A side loading, top opening reclosable carton, formed from a one piece blank has multiple layer front, rear and side walls, and single layer top and bottom walls, providing efficient placement of multiple layers of material only in the vertical walls, which are subjected to substantial stacking stresses. An optional, and novel, end lock has a male lock tab on a front side flap confined between embossments on two rear side flaps. The lock is secured by adhesion provided by a bottom side flap and bridging the front side flap and the outer rear side flap.

BACKGROUND OF THE INVENTION 
This invention pertains to crush-resistant cartons. Such cartons are 
typically used in the packaging of heavy articles which may be stacked or 
otherwise roughly handled. When a group of packages is handled together, 
as is common in shipping and handling, the weight of overlying packages 
may exert large downward forces on the carton front, rear, and side walls. 
Similarly, the combined mass of the group of packages exerts substantial 
inertial forces on the package walls as a result of shocks such as are 
experienced in loading and unloading of trucks. 
Thus reinforcement of certain walls of the package may be highly desirable. 
However, increasing the package material thickness overall may cause the 
use of more materials than necessary on some package walls. For example, 
in the packaging of fruit cake, the heavy product provides a modest, but 
adequate, degree of support to the top and bottom walls of the carton. The 
front, rear, and side walls, however, require reinforcement. Thus, an 
overall increase in material thickness would result in excessive material 
use in the top and bottom walls. While certain existing cartons have 
reinforced walls, known cartons are deficient in one or more areas of 
package function. 
Patents believed material to the examination of this application are United 
States Patents: 
Re. 15,453 
149,139 
622,495 
622,496 
1,869,742 
3,014,633 
3,503,550 
3,543,994 
3,638,850 
SUMMARY OF THE INVENTION 
In brief, the invention is a novel side loading top-opening carton having 
reinforced stacking strength in its front, rear and side walls, and formed 
from a one-piece blank, the carton comprising opposing front and rear 
walls, and left and right side walls, a bottom wall hingedly attached to 
the front and rear walls, and a top wall hingedly attached to the rear 
wall. The front wall comprises an inner front wall panel, and an outer 
skirt connected to the front edge of the top wall. The outer skirt 
comprises an outer skirt panel having the connection to the top wall, and 
projecting downwardly substantially the entire height of the carton, from 
top to bottom thereof, and an inner skirt panel connected to the bottom of 
the outer skirt panel at a predetermined fold line, and to the top of the 
inner front wall panel. The inner skirt panel is disposed between, and 
facing, both the outer skirt panel and the inner front wall panel. The 
front wall has a line of weakness extending from one said side edge to the 
other said side edge. The inner and outer front skirt panels are affixed 
to each other between the line of weakness and the predetermined fold 
line. The rear wall comprises a first panel hingedly attached to the top 
wall and extending downwardly substantially the entire height of the rear 
wall, and a second panel hingedly attached to the bottom wall and 
extending upwardly substantially the entire height of the rear wall. 
The carton may further have novel side locks wherein each side wall has a 
front side flap connected to, and projecting rearwardly from, the front 
wall, and a male locking tab projecting rearwardly from its rear edge. 
Each side wall also has a pair of inner and outer rear side flaps 
connected to, and projecting frontwardly from, the rear wall, the rear 
side flaps being secured to each other in face to face relationship. The 
inner rear side flap has a first front edge substantially coincident with 
the rear edge of the corresponding front side flap, and has a pair of 
shoulders projecting frontwardly from its front edge on its top and 
bottom. The rear inner side flap has an inward embossment extending 
rearwardly from the front edge and corresponding in shape with, and 
underlying, the male locking tab, and has a cut line extending rearwardly 
from the front edge of the flap across the embossment. The outer rear side 
flap has a second front edge located frontwardly of the first front edge. 
Each side wall also has a bottom securing flap hingedly attached to the 
corresponding side edge of the bottom wall, the bottom securing flaps 
overlying, and being secured to, corresponding ones of both the outer rear 
side flaps and the front side flaps. The outer rear side flap may have an 
outer embossment corresponding in shape to, and overlying, the male 
locking tab.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Turning now to FIG. 1, the carton blank is designated generally as 10. 
