the lid frame. The
lid
frame will include opposite corner latching tabs for sealing the same onto the
container.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the invention, reference will be made to the
accompanying drawings illustrating embodiments thereof, in which:
FIG. 1 is an exploded isometric view of an example of a container and lid
assembly based on the proposed concept;
FIG. 2 is an isometric view of the container and lid assembly in FIG. 1, where
the
assembly is illustrated in a closed position;
FIG. 3 is a top plan view of the container and lid assembly shown in FIG. 2;
FIG. 4 is a view similar to FIG. 2 but where the assembly is illustrated in an
opened position as the lid is unconnected to the container;
FIG. 5 is an enlarged isometric view of the area inside line 5-5 in FIG. 4;
FIG. 6 is a transversal cross section view taken along line 6-6 in FIG. 2;
FIG. 7 is an enlarged view of the area inside line 7-7 in FIG. 6;
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FIG. 8 is a semi-schematic view of an example of a mold in which the container
= and the lid frame are molded together;
FIG. 9 is a cross-sectional view of a variation of a lid frame;
FIG. 10 is a top plan view of a bowl when thermoformed;
FIG. 11 is top plan view of the bowl and ring after the exterior edges are
folded;
and
FIG. 12 to 14 illustrate the sequential operation of folding the edge of the
bowl.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an exploded isometric view of an example of a container and lid
assembly 100 based on the proposed concept. The assembly 100 is used for
packaging a
product, for instance one or more food items. Although the proposed concept is
especially
well adapted for holding meals and other food items, it is possible to design
and/or use
the assembly 100 for holding one or more products that are unrelated to the
food industry.
The following detailed description refers to the context of the commercial
food
processing industry only for the sake of simplicity.
As suggested by its name, the assembly 100 includes a container 102 and a
corresponding lid 104. The container 102 includes a main body 110 having one
or more
walls defining a hollow interior compartment 112 for storing the food items to
be packed
therein. The container 102 has an opening 114 at the top that is defined by
the inner edge
of an outwardly-projecting container rim 120. The container rim 120 is made
integral
with the main body 110. The top of the container rim 120 is at the horizontal
in normal
use. The opening 114 is substantially rectangular in shape, with rounded
corners and
slightly curved sides between the corners. Variants are possible as well. For
instance, the
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container 102 could have an opening with substantially straight sides and
sharper corners,
an opening with a nonrectangular shape, such as a rounded shape, a triangular
shape or a
shape with more than four sides, etc. Many other variants are possible as
well.
In the illustrated example, the main body 110 includes a bottom wall and four
upwardly-disposed side walls configured to form a bowl or the like. The wall
or walls
forming the main body 110 are airtight and liquid tight.
It should be noted that the shape of the main body 110 of the illustrated
container 102 is only one example of implementation. Variants are possible.
The container 102 can be made using a thermoforming process or an injection
molding process, for instance using a plastic material. Other materials and/or
manufacturing processes can be used as well. The wall or walls forming the
main
body 110 of the container 102 can be relatively thin and the container rim 120
will stiffen
the container 102, even if the container rim 120 is also relatively thin to
minimize the
quantity of material.
The lid 104 includes a ring-shaped lid frame 130 and a membrane 132 that will
be
attached over the lid frame 130 at some point of the packaging and/or
manufacturing
process. The lid frame 130 includes a relatively flat strip portion 134 having
a continuous
flat top surface and a continuous flat bottom surface. The periphery of the
membrane 132
will adhere to the top surface of the lid frame 130 to form an airtight and
liquid tight seal.
The lid 104 is thus made with a minimized quantity of material and will be
very light.
The lid frame 130 can be made using an injection molding process, for instance
using a plastic material. Other materials and/or manufacturing processes can
be used as
well. However, the lid frame 130 is not molded directly to or over the
container rim 120.
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The lid frame 130 is only put in position onto the container rim 120 after the
molding
process.
The membrane 132 is in the form of a thin film, for instance a plastic film or
a foil.
Other materials can be used as well, depending on the actual implementation.
The
membrane 132 can be transparent, translucent or opaque, depending on the
needs.
The lid frame 130 of the illustrated example also includes two diametrically
opposite corner latching tabs 136, 138 that are each made integral with the
outer side
edge of the lid frame 130. Each latching tab 136, 138 has a proximal section
that extends
outwards from the side edge of the flat strip portion 134 and a distal section
that extends
downwards. The latching tabs 136, 138 are designed to prevent them from
interfering
with the continuity of the contact of the bottom surface of the flat strip
portion 134 with
the outer peripheral top surface 122 when it rests thereon. The lid frame 130
of the
illustrated example also includes a lift tab 140 that is made integral with
the free
end of the distal section of the first corner latching tab 136. Only one lift
tab is provided
in the illustrated example. The lift tab 140 extends horizontally outwards
from the distal
portion of the first corner latching tab 136. Variants are possible as well.
