Note: Descriptions are shown in the official language in which they were submitted.
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METHODS OF REDUCING THE STACKING HEIGHT OF
CONTAINERS, LIDS, AND BASES
FIELD OF THE INVENTION
[0001] The present invention generally relates to the packaging industry. More
particularly, the present invention relates to reducing the stacking height of
a stack of
containers, lids, or bases.
BACKGROUND OF THE INVENTION
[0002] The packaging industry has produced a number of containers, lids, and
bases to be used in applications such as egg cartons, carry-out containers,
fruit trays, and
other container types. These containers, lids, and bases are typically
transported from a
manufacturer to an entity that utilizes a container, lid, or base. The
containers often have
locking mechanisms between its bases and lids. A container that is not
securely closed
could open inadvertently and spill the contents of the container. Typically
this locking
mechanism is controls the design of the stack height. These containers, lids,
and bases
are often transported by being stacked inside boxes. The size of these
transportation
boxes is often referred to as the cube of the outer packaging.
[0003] Referring now to prior art FIG. 1, a portion of a stack 30 that
includes a
plurality of containers 10 is shown. The distance indicated by arrow A is the
stack height
between two containers. The term "stack height" as used in this application
means the
distance between identical features of adjacent containers in a stack. It can
be observed
in prior art FIG. I that the stack height A is governed by a lead-in surface
18 of the
locking mechanism of the top container of the stack 30 resting on an undercut
rim 16 of
the locking mechanism of the bottom container of the stack 30.
10004] Similarly, in prior art FIG. 2 a portion of a stack 40 that includes a
plurality of containers 20 is shown. The distance indicated by an arrow B is
the stack
height between two containers. The stack height B of prior art FIG. 2 is
driven by an
undercut rim 26 of the locking mechanism of the first container resting on a
lead-in
surface 28 of the locking mechanism of the second container in the stack 40.
[0005] A greater stack height results in a larger cube for the transportation
boxes.
A typical stack may include several hundred or even several thousand
containers, lids,
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bases, and combinations thereof. Having an inefficient stacking of containers,
lids, and
bases is costly because of the higher transportation costs involved.
Additionally,
potential storage costs may be incurred by the entities that use such items
because of the
inefficient stacking. Further, a large stack also requires additional store
shelf-space,
which increases the cost associated with marketing the containers. Such costs
are
ultimately passed onto the end user of the containers, lids, and bases.
[0006] A need therefore exists for a method to stack containers that results
in a
reduced stack height for an equal number of containers.
SUMMARY OF THE INVENTION
[00071 A method for forming a reduced-height stack of a plurality of
containers
provides a first and second container. The first container has a first
undercut and a first
undercut receiving structure. The first undercut is located at a first
position. The first
undercut receiving structure is located at a second position. The second
container has
a second undercut and a second undercut receiving structure. The second
undercut is
located at a third position. The second undercut receiving structure is at a
fourth
position. The third position is a different location from the first position.
The fourth
position is a different location from the second position. The first and
second
containers are generally equal in size. The method arranges the first and
second
container to form a stack of a plurality of containers. The first undercut at
the first
position aligns with and fits within the second undercut receiving structure
at the
fourth position to reduce the stack height.
[00081 According to another method of the present invention, a method of
forming a reduced-height stack of containers provides a mold base that
comprises a
first mold cavity that has a first design and a second mold cavity that has a
second
design. The first design is different from the second design. This method
makes a first
container in the first mold cavity that has a first undercut located at a
first position and
a first undercut receiving structure located at a second position. The method
also
makes a second container in the second mold cavity that has a second undercut
located
at a third position and a second undercut receiving structure located at a
fourth
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position. The third position is a different location than the first position.
The fourth
position is a different location than the second position. This method removes
the
first and second containers from the respective first and second mold
cavities. The
method arranges the first and second containers to form a two-container stack.
The
first undercut at the first position aligns with and fits within the second
undercut
receiving structure at the fourth position to reduce the height of the two-
container
stack.
[00091 According to a further method of the present invention, a method of
forming a reduced-height stack of containers provides a mold base that
comprises a
first mold cavity and a second mold cavity. The design of the first mold
cavity is
substantially identical to the design of the second mold cavity. The second
mold
cavity is rotated in the mold base relative to the first mold cavity. This
method
makes a first container in the first mold cavity that has a first undercut
located at a
first position and a first undercut receiving structure located at a second
position.
The method also makes a second container in the second mold cavity that has a
second undercut located at a third position and a second undercut receiving
structure
located at a fourth position. The third position is a different location than
the first
position. This method removes the first and second containers from the
respective
first and second mold cavities. The method arranges the first and second
containers
to form a two-container stack. The first undercut at the first position aligns
with and
fits within the second undercut receiving structure at the fourth position to
reduce the
height of the two-container stack. The containers align without further
rotation of the
containers after they are removed from the mold cavities.
