Food container

A thermoplastic molded or formed container has four trapezoidal walls that incline upwardly and outwardly upstanding from a bottom wall to create a top opening that is larger than the bottom wall. Each side wall has a closure flap that is connected to it at an upper edge by a living hinge. A locking handle member in the shape of a loop with locking extensions extends from an edge of one flap and engages a slot in an opposite flap. The handle member is a loop with locking projections which engage the opposite flap surface, the handle member passing through the slot for manually grasping. The container may be square or rectangular in transverse section or a combination thereof with a conical truncated section.

BACKGROUND OF THE INVENTION 
This invention relates to food containers, and, more particularly, to 
molded thermoplastic food containers. 
Of interest is commonly owned U.S. Pat. No. 5,489,063 in the name of the 
present inventors and incorporated by reference herein. 
Food containers made from folded cardboard--such as SBS or bleached 
board--or similar paper-like materials are known. For example, see U.S. 
Pat. No. 1,088,964. Once the cardboard has been appropriately folded, the 
resulting container typically includes a flat bottom surrounded by four 
sloped upstanding side walls, the upper edges of which define an opening 
which is above and opposite the flat bottom. The opening is closeable by 
four flaps each of which is connected to the upper edge of one of the side 
walls. 
The flaps are outwardly folded to expose the opening to permit placement of 
food into the container. Thereafter, the flaps are inwardly folded to 
cover and close the opening. One of the flaps may include a slit or slot 
near its free edge and the diametrically opposed flap may include a tab or 
tongue on its free edge. The tab may be interfitted into the slot to hold 
the flaps closed. The ends of a piece of formed wire are inserted through 
and attached to portions of the folded cardboard to constitute a handle 
for the container and to maintain the container in its folded condition. 
The slope of the side walls of such folded cardboard food containers has 
traditionally been approximately 6.degree. away from the vertical major 
axis of the container. Such a 60.degree. slope offers several advantages. 
Specifically, the 6.degree. slope permits empty folded containers with 
their flaps unfolded and not covering their openings to be conveniently 
nested and stacked and thereafter separated for use and storage. Nesting 
and stacking is achieved by inserting an upper container into a lower 
container. An angle much smaller than 6.degree. (i.e., about 4.degree.) 
results in the containers becoming self-locking or jammed together and 
difficult to separate. A significantly larger angle may render a nested 
stack of the containers unstable and permit the stack to fall over. 
Folded cardboard containers have several disadvantages. First, much of the 
cardboard which goes into the folded container is "wasted" in that it 
serves no function other than to permit the container to be folded into a 
leak-proof unit. Those portions of the folded cardboard to which the ends 
of the wire handle are usually connected constitute, for the most part, 
excess cardboard, the elimination of which would constitute a savings. 
Second, although the typical cardboard (e.g., SBS or bleached board) used 
to form folded food containers often includes a moisture-resistant 
coating, the presence of food in a container for a substantial period time 
can nonetheless degrade the cardboard; it is not certain that such 
cardboard containers are suitable for long term storage of food therein. 
Third, the presence of a wire handle on the container renders these 
containers generally unsuitable for reheating the contents thereof in 
certain microwave ovens, the presence of metal in which can cause certain 
operating difficulties. Fourth, removal of the metal handle--to facilitate 
microwave heating or for other reasons--permits the cardboard container to 
unfold and can destroy its leak-proof integrity. Fifth, although the 
traditional cardboard container, as noted, has its side walls sloped at 
6.degree. from the vertical to facilitate nested stacking and removal of 
containers from the stack, the surface of the cardboard and the ease of 
forcing together adjacent containers in the stack sometimes renders 
inconvenient the removal of a single container from the stack for the 
placement of food therein. 
An object of the present invention is the provision of a molded plastic 
container which meets the criteria of the traditional folded cardboard 
container, for example, those used for the sale of oriental foods, but 
which avoids the disadvantages of such prior art containers. 
SUMMARY OF THE INVENTION 
A container according to the present invention comprises a molded or formed 
one piece plastic container having a bottom wall and a plurality of 
integral, contiguous upstanding side walls defining a top opening and a 
plurality of upper edges. A flap is associated with the upper edge of each 
of a plurality of the side walls. Living hinge means join one edge of each 
flap to the upper edge of its associated side wall and is for permitting 
the flaps to be inwardly folded to overlie and close the opening and fully 
unfolded to uncover the opening. 
