BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first embodiment of the invention shown in a generally assembled state;
FIG. 2 is a detailed perspective view of a portion of the double liner corrugated material used in the construction of the first embodiment;
FIG. 3 is a plan view of the first embodiment with the upper flaps shown in phantom to better illustrate the layering of the corrugated material;
FIG. 3
a is a detailed plan view of a corner of the embodiment shown in FIG. 3;
FIG. 4 is a plan view of a “blank” used to form the first embodiment of the invention;
FIG. 5 is a detailed plan view of a stress relief feature and vertical crush resistance geometry feature of the first embodiment of the invention;
FIG. 6 is a perspective view of a first step in forming a multi-walled container using the “blank” of FIG. 4 where the middle flaps are folded into close proximity to form a middle sidewall of corrugated material;
FIG. 7 is a perspective view of a second step in forming a multi-walled container using the “blank” of FIG. 4;
FIG. 8 is a perspective view of a third step in forming a multi-walled container using the “blank” of FIG. 4 where the combined inner panel and middle flaps are involuted;
FIG. 9 is a perspective view of a fourth step in forming a multi-walled container using the “blank” of FIG. 4 where an inner glue tab is attached to an inner panel, thereby forming a basic container shape;
FIG. 10 is a perspective view of a fifth step in forming a multi-walled container using the “blank” of FIG. 4 where the outer panels are wrapped around the basic container of FIG. 9;
FIG. 11 is a perspective view of a sixth step in forming a multi-walled container using the “blank” of FIG. 4 where an outer glue tab is attached to an outer panel, completing formation of the first embodiment; and
FIG. 12 is a detailed perspective view of a stress relief feature shown in FIG. 5 when the “blank” of FIG. 4 is converted into the container of FIG. 11, and the upper and lower flaps are folded inward.
DESCRIPTION OF THE INVENTION EMBODIMENTS
The following discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the embodiments shown herein will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention, as defined by the appended claims. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Turning then to the several Figures, where like numerals indicate like parts, and more particularly to FIGS. 1-4, an embodiment of the invention employing many of the features and elements of the invention will now be described. Container 20 comprises “blank” 22, which is preferably constructed from a double lined, single wall corrugated material such as 5/16″ L flute corrugated board shown in FIG. 2. In the illustrated embodiment, container 20 has dimensions of about 42″ H×48″ W×40″ D, while blank 22 has maximum dimensions of about 355″ L×83″ W. In the illustrated embodiment, container 20 has triple sidewalls and single overlapping bottom and top flaps.
In order to form container 20, it is necessary to create container blank 22 either prior to assembly or in line with the assembly process. As is best shown in FIG. 4, container blank 22 is a unitary piece of corrugated material, such as of the type shown in FIG. 2, with the direction of corrugation running laterally. From a single sheet, selected scores, cuts and perforations are carried out, such as by rotary die cutter(s) or other means appreciated by the skilled practitioner. Each container blank 22 then comprises inner panel 40, opposing middle flaps 50, outer panel 60, and a plurality of end flaps 70. Container blank 22 preferably further comprises inner glue tab 30 and outer glue tab 80. For convention purposes, the observed sides of all panels and flaps are as indicated, with the reverse side being numbered similarly, but within the one hundred series. Thus, the reverse side of inner panel 40, for example, is labeled as inner panel 140.
