This application claims the benefit of priority of French Patent Application No. 03/12,708, filed Oct. 30, 2003, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polygonal box for use as packaging, for example for products to be consumed or for medicinal products.

2. Description of the Art

A polygonal box of this invention includes faces, an apical surface and a base surface. Conventionally, the box may include four faces, possibly three or more than four, depending on the model.

With reference to FIG. 1, a brief description will be given of a known box of this type having four faces 1, 2, 3, 4, the faces 3 and 4 not being clearly visible from the perspective of the figure. The apical 5 and basal 6 surfaces are generally similar and often differ only in terms of the printing on the box, which indicates the direction in which the product has been arranged. The description of the apical surface 5 therefore applies, in the following text, also to the base surface 6.

The apical surface 5 comprises a lid 7 provided with a tab 8 and with two flaps 9, 9â€². The flaps 9, 9â€² are designed to be folded down, inserted under the lid 7 when the latter is folded for closure of the box, and the tab 8 is designed to be folded into a coplanar position against the inner wall of a first face 1, called the â€œfront faceâ€ , when the box is closed.

The lid 7 has an edge that it shares with a face 4 of the box, called the â€œrear faceâ€ , and an edge shared with the tab 8. The lid 7 is folded around the fold line defined by the edge shared with the rear face 4, and the tab 8 is folded around the edge shared with the lid 7. The flaps 9, 9â€² each have an edge shared with the respective lateral faces 2, 3, these edges defining flap fold lines.

Boxes of this type are well known and have been in wide use for a number of years. These boxes may be opened by removing the tab from its position where it is folded against the first face and by lifting the lid and the flaps, and then they may be closed again by folding down the flaps and the lid and by sliding the folded tab against the inner wall of the first face. The box may be thus opened and closed a very great number of times without apparent modification to the appearance of the box, which guarantees its great durability.

However, precisely because of the absence of apparent modifications occurring during opening and closure, it is possible for these boxes to be tampered with, with the aim, for example, of replacing the contents of the box with an undesirable product.

There is therefore a need to detect tampering with the products contained in such boxes, while guaranteeing the possibility of multiple openings and closures without affecting the appearance of the box. In particular, there is a need to detect first opening of the box after industrial packaging of the product.

A known solution for detecting first opening of the box consists in affixing a seal to the opening device when the product is packaged. Such a seal may consist, for example, of a disk arranged so that it straddles one face and the lid, the disk being torn away by unfolding of the lid at the time of opening. This solution is, however, easy to get around in terms of unauthorized first opening, it being possible for the seal to be repositioned or replaced by someone tampering with malicious intent. Furthermore, production and affixing of the seal increase the production price of the box.

Another solution is known from document FR 2 832 982, which is incorporated herein by reference in its entirety, and consists in producing, on the flaps, a surface that has over its perimeter a zone of relatively low mechanical strength. When the lid is raised, the tab pinches this zone and causes this zone to tear away. This tearing-away cannot be repaired, and first opening of the box is thus detected by the tearing of a flap surface.

However, it has been observed that such boxes may be damaged when the product is packed within the context of industrial packaging: the machines used have mechanical arms for bearing on the flaps in order to fold them down over the apical (and base) surface before folding down the lid. In point of fact, these mechanical arms give rise to tearing of the zone of weak mechanical strength when they bear on the flap.

Such tearing during packaging thus prevents subsequent detection of first opening, as the surfaces of the flap or flaps have already been torn away by handling at the time of packing.

The intention of the present invention is to solve these problems and it proposes a box that makes it possible reliably to detect a first opening without altering the appearance of the box and that is compatible with industrial packing techniques.

SUMMARY OF THE INVENTION

To this end, the invention proposes a polygonal box comprising:

- faces;
- a lid provided with a tab suitable for arranging in a folded position against a first face of the box;
- a flap that can be folded down around an edge shared with a second face of the box, the flap having a zone of mechanical weakening that is inclined relative to said edge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, as already described above, shows a diagrammatic perspective view of a polygonal box.