In one aspect, there are at least three of the side walls and at least two 
flaps. 
In a further aspect, the side walls are planar and there are four side 
walls and at least two flaps. 
In still a further aspect, there are four flaps, one associated with each 
side walls. 
In a further aspect, two of the side walls and two of the plurality of 
flaps are in opposing relation, the container including locking means 
coupled to each of the two opposing flaps for releasably retaining all of 
the flaps in place in a locked condition after they have been inwardly 
folded. 
In yet another aspect, the locking means comprises a slot in one of the two 
flaps and a locking member secured to the other of the two flaps, the 
locking member being arranged to engage the slot and form a handle for the 
container when engaged while simultaneously locking the flaps in place.

DETAILED DESCRIPTION 
In FIG. 1, a molded plastic container 10 according to an embodiment of the 
present invention may comprise a plurality of different moldable or 
formable plastic materials, including, without limitation, polypropylene, 
polyethylene, PET or copolymers of the foregoing, and may be formed by a 
variety of techniques such as injection molding and thermo (or vacuum) 
forming. The container 10 is described in the aforementioned U.S. Pat. No. 
5,489,063 incorporated by reference herein. 
In FIGS. 1-3, the molded plastic container 10 of the present invention has 
the general configuration and appearance of typical prior art folded 
cardboard container of U.S. Pat. No. 1,088,964 used for the storage, sale 
and off-premises consumption of hot and cold foods such as oriental foods. 
The container 10 has a generally planar rectangular bottom wall 12 and 
four integral, contiguous upstanding planar side walls 14, 16, 18 and 20 
having respective upper edges 14a, 16a, 18a and 20a. The bottom wall 12 
may have a depression (not shown) for molding purposes or otherwise. The 
walls are relatively thin and have a thickness similar to the prior art 
similar cardboard or paperboard containers. 
The side walls define a top opening 22 in communication with the interior 
cavity volume of the container 10. Associated with the upper edges 14a, 
16a, 18a and 20a are respective flaps 24, 26, 28 and 30. The flaps are one 
piece and integral and contiguous with the respective side walls through 
living hinges. 
The flaps 24, 26, 28 and 30 are joined to the edges 14a, 16a, 18a and 20a 
by hinges 40, which are, preferably, so-called living hinges. As is well 
known, the living hinges 40 constitute decreased thickness portions of 
molded plastic which permit the flaps 24, 26, 28 and 30 to be pivoted or 
rotated relative to the respective side walls 14, 16, 18 and 20 to which 
they are connected. The living hinges 40 permit each flap 14, 16, 18, and 
20 to be inwardly folded to overlie and together close the opening 22 and, 
as shown in FIGS. 1-3, to be fully unfolded to uncover the opening 22. The 
living hinges 40 are formed during the molding or forming of the container 
10 wherein the entire container and flaps are one piece. The flaps 
individually are smaller in area than the top opening 22, but together, 
when folded over one another, are juxtaposed with and close the opening. 
A flap locking arrangement 42 maintains the flaps 24, 26, 28 and 30 in the 
folded condition (not shown) after they have been inwardly folded closing 
the opening 22. Preferably, the flaps 26 and 30 are folded radially 
inwardly toward one another in overlying relation first and then the flaps 
24 and 28 are folded inwardly to overlie the flaps 26 and 30. In FIGS. 
1-3, the locking arrangement 42 preferably constitutes a slot 44, which 
may also be a slit, formed through one flap 28 near its free edge 28a and 
a tab 46 or tongue formed integral and contiguous with as one piece 
therewith and extending from the free edge 24a of the diametrically 
opposed flap 24. The tab 46 has two opposing slots adjacent to the flap 24 
edge 24a to engage and lock to the flap 28 after the tab is inserted into 
the slot 44. The locking member or tab 46 is arranged to engage and pass 
through the slot 44. The tab 46 terminates in terminal undercut 
extensions. Sufficient insertion of the locking member into the slot 44 
causes the extensions to engage and be momentarily deformed by the termini 
edges of the slot 44, following which continued insertion of the tab 46 
permits the extensions to become undeformed to engage and lock to the 
surface of the slot-containing flap adjacent the slot termini. 
