Lunch box carton and a blank for forming same

A lunch box carton made from a single cardboard blank with an attractive reclosable gabled top and an auto-erecting lock bottom. The lunch box carton has a tapered side wall construction, forming an inverted truncated pyramidal configuration to enable stacked nesting of a plurality of the cartons. The lunch box carton is of a knock-down variety which can be shipped in a flattened configuration and is further provided with an auto-erecting lock bottom to facilitate erection of the carton. The top portion of the carton is attractively gabled in configuration, providing additional interior volume, and includes integral carrying handles. Further, the carton is provided with movable wedge shaped locking portions pivotally connected on the top of the carton which can be interengaged with apertures provided in the side wall of the carton, to securely lock the carton in the closed condition. In addition, to prevent lateral shifting of the top of the carton, the carrying handles are secured by folding tabs.

The subject invention relates to a new and improved lunch box carton and a 
blank for forming the same, with an attractive recloseable gabled top and 
an anto-erecting lock bottom. More particularly, the subject invention 
relates to a lunch box carton whose upper portion is closed by outwardly 
pushing two side panels of the top portion of the carton to form a wedge 
shaped locking configuration, thus causing the upper portions of the other 
opposed upper side panels to be drawn together forming a gabled 
configuration, whereupon the wedge shaped locking portions are inserted 
into generally triangular shaped openings cut into the side of the carton, 
resulting in an interengagement, thus sealing the carton. 
The carton is intended to be used for storage and transportation of various 
items such as food or toys. To reduce shipping costs, it is a requirement 
that such cartons be shipped from the manufacturer in a flattened 
configuration. In applications where the carton is a take-out container 
for food, as for example in a fast food establishment, it is desirable 
that the carton be readily erected by the retailer, preferably during 
off-peak hours. Thus, it is also desirable, when many cartons are erected 
at one time, that the erected carton occupy as little space as possible. 
Therefore, it is an object of the subject invention to provide a carton of 
the knockdown variety which can be shipped in a flattened configuration. 
It is a further object of the subject invention to provide a carton which 
can be quickly and easily erected. 
It is still a further object of the subject invention to provide a carton 
which can be stacked in a nested condition, after erection, prior to being 
used. 
It is another object of the subject invention to provide a carton which is 
capable of being securely closed and easily reopened, and which includes 
an integral handle. 
It is still a further object of the subject invention to provide a carton 
that is both attractive and aesthetically pleasing.

Referring to FIG. 1, the lock bottom carton of the subject invention is 
designated generally by the numeral 10 and is intended for the storage and 
transportation of items, such as food or toys. The carton is generally 
rectangular in shape with the top portion 12 assuming a gabled 
configuration which, in addition to being attractive, provides extra 
interior volume for the closed carton. The latter is provided with 
matching handle tabs 14 and 16 for carrying the carton. 
FIG. 7 illustrates the blank 20 for forming the carton of the subject 
invention. Blank 20 includes a first locking side panel 22 having a pivot 
panel 24, of generally triangular configuration, which is pivotally 
connected thereto along hinge line 26. The remaining two sides of pivot 
panel 24 are defined by irregular cut line 28. The cut line 28 partially 
extends along the opposed ends of fold line 26 to facilitate the movement 
of the pivot panel 24. A cut or nick 30 is provided in the first locking 
side panel 22 directly below the pivot panel 24 to facilitate the 
insertion of a wedge shaped locking tab of the top panel into the locking 
side panel 22, as more fully described hereinafter. Cut line 28 defines 
two triangular projections 27 which are provided for effecting the 
interengagement of the wedge shaped locking tabs with the side panel 22 
for locking of the carton in the closed configuration as shown in FIG. 1. 
A first minor bottom panel 32 is hingedly connected along fold line 34 to 
the first locking side panel 22 while a first locking top panel 36 is 
hingedly connected along fold line 37 to the first locking side panel 22. 
The first locking top panel 36 includes a base triangular section 40 and 
two opposed equilateral support triangular sections 38, 42 which are 
hingedly connected to each other along fold lines 44 and 46, with their 
apexes meeting at a common point at the top center of locking top panel 
36. Support triangle 42 has a flattened apex area 48 which in the wedge 
shaped configuration of top panel 36, will overlap the apex of the support 
triangle 38 in the closed carton, thereby affording greater structural 
rigidity to and securely closing the carton. 
