Multicell corrugated bulk container

A bulk container for shipping granular products or the like. A pair of rectangular tubular cells having interior manufacturer's joints are surrounded by an outer rectangular sleeve glued in continuous surface-to-surface contact therewith. The sleeve panels carry depending flaps that form a tubular, bellows, bottom closure, and the sleeve contains an exterior manufacturer's joint that extends downward into the closure. One pair of closure flaps each include converging 45.degree. score lines which meet short of its free edge, and a slot extends inward past the point of meeting.

The invention relates generally to bulk containers and more particularly to 
multiple cell containers made of corrugated fiberboard for holding large 
amounts of granular material. 
Various types of multi-cell containers have been developed and are now 
being used for bulk shipments of flowable materials, particularly 
materials in granular form. Examples of such bulk containers may be found 
in U.S. Pat. Nos. 3,403,835, issued Oct. 1, 1968, 3,425,615 issued Feb. 4, 
1969, and 3,543,991, issued Dec. 1, 1970. 
The present invention provides an improved reusable bulk container made of 
corrugated fiberboard having excellent strength characteristics which 
enable it to hold a ton or more of granular material. The container design 
of laminated construction eliminates gaps within its interior or its 
sidewalls; thus, it is particularly adapted for shipment of granular food 
material, for example, shelled peanuts, where cleanliness and the ability 
to completely empty the container are of substantial importance.

A twin-cell bulk container 11 is depicted in FIG. 1 set-up to a 
configuration ready to receive the material to be shipped, for example, a 
ton of shelled peanuts. The container 11 has a pair of inner cells 13 
surrounded by an outer sleeve or box 15, is fabricated from three separate 
corrugated pieces or blanks 17 and 19 and has a self-contained bottom 
closure of the type generally referred to as a bellows bottom. The 
container 11 has short flanges 21 at the upper ends of the four sidewalls. 
These flanges are folded inward at 90.degree. to the sidewalls, and a 
separate top cap (not shown) of the standard construction slides downward 
over the upper end of the container and holds the top flanges in this 
desired position where they add strength to the overall container. Because 
of its weight when filled, the bulk container 11 is usually used in 
combination with a pallet 22 of standard design. 
A substantial portion of the strength of the container results from the 
fact that it, in essence, consists of three separate boxes laminated 
together into a single assembly which includes its own self-contained 
bottom closure. Basically, the duplicate inner cells 13, which are 
surrounded by the rectangular outer box 15, divide the container into two 
equal compartments. A container 11 suitable for shipping a ton of shelled 
peanuts can be made from one outer box blank 17, which is about 175 inches 
by 71 inches, and two inner cell blanks 19, which are each about 126 
inches by 45 inches. All three blanks are made from corrugated fiberboard 
wherein the corrugations run vertically in the container 11 so as to 
provide sufficient stacking strength to enable these containers, when each 
is filled with a ton of peanuts, to be stacked three high. Suitable blanks 
may be made from B/C flute doublewell corrugated board (500 pound test); 
however, other size flutes as well as other corrugated board, for example, 
triplewall, may also be used. 
As best seen in FIGS. 5a and 5b, the blanks 19 for the inner cells consists 
simply of four serially connected panels 23a,b,c,d, plus a glue flap 25 
which are defined by four vertical score lines 27. Although the term 
"score line" is used throughout the application, it should be understood 
that use of this term is simply meant to indicate the employment of a 
suitable line of weakness which may be made in any conventional manner, as 
by scoring, perforating, slitting, cutting or the like. In addition, a 
pair of upper and lower nick slots 29 are provided, each about 1/2 inch 
deep, which facilitate alignment in the fabrication of the laminated 
containers 11 as explained hereinafter. The blanks 19 are sized so that 
the narrower side panels 23a and c have a width approximately equal to 
one-half the longitudinal dimension of the rectangular container 11, 
whereas the wider side panels 23b and d are substantially equal to the 
transverse or lateral dimension of the container. 
To fashion the manufacturer's joint in each cell, a line of adhesive is 
either applied to the underside of the glue flaps 25 as shown in FIG. 5a, 
and 5b, or upon the upper surface of the side panel 23a, and then folding 
is carried out along the vertical score lines 27a and 27b to create the 
flat-folded tubes depicted in FIGS. 5c and 5d. Fabrication in this manner 
adheres the glue flap 25 to the inside surface of the cell wall and thus 
disposes it within the interior of the cell, so that an undesirable gap is 
not created between the outside surface of the cell 13 and the inside 
surface of the surrounding box 15 to which it will be laminated, the 
importance of which is discussed hereinafter. 