As noted, the two flaps 26 and 30 are first folded inwardly to partially 
close the opening 20 and then following inward folding of the flaps 24 and 
28, the tab 46 is inserted into the slot 44 to retain all of the flaps 
folded over the opening 22. Other locking arrangements, such as a 
differently shaped tab and/or slots or interlocking tabs, may also be 
employed. 
For example, such different locking arrangements may include the locking 
arrangement of FIGS. 7 and 8 to be described below herein. 
A locking stud 50 is on opposed side walls, preferably on walls 14 and 18 
with which the flaps 24 and 28 are respectively associated. The stud 50 is 
employed to mount a strap 52 (FIGS. 4-6) to the container 10. The studs 50 
each preferably includes an arrowhead type conical or tapered projection 
54 extending from a cylindrical shank attached to and extending from the 
respective side wall 14 and 18. The projection 54 extends away from the 
side walls 14 and 18 near the upper edges 14a and 18a thereof. 
The strap 52 preferably is molded thermoplastic having a single hole 56 at 
one end thereof and a plurality or series of holes 58 formed at and 
extending away from the other opposite end of the strap 52. In use, the 
hole 56 is forced over one projection 54 until the hole 56 resiliently 
bypasses the head and is retained on the stud 50 shank. Thereafter, as 
shown in FIG. 5, a hole 58 at or near the other end of the strap 52 may be 
similarly placed over the stud 50 projection 54 on the opposite side wall 
so that the strap 52 assumes the configuration of a carrying handle, FIG. 
5. 
In FIG. 6, the strap 52 may also serve the function of a flap hold-down. 
Specifically, after placing the hole 56 over one stud 50 projection 54, a 
hole 58 remote from the other end of the strap may be placed over the 
other stud 54 so that the strap 52 conforms to and holds down the inwardly 
folded flaps 24, 26, 28 and 30 of the container 10. 
The strap 52 may be affixed to the studs 50 by the manufacturer or supplier 
or, as is preferable, by the end user, in which latter event containers 10 
and straps 52 are supplied separately and disassociated. The studs 50 may 
have other configurations or may be replaced by functionally equivalent 
members, such as hooks or the like. Further, if wire handles are deemed to 
be not disadvantageous, the studs 50 projections 54 may be replaced by a 
respective hole through each stud 50 shank for attachment thereto of such 
wire handles. 
Molded into the container 10 on the interior of on or more of the side 
walls 14, 16, 18 and 20 or on the bottom 12 are preferably one or more 
ledges or stops 60. When the containers 10 are stored prior to use it is 
preferred that they be nested in stacked relation. To this end, the side 
walls 14, 16, 18 and 20 of the container 10 may be formed at an angle, 
preferably approximately 6.degree. relative to the vertical in FIGS. 1 and 
2 from the top to bottom of the drawing figure. The handle-mounting studs 
50 (or their functional equivalents) and the ledges 60 ensure that a 
containers 10 may be conveniently removed from the nested stack. 
When a first container 10 is placed within a second container 10, following 
a certain amount of insertion, the studs 50 on the opposed walls 14 and 18 
contact the edges 14a and 18a of the container 10 into which the first 
container 10 is inserted. This engagement limits the amount of inward 
insertion of the first container 10 into the second container 10 to that 
which permits the inserted container to be later easily removed-without 
jamming or self-locking. Similarly, the bottom of the first inserted 
container preferably engages the ledges 60 at approximately the same time 
that the studs 50 of the inserted container 10 engage the edges 14a and 
18a of the second container. It should be clear that the studs 50 alone or 
the ledges 60 alone may serve the function of limiting insertion of the 
nested containers 10 into each other in a stack of containers 10 to permit 
convenient removal thereof. It is preferred, however, that both be 
present. 