[00101 According to yet another method of the present invention, a method of
forming two reduced-height stacks of containers provides a mold base that
comprises at
least a first mold cavity, a second mold cavity, a third mold cavity, and a
fourth mold
cavity. The mold cavities are arranged in two rows and two columns. The first
and
second mold cavities comprise a first column of mold cavities. The third and
fourth
mold cavities comprise a second column of mold cavities. The design of the
first mold
cavity is different than the design of the second mold cavity. The design of
the third
mold cavity is different than the design of the fourth mold cavity. This
method makes a
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first container in the first mold cavity that has at least one undercut
located at a first
position and at least one undercut receiving structure located at a second
position. The
method also makes a second container in the second mold cavity that has at
least one
undercut located at a third position and at least one undercut receiving
structure located
at a fourth position. The third position is a different location than the
first position. A
third container is made in the third mold cavity that has at least at least
one undercut
located at a fifth position and at least one undercut receiving structure
located at a sixth
position. A fourth container is made in the fourth mold cavity that has at
least at least
one undercut located at a seventh position and at least one undercut receiving
structure
located at an eighth position. The fifth position is a different location than
the seventh
position. This method removes the first, second, third, and fourth containers
from the
respective first, second, third, and fourth mold cavities. The method arranges
the first
and second containers to form a two-container stack. The at least one undercut
of the
first container at the first position aligns with and fits within the undercut
receiving
structure at the fourth position of the second container to reduce the height
of the two-
container stack. The method arranges the third and fourth containers to form a
two-
container stack. The at least one undercut of the third container at the fifth
position
aligns with and fits within the undercut receiving structure at the eighth
position of the
fourth container to reduce the height of the two-container stack.
[0011] According to yet a further method, a method of forming two reduced-
height stacks of containers provides a mold base that comprises at least a
first mold
cavity, a second mold cavity, a third mold cavity, and a fourth mold cavity.
The mold
cavities are arranged in two rows and two columns. The first and second mold
cavities
comprise a first column of mold cavities. The third and fourth mold cavities
comprise a
second column of mold cavities. The design of the first mold cavity is
substantially
identical to the design of the second mold cavity. The second mold cavity is
rotated
within the mold base relative to the first mold cavity. The design of the
third mold cavity
is substantially identical to the design of the fourth mold cavity. The fourth
mold cavity
is rotated within the mold base relative to the third mold cavity. This method
makes a
first container in the first mold cavity that has at least one undercut
located at a first
position and at least one undercut receiving structure located at a second
position. The
CA 02523284 2005-10-11
method also makes a second container in the second mold cavity that has at
least one
undercut located at a third position and at least one undercut receiving
structure located
at a fourth position. The third position is a different location than the
first position. A
third container is made in the third mold cavity that has at least at least
one undercut
located at a fifth position and at least one undercut receiving structure
located at a sixth
position. A fourth container is made in the fourth mold cavity that has at
least at least
one undercut located at a seventh position and at least one undercut receiving
structure
located at an eighth position. The fifth position is a different location than
the seventh
position. This method removes the first, second, third, and fourth containers
from the
respective first, second, third, and fourth mold cavities. The method arranges
the first
and second containers to form a two-container, stack. The at least one
undercut of the
first container at the first position aligns with and fits within the undercut
receiving
structure at the fourth position of the second container to reduce the height
of the two-
container stack. The first and second containers align without further
rotation of the first
and second containers after they are removed from the mold cavities. The
method
arranges the third and fourth containers to form a two-container stack. The at
least one
undercut of the third container at the fifth position aligns with and fits
within the
undercut receiving structure at the eighth position of the fourth container to
reduce the
height of the two-container stack. The third and fourth containers align
without further
rotation of the third and fourth containers after they are removed from the
mold cavities.
(0012] According to still another method of the present invention, a method of
forming a reduced-height stack of containers provides a mold base that
comprises at least
a first mold cavity and a second mold cavity. The design of the first mold
cavity is
substantially identical to the design of the second mold cavity. This method
makes a first
container in the first mold cavity that has at least one undercut located at a
first position
and at least one undercut receiving structure located at a second position.
The method
also makes a second container in the second mold cavity that has at least one
undercut
located at a third position and at least one undercut receiving structure
located at a fourth
position. The third position is a different location than the first position.
This method
removes the first and second containers from the respective first and second
mold
cavities. At least one of the containers rotates after it is removed from the
mold cavity.
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The method arranges the first and second containers to form a two-container
stack.
The at least one undercut of the first container at the first position aligns
with and fits
within the undercut receiving structure at the fourth position of the second
container
to reduce the height of the two-container stack.