As can be seen, the lid 104 is devoid of a peripheral skirt or the like. The
size of
the latching tabs 136, 138 is also kept to a minimum. Overall, this will
greatly facilitate
the opening and closing of the lid 104. A lesser force is required to handle
it and as a
result, it is less likely to undergo a plastic deformation because the
customer exerted an
excessive pulling force. The lid frame 130 is
relatively small and can be prone to deformation when subjected to an
excessive pulling
force.
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FIG. 2 is an isometric view of the container and lid assembly 100 in FIG. 1,
where
the assembly 100 is illustrated in a closed position. The lid 104 is then
attached to the
container 102, more specifically to the container rim 120. In FIG. 2, the
membrane 132 is
sealingly attached to the lid frame 130.
FIG. 3 is a top plan view of the container and lid assembly 100 shown in FIG.
2.
FIG. 4 is a view similar to FIG. 2 but where the assembly 100 is illustrated
in an
opened position. The lid 104 is then unconnected to the container 102.
As can be seen, for instance in FIGS. 3 and 4, the top side of the container
rim 120
includes an outer peripheral top surface 122 and an inner peripheral top
surface 124. Each
of these surfaces 122, 124 are flat and continuous. They are also
substantially horizontal
in normal use. However, the outer peripheral top surface 122 is slightly
vertically below
the inner peripheral top surface 124 so as to receive the bottom surface of
the lid
frame 130 when the lid 104 is in a closed position. These mating surfaces are
configured
and disposed to form an uninterrupted seal around the entire perimeter of the
container
rim 120.
FIG. 5 is an enlarged isometric view of the area inside line 5-5 in FIG. 4. As
can
be seen, the outer peripheral top surface 122 includes a through hole 150 at
the corner
where the first latching tab 136 is located when the lid 104 is in a closed
position. A
similar hole 150 is also provided at the opposite corner, thus at the corner
where the
second latching tab 138 is located. In the illustrated example, these holes
150 have an
oblong shape that is generally oriented parallel to the medial axis of the
outer peripheral
top surface 122. Variants are possible as well. For instance, the holes 150
can be provided
with other shapes, including for instance a "lens" shape to help in aligning
the studs 152
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at the center of the holes 150.
FIG. 5 also shows that the container rim 120 of the illustrated assembly 100
includes a downwardly projecting skirt 126 extending around the entire
periphery of the
container 102. The skirt 126 promotes rigidity. Variants are possible as well.
FIG. 6 is a transversal cross section view taken along line 6-6 in FIG. 2. It
thus
shows the lid 104 in a closed position. FIG. 7 is an enlarged view of the area
inside line 7-7
in FIG. 6. As can be seen, these figures show one of the studs 152 provided to
engage the
inner edge of a corresponding hole150, as best shown in FIG. 7. A similar stud
152 is
provided at the opposite corner to engage the other hole 150. These studs 152
have a
substantially circular cross section in the illustrated example. The
engagement of the
studs 152 with their corresponding holes 150 can be an interfering engagement,
including
for instance using a notch (not shown) or the like to create a snap fit
interlocking
connection. This removable interfering engagement will create a retention
force
resisting the lifting of the lid 104 and interlocking the lid 104 with the
container 102.
However, the interfering engagement can be removed upon lifting the lid frame
130 using
a mild force. Using the studs 152 and the corresponding holes 150 also greatly
facilitates
the closing of the lid 104 since the lid frame 130 is made of a relatively
flexible part. It can
become very flexible at high temperatures and the studs 152 can facilitate the
positioning.
The customer can used their thumbs to urge the studs 152 into the holes 150
when closing
the lid 104. Variants are possible as well.
The latching tabs 136, 138 also help in centering the lid 104 on the container
102
and they can be shaped to engage, with a mild interfering force, the bottom
edge of the
skirt 126. Each latching tab 136, 138 can be provided with an undercut (not
shown) or a
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similar feature to create an interlocking connection with the bottom edge of
the skirt 126.
They can even replace the studs 152 and their holes 150 in some
implementations. Variants
are possible as well.
The holes 150 have an oblong shape in the illustrated example. This feature is
to
facilitate
the positioning by the customer. Variants are possible as well.
FIG. 7 also shows that the top surface of the lid frame 130 and the inner
peripheral
top surface 124 of the container rim 120 are substantially flush with one
another when the
lid 104 is in a closed position. The bottom surface of the membrane 132 is
then directly
above the inner peripheral top surface 124.
Still, FIG. 7 shows that the inner side edge of the flat strip portion 134 is
spaced
apart from the outer edge bordering the inner peripheral top surface 124. This
space can
provide more room for aligning the parts when they are hot. The space also
provides an
increase of the manufacturing tolerances, thus mitigating the risks of having
parts being
rejected because they are too wide after the molding process.
During the packaging process, the item or items can be put inside the hollow
interior compartment of each container 102 with the lid frame 130 being
already in an
interlocking engagement with the container rim 120. This previous step can be
achieved by
hand or by an appropriate equipment. The containers 102, with their lids 104
thereon, can
still be stacked so as to minimize space. Variants as possible as well.