Beginning at the left edge of FIG. 1, the main body panels of the carton 
blank are outer rear panel 14, bottom wall panel 18, inner front wall 
panel 22, inner skirt panel 26, outer skirt panel 30, top wall panel 34 
and inner rear panel 38. Panels 14 and 18 are joined by creased score line 
42. Panels 18 and 22 are joined by score line 46. Panels 26 and 30 are 
joined by score line 50. Panels 30 and 34 are joined by score line 54. 
Panels 34 and 38 are joined by score line 58. Panels 22 and 26 are joined 
by dashed cut line 62. A line of weakness 66 extends across panel 26 as 
shown. 
Inner rear side flaps 68 are connected to panel 14 by hinge lines 69. Each 
hinge line 69 is interrupted along its length by a narrow, elongated hole 
70. Outer rear side flaps 72 are connected to panel 38 by hinge lines 74. 
Bottom side flaps 76 are connected to bottom wall 18 by hinge lines 78. 
Front side flaps 80 are connected to inner front wall panel 22 by hinge 
lines 82. Skirt connecting tabs 84 are connected to outer skirt panel 30 
by hinge lines 86. Side skirt flaps 88 are connected to top wall panel 34 
by hinge lines 90. 
Each front side flap 80 has a rear edge 92 and a male lock tab 94 
projecting outwardly beyond edge 92. 
Inner rear flaps 68 have a front edge 96, and shoulders 98 projecting 
outwardly beyond front edge 96. Embossments 97 are defined by lines 97a 
and front edge 96, and extend from front edge 96 toward panel 14, assuming 
a generally planar shape similar in shape to, and, in the flat blank, 
opposite in direction from, male tab 94. Cut lines 95 extend across 
embossments 97 from the front edge 96 to lines 97a. 
Outer rear side flaps 72 have embossments 93 defined by lines 93a and front 
edge 91, the embossments extending from front edge 91 toward panel 38. The 
inner edges 93a of embossments 93 are generally similar in shape to, and 
in the flat blank, opposite in direction from, the outer edges of tabs 94. 
The cooperation of tabs 94 with embossments 93 and 97 is more fully 
described hereinafter. 
Adhesive patterns are shown at 89 on panel 26 and 87 on panel 38 and flaps 
72. Adhesive is additionally applied at 99 to flaps 76, as shown in FIG. 
1, and to the bottom side of flaps 84 as at 85 in FIG. 4. 
Hole 83 is located at the approximate mid-point of hinge line 50 and serves 
as a convenient location for grasping the lower edge of the front wall 
when opening the carton. 
One skilled in the art will appreciate that terminology regarding a carton 
blank is somewhat different from the terminology regarding the set up 
carton. Thus, the blank is described as having panels and flaps as its 
main members. The carton is herein described as having walls, the walls 
being composed of one or more panels and/or flaps. It follows, then, that 
a panel in the carton blank may be described as a wall in the carton. In 
the illustrated embodiment of the carton, the top and bottom walls are 
composed of single panels. The front and rear walls are composed of 
multiple panels. The side walls are composed of multiple flaps. Similarly, 
panels and flaps may be combined in forming carton walls. Thus is the 
recitation, for example of "top wall panel 34" in the carton blank 
consistent with the recitation of "top wall 34" in the carton. 
In gluing the carton, panel 14 is first folded about line 42 onto panel 18. 
Panels 30, 34, and 38 are then folded about line 50, and onto panels 14, 
18, 22 and 26. Finally, panels 26 and 30 are folded about hinge lines 62 
and 54 onto panel 22. FIG. 2 indicates, in three dimensions, the 
relationships of the various carton components resulting from the above 
recited sequences, while artificially holding the components apart for 
ease of viewing. In reality, at this stage, the adhesive 87 on panel 38 is 
adhered to panel 14 and the adhesive on panel 26 is adhered to panel 30; 
thus forming panels 26 and 30 into the front skirt, and forming panels 14 
and 38 into the rear wall. Similarly, the adhesive 87 on flaps 72 adheres 
flaps 72 to the corresponding flaps 68. 