[00131 According to one embodiment, a stack of containers comprises a first
container and a second container. The first container comprises a locking
mechanism. The first container locking mechanism includes a first undercut at
a first
position and a first undercut receiving structure at a second position. The
second
container comprises a locking mechanism. The second container locking
mechanism
includes a second undercut at a third position and a second undercut receiving
structure at a fourth position. The first and second containers stack such
that the first
undercut at the first position is aligned with the second undercut receiving
structure at
the fourth position. The first undercut at the first position contacts the
second
undercut receiving structure at the fourth position to reduce the height of
the stack.
[00141 According to another embodiment, a stack of containers comprises a
first container, a second container, a third container, a fourth container,
and a fifth
container. The first container comprises a locking mechanism. The first
container
locking mechanism includes a first undercut at a first position and a first
undercut
receiving structure at a second position. The second container comprises a
locking
mechanism. The second container locking mechanism includes a second undercut
at
third position and a second undercut receiving structure at a fourth position.
The
third container comprises a locking mechanism. The third container locking
mechanism includes a third undercut at a fifth position and third undercut
receiving
structure at a sixth position. The fourth container comprises a locking
mechanism.
The fourth container locking mechanism includes a fourth undercut at a seventh
position and a fourth undercut receiving structure at an eighth position. The
fifth
container comprises a locking mechanism. The fifth container locking mechanism
includes a fifth undercut at a ninth position and sixth undercut receiving
structure at a
tenth position. The second container aligns so that the second undercut at the
third
position aligns with the first undercut receiving structure at the second
position. The
third container aligns so that the third undercut at the
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fifth position aligns with and fits within the second undercut receiving
structure at the
fourth position. The fourth container aligns such that the fourth undercut at
the
seventh position aligns with and fits within the third undercut receiving
structure at
the sixth position. The fifth container aligns so that the fifth undercut at
the ninth
position aligns with the fourth undercut receiving structure at the eighth
position.
The stack height between the second, third, and fourth containers is
minimized, and
the total stack height is reduced.
According to an aspect of the present invention, there is provided a method
for forming a reduced-height stack of a plurality of containers comprising:
providing a first container having a first locking mechanism, the first
locking
mechanism including a first undercut and a first undercut receiving structure,
the first
undercut being located at a first position, the first undercut receiving
structure being
located at a second position;
providing a second container having a second locking mechanism, the second
locking mechanism including a second undercut and a second undercut receiving
structure, the second undercut being located at a third position, the second
undercut
receiving structure being located at a fourth position, the third position
being a
different location from the first position, the fourth position being a
different location
from the second position, the first and second containers being of generally
equal
sizes; and
arranging the first and second containers to form a stack of a plurality of
containers, wherein the first undercut at the first position aligns with and
fits within
the second undercut receiving structure at the fourth position so as to reduce
the stack
height,
wherein the first and second locking mechanisms securely close a container.
According to another aspect of the present invention, there is provided a
method for forming a reduced-height stack of containers comprising:
providing a mold base comprising a first mold cavity having a first design and
a second mold cavity having a second design, the first and second designs
being
different;
making a first container in the first mold cavity, the first container having
a
first locking mechanism, the first locking mechanism including a first
undercut
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located at a first position and a first undercut receiving structure located
at a second
position;
making a second container in the second mold cavity, the second container
having a second locking mechanism, the second locking mechanism including a
second undercut located at a third position and a second undercut receiving
structure
located at a fourth position, the third position being a different location
from the first
position, and the second position being a different location from the fourth
position;
removing the first and second containers from the respective first and second
mold cavities; and
arranging the first and second containers to form a two-container stack,
wherein the first undercut at the first position aligns with and fits within
the second
undercut receiving structure at the fourth position so as to reduce the height
of the
two-container stack,
wherein the first and second locking mechanisms securely close a container.
According to a further aspect of the present invention, there is provided a
method for forming a reduced-height stack of containers comprising:
providing a mold base comprising a first mold cavity and a second mold
cavity, the design of the first mold cavity being substantially identical to
the design of
the second mold cavity, the second mold cavity being rotated in the mold base
relative to the first mold cavity;
making a first container in the first mold cavity, the first container having
a
first locking mechanism, the first locking mechanism including a first
undercut being
located at a first position and a first undercut receiving structure being
located at a
second position;
making a second container in the second mold cavity, the second container
having a second locking mechanism, the second locking mechanism including a
second undercut being located at a third position and a second undercut
receiving
structure being located at a fourth position, the first position being a
different location
from the third position relative to the mold base;
removing the first and second containers from the respective first and second
mold cavities; and
arranging the first and second containers to form a two-container stack, the
first undercut at the first position being aligned with and fitted within the
second
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undercut receiving structure at the fourth position so as to reduce the height
of the
two-container stack, without further rotating the containers after removing
the
containers from the mold cavities,
wherein the first and second locking mechanisms securely close a container.
