DE69519442T2 - SELF-CLOSING FOLDING BOX - Google Patents

Abstract

A box, formed by folding from a flat creased cardboard blank of thin and resilient material, is of generally polyhedral shape and has an edge (the closure line) (25) at which two faces (the closure faces) (17, 18) meet separately; pressing the vertices at the ends of that line together (at 26) splays those faces resiliently apart (at 27) along that line to allow access to the interior of the box. The closure line may be closed by temporary sealing means (e.g., peelable adhesive tape or a tear-off closure strip) (37-39). The closure faces may have an overlap (Figs. 3A-3C) for firmer closure; the overlap may be initially folded in to form a "pillow pack" (Fig. 4). A variety of shapes are possible, preferably having a flat base with the closure line lying above and parallel to the base. One basic shape is a triangular prism lying on its side (Figs. 2A and 2B); another is a rectangular base with, rising from it, four vertical sides with their top ends sloped in zig-zag fashion, and closed by two sloping triangular top faces - the side faces may be trapeziform (Fig. 5) or triangular (Fig. 6). The boxes may be nested together in partially assembled form with open bases. The boxes may be stored flat, with their bases automatically assembling when they are opened out.

Description

The present invention relates to self-closing boxes, which are made in particular, but not necessarily, of cardboard.

Certain snacks and other foods cause considerable inconvenience in entertainment establishments and elsewhere when they are discarded half-empty, because the residue can easily spill out of their containers if the containers are not properly placed in waste receptacles. Popcorn, for example, presents a special problem because it is light in weight and easily breaks open, and also sticks together with burnt sugar, so that carpets, etc., in establishments such as cinemas, can often be contaminated.

The present invention is based on the object of creating a self-closing folding box that avoids all such problems.

According to the invention there is provided a box made of thin and resilient material of generally polyhedral shape, characterized in that it has an edge forming a closure line at which two surfaces forming the closure surfaces meet in a separable manner such that compression of the vertices at the ends of this line resiliently spreads those surfaces apart along this line to make the interior of the box accessible.

The box may conveniently be constructed from a flat blank of cardboard material cut and folded to the appropriate shapes.

In order to ensure greater initial security for the contents of the box, the two closure surfaces are initially secured by temporary connecting means along their closure line, with the edges lying along the closure line. For this purpose, a strip of peelable adhesive tape may be used and instead the two closure surfaces may have extensions which are initially connected to each other. These extensions may be secured by a cord passed through fitting holes therein. Instead, the tabs may be defined by perforated lines such that they can be torn away from the closure panels. In this case, the tabs may be formed from a continuous section of the carton which is folded in half to form a flap projecting over the two closure panels at the closure line, or they may be formed separately on the two closure panels and glued together. Another possibility for certain shapes of box is a detachable cap which has the same shape as the top of the box (ie the part around the closure line) and which is slightly larger than that part to provide a close fit, but is removable over that part of the box.

The sealing edges of the two sealing surfaces may simply abut each other at the sealing line. However, to provide a more secure closure of the box, the sealing surfaces may overlap. To do this, the two sealing surfaces both protrude in the same direction beyond the geometrically straight line between the two vertices (ends) of the sealing line and come away from the inside to the outside when the two vertices are pressed together. This design causes the two sealing surfaces to be distorted into a slightly concave shape, with the tension resulting from this concave shape tending to hold the sealing edges together.

Different shapes can be used for the box. Conveniently, the box has a flat base with the closure line above and parallel to the base.

A suitable shape is a triangular prism with one rectangular face forming the base of the box, while the other two rectangular faces (side faces) form the closure faces (so that the edge where they meet, i.e. the edge opposite the base, forms the closure line) and the two triangular faces form the ends of the box. The two closure faces may have integral extensions to conformably overlap. Instead, this shape may be modified by the addition of a crescent-shaped element to the top edge of each rectangular side face to form two closure faces with a sliding overlap.

This shape can be modified by shortening the closure line so that the two closure surfaces become trapezoidal. This creates the possibility of stacking the boxes in a partially assembled form with the base of each open. The stack can be kept top down and a fill poured into the top box of the stack. The base is then closed off and the box removed from the stack. Instead, the closure line can be extended so that the two closure surfaces become trapezoidal in mutual orientation.

