One-piece Box With Hingedly Connected Lid

Abstract

A one-piece carton of the type having a lid portion hingedly connected thereto wherein the lid portion is adapted to fit over the container portion by making the open end of the container portion smaller than the open end of the lid while the closed upper end of the lid portion and the bottom end of the container portion are substantially the same dimensions. The open end of the container portion is made smaller than the open end of the lid portion by ensuring that upon assembly of the container portion the side walls are toed inwardly. The side walls of the container portion are maintained in the inwardly toed position by articulated panels which are connected to adjacent side walls of the container portion and the lid portion. The articulated panels are creased along angularly inclined fold lines which extend from the base of the side walls of the container portion and the lid portion and intersect one another, the angle formed between the back wall and the fold line which extends from the lid portion whereby the side walls of the container portion are toed inwardly in a direction away from the bottom wall. Preferably the lid portion has a height which is less than 50 per cent of the height of the container portion.

Description

This invention relates to one-piece cartons of the type having a hingedly connected lid portion. In particular, this invention relates to improvements in one-piece cartons of the type having a hingedly connected lid portion and an articulated panel or bellows construction connected to the back wall of the container portion to facilitate assembly of the container.

Cartons having a back wall of the container portion hingedly connected to the bottom wall of the container portion and employing articulated panel means for connecting the back wall to the lid or the container portion are well known. If the articulated panels are not connected to the side walls of the container portion, the side walls of the container portion are free to fold inwardly of the area of the container when the carton is assembled and may interfere with the carton loading operation. For this reason it is more common to connect the edges of the side walls of the container portion to the articulated panels and to leave the edge of the side wall of the lid portion free from the articulated panels. The disadvantage of this construction is that the side walls of the lid portion are free to bend outwardly adjacent their back edge, and this results in the formation of "dog ears" during handling, loading and shipping of cartons of this type.

While it required have been said that it was apparent that this difficulty could be overcome by connecting both the side wall of the container portion and the side wall of the lid portion to the articulated panels, this would have requierd a construction wherein the articulated panels and the side walls are hingedly connected along aligned hinged lines to the top, bottom and back panels respectively. This was not previously thought to be possible due to the fact that it would result in the top wall panel of the lid portion being the same size as the bottom wall panel of the container portion so that the lid would not fit over the container portion. The practice in the industry has been to make the top wall panel of the lid portion larger than the bottom wall panel of the container portion so that the lid will fit over the container portion. To achieve this construction it is necessary to place the fold lines of the side walls of the container portion out of alignment with the fold lines of the side wall panels of the lid portion. As previously described, this construction would not permit the articulated panels to be connected to both the side walls of the container portion and the side walls of the lid portion, and consequently it was not previously thought to be possible to overcome the dog-ear problem by connecting the articulated panels to the side walls of both the lid and container portions.

Difficulty has also been experienced in attempting to construct the unitary blank for manufacturing a carton of the kind described above such that the blank may be struck from a sheet of material in a single cut operation. It has not previously been possible to provide the clearances required for the end flaps without spacing the side edges of the blanks away from one another in their outline on the sheet from which they are to be struck.

SUMMARY

The present invention overcomes the difficulties of the prior art described above and provides a simple and inexpensive one-piece container wherein the side walls of the container portion and lid portion are restrained by articulated panels and wherein the lid portion is adapted to fit over the container portion without buckling.

According to an embodiment of the present invention there is provided in a one-piece carton having a container portion and a lid portion having side walls hingedly connected along aligned hinge lines, the improvement wherein at least one pair of the side walls is angularly inclined along the aligned hinge lines such that the open end of the lid portion is larger than the open end of the container portion and fits over the open end of the container portion without buckling.

The present invention also provides a nestable blank construction wherein the nesting edges of adjacent blanks may be formed in a single cut operation.

The invention will be more clearly understood after reference to the following detailed specification read in conjunction with the drawings wherein

FIG. 1 is a plan view of a blank according to an embodiment of the present invention;

FIG. 2 is pictorial view showing the first step in the formation of the carton from the blank of FIG. 1;

FIG. 3 is a pictorial view showing a further step in the formation of the closed one-piece container;

FIG. 4 is a view of a closed container; and

FIG. 5 is a sectional view along line 5--5.