According to a further aspect of the present invention, there is provided a
stack of containers comprising:
a first container comprising a first locking mechanism including a first
undercut at a first position and a first undercut receiving structure at a
second
position; and
a second container comprising a second locking mechanism including a
second undercut at a third position and a second undercut receiving structure
at a
fourth position, the first and second containers being stacked such that the
first
undercut at the first position is aligned with the second undercut receiving
structure at
the fourth position, and the first undercut at the first position contacts the
second
undercut receiving structure at the fourth position thereby reducing the stack
height,
wherein the first and second locking mechanisms securely close a container.
According to a further aspect of the present invention, there is provided a
stack of containers comprising:
a first container comprising a first locking mechanism including a first
undercut at a first position and a first undercut receiving structure at a
second
position; and
a second container comprising a second locking mechanism including a
second undercut at a third position and a second undercut receiving structure
at a
fourth position;
a third container comprising a third locking mechanism including a third
undercut at a fifth position and a third undercut receiving structure at a
sixth position;
a fourth container comprising a fourth locking mechanism including a fourth
undercut at a seventh position and a fourth undercut receiving structure at an
eighth
position; and
a fifth container comprising a fifth locking mechanism including a fifth
undercut at a ninth position and a fifth undercut receiving structure at a
tenth
position, wherein the second container is aligned such that the second
undercut at the
third position is aligned with the first undercut receiving structure at the
second
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7c
position, the third container is aligned such that the third undercut at the
fifth position
is aligned with and fitted within the second undercut receiving structure at
the fourth
position, the fourth container is aligned such that the fourth undercut at the
seventh
position is aligned with and fitted within the third undercut receiving
structure at the
sixth position, and the fifth container is aligned such that the fifth
undercut at the
ninth position is aligned with the fourth undercut receiving structure at the
eighth
position, such the stack height between the second, third, and fourth
containers is
minimized and the overall stack height is reduced,
wherein the first, second, third, fourth and fifth locking mechanisms securely
close a container.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Other advantages of the invention will become apparent upon reading the
following detailed description and upon reference to the drawings.
[0016] FIG. 1 is a sectional view of a prior art stack of containers;
[0017] FIG. 2 is a sectional view of another prior art stack of containers;
[0018] FIG. 3 is a sectional view of a locking mechanism for a container
according to one embodiment of the present invention;
[0019] FIG. 4 is a sectional view of a locking mechanism for a container
according to another embodiment of the present invention;
[0020] FIG. 5a is a schematic view of a stack of two containers according to
one
embodiment of the present invention;
[0021] FIG. 5b is a sectional view of a stack of two containers according to
another embodiment of the present invention;
[0022] FIG. 6 is a functional diagram of a mold base to be used to manufacture
containers according to one embodiment of the present invention;
[0023] FIG. 7 is a functional diagram of a mold base to be used to manufacture
containers according to another embodiment of the present invention;
[0024] FIG. 8 is a functional diagram of a mold base according to a further
embodiment of the present invention;
[0025] FIG. 9 is a functional diagram of a mold base according to yet another
embodiment of the present invention;
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[0026] FIG. 10 is a sectional view of a stack of five containers according to
yet
another embodiment of the present invention; and
[0027] FIG. 11 is a functional diagram of a mold base according to yet a
further
embodiment of the present invention.
[0028] While the invention is susceptible to various modifications and
alternative
forms, specific embodiments thereof have been shown by way of example in the
drawings and will herein be described in detail. It should be understood,
however, that it
is not intended to limit the invention to the particular forms disclosed but,
on the
contrary, the intention is to cover all modifications, equivalents, and
alternatives falling
within the spirit and scope of the invention as defined by the appended
claims.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
[0029] Turning now to the drawings, FIG. 3 shows a locking mechanism 12 of a
container I in the closed position. As used in this application the word
"container" is
defined herein as including, trays, lids, bases, bowls, combinations of lids
and bases,
combinations of lids and bowls, bases with hinged lids, bowls with hinged
lids, and
combinations thereof. The locking mechanism 12 comprises a rim flange 14 and a
corresponding undercut 16. The locking mechanism 12 functions by having the
undercut
16 go over the rim flange 14 so as to close the container 1. The undercut 16
of FIG. 3
includes a lead-in surface 18.
[0030] Referring to FIG. 4, a locking mechanism 22 of a container 2 is shown
in
the closed position according to another embodiment. The locking mechanism 22
comprises a rim flange 24 and an undercut 26. The locking mechanism 22
functions by
having the rim flange 24 inserted into the undercut 26 so as to close the
container 2. The
undercut 26 has a lead-in surface 28.