An interesting benefit of the proposed concept is that since no peripheral
skirt is
provided on the lid 104, the handling of the container 102 with the pre-
connected lid
frame 130 during the packaging process is made easier since a stack of these
parts can be
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supported anywhere underneath the container rim 120, with the exception of the
two
corners with the latching tabs 136, 138 are provided, without the risks of
accidentally
lifting a portion of the lid frame 130 from the container rim 120.
The membrane 132 is added at the end of the packaging process to
simultaneously
form the lid 104 and to seal the whole assembly 100. For instance, if the
membrane 132 is
made of a thermoplastic material, the membrane 132 can be heated and pressure
can be
applied so as to simultaneously bond the outer perimeter of the membrane 132
to the outer
and inner peripheral top surfaces 122, 124. This can be done in a single
operation during
which the underside of the container rim 120 is supported by a die while the
membrane 132 is urged onto the lid frame 130 and onto the exposed inner
peripheral top
surface 124 by a heated pressure plate. The combination of heat and pressure
bonds the
membrane 132 over the top surface of the lid frame 130 and over the inner
peripheral top
surface 124.
If desired, the inner peripheral top surface 124 can be positioned slightly
lower than
the top surface of the flat strip portion 134 when the lid 104 is in a closed
position. This
will make the bond between the inner peripheral top surface 124 and the
membrane 132
slightly weaker than the bond between the top surface of the flat strip
portion 134 and the
membrane 132. Still, as shown in FIG. 7, the width of the outer section of the
membrane 132 that is fused onto the top surface of the flat strip portion 134
is larger than
the width of the adjacent inner section of the membrane 132 that is fused onto
the inner
peripheral top surface 124. These features will make the membrane 132 less
prone to
detach from the lid frame 130 during the initial unsealing of the assembly 100
by the
customer and will also decrease the required pulling force. This decrease of
the pulling
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force can mitigate the risks of accidentally tearing the membrane 132 when the
assembly 100 is unsealed. Variants are possible as well.
In use, to open the sealed assembly 100, the customer will move the lift tab
140
upwards to create a peeling force that will progressively detach the membrane
132 from
the inner peripheral top surface 124 of the container rim 120, starting at the
corner adjacent
to the lifting tab 140. The membrane 132 will stay attached on the lid frame
130 since the
peeling motion will only remove the membrane 132 from the inner peripheral top
surface 124. Thus, it is relatively easy for the customer to lift a corner of
the lid 104 using
the lift tab 104 and then lift the whole lid 104 to access the interior of the
container 102.
This way, the customer can add liquids or other ingredients, for instance
additional
ingredients from a pouch or the like. The lid 104 can be reclosed before
continuing the
heating/cooking process.
FIG. 8 is a semi-schematic view of a mold 200 in which the container 102 and
the
lid frame 130 15 are molded together in a same injection shot of molten
plastic material but
in separate cavities. The mold 200 includes a first cavity 202 for the
container 102 and a
second cavity 204 for the lid frame 130. Both cavities 202, 204 are in fluid
communication
using an intervening channel 206. The channel 206 will also be filled with the
molten
plastic material after the injection shot and as the plastic material
solidifies, it will form a
connector linking the outer edge of the container rim 120 to the outer edge of
the lid
frame 130. This connector 206 can be removed or cut to completely separate the
container 102 and the lid frame 130. However, one can also keep the connector
206 to
facilitate handling during the packaging and/or by the customer, provided that
the
connector 206 remains relatively flexible at room temperature and is located
at the corner
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opposite the corner with the lift tab 140. The connector 206 can be useful for
keeping the
orientation of the lid frame 130 with reference to the container 102 and for
preventing a
customer from attempting to close the lid 104 while the studs 152 are at the
corners where
no holes are present.
FIG. 9 illustrates an alternative embodiment in which an injection molded snap
ring 208 is placed on top of a flange 210 to a thermoformed bowl. The flange
210 is
welded to the thermoformed bowl. The ring can also be welded directly to the
container so
that when one opens the lid, the film will stick to the ring, but the ring
will be detached
from the container. The ring will also snap in the flange. Preferably, the
flange and ring
are injected molded.
An alternative embodiment is illustrated in FIGS. 10 to 14. In this
embodiment,
bowl or container 302 is thermoformed as previously described. The bowl is
formed with
a flange 310. Also thermoformed at the same time as container 302 is a snap
ring 308
which, as may be seen, is formed as an extension of flange 310. Ring 308 is
folded over
and into channel 306 as shown in FIG. 13 by arrow 315. Subsequently, the
connection
point is cut as indicated by arrow 317 such that snap ring 308 is separated
therefrom.
This embodiment provides the advantage of eliminating the step of injection
molding a separate snap ring. Rather, the snap ring is formed integrally with
the
container 302.
It will be understood that the above described embodiments are for purposes of
illustration only and that changes and modifications may be made thereto
without departing
from the spirit and scope of the invention.
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