In FIG. 7, container 70 in a further embodiment comprises a preferably 
planar circular bottom wall 72. A truncated conical side wall 74 is 
integral with and molded or otherwise formed as a one piece construction 
with the bottom wall 72. Side wall 74 forms a truncated conical bottom 
volume. The side wall 74 preferably tapers relative to the vertical axis 
76 from the top to bottom of the container at an angle of about 6.degree. 
to permit nesting of the containers 70 as discussed above in connection 
with container 10. 
An upper portion 78 of side wall merges into four opposing planar side 
walls 80, 82, 84 and 86 terminating in a preferably square or rectangular 
opening 88 at the container 70 top. The planar side walls are integral, 
contiguous and formed as one piece with the side wall 74. The planar side 
walls form a polygon upper volume contiguous with the lower volume. This 
container would be similar to a solid object that was initially square in 
cross section and truncated. The bottom section portion would then be 
reduced in diametrical dimension by forming this section into a truncated 
conical section. The junction between the planar side walls and the 
conical section are rounded and gradual so no line of demarcation is 
present therebetween. 
The opening 88 may also have other polygon shapes, three, five, six or more 
sides for example, according to a given implementation. The side walls 80, 
82,84 and 86 each gradually curve and terminate at a respective upper 
linear edge formed into respective linear living hinges 80a, 82a, 84a and 
86a. 
Flaps 90, 92, 94 and 96 are connected to respective hinges 80a, 84a, 86a 
and 88a. The flaps 90, 92, 94 and 96, the associated hinges, the 
associated side walls and bottom wall are formed or molded as a one piece 
plastic structure of generally uniform thickness except for the living 
hinges which are reduced thickness to permit the hinge function. 
Preferably opposite flaps 90 and 92 are of generally the same peripheral 
dimensions. Opposite flaps 94 and 96 are also preferably of the same 
peripheral dimensions. 
An outwardly extending step 89 forming an upwardly facing shoulder is 
formed in each side wall adjacent to the corresponding hinge 80a, 82a, 84a 
and 86a. The step 89 is present on the interior and external surfaces of 
the side walls. The step 89 permits stacked nesting of the containers 70 
as the ledges 60 in the embodiment of FIGS. 1 and 2. 
The external portion of the step 89 of an inner nested container rests on 
the living hinges of the outer nested container to preclude wedged jamming 
of the nested containers. The steps extend for the length of each living 
hinge and do not damage the hinges because the weight of the stacked 
containers is distributed over the length of the hinges. 
The flaps 90, 92, 94 and 96 enclose the opening 88 in overlying relation 
when folded radially inwardly toward one another. A locking arrangement 98 
releasably secures the flaps closed. The arrangement 98 includes a tab 
loop member 100 extending from edge 102 of flap 96 distal hinge 82a and a 
slot 104 adjacent to edge 106 of flap 94 distal hinge 86a. The loop member 
serves as a locking arrangement and as a handle for the container. 
The loop member 100 defines an opening 108. A pair of slots 110 are between 
the member 100 and edge 102 forming a locking projection 112 on opposite 
sides of the member 100. The locking projections 112 comprise outwardly 
tapered flared portions for forming the slots 110. The member 100 forms a 
locking tab by insertion of the member 100 through the slot 104 in flap 
94, the projections 112 engaging and locking to the flap 94. The loop 
member 100 serves as a locking tab releasably retaining and locking the 
flaps closed. No handle securing projections such as projections 54 of the 
embodiment of FIG. 2 are needed. 
The loop member 100 when inserted through the slot 104 projects 
substantially beyond the flap 94 in the closed condition. The loop member 
100 is upright and extends generally along axis 76 away from the container 
70 when the flaps are closed and locked. Loop member 100 thus also forms a 
handle for the container 70. No further handle or strap is required to 
either hold the flaps closed or to provide a carrying structure for the 
filled container, which may be filled with hot food. The loop member 100 
is sufficiently large to permit one or more fingers of a person to pass 
therethrough for safely carrying the container. The container 70 is formed 
as a one piece integral molded or formed structure with all walls and 
flaps and the loop member contiguous as shown. 
The loop member while generally looped and elongate may be other shapes. 