[0031] FIG. 5a shows a schematic view of a two container stack 50 that
includes
a first container 52 and a second container 54. The first and second
containers 52, 54
comprise respective locking mechanisms 22, 32 that further comprise an
undercut
receiving structure 56 and an undercut 58. The undercut receiving structure 56
is
designed to allow the undercuts 58 of the locking mechanisms 22, 32 of the
containers
52, 54 in the stack 50 to be in closer proximity to each other, thus reducing
stack height
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C (FIG. 5b) of the stack 50. The undercut receiving structures 56, as well as
the
undercuts 58, of the locking mechanisms 22, 32 of the containers 52, 54 are
offset
relative to each other in stack 50. This offset allows the undercut receiving
structure 56
of the locking mechanism 32 of the container 54 to align with the undercut 58
the locking
mechanism 22 of the container 52 in the stack 50.
[0032] Turning to FIG. 5b, a partial section view of the container stack 50 is
shown. The stack height C of the stack 50 is reduced because the undercut 58
of the
locking mechanism 32 of the container 54 aligns with the undercut receiving
structure 56
of the locking mechanism 22 of the container 52. The depth of undercut
receiving
structure 56 of the locking mechanism desirably corresponds with the height of
the
undercut 58 of the locking mechanism. For example, a deeper undercut receiving
structure 56, up to the depth of the undercut 58, reduces the stack height C
by a greater
amount, while a shallower undercut receiving structure 56 reduces the stack
height C by
a lesser amount. The shape of the undercut receiving structure 56 may vary
from that
depicted in FIG. 5b, so long as the shape of the undercut receiving structure
56 is
capable of stacking on the undercut 58 of the container below it in the stack
and of
receiving the undercut 58 of the container above it in the stack. Methods of
obtaining the
offset of the undercut receiving structure 56 of the locking mechanism 32 of
the
container 54 relative to the undercut 58 of the locking mechanism 22 of the
container 52
are shown in FIGs. 6 and 7.
[0033] FIG. 6 shows a mold base 60 comprising mold cavities 62a-d for
producing containers. The containers produced by the mold cavities 62a-d are
shown to
be an approximately square shape. Other shapes are contemplated, such as
rectangular,
or polygonal. The mold base 60 is a two by two mold base because it has two
columns
and two rows of mold cavities, and may mold four containers at once. Each of
the mold
cavities 62a-d is shown with four undercut receiving structures 64 and four
undercuts 66.
According to one process, once the containers have been molded, they are
removed from
the mold base 60 and trimmed to the proper shape. The trimmed containers are
then
stacked. It is contemplated that the container stack order may be from bottom
to top as
follows: the container from the mold cavity 62a, the mold cavity 62b, the mold
cavity
62d, and the mold cavity 62c. Stacking the containers in this order reduces
the stack
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height, because the undercuts 66 of the locking mechanisms of the containers
are aligned
with the undercut receiving structures 68 of the locking mechanisms of the
container
directly preceding it in the stack. It is contemplated that the containers
produced by mold
cavities 62a-d of several cycles of mold base 60 may be stacked in the order
described
above so that a stack with more than four containers is produced.
[0034] Other stack orders are also contemplated in the present invention. An
alternate container stack order may be from bottom to top as follows: the
container from
the mold cavity 62a, the mold cavity 62d, the mold cavity 62c, and the mold
cavity 62b.
This order reduces the stack height, but the reduction in stack height is not
as significant
as the prior stacking order. The stack height is not reduced as much in this
stacking order
because undercut to undercut contact occurs in the stack of containers.
[0035] It is further contemplated that larger mold bases, such as a four by
two
cavity mold base, or an eight by four cavity mold base may be used in the
current
invention. It is also contemplated that a stack of containers would be formed
from each
column of the mold base 60. According to one process, the order of the first
stack of
containers may be from bottom to top as follows: the container from the mold
cavity 62a,
the mold cavity 62c. The order of the second stack may be from bottom to top
as
follows: the container from the mold cavity 62b the mold cavity 62d. It is
contemplated
that the containers of several cycles of mold base 60 may be stacked in this
order to
produce two stacks with more than two containers per stack. It is further
contemplated
that a non-matrix mold may be used.
[0036] The embodiment depicted in FIG. 7 is similar to that depicted in FIG. 6
except that the mold base 70 produces containers that have a generally
circular shape in
mold cavities 72a-d. Other shapes are contemplated, such as oval or oblong.
The mold
base 70 depicted in FIG. 7 is a two by two mold base because it has two
columns and two
rows of mold cavities and may mold four containers at once. Each of the mold
cavities
72a-d is shown with three undercut receiving structures 74 and three undercuts
76.
According to one process, once the containers have been molded, they are
removed from
the mold base 70 and trimmed to the proper shape. The trimmed containers
produced by
the mold cavities 72a-d are then stacked. It is contemplated that the stack
order may be
from bottom to top as follows: the container from the mold cavity 72a, the
mold cavity
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72c, the mold cavity 72b, and the mold cavity 72d. Stacking the containers in
this order
reduces the stack height, because the undercuts 76 of the locking mechanisms
of the
containers are aligned with the undercut receiving structures 78 of the
locking
mechanism of the container directly preceding it in the stack. It is
contemplated that the
containers of several cycles of mold base 70 would be stacked in the order
described
above so that a stack with more than four containers was produced.