A first side panel 50 is hingedly connected along fold line 52 to the first 
locking side panel 22. A first major bottom panel 54 is hingedly connected 
along fold line 56 to the first side panel 50, and includes a first 
folding section 58 hingedly connected along fold line 60. When the carton 
is in the knockdown flattened configuration for shipping, the first 
folding section 58 is folded back into abutting relation with the first 
major bottom panel 54. A first top panel 62 is hingedly connected to both 
the first side panel 50 and the first locking top panel 36 along fold 
lines 64 and 52, respectively. A first handle tab 14 is hingedly connected 
along fold line 70 to the first top panel and includes two apertures 66, 
defining finger grips. 
A second locking side panel 72 is hingedly connected along fold line 74 to 
the first side panel 50. The second locking side panel substantially 
corresponds to the configuration of the first locking side panel 22 and 
includes a pivot panel 76 pivotally connected thereto along hinge line 78, 
and further defined by cut line 80. Triangular projections 77 and nick 82 
are similarly provided in side panel 72. A second minor bottom panel 84 is 
hingedly connected along fold line 86 and substantially corresponds to the 
configuration of the first minor bottom panel 32. A second locking top 
panel 88 is hingedly connected to the second locking side panel 72 and the 
first top panel 62 along fold lines 90, and 74, respectively. The second 
locking top panel 88 substantially corresponds to the configuration of the 
first locking top panel 36 and includes a base triangular section 96 and 
two opposed equilateral support triangular sections 94 and 98 hingedly 
connected along fold lines 92 and 93. Support triangle 98 is provided with 
a flattened apex portion 100. 
A second side panel 102 is hingedly connected to the second locking side 
panel 72 along fold line 104 and substantially corresponds to the 
configuration of the first side panel 50. A second major bottom panel 106 
is hingedly connected along fold line 108 to the second side panel 102 and 
substantially corresponds to the configuration of the first major bottom 
panel 54. The second major bottom panel 106 includes a second folding 
section 110 hingedly connected along fold line 112, while a second top 
panel 114 is hingedly connected to the second side panel 102 and the 
second locking panel 88 along fold lines 116 and 104, respectively. Panel 
106 substantially corresponds to the configuration of the first top panel 
62. A second handle tab 16 is hingedly connected along fold line 122 to 
the second top panel 114 and substantially corresponds to the 
configuration of the first handle tab 14, and includes two apertures 126 
defining finger grips. A first glue tab 124 and a second glue tab 128 are 
respectively hingedly connected along fold line 130 to the second top 
panel 14 and the second side panel 102. 
To allow for nesting or stacking of the erected cartons, all the panels of 
the blank, except for the major and minor bottom panels (32, 54, 84 and 
106) are tapered and are narrower near their bottom portions. This is 
accomplished by angling the vertical fold lines 51, 52, 74, 104, and 130 
inwardly towards the bottom of the blank. The upper and lower edges of 
each of the panels are parallel to one another, for example, in first side 
panel 50 the fold lines 56 and 64 are parallel, while the vertical edges, 
52 and 74 are tapered inwardly near the bottom of the panel. By this 
arrangement, the erected cartons can be nested or stacked within each 
other, as illustrated in FIG. 6. 
The subject carton is intended to be glued and folded into a flattened 
configuration by the carton manufacturer. This configuration allows for 
reduced shipping costs. The bottom panels 32, 54, 84, and 106 are folded 
upwardly along their respective fold lines. The first and second folding 
sections 58 and 110 are folded back into abutting relation with the major 
bottom panels 54 and 106. Then the first locking side panel 22 and the 
second side panel 102 are folded inwardly along the fold lines 52 and 104, 
respectively, forming the flattened configuration. Then the inner surface 
of each folding section 58 and 110 is adhesively joined with the outer 
surface of minor bottom panels 32 and 84 respectively. The first and 
second glue tabs 124 and 128 are adhesively joined with the inner surfaces 
of the first locking top panel 36 and the first locking side panel 22 
respectively. 
When a carton reaches the retailer, it is erected simply by expanding the 
flattened configuration, by separating fold lines 74 and 130 from their 
abutting relation, forming a rectangular configuration such that the 
locking side panels 22 and 72 are parallel to each other and in an 
orthogonal relationship to the side panels 50 and 102. This results in the 
automatic erection of the lock bottom, which in turn prevents the carton 
from collapsing (see FIG. 8). The bottom panels are securely interengaged 
and the carton can be collapsed only by pushing inwardly at the center of 
the bottom of the carton thereby releasing the interengagement of the 
bottom panels. 
Many cartons 10 may be readily erected in a short period of time. Since the 
side panels are tapered towards the bottom of the carton, creating a 
truncated inverted pyramidal configuration, the erected cartons can be 
stacked or nested, as illustrated in FIG. 6, and thus readily accessible 
as required. 