Since the projections 112 lock to the flap 94 at slot 104, the remainder 
of the loop member need only be dimensioned and shaped to pass through the 
slot 104. By making the loop member sufficiently flexible by reason of its 
thickness and flexibility of its material from which it is formed, it can 
be folded to pass through the slot 104 and then unfolded into a relatively 
large handle. The slot can be shaped and dimensioned accordingly. 
By way of example, the loop member may be a solid tab like member similar 
to the tab 46 of FIG. 3, but relatively more elongate to serve as a 
convenient handle. In a further example, the loop member may be formed as 
a tether like device, e.g., an elongate strap whose end distal the 
projections 112 remains unattached to the container but useful for 
grasping as a handle. 
By way of further example, the loop member may be a circular or polygon in 
transverse section cylindrical, but pliable tether (not shown) extending 
from projections 112. The slot 104 may have a central enlarged opening 
(not shown) shaped to permit the tether to pass therethrough. Once the 
projections are releasably locked to the slot, the enlarged central 
opening has no significant effect on the locking action of the projections 
which are at opposing edges of the slot distal the central opening. In the 
alternative, the locking projections may comprise a conical section 
tapering outwardly at the base of the tether where attached to a flap. 
In FIG. 8, a container 114 according to a further embodiment includes a 
preferably circular planar bottom wall 116 and an upstanding truncated 
conical side wall 118 similar to the side wall 74 of the container 70, 
FIG. 7. The annular tapered side wall 118 is formed into four planar side 
walls 120, 122, 124 and 126. The side walls each have a line of 
demarcation 129 separating the planar side walls from the conical side 
wall 118. The line of demarcation is present because in this case the 
planar side walls are formed as if the container was originally a tapered 
conical segment from top to bottom and the planar side walls formed by 
reducing the diameter of the conical portion at the upper end of the 
container. Thus this container 114 is somewhat similar to the container 
70, FIG. 7. 
Flaps 90', 92', 94' and 96' which may be identical to flaps 90, 92, 94 and 
96 of FIG. 7, are connected to the respective side walls 122, 126, 120 and 
124 by respective corresponding living hinges 122a, 126a, 120a and 124a. 
Hinges 120a, 122a, 124a, and 126a extend for the full extent of the 
junction between the corresponding side wall and flap as do all of the 
hinges in the various embodiments disclosed herein. However, the hinges 
may extend partially along each flap with the remaining portion of the 
junction of each flap and corresponding side wall spaced by a slot (not 
shown). 
A step 89' is formed in the planar side walls similar to step 89, FIG. 7. 
This step is for the same purpose, i.e., to permit stacking in nested 
relation of the containers 114 without wedging of the nested containers. 
A handle member 100 is secured to flap 96' and a slot 104 is formed in the 
flap 94' to receive the member 100 as described above in connection with 
the FIG. 7 embodiment. 
In FIG. 9, a further embodiment includes a container 130 which is 
substantially identical to the container of FIG. 1 except the studs 50 and 
projections 54 are omitted. The side walls and living hinges of container 
130 are identical to those of container 10 of FIGS. 1-2. A further 
exception, is that a handle loop member 132 identical to the loop member 
98 of FIG. 7 is attached to the free edge of flap 134. The opposing flap 
136 is identical to flap 28, FIGS. 1-3. Flap 136 has a slot (not shown) 
through which the handle loop member 132 is passed. Four flaps 134, 136, 
138 and 140 are employed in the container 130, each hinged to a 
corresponding sidewall. 
In a further embodiment (not shown), the flaps may be dimensioned so as to 
overlap one another in interlocking overlying relation without the need 
for further locking tabs or structure. For example, the flaps may each 
overly one another and the opening of the container an extent so that by 
bending the flaps at corners thereof, the corners may be manually forced 
over and under one another to form a releasable locking arrangement. 
Those skilled in the art will appreciate that changes to the embodiments 
described herein, which are given by way of illustration and not 
limitation, may be made without departing from the spirit and scope of the 
following claims. For example, a square or rectangular container is 
illustrated with four flaps. However, the container may be triangular in 
plan view and may have a flap associated with only two of the three side 
walls. Also, two flaps may be associated with four or more side walls, as 
long as the flaps are dimensioned to close the container opening. In this 
case two living hinges are provided. Also, three flaps or more flaps may 
also be provided with a four or more sided container.