[0037] Other stack orders are also contemplated in the present invention.
Using
the mold 70, an alternate stack order may be from bottom to top as follows:
the container
from the mold cavity 72a, the mold cavity 72b, the mold cavity 72c, and the
mold cavity
72d. This order reduces the stack height, but the reduction in stack height is
not reduced
as much as the prior stacking order using containers formed from mold 70, as
undercut to
undercut contact is taking place.
[0038] It is further contemplated that larger mold bases, such as a four by
two
cavity mold base, or an eight by four cavity mold base may be used in the
current
.invention, or any other matrix mold base may be used. It is also contemplated
that a
stack of containers may be formed from each column of the mold base 70.
According to
one process, the order of the first stack may be from bottom to top as
follows: the
container from the mold cavity 72a, the mold cavity 72c. The order of the
second stack
may be from bottom to top as follows: the container from the mold cavity 72b,
the mold
cavity 72d. It is contemplated that the containers of several cycles of the
mold base 70
may be stacked in this order to produce two stacks with more than two
containers per
stack. It is also contemplated that non-matrix mold base may be used.
[0039] Turning now to FIG. 8, a mold base 80 is shown that is capable of
producing three containers per cycle in mold cavities 82a-c. Mold base 80 is a
1 by 3
mold base because it has one column of mold cavities and three rows of mold
cavities.
The mold cavities 82a-c are identical except that the first cavity 82a is at a
first angle D
relative to the mold base 80, the second cavity 82b is at a second angle E
relative to the
mold base 80, and the third cavity 82c is at a third angle F relative to the
mold base 80.
The first angle D is from about 80 to about 100 , the second angle E is from
about 50 to
about 70 , and the third angle F is from about 20 to about 40 .
CA 02523284 2005-10-11
12
[0040] Each of the mold cavities 82a-c is shown with three undercut receiving
structures 84 and three undercuts 86. According to one process, once the
containers are
molded they are removed from the mold base 80 and trimmed to the proper shape.
The
trimmed containers are then stacked. It is contemplated that the stack order
may be from
bottom to top as follows: the container from the mold cavity 82a, the mold
cavity 82c,
and finally the mold cavity 82c. Stacking the containers in this order reduces
the stack
height, because the undercuts 86 of the locking mechanisms of the containers
are in
alignment with the undercut receiving structure 88 of the locking mechanism of
the
container directly preceding it in the stack.
[0041] It is contemplated that the containers of several cycles of mold base
80
would be stacked in the order described above so that a stack with more than
three
containers is produced.
[0042] It is further contemplated that larger mold bases, such as a two by
three
cavity mold base, or an eight by four cavity mold base may be used in the
current
invention. It is also contemplated that a stack of containers would be formed
from each
column of a multi-column mold base. It is also contemplated that a non-matrix
mold
base may be used.
[0043] It is additionally contemplated that the mold cavities as shown in FIG.
8
may have a different shape from the generally round shape depicted. For
example, the
mold cavities may be generally polygonal. If generally polygonal mold cavities
are
employed, the angle of rotation of the mold cavities within the mold base
would vary
from that described in connection to FIG. 8. For example, if a generally
rectangular mold
cavity is employed the angle of rotation between each mold cavities is
approximately one
hundred and eighty degrees (180).
(0044] It is additionally contemplated that the .methods of using mold bases
70,
80 may be combined such that a mold base with mold cavities of varying
geometry are
combined with the rotation of the mold cavities relative to the mold base to
produce a
stack of containers with undercuts aligning with the undercut receiving
structures of the
preceding container in the stack.
(0045] Referring to FIG. 9, a mold base 90 is shown comprising mold cavities
92a-f. The mold base 90 of FIG. 9 is a two by three mold base because it has
two
CA 02523284 2005-10-11
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columns of mold cavities and three rows of mold cavities and is capable of
molding six
containers at once. Each of the mold cavities 92a-f of the mold base 90 is of
an
approximately polygonal shape. Each of the mold cavities 92a-f is shown with
four
undercut receiving structures 94 and four undercuts 96. According to one
process, there
are two mold cavity designs in mold base 90 of FIG. 9. The mold cavities 92a,
92c, and
92e are the first mold cavity design, and mold cavities 92b, 92d, and 92f are
the second
mold cavity design. Once the containers have been molded they are removed from
the
mold base 90 and trimmed to the proper shape. The trimmed containers are then
stacked.