The blank 17 for forming the outer box, as illustrated in FIG. 6, includes 
four vertical score lines 31 which define the four serially connected side 
panels 33 plus a glue flap 35 at the left-hand edge of the blank. The 
score lines 31 extend for substantially the full height of the blank and 
are crossed by upper and lower transverse score lines 37 and 39. The upper 
transverse score line 37 defines the four top flanges 21 which are 
preferably separated from one another by slots 41 and which are 
individually hinged to one of the side panels 33. The lower score line 39 
defines four interconnected bottom flaps 43 which are individually 
hingedly attached to the bottom edge of one of the four side panels 33. 
The bottom flaps 43a and 43c which are hinged to the narrower side panels 
33a and 33c, are herein referred to as the lateral bottom flaps and are 
appropriately scored and slotted so that, upon completion of the 
manufacturer's joint, the bottom closure flaps 43 provide an improved 
bellows bottom closure. The remaining pair of bottom closure flaps 43b, 
and 43d, which are hinged to the longitudinal or wider side panels 33b and 
33d, are referred to as the longitudinal bottom flaps and are integrally 
connected to the lateral closure panels along the vertical score lines 31. 
Each of the lateral flaps 43a, 43c is provided with a pair of converging 
score lines 45 which are oriented at about 45.degree. to the lower 
transverse score line 39, beginning at the intersections between it and 
each one of the vertical score lines 31. Moreover, a short slot 47 extends 
from the free or bottom edge of the lateral flaps 43a,43c to a location 
past the intersection of the converging score lines 45. The function of 
the slots 47 is described hereinafter, together with a description of the 
closing of the bottom of the container 11. 
The container 11 is designed to be efficiently fabricated on suitable 
laminating equipment. The inside surface of blank 17 for the outer box is 
positioned appropriately, and an adhesive pattern 51 in the form of a 
plurality of parallel strips, which cover more than 60 percent of the area 
of the side panels 33, is applied running from the left-hand edge of the 
blank continuously across to a location just short of the glue flap 35. 
The flat-folded blank 19 for the first inner cell is then positioned upon 
the outer box blank, as shown in FIG. 5e with the manufacturer's joint in 
the upper location. The nick slots 29 facilitate appropriate positioning 
because they can be aligned by the operator with the vertical score line 
31c. A similar adhesive strip pattern 53 is then applied over the major 
portion of the outside surface of the panel 23d of the first cell that 
will be in surface-to-surface contact with the second cell. The second 
cell is then positioned as depicted in FIG. 5f with its manufacturer's 
joint down and with its wider side panel 23d in contact with the 
corresponding side panel 23d on the first cell to which the adhesive 
pattern 53 has just been applied. 
After the application of adhesive 55 to the upper surface of the glue flap 
35 at the right-hand edge of the outer box blank, the lateral panel 33a at 
the left-hand edge is first folded over the second cell to contact panel 
23b, and then the longitudinal side panel 33d, carrying the glue flap 35, 
is folded over and onto it to locate the manufacturer's joint on the 
outside surface of the container 11. The folded and glued, three-blank 
assembly is then subjected to compression while the adhesive sets up and 
effects the fiberboard-to-fiberboard bonding. As a result of the 
continuous glue patterns provided on the outer box blank 17, there is a 
tight connection between the outer box 15 and the laminated inner cells 13 
at all four corners of the container that not only adds to the overall 
strength of the container but guards against peanuts from becoming lodged 
in such corner gaps. 
The containers are shipped to the customer in the flat-folded condition 
depicted in FIG. 5g, and because of the improved bellows bottom closure, 
they can be set up by a single operator, need not be glued and are 
reusable for additional trips after reaching their destination and being 
emptied. To ready the container 11 for filling, the operator squares it in 
the inverted position and then folds the rectangular, longitudinal bottom 
closure flaps 43d and 43b inward first, in accordance with the instruction 
printed on panel 43d, see FIG. 6. The inward folding of the longitudinal 
flaps causes the lateral flaps 43a,43c to break and fold along the 
45.degree. score lines 45 which define major triangular panels 57 flanked 
by minor triangular panels 59. 
The depth of the tubular bottom closure is such that the longitudinal flaps 
43b,43d overlap, preferably by at least about two inches. To avoid having 
to die-cut the blank 17, the depth of each of the bottom flaps 43 is the 
same, and each is about one-inch deeper than half the width of the lateral 
panels 33a,33c of the outer box blank, to which the flaps 43a,43c 
containing the converging score lines 45 are hinged. This overlapping 
assures a tight joint at the bottom of the container below the twin cells 
13 without requiring strict tolerances in dimensions in a large bulk 
container of this type. 