After a carton 10 has been filled, it is easily closed. The locking top 
panels 36 and 88 are pushed outwardly (see FIGS. 2 and 9) at the top of 
the center of the panels 36 and 88 which results in the upper portions of 
the top panels 62, and 114 being drawn together to form an attractive 
gabled configuration. The movement of the locking top panels 36 and 88 
caused the pivot panels 24 and 76 to swing inwardly into the carton 
creating generally triangular shaped openings 140 and 142 (See FIG. 9). 
Assuming the carton is not so completely packed so as to hinder the 
movement of said pivot panels, the latter will rotate around the hinged 
axes 37 and 80 to a maximum of 180.degree.. However, it is only necessary 
that a slight displacement of approximately 5.degree., relative to the 
plane of the associated locking side panel 22 and 72 take place to afford 
adequate clearance for insertion of the end portions of the wedge shaped 
locking tabs into the triangular shaped openings 140 and 142. Thus, even 
if the carton is fully packed, an interengagement can still be obtained. 
Continued rotation of the locking top panels 36 and 88 around the hinged 
axes 26 and 78 causes the support triangular sections 38, 42 and 94, 98 of 
the panel to overlap the associated base triangles 40 and 96 forming wedge 
shaped tabs 150 and 152, illustrated in FIG. 2. The flattened apex portion 
48 and 100 of the triangular sections 36 and 88 respectively, additionally 
overlap the triangular sections 38 and 94, creating a triple ply of 
paperboard at the end points of the wedge shaped tabs 150 and 152 (see 
FIG. 5). This overlapping functions to increase the structural rigidity of 
the locking mechanism and insures a secure closure of the carton. 
The wedge shaped tabs 150 and 152 have a cross section greater than the 
cross-section of the triangular shaped openings 140 and 142. The nicks 70 
and 82 are provided to permit a temporary enlargement of the openings 140 
and 142 allowing a portion of the wedge shaped tabs 150 and 152 to be 
inserted therein. Once the wedge shaped tabs 150 and 152 are inserted, 
they are held in place by the angled projections 27 and 77 respectively. 
(See FIGS. 4 and 5). 
As illustrated in FIG. 1, the handle tabs 14 and 16 are drawn together in 
an aligned and abutting relation, with the apertures 66 and 126 being in 
register and forming finger grips allowing the carton to be easily 
carried. 
When it is necessary for the carton to be reopened, to obtain the contents 
therein, the wedge shaped tabs 150 and 152 are manually popped out of the 
triangular openings 140 and 142, and the top sides of the carton are 
readily separated, exposing all of the graphics on the carton. The subject 
carton is capable of being repeatedly reclosed and reopened. 
A second embodiment of the subject invention is illustrated in FIGS. 10 and 
11. In this embodiment, handle 214 is additionally provided with tabs 202 
and 204, which are hingedly connected along the base of apertures 266. 
Additionally, the apertures 226 of handle 216 are slightly enlarged near 
their base. As illustrated in FIG. 11, after wedged shaped tabs 250 (252) 
are inserted into side panels 222 (272), tabs 202, 204 are folded through 
apertures 226 and into abutting relation with handle 216. By enlarging 
apertures 226, the insertion of the tabs 202, 204 therethrough is 
facilitated. The additional locking arrangement provided by tabs 202, 204 
aids in preventing lateral shifting of top panels 262, 224 relative to 
each other, which insures that apertures 266, 226 remain aligned, while 
affording greater structural rigidity and a more secure closure of the 
carton. When it is necessary for this embodiment of the subject carton to 
be reopened, the tabs 202, 204 are simply unfolded into an upright 
position whereupon the wedged shaped tabs 250 (252) are manually popped 
out of the triangular openings 240 (242) and the carton is opened as in 
the first embodiment. 
Accordingly, there is provided a new and improved lunch box carton and 
blank for forming same for carrying items such as food or toys. The carton 
can be shipped from the manufacturer in a flattened configuration, thereby 
saving shipping costs, and can be readily erected and stacked until 
needed. The carton can be easily closed and reopened employing the new and 
improved locking means described above. The subject invention further 
provides a top portion which is attractively gabled in configuration, 
provides additional interior volume, and includes integral carrying 
handles. 
The present invention has been described in the above specification with 
reference to a specific embodiment, and such reference has been made for 
purely illustrative purposes and various modifications in the details 
included therein may be made without departing from the scope or spirit of 
the invention as will be obvious to those skilled in the art.