It is contemplated that the stack order may be from bottom to top as follows:
the
container from the mold cavity 92a, the mold cavity 92b, the mold cavity 92c,
the mold
cavity 92d, the mold cavity 92e, and the mold cavity 92f. Stacking the
containers in this
order will reduce the stack height, because the undercuts 96 of the locking
mechanisms
of the containers are in alignment with the undercut receiving structures 94
of the locking
mechanisms of the container directly preceding it in the stack. It is
contemplated that the
containers produced by mold cavities 92a-f of several cycles of mold base 90
would be
stacked in the order described above so that a stack with more than six
containers is
produced.
[0046] It is further contemplated that larger mold bases, such as a four by
two
cavity mold base, or an eight by four cavity mold base may be used in the
current
invention. It is also contemplated that a stack of containers would be formed
from each
column of mold base 90. According to one process, the order of the first stack
may be
from bottom to top as follows: the container from the mold cavity 92a, the
mold cavity
92b, and the mold cavity 92c. The order of the second stack may be from bottom
to top
as follows: the container from the mold cavity 92d, the mold cavity 92e, and
the mold
cavity 92f. It is further contemplated that the containers of several cycles
of mold base
90 may be stacked in this order to produce two stacks with more than three
containers per
stack.
[0047] FIG. 10 shows a partial stack 100 of containers produced by a column of
the mold base 90 of FIG. 9. The stack 100 comprises containers 102-110, the
containers
are from three cycles of mold base 90. The first container 102 is from the
third cycle of
the mold base 90, the second, third, and fourth containers 104,106,108 are
from the
CA 02523284 2005-10-11
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second cycle of the mold base 90, and the fifth container 110 is from the
first cycle of the
mold base 90. The container 102 at the top of the stack, and the container
that is second
from the bottom of the stack 108 were produced in the third mold cavity 92c of
the mold
base 90 of FIG. 9. The second container from the top 104 of the stack 100 and
the
bottom container 110 of the stack 100 were produced in the first mold cavity
92a of the
mold base 90 of FIG. 9. The middle container 106 of the stack 100 were
produced in the
second mold cavity 92b of FIG. 9.
[0048] The middle container 106 of the stack 100 is the only container that is
made by a mold cavity with the second mold cavity design in this stack 100.
Therefore,
the undercuts of the locking mechanism of the container 104 are in alignment
with the
undercut receiving structures of the locking mechanism of the container 106,
and the
undercuts of the locking mechanism of the container 106 are in alignment with
the
undercut receiving structures of the locking mechanism of the container 108.
However,
the undercuts of the locking mechanism of the container 102 are in alignment
with the
undercuts of the locking mechanism of the container 104, and the undercuts of
the
locking mechanism of the container 108 are in alignment with the undercuts of
the
locking mechanism of the container 110. The overall height of stack 100
therefore is not
truly optimized, as undercut to undercut alignment is occurring among the
locking
mechanisms of the containers. However, this undercut to undercut alignment of
the
locking mechanisms is unavoidable when an odd number of rows of mold cavities
are
present in a mold base, and the shape of the containers prevents the rotation
of the
containers when forming the stack 100.
[0049] This process reduces the stack height of the stack 100, since locations
are
present where the undercuts of the locking mechanism of one container are in
alignment
with the undercut receiving structures of the locking mechanism of the
preceding
container. For example, a stack height H between the second container 104 from
the top
of the stack 100 and the middle container 106 of the stack 100, and between
the middle
container 106 of the stack 100 and the second container from the bottom 108 of
the stack
100 is the reduced stack height. A stack height G between the top container
102 and the
second container 104 from the top of the stack 100 and between the second
container
from the bottom 108 and the bottom container 110 is the full stack height.
CA 02523284 2005-10-11
[0050] Referring to FIG. 11, a mold base 200 is shown comprising mold cavities
210a,b. The mold base 200 of FIG. 11 is a one by two mold base because it has
one
columns of mold cavities and two rows of mold cavities and is capable of
molding two
containers at once. Each of the mold cavities 210a,b of the mold base 200 is
of an
approximately polygonal shape. Each of the mold cavities 210a,b is shown with
four
undercut receiving structures 212 and four undercuts 214. As shown in FIG. 11,
each of
the undercut receiving structures 212 and each of the undercuts 214 are
located generally
within each of the corners of the containers formed by the cavities 210a,b and
are at a
generally diagonal orientation. According to one process, there are two mold
cavity
designs in mold base 200 of FIG. 11. The mold cavity 210a is a first mold
cavity design,
and mold cavity 210b is a second mold cavity design. Once the containers have
been
molded they are removed from the mold base 200 and trimmed to the proper
shape. The
trimmed containers are then stacked. It is contemplated that the stack order
may be from
bottom to top as follows: the container from the mold cavity 210a, the mold
cavity 210b.