A second suitable design has a rectangular base with four vertical sides rising from it, the upper ends of which are zig-zagged and closed by two bevelled triangular upper surfaces which form the closure surfaces, the closure line passing between the two uppermost points of the side surfaces. The side surfaces may be trapezoidal in shape, or they may be bevelled with their upper edges downwards towards the base so that they are triangular. (By further bevelling, the two "upper" surfaces become trapezoidal and the base becomes hexagonal.)

The box may be designed to be stored flat in a partially assembled form. The base may have a construction which provides automatic assembly when such a partially assembled box is opened.

Various boxes that form the subject of the invention are described below using exemplary embodiments that are shown in the drawing. In the drawing:

Fig. 1 shows a cardboard blank for a first box;

Fig. 2A and 2B show the first box in the closed state and in the open state, respectively;

Fig. 3A to 3E show variations of this first box;

Fig. 4 shows a further modification of the first box;

Fig. 5 and 5A, 6 and 6A, 7 and 7A and 8 and 8A show further boxes and cut-outs intended for them.

Fig. 1 shows a cardboard blank from which a first box can be made. The cardboard must be stiff but resilient and capable of remaining permanently folded along the fold lines. (It is clear that any thin sheet material with these properties can be used.)

The box is made by scoring and folding the blank along the dashed lines; all folds are made in the same direction. The sides of the box are formed by the two rectangles 17 and 18 and the two triangles 19 and 20. A flap 21 on the triangle 20 is glued to the edge area 22 of the rectangle 17 to give the shape of the box. The base is a rectangle and this is assembled by folding four flaps 10 to 13 together. The flaps 11 and 13 are folded first and then the flaps 10 and 12 are folded together, the flap forming part of the flap 10 being inserted into the slot 14 of the flap 12.

This results in a box with a shape as shown in Fig. 2A. In this box, the two rectangular sides 17 and 18 form the closure surfaces. In the normal closed state of the box according to Fig. 2A, the two upper edges 25A, 25B of these closure surfaces form a single common closure line 25. When the upper corners of the box are manually pressed together at the ends of the edge 25, as indicated by the arrows 26 in Fig. 2B, the closure edges 25A, 25B are spread open, as shown by the arrows 27, so that the contents of the box become accessible. When the pressure on the corners of the box is removed, the stiffness and elasticity of the cardboard return the box to the closed state.

When the box is partially assembled by gluing the flap 21 to the area 22 of the side surface 17, the box can be laid out flat by folding the sides 19, 20 (together with the base flaps 11 and 13) along the fold lines 30 and 31. A large number of boxes can then be stacked in a compact manner. For this reason, the base flaps 10 to 13 are left flat, ie not folded out of their planes of the associated sides 17, 19, 18 and 20. In order to assemble To complete the box, sides 19 and 20 (along with their associated base flaps 11 and 13) are laid out flat and the base flaps are then folded together as described above.

Instead of stacking the partially assembled boxes in a completely flat condition, they can be given a slight fold along the stack fold lines 30 and 31 and then nested to form a stack. This provides the opportunity for them to present a taper and be removed without jamming. When the stack is then turned upside down, the top box in the stack can be filled (for example with Popcom), the base can be nested together and the completed and filled box can be removed from the stack and properly turned over and presented to a buyer.

Fig. 3A shows a modified closure face shape for the box of Fig. 1. Here, the closure face 17 has an upper edge 25A which is curved in the manner shown. The other closure face 18 is similarly designed. The closure line of the box is therefore curved upwards over the geometric line 25 of Fig. 2A and the upper parts of the closure faces 17 and 18 are in a conforming overlap when the box is closed. The closure faces are forced into a slightly curved shape when the box is closed, with a positive pressure between their overlapping areas near the closure edges. This modified form of box, like the other variations using the closure face shape of Figs. 3B to 3E, may be desirable for a distinctive appearance.

A hole 26 may be provided near the top edge of the face 17, and a corresponding hole is then provided in the face 18. Then a strap or cord may be passed through the two holes to form a temporary securing device which can be released when the box is to be made accessible.

Fig. 3B shows a modification that corresponds to the embodiment according to Fig. 3A. However, here the closure surface 17 has a straight fold line 31 that is folded back slightly. The overlapping sections of the closure surfaces 17 and 18 then lie against each other, but without pushing the main parts of these surfaces out of their flat state.