Inner panel 40 comprises inner panel portions 42, 44, 46 and 48, separated by scores 34a, 34b, and 34c. Inner glue tab 30 extends longitudinally from inner panel portion 42, and is separated there from by score 32. Extending laterally outwardly from inner panel portions 42, 44, 46 and 48, and defined in part by slit-scores 43a/b, 45a/b, 47a/b and 49a/b, and by scores 34a, 34b, and 34c (as well as edges 51a/b, and slits 73a and 73b), are respective middle flaps 50, identified in this embodiment as middle flap portions 52a/b, 54a/b, 56a/b and 58a/b. While those persons skilled in the art will appreciate that other forms of scoring (e.g., point-to-flat) as well as slitting or even slotting can be used instead of those portions of scores 34a, 34b, and 34c that partially define each middle flap portion pair 52a/b, 54a/b, 56a/b and 58a/b, additional strength and handling advantages can be realized by retaining robust physical linkage between adjacent middle flap portions, as will be described below. Moreover, each “flap” 50 may comprise physically discrete flap portions (as are end flaps 70, discussed below), visually discrete flap portions as illustrated herein, or may be wholly contiguous (no scoring). Because it is only necessary to form a wall or layer within container 20, there is no intrinsic need to form physically discrete flap portions as long as those portions of blank 22 that fold to meet the opposing portions of blank 22 can result in the creation of such wall or layer.
The distal ends of each middle flap portion are characterized by chevron edges 53a/b, 55a/b, 57a/b and 59a/b, again as shown best in FIG. 4. The inclusion of these chevron edges, or any non-linear edge, will beneficially delocalize burst and column compression stresses that may occur after assembly and use of container 20, as will be described in later detail below. Thus, curvilinear edges or rectilinear edges such as repeating square or saw-tooth geometries are considered desirable. However, it is not necessary to the operation or constitution of the embodiments of the invention to incorporate such non-linear edges, and a linear edge will provide benefits as herein described.
While inner panel 40 and middle flaps 50 both form sidewalls of the container, only outer panel 60 forms sidewalls; end flaps 70 constitute single bottom and top sides of container 20 as shown in FIG. 11. Outer panel 60 comprises outer panel portions 62, 64, 66 and 68, separated by scores 38a, 38b, and 38c; outer panel portion 62 is separated from inner panel portion 48 by score 36. Outer glue tab 80 extends longitudinally from inner panel portion 42, and is separated there from by score 82. Extending laterally outwardly from outer panel portions 62, 64, 66 and 68, and defined in part by point-to-point scores 63a/b, 65a/b, 67a/b and 69a/b, and by slits 73a/b, 75a/b, 77a/b and 79a/b (as well as edges 71a/b), are respective end flaps 72a/b, 74a/b, 76a/b and 78a/b, as shown. Those persons skilled in the art will appreciate that slots can be used instead of slits 73a/b, 75a/b, 77a/b and 79a/b, although as will be described in detail below, advantages can be achieved through the use of slits with respect to stress relief feature 90.
It should be noted that the lateral width (or as assembled, the height) of outer panel 60 is greater than that of inner panel 40. This increased dimension addresses the consequence of the increased external dimensions as container 20 is formed (discussed and shown below). Similarly, the longitudinal length (or as assembled, the width and depth) of outer panel 60 is greater than that of inner panel 40. Those persons skilled in the art will appreciate that the increases are related to the number of walls used to form the container, as well as the thickness of the material comprising the walls.
FIG. 5 illustrates two features of the subject embodiment, namely, stress relief feature 90, which is characterized as a hole of approximately 0.375″ diameter, and flap offsets. It is well known in the art that flaps on containers frequently tear at the exposed edge interface between the flap and a sidewall panel. This is due in part to the effect of the three edge corner present on the underside of the flap: the three edge corner causes a crushing of the flap at its edge, thereby compromising the structural integrity of the flap and related structure. This consequence, in conjunction with the inherent weakness of the material at this position, often invites mechanical failure during repeated use or operation of the flap. By establishing a hole, and preferably, but not necessarily, a round or circular hole, the three edge corner will not directly impinge upon the underside of the flap. Depending upon the number of walls for any particular container, additional stress relief features may be employed with respect to interior or middle walls, as the case may be.