Stacking the containers in this order will reduce the stack height, because
the undercuts
214 of the locking mechanisms of the containers are in alignment with the
undercut
receiving structures 212 of the locking mechanisms of the container directly
preceding it
in the stack. It is contemplated that the containers produced by mold cavities
210a,b of
several cycles of mold base 200 would be stacked in the order described above
so that a
stack with more than two containers is produced.
[0051] It is further contemplated that undercuts and undercut receiving
structures
located generally within a corner of a container at a generally diagonal
orientation may
vary from that depicted in FIG. 11. For example, it is contemplated that a
mold base may
contain a first mold cavity that contains two undercut receiving structures in
a first corner
and a second corner along a first lateral edge, and two undercuts in a third
corner and a
fourth corner along a second lateral edge, generally opposite the first
lateral edge. The
mold base contains a second mold cavity that contains two undercut receiving
structures
in a fifth corner and a sixth corner along a third lateral edge, and two
undercuts in a
seventh corner and an eighth corner along a forth lateral edge, generally
opposite the
third lateral edge. A first container made in the first mold cavity would be
stacked with a
CA 02523284 2005-10-11
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second container made in the second mold cavity such that the under cut
receiving
structures of the second container align with the undercuts of the first
container.
[0052] It is further contemplated that various methods of reducing the
stacking
height of containers may be combined. For example, it is contemplated that a
mold base
may have three mold cavities, wherein the first mold cavity and the second
mold cavity
have generally identical designs that are at a different orientation relative
to each other,
and the third mold cavity has a different design.
[0053] It is still further contemplated that a mold base may have three mold
cavities, wherein the first mold cavity and the second mold cavities have a
different
design, and the third mold cavity has a design that is generally identical to
the design of
the first mold cavity, but the third mold cavity is rotated within the mold
base relative to
the first mold cavity.
[0054] The amount of stack height reduction achieved will vary based on the
geometry of the container that is being stacked. According to one embodiment,
the stack
height was reduced by about sixty percent (60%). In an embodiment of the
present
invention where only partial stack height reduction may be achieved based on
the number
of mold cavities and the mold base cavity geometry the stack may only be
reduced by
about twenty percent (20%).
[0055] The reduction in stack height reduces the cube size of the
transportation
packaging for a stack of containers. A reduced cube size for the
transportation packaging
reduces the transportation costs for transporting a stack of containers, as
smaller
containers are generally more cost effective to ship than larger containers. A
reduction in
the cube size for the transportation packaging also lowers the cost of storing
the
containers before the are used, because the smaller transportation packaging
occupies
less storage space.
[0056] The containers of the present invention are typically formed from
polymeric materials, but may be formed from materials such as paper or metal.
The
polymeric containers are typically formed from orientated polystyrene (OPS),
polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyolefins (e.g.,
polypropylene), and combinations thereof. It is contemplated that other
materials may be
used to form the polymeric containers. The containers may be made from a
mineral-
CA 02523284 2005-10-11
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filled polymeric material such as, for example, talc or calcium carbonate-
filled
polyolefin. An example of paper that may be used in forming the containers is
paperboard or molded fiber. Paperboard and molded fiber typically have a
sufficient
coefficient of friction to maintain the first and second containers in a
lockable position.
[0057] The materials used in forming the containers may assist in releasably
locking the containers. For example, the material(s) forming the containers
may have a
fairly tacky laminate on one side that corresponds with a fairly tacky
laminate on the
opposing side, resulting in a desirable releasably lockable container. It is
contemplated
that additives may be added to the containers.
[0058] The containers of the present invention are typically made from a
thermoforming process. However, it is also contemplated that the containers
may be
made using other processes known in the art such as, but not limited to, an
injection
molding process, a rotomolding process, a rotational molding on a planar
surface
process, a stamping process, or a molded fiber process.
[0059] The containers of the present invention are typically disposable, but
it is
contemplated that they may be reused at a future time.
[0060] As discussed above, the containers may be used with food items. A
method of using such containers includes placing the food and locking the
container to
form a container with food therein. The container is then placed in a heating
apparatus
and heated. Typical heating apparatuses include microwaves and conventional
ovens.
The containers may contain solid food products. The containers may be used for
storage
in the refrigerator and/or the freezer.
[0061] The thickness of the container generally ranges from about 0.002 to
about
0.25 inch, but is typically from about 0.005 to about 0.04 inch. The
containers may be
opaque or a variety of colors or color combinations. The containers may be
transparent if
it is desired for the customer to ascertain the nature of the accommodated
product and the
condition thereof without having to open the container.
[0062] While particular embodiments and applications of the present invention
have been illustrated and described, it is to be understood that the invention
is not limited
to the precise construction and compositions disclosed herein and that various
modifications, changes, and variations may be apparent from the foregoing
descriptions
CA 02523284 2005-10-11
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without departing from the spirit and scope of the invention as defined in the
appended
claims.