As the folding inward of the longitudinal flaps 43b,43d is completed, the 
minor triangular panels 59 are folded to contact with the central major 
triangular panel 57. The provision of the slot 47 frees the outer corners 
of the minor panels 59 and allows this folding to take place without 
restraint. Following the infolding of both longitudinal bottom flaps, the 
bottom closure is completed by folding in the major triangular panels 57 
so that the bottom takes the shape depicted in FIG. 3. 
As shown in FIG. 6, the glue flap 35 on the outer box preferably includes a 
downward extension 35a which is a part of the bottom closure. It is also 
positioned at a corner of the box 15, as are the manufacturer's joints of 
the inner cells 13 positioned at corners, so as to avoid the creation of 
any gap between the laminated sidewalls of the outer box and the inner 
cells which could provide an open region wherein peanuts could accumulate. 
When the outer box blank 17 is made from a strong thick material, such as 
doublewall corrugated fiberboard, the thicknesses which are created at the 
location of the extension 35a of the glue flap into the bellows closure 
can exert a considerable restraint to bending. Bending can be eased by 
providing a short, horizontal slit 61 in the glue flap in line with the 
lower transverse score line 39 and furthermore by providing a second slit 
63 at an angle where the glue flap extension 35a will overlap the score 
line 45 of the closure panel 43a to which it will be laminated. The second 
angular slit facilitates the 180.degree. bend which occurs when the 
flanking triangular panels 59 are folded onto the major triangular panel 
57 (FIG. 2) and the short horizontal slit 61 facilitates the 90.degree. 
bend which completes the bottom closure by the infolding of the triangular 
panels 57 (FIG. 3). 
With the container 11 set up as depicted in FIG. 1, it is ready to be 
filled by loading the inner cells 13 with about 1000 pounds of peanuts 
apiece. This is generally accomplished by positioning a chute over the 
cells through which a weighed amount of granular product is allowed to 
fall by gravity. The container 11 may be vibrated if desired during the 
loading, which may be performed incrementally, to assure complete filling 
is accomplished. 
The upper flanges 21 are generally outfolded in order to set the container 
on the floor during the set-up of the bellows bottom, and the flanges 21 
may be left in this position during filling. However, once filling is 
completed, the upper flanges 21 are folded inward so that they overlie the 
adjacent upper edges of the sidewalls of the inner cells 13 to which the 
outer box sidewalls have been laminated, and the flanges are retained in 
this horizontal orientation by the downward application of a top cap. If 
desired, the flanges may be temporarily taped to each other to hold them 
in this position until the cap has been installed. Thereafter, one or more 
metal or plastic straps or bands may be encircled around the capped and 
filled container as an added guarantee against separation of the cap 
during shipment and handling. The provision of the upper flaps and their 
inward folding at 90.degree. to the vertical sidewalls increases the 
sidewall strength of the box and is particularly effective in resisting 
bulging. 
As earlier indicated, the overall laminated twin-cell construction is 
particularly suited for shipping a granular food product, such as peanuts, 
where complete unloading of the container prior to its knockdown and 
return for reuse is of importance. Its strength which is achieved by the 
provision, in essence, of two separate boxes which are laminated to each 
other and within a third box that contains a bellows bottom that unites 
the overall structure, and such excellent overall strength is achieved to 
allow these bulk containers to be stacked three levels high. Moreover, the 
improved bellows bottom not only provides a tight seal that prevents such 
a granular product from escaping at the bottom, but it also provides a 
tight fit where the side edges of the longitudinal flaps 43b,43d abut the 
inside surface of the lateral side walls 23b of the inner cells and thus 
minimizes the entrapment of peanuts therein. Thus, the bulk container 11 
is advantageously suited for repeated shipments of a granular food product 
not only in quantities of at least a ton at a time, but also in stacked 
array to facilitate efficient transport by truck or rail. 
Although the invention has been described with regard to certain preferred 
embodiments, it should be understood that various changes and 
modifications as would be obvious to one having the ordinary skill in this 
art may be made without deviating from the scope of the invention which is 
defined solely by the claims appended hereto. For example, instead of 
providing the flanges 21 at the top of the panels 33 of the blank 17, top 
flanges could be provided atop the panels 23 of the blanks 19 and would be 
infolded in similar fashion before the top cap is installed. Various of 
the features of the invention are set forth in the claims which follow.