Also shown in FIG. 5 is an offset with respect to the slits separating adjacent flaps 70 and the point-to-point scores separating adjacent outer panel 60. Unlike the continuous scores 34a, 34b, and 34c of inner panel 40 (which create inner panel portions 42, 44 and 46) and middle flaps 50 (which partially define each middle flap portion pair 52a/b, 54a/b, 56a/b and 58a/b), and which result in equally dimensioned walls, flaps 70 have differing dimensions when compared to their companion panels. Because flaps 70 form end walls as opposed to sidewalls, there is no need for such symmetry. Moreover, and as best shown in FIG. 3, because flaps 70 will be positioned orthogonal to the sidewalls comprising inner panel 40, middle flaps 50 and outer panel 60, the dimensionally larger flaps will extend over the entire exposed edges of outer panels 60 when container 20 is in the assembled configuration. The consequence of this arrangement is that all exposed vertical sidewall edges can be “covered” by the end flaps, and that vertical compression loads can be evenly distributed to the end flaps. See also FIG. 11.
Turning then to FIGS. 6-12, the assemblage of container 20 is shown in detail. Completed blank 20, as described in FIG. 4, emerges from a converting machine and enters a folding and gluing section of the process. Using folding rails or paddles, co-joined middle flap portions 52a, 54a, 56a and 58a, and 52b, 54b, 56b and 58b are down folded 180°, along slit-scores 43a, 45a, 47a and 49a, and 43b, 45b, 47b and 49b to join in surface-to-surface area contact with respective inner panel portions 42, 44, 46 and 48 as shown in FIG. 6. Prior to initiation or completion of the 180° folding process, adhesive is applied to the contact area surfaces using an extrusion or roller coating system. On completion of the 180° folding and gluing process, chevron edges 53a/b, 55a/b, 57a/b and 59a/b meet about mid way of inner panel portions 42, 44, 46 and 48. The ‘serrated’ and intermeshing nature of chevron edges 53a/b, 55a/b, 57a/b and 59a/b distribute the joined line over a greater area than a pure straight cut and now appear on the underside of the flat box blank.
Using a gripper mechanism, inner glue tab 30 is up-folded 90° at score 32, inner panel portion 42 (with middle flap pair 52a/b) is up-folded 90° at score 34a, inner panel portion 44 (with middle flap pair 54a/b) is up-folded 90° at score 34b, inner panel portion 46 (with middle flap pair 56a/b) is up-folded 90° at score 34c, and inner panel portion 48 (with middle flap pair 58a/b) is up-folded 90° at score 36, as is shown in FIG. 8. All 90° folds are ‘up’ and therefore away from the surface joint of chevron edges 53a/b, 55a/b, 57a/b and 59a/b. The resulting structure is best shown in FIG. 9.
Adhesive is applied to the intended mating surfaces of outer panel portions 62, 64, 66 and 68, and the up-folding process continues with outer panel portion 62 folding 90° at score 38a, outer panel portion 64 folding 90° at score 38b, outer panel portion 66 folding 90° at score 38c, and outer panel portion 68 folding 90° at score 82, with outer glue tab 80 completing the folding and gluing process. This process is best shown in FIG. 10. As those persons skilled in the art will appreciate, the up-folding process may be accomplished by use of a forming mandrel or other aid.
The collective effect of the multiple-90 degree folding and gluing process takes the original flat, rigid corrugated board blank, comprising inner glue tab 30, inner panel 40, middle flaps 50, which form an intermediate panel, and outer panel 60, as well as outer glue tab 80, all as shown in FIG. 4, and forms a multi-walled, four sided, finished container/bin, with single wall flaps top and bottom, that has no ‘manufacturers-joint’, as best shown in FIG. 11. Because the relaxed state (manufacturer's resting position) is the use state of the container, there is a natural tendency of the container to return to its resting position if collapsed. In single wall construction containers, this advantage is of little consequence; however, in multi-walled containers the force necessary to form the desired container shape can be significant. Therefore, there is a significant labor advantage to constructing a container to have a resting position the same as its use position regarding multi-walled containers. Furthermore, by incorporating panel scores at each edge, knockdown of the container is made easier (the score lines further localize any resulting crushing, thereby preserving the structural integrity of the container at locations adjacent to the edges).
Patent Application
20080054060