Fig. 3C shows a modification similar to Fig. 3B. However, here the closure surface 17 has a fold line 32 which is curved in the opposite direction to the upper edge 25A. The main purpose of this shape arises in connection with the design according to Fig. 4 described below.

Figures 3D and 3E show further variations of the box of Figure 1, in which the sides 17 and 18 are trapezoidal in shape. This results in a shape of the box in the form of a horizontal triangular prism with bevelled ends. If the shape according to Figure 3E is suitably chosen to ensure conformity to the triangle ends, the blank from which the box is made can be provided with straight fold lines (i.e. with straight fold lines between the sides of the box and the various flaps forming the base).

Fig. 4 shows a further modification of the carton of Fig. 1. In this embodiment, the closure panels 17 and 18 have the shape shown in Fig. 3C, but the fold line 31 is initially made in the same sense as the other fold lines. The portions 17A and 18A of the panels 17 and 18 therefore extend substantially horizontally and form inwardly facing overlapping crescent-shaped portions on those panels. (This also causes the panels 17 and 18 to be slightly curved.) The result is a "pillow pack" type shape in which the contents are retained with considerable reliability. In effect, the crescent-shaped portions 17A and 18A temporarily form initial closure means. In order to provide access to the interior of the box, these sections 17A and 18A must be pulled out to form smooth extensions of the surfaces 17 and 18. The box then takes on the shape shown in Fig. 3C. (Of course, this embodiment can be combined with the embodiments shown in Fig. 3D or 3E.)

Fig. 5 shows a second embodiment of the box, based on a vertical square prism. This box has a base 30 and four vertical sides 31 to 34, and each vertical side has the shape of a rectangle, with the upper end bevelled to turn it into a trapezoid. The box is formed by two inclined triangular surfaces 35 and 36 at the top. closed, and these two surfaces form the closure surfaces. Their common edge 37 forms the closure line of the box. This box is made from the blank shown in Fig. 5A. All the flaps to be glued are shown in Fig. 5A. Some of these are shown in light dashed lines in Fig. 5.

It will be seen from the drawing that the closure line 37 of the box of Fig. 5 has a strip 38 thereover. Fig. 5A, which forms the blank for this box, shows this strip as a double strip connected to the panels 35 and 36 and having a fold line 39 in the middle. When the box is assembled, the strip 38 is folded in half along the line 39. Its connection to the panels 35 and 36 is defined by perforation lines shown at 37 which form the closure edges of the panels 35 and 36. When the box is initially assembled, it is therefore sealed by the strip 38 which provides a temporary seal. In order to access the contents of the box, the strip 38 must be torn off. The box can then be opened along its closure line 37 by pressing the corners of the ends of this line together and the box will then automatically close again when this pressure is released. If this box is made according to Fig. 5 without the sealing strip 38 then it can be made from a "stretched" blank in which the four main sides 31 to 34 form a stretched band.

With this design of box, alternative temporary closure means may be used in the form of a large cap having the same shape as the top of the box and which fits tightly over the top of the box.

Fig. 6 shows a box whose shape is a variation of the shape shown in Fig. 5, with the triangular closure surfaces 35 and 36 extending down to the base 30. Consequently, the side surfaces 31 to 34 are triangular. (For clarity, the tabs and temporary sealing strips are omitted from Fig. 6.) The shape of this second box can also be modified in other ways, for example analogous to Figs. 3D and 3E. Fig. 6A shows a blank for this box. This shape can be partially assembled and stacked flat, leaving only the base assembled for the final construction.

The shape according to Fig. 5 cannot be treated in the same way because when the three surfaces 31, 32 and 35 are joined, they obtain a three-dimensional shape which cannot be flattened. However, for certain applications it may be acceptable to assemble the shape according to Fig. 5 in a flattened form, whereby the connections between the surfaces 31 and 32 and the surfaces 33 and 34 are not made.

It is also possible to use the techniques of Figs. 3A to 3C in connection with boxes of the type shown in Fig. 5. When this is done, the temporary sealing strip can be provided with a straight central fold line and curved perforation lines. Alternatively, it can be made in other ways, for example by gluing two sections together, one attached to each closing surface. The technique of Fig. 4 can also be used in connection with boxes of the form shown in Figs. 5 and 6, although this would require that the sealing strip be omitted. If required, a strip of removable adhesive tape can be used to provide a temporary seal for the box.