With reference to the drawings, the refence numeral 10 refers generally to a unitary blank according to an embodiment of the present invention. The blank 10 consists of a fold-over flap 12, a lid front wall 14, a lid top wall 16, a container back wall 18, a container bottom wall 20, a container front wall 22 and a fold-over flap 24, which are connected to one another along longitudinal fold lines 13, 15, 17, 19, 21 and 23. Top side walls 26, articulated panel means 28 and bottom side wall panels 30 are connected to top wall 16, back wall 18 and bottom wall 20 respectively along fold lines 36a and 36b, 38a and 38b, 40a, and 40b. The fold lines 36a, 38a and 40a are aligned with one another and similarly the fold lines 36b, 38b and 40b are aligned with one another so that the top, back and bottom walls are of the same length. The articulated panels 28 are connected to the back edges of the top side wall panels and the back edges of the bottom side wall panels along hinge lines 42, 44 respectively.

The articulated panels 28 are formed with a first diagonal fold line 46 and a second diagonal fold line 48. The first diagonal fold line 46 extends at an angle .theta..sup.1 with respect to the fold lines 38a and 38b and the second diagonal fold line 48 extends at an angle .theta..sup.2 with respect to the fold lines 38a and 38b. An important feature of the present invention is that the angle .theta..sup.2 is greater than the angle .theta..sup.1 so that the open end of the container portion will be smaller than the open end of the lid portion so that the lid will fit over the open end of the container portion without buckling. Preferably the angle .theta..sup.1 is 45.degree., while the angle .theta..sup.2 is about 46.degree.. It has been found that by increasing the angle .theta..sup.2 to 46.degree. the side walls of the container may be sufficiently inwardly toed on assembly to permit the lid portion to fit over the container portion without buckling of the container portion.

To further insure that the side walls of the container portion are inwardly toed on assembly, the flaps 50, which extend outwardly from hinge lines 52 at the front edge of the side walls 30, are formed with an upper edge 54 which is outwardly inclined at an angle .theta..sup.4 from the plane of the upper edge of the side walls. The angle .theta..sup.4 is sufficient to insure that the height H4 is about a sixteenth of an inch greater than the height of the side walls 30. The lower edge 56 of each flap 50 is spaced outwardly from the plane of the fold line 40a. As shown in FIG. 5, the upper edge 54 of the flap 50 is engaged by the underside of the flap 24 in a position such that the side walls 30 are retained at the front edge in the toed in configuration.

As previously indicated, the practice in the manufacture of cartons of the type described has been to make the dimensions of the top wall panel of the lid larger than the dimensions of the bottom wall panel of the container. The previously described toeing in of the side walls permits the length of the panels 16 and 20 to be equal to one another. By similarly toeing in the front wall panel 22, it is possible to make the width of the top wall panel 16 equal to the width of the bottom wall panel 20, thereby effecting a saving in material. In order to obtain the required toeing in action, the side edges 22a of the front wall 22 are inclined at an angle .theta..sup.5 to the plane of the fold lines 40a, 40b.

Referring again to the articulated panel means 28, it will be seen that each articulated panel 28 consists of sub-panels 28a, 28b and 28c. It will be noted that the upper edge 29 of the panel 28c follows a curved contour in extending between the section of the fold lines 44 and 48 and the upper edge of the side wall 30. It will be noted that the curved edge 29 is symmetrical about the plane defined by the broken line 60. The plane defined by the broken line 60 is disposed centrally of the transverse width of the blank so that by forming the portion of the panel 28c symmetrical about the line 60 it is possible to form adjacent blanks by forming one straight cut. The portion of the panel 28c adjacent the side wall 30 is formed with a greater width than would otherwise be provided by a straight diagonal so as to form an end post which adds considerably to the stacking strength of the container. One of the problems frequently experienced when the side walls of the container portion are not secured to articulated panels is that the side wall does not enhance the stacking strength of the carton in the corner area to any extent.

In the normal construction of a carton it is customary to decrease the upper edge of the flaps 62 which are connected to the side walls 26 by an amount sufficient to permit the flap 12 to fold over the flap 62 while the front panel 14 and side panels 26 are of the same height. Normally this is done by a stripping operation after the blank is formed. The present invention eliminates the need for a stripping operation by cutting the upper edge 64 at an angle .theta..sup.3 relative to the plane of the upper edge of the major portion of the side walls 26. Angle .theta..sup.3 is equal to the angle .theta..sup.4 and the cut is made of a sufficient length to extend over the distance a which is equal to the length a of the flaps 50. This construction permits the flaps 64 to be recessed to a sufficient extend to permit the closure flap 12 to be folded over, while also permitting the same cut which is used to form the angle .theta..sup.4 at the edge 54 to form the angle .theta..sup.3 at the edge 64 so that it is possible to form two blanks with identical side edges by a single straight cut.