The carton is then set up into tubular form by pushing hinge lines 42 and 
54 toward each other. The carton may then be filled with product and the 
sides closed. For purposes of illustration, FIG. 3 shows the carton empty 
when the side is being closed. 
First, the front and rear side flaps are brought together as shown in FIG. 
3. Tab 94 is inserted into the space created by the spaced embossments 93 
and 97 on underlying rear inner side flap 68 and overlying rear outer side 
flap 72. See also FIGS. 7 and 8. The facing surfaces of flaps 68 and 72, 
except for embossments 93 and 97, are held in substantially face to face 
contact by adhesive 87. Cut line 95 provides additional resilience to 
embossment 97, allowing it to flex and temporarily increase the space 
between portions of embossments 95 and 97 on insertion of tab 94. 
Shoulders 98 extend past the rear edge 92 of flaps 80 and are positioned 
adjacent the outside surface of flaps 80. With tab 94 fully seated in the 
space beween flaps 68 and 72, the side of the carton appears as in FIG. 4. 
Bottom side flaps 76 are then folded up about lines 78 and adhered to 
flaps 72 and 80. Tabs 84 are folded back against flaps 80, and side skirts 
88 are folded down against tabs 84 and flaps 76; adhering skirts 88 to 
tabs 84. 
The thus completed carton appears as in FIGS. 5-8. These figures reveal 
that the front, rear, and right and left side walls, of the completed 
carton all have multiple thicknesses of carton material, for substantially 
the full height of the carton, which gives the carton an excellent 
capability to withstand crushing. Concurrently, the top and bottom walls 
have only a single thickness of carton material for purposes of economy 
and conservation. See FIG. 6. 
FIGS. 6, 7 and 8 show in detail the locations of the various elements of 
the carton side wall. Further, the combination of the size and locations 
of the various side flaps, along with their adhesive connections, make the 
side walls highly contributory to the overall rigidity of the package; 
such that, in addition to its crush resistance, this side loaded carton 
has a surprising resistance to bending and twisting stresses. 
The carton is opened by raising the top of the carton, along with the front 
and side skirts, and breaking line of weakness 66. The opened carton is 
shown in FIG. 9. The carton may be repeatedly opened and reclosed, with 
latching, as is customary for flip top style cartons. 
Accordingly, line of weakness 66 should be weaker than dashed cut line 62, 
in order that the break will occur at 66. Conversely, if 62 is the weaker 
line, the break will occur there, and the latching feature on reclosure is 
sacrificed. Both constructions are contemplated by the invention. In a 
combination construction, lines 62 and 66 are merged into one line of 
weakness at 62. Similarly, line 62 may be formed by a crease score when 
separate lines 62 and 66 are provided. 
Line of weakness 66 may be located, by appropriate adaptation on any of 
panels 22, 26 and 30. The line of weakness would still extend across the 
front wall, but need not extend onto depending flaps. Moreover, if the 
line of weakness does extend onto depending flaps, one skilled in the art 
can ensure that adhesive on the subject flaps does not preclude opening of 
the package. 
For example, the line of weakness could extend across panel 22, between 
lines 46 and 62 and terminate, by means of angular connecting lines, at 
the intersections of lines 82 and 62. However, it is important to note 
that the area of adhesion provided in the set-up carton, such as that 
provided by 89 in FIG. 1, is between the hinge line 50 and the line of 
weakness which breaks when the carton is opened. This property is observed 
by traversing the vertical cross-section of the front wall, as, for 
example, in FIG. 6, from the line of weakness 66 along the line of 
material exposed by the cutting away, to hinge line 50. Observing this 
property ensures that the breaking of the line of weakness is effective to 
separate the front wall into a receptable portion and a cover portion. 
While this general description is effective in forming the carton 
structure, the flip-top reclosure feature is most easily employed when the 
line of weakness is on panel 26 as shown. 
The invention having been described in terms of the illustrated embodiment, 
it is intended that the property right be limited only by the scope of the 
appended claims.