In a rectangular box which is stackable when flat, a technique is known for producing a base by gluing and folding flaps upright within the box such that when the box is opened the base flaps are pulled downwards and automatically lock together to automatically form a substantially rigid base. This technique can be applied to most of the boxes according to the invention.

However, some forms of the box according to the invention require slight modifications to this technique. The box according to Fig. 7 (which is a box of the type according to Fig. 1 modified by combining Figs. 3B and 3D) is an example of this. Fig. 7A is a blank for this box. This consists of four panels 41 to 44 with a flap 45 glued to the outer end of the panel 44, and furthermore this box consists of base parts 46 to 53. The base parts consist of two main flaps 46 and 50 and various smaller flaps and sections 47 to 49 and 51 to 53. The two sections 47 are glued together and the two sections 51 are also glued together.

When the box is partially assembled by the bonding just mentioned, it can be stacked in a flat form with the center lines of the end faces 42 and 44 bent downwards by 180º and with the base flaps all folded in towards the inside of the box. When the box is to be fully assembled, it is opened by pulling the sides 41 to 44 apart. This pulls the base flap sections downwards from the inside of the box. As a result, the lowermost parts of the main flaps 46 and 50 form two tongues which automatically interlock (each sliding over the adjacent part of the other flap) to form a firm and secure base.

Figures 8 and 8A show a box and blank therefor which are generally similar to the box of Figure 5, but this box is assembled in a different manner. The box has sides 55 to 58, upper closure surfaces 58 and 59 and a base 60. This box can be stacked flat in partially assembled form, with only tongue and groove adjustment being required for final assembly.

Claims (19)

1. Box made of thin and resilient material and of generally polyhedral shape, characterized in that it has an edge forming a closure line (25) at which two surfaces forming the closure surfaces (17, 18) meet in a detachable manner such that compression of the vertices at the ends of this line (at 26) resiliently spreads those surfaces apart along (at 27) that line in order to make the interior of the box accessible. 2. Box according to claim 1, characterized in that it is composed of a flat blank of cardboard material which is cut and folded to the appropriate shapes. 3. Box according to one of the preceding claims, characterized by temporary fastening means which are attached to the closure edges (the edges lying along the closure line) of the two closure surfaces. 4. A box according to claim 3, characterized in that the temporary closure means comprise a removable adhesive tape. 5. Box according to claim 3, characterized in that the temporary fastening means comprise extensions (38) of the two closure surfaces (35, 36) which are fastened to one another and delimited by perforated lines (37) so that they can be torn off from the closure surfaces. 6. Box according to claim 3, characterized in that the temporary fastening means comprise a cap of the same shape as the box in the region of the closure line, which is removably fitted over this part of the box. 7. Box according to claim 5, characterized in that the extensions are formed from a continuous part of the blank which is folded twice (at 39) to form a flap (38) projecting beyond the two closure surfaces at the closure line. 8. Box according to claim 5, characterized in that the extensions are formed separately on the two closure surfaces and glued together. 9. Box according to one of the preceding claims, characterized in that the closure surfaces have either a mating or a sliding overlap. 10. Box according to one of the preceding claims, characterized in that the box has a flat base, the closure line being above and parallel to the base. 11. Box according to claim 10, characterized in that the box is a three-sided prism, with a rectangular surface (10-13) forming the base surface of the box and the two other rectangular surfaces (side surfaces) (17, 18) forming the closure surfaces. 12. Box according to claims 9 and 11, characterized in that the two closure surfaces have integral extensions to form an overlap. 13. A carton according to claim 12, characterized in that the extensions are initially folded inwards to overlap and give a "pillow pack" shape. 14. Box according to claim 10, characterized in that the closure surfaces are trapezoids. 15. Box according to claim 10, characterized in that it has a rectangular base with ascending four vertical sides, the upper ends of which are inclined in a zigzag manner and which are closed by two inclined triangular upper surfaces which form the closing surfaces. 16. Box according to claim 15, characterized in that the side surfaces are trapezoids. 17. Box according to claim 15, characterized in that the side surfaces are triangular. 18. A stack of boxes according to any one of the preceding claims, which are nested in a partially assembled form. 19. A box according to any one of claims 1 to 17, characterized in that it can be stored in a flat state in partially assembled form and in that its base is automatically assembled when the partially assembled box is opened.