To assemble the carton of the present invention the blank is folded along the aligned transverse fold lines 36a, 38a, 40a and 36b, 38b, 40b. Flaps 50 are folded into the position overlying the fold line 20 and the front wall 22 is folded upwardly into an outwardly overlying relationship with respect to the flaps 50. The closure flap 24 is then folded over the flaps 50 and secured in a position wherein the side walls 30 are toed inwardly. As previously indicated, the upwardly inclined upper edge 54 of the flaps 50 engages the underside of the fold line 23 so as to retain the front edge of the side walls 30 in the inwardly toed relationship.

The lid is assembled by folding the flaps 62 inwardly to a position overlying the fold line 15 and folding the front wall upwardly to a substantially vertical position and subsequently folding the flap 12 over the flaps 64 and securing the flap 12 in a folded position.

To close the carton the lid is raised and the back wall 18 is raised. The action of raising the lid and the back wall 18 causes the articulated panels to fold inwardly of the carton, and by reason of the fact that the angle .theta..sup.2 is greater than the angle .theta..sup.1, the fold line 48 serves to cause the adjacent edge of the side walls 30 to be inwardly inclined so that the side walls are "toed in" by the closing action so that the area of the open upper end of the container is less than the area of the open lower end of the lid. As a result of this toeing in action, it is possible to fit the lid over the upper end of the container portion without causing any buckling of the lid or the container portion. By reason of the fact that the articulated panels are secured to both the side walls 30 of the container portion and to the side walls 26 of the lid portion, no dog ears exist. In addition, it has been found that the enlarged portions of the panels 28c serve to bear against the portions 28b of the panel during the closing operation so as to insure that when the articulated panels are in the closed position, they are directed into a face to face relationship with the back wall 18 of the container.

It has been found that with the construction described above it is possible to make cartons from a material having a calibre of at least .040 inches without any buckling occurring during the closing operation.

Preferably the height of the lid portion is substantially less than the height of the container portion so that in closing the lower end of the lid portion is spaced above the plane of the bottom wall 20 which, as previously indicated, is at least the same width as the top wall 16. It has been found that if the lid portion 16 is no more than half the height of the container portion, it is possible to achieve the required closing action without buckling.

From the foregoing it will be apparent that the present invention provides a simple and inexpensive carton construction capable of effecting a saving in material, while eliminating the dog ears which have created problems with the cartons of the prior art.

Claims

What I claim as my invention is:

1. In a one-piece carton of the type having a bottom wall, a front wall, a back wall and a pair of oppositely disposed side walls defining a container portion having an open upper end and a lid portion hingedly connected to the back wall of the container portion and having a top wall, a front wall and a pair of oppositely disposed side walls defining an open lower end, the side walls of the said container portion being folded along the fold lines which are aligned with the fold lines along which the side walls of the lid portion are folded, the improvement wherein said front wall of said container portion has a fold-over flap at its upper edge and said side walls of said container portion each have a front edge and a flap panel hingedly connected to and projecting connected from said front edge and folded to a position inwardly of said front wall and underlying said fold-over flap when the container portion is erected, said flaps each having an upper edge which is upwardly inclined in a direction away from its connection with said side wall panels of extending container portion whereby said upper edge of said flap portion is engaged by said fold-over flap of said front wall to retain said side walls of said container portion in said inwardly inclined position.

2. A unitary nestable blank for forming a carton comprising a lid front wall fold-over flap, a lid front wall, a lid top wall, a container back wall, a container bottom wall, a container front wall and a container front wall fold-over flap hindedly connected along longitudinally extending spaced parallel hinge lines, a pair of container side wall panels hingedly connected to said bottom wall along parallel transverse hinge lines, a pair of articulated panels hingedly connected to said back wall along parallel transverse hinge lines and a pair of lid side walls hingedly connected to said lid portion along parallel transverse hinge lines, said parallel transverse hinge lines being aligned with one another, said articulated panels being foldable along weakened fold lines extending inwardly thereof from the intersections of the transverse and longitudinal hinge lines thereof, said articulated panel means being connected to said side walls of said lid and said container portion along longitudinally extending hinge lines, first flap panel means hingedly connected along the longitudinally extending hinge lines to said side walls of said container portion and projecting outwardly therefrom and second flap panel means hingedly connected along longitudinally extending hinge lines to said side walls of said lid portion and projecting outwardly therefrom, said flap panels, said side walls of said container portion, said articulated panel means and said side walls of said lid portion having a single cut nestable edge extending continuously thereof, the portion of the nestable edge extending from the hinge line connecting the flap panels to the side walls of the container portion being angularly inclined outwardly in a direction away from said hinge line and the portion of the nestable edge extending inwardly from the end of the flap panels which are connected to the side walls of the container portion and the adjacent side wall being angularly inclined inwardly in a direction towards the outer end of the flap panel equal to the outward angle of inclination of the nesting edge of the first mentioned flap panel.