FIG. 2 shows a diagrammatic perspective view of a box according to the invention, open on its apical surface.

FIG. 3 shows a diagrammatic view of a first embodiment of the box according to the invention, in the open state before packing.

FIG. 4 shows a diagrammatic view of a second embodiment of the box according to the invention, in the open state before packing.

FIG. 5 shows a diagrammatic view of the box of FIG. 3 in the closed state.

FIG. 6 shows a diagrammatic view of the box of FIG. 3 in the state of first opening after packing.

FIG. 7 shows the outline of the cut-out blank for the box according to the first embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

According to one characteristic, the flap has a first surface delimited by the edge shared with a face and by the zone of weakening, and a second surface delimited by the zone of weakening and by the end of the flap opposite the edge, said first surface being larger than said second surface, and the second surface being designed to be pinched between the tab and the lid and torn away by tearing of the zone of weakening when the tab is unfolded from its position against the first face of the box.

According to one embodiment, the flap has lateral borders extending from the edge shared with a face, the zone of weakening extending in a curved line from a lateral border of the flap.

According to one characteristic, the curve of the zone of weakening is concave along the first surface.

According to one characteristic, the curve of the zone of weakening defines an arc of a circle with a diameter greater than or equal to the edge shared by the flap and a face.

According to one characteristic, the diameter of the arc of the circle of the curve of the zone of weakening is between 100% and 150% of the length of the edge shared by the flap and a face.

According to another embodiment, the flap has lateral borders extending from the edge shared with a face, the inclined zone of weakening extending in a straight line from a lateral border of the flap.

According to one characteristic, the angle of inclination of the zone of weakening relative to the edge shared by the flap and a face is between 10Â° and 80Â°.

According to one embodiment, the box also comprises a zone of weakening arranged on the first face opposite the tab in the folded position.

According to one characteristic, the zone of weakening of the first face is an arc of a circle of which the ends are arranged on an edge of the first face.

According to one embodiment, the box also comprises a zone of weakening arranged on the lid.

According to one characteristic, the zone of weakening of the lid is an arc of a circle of which the ends are arranged on an edge shared by the lid and the tab.

According to one characteristic, the zone of weakening of the lid is a line extending from an edge shared by the lid and the tab toward a lateral border of the lid extending from said edge.

According to one embodiment, the zone of weakening comprises perforations.

According to one embodiment, the box comprises at least three faces and preferably four faces.

According to one embodiment, the box is composed mostly of cardboard.

The invention also relates to a pre-cut-out blank comprising:

- fold zones for forming the edges of the box according to the invention; and
- a zone of weakening extending over a portion of the blank designed to form a flap, this zone extending in a line that is inclined relative to an edge shared by the flap and a face of the box according to the invention.

Further characteristics and advantages of the invention will become apparent on reading the following detailed description of embodiments of the invention, which are given solely by way of example and with reference to the drawings, as disclosed herein.

The invention proposes a polygonal box, as shown in FIG. 2. The elements shared with the known box of FIG. 1 bear the same reference numerals.

A box of this type comprises faces 1, 2, 3 and an apical surface 5. This apical surface 5 comprises a lid 7 provided with a tab 8 suitable for being arranged in a folded position against a first face 1 of the box and a flap 9 that can be folded down, suitable for being inserted under the lid 7. The flap has an edge 29 shared with a second face 2 of the box, which forms a fold zone for folding the flap 9 on the apical surface 5.

This description of the apical surface 5 applies to the base surface 6 that cannot be seen in FIG. 2, and in the following text the lid, tab and flap elements may correspond, without distinction, to elements of the apical 5 or base 6 surface of a box.

In the case illustrated of a four-face box, the apical 5 and base 6 surfaces each have two flaps. The following description denotes these two flaps by means of the same reference numeral 9, in order not to overload the drawings. In particular, it is understood that each flap 9 comprises an edge 29 shared with a second (and third) face 2, 3 of the box. In the following text, one flap is described, and it is understood that the description may apply to each of the flaps, as appropriate.

The flap 9 has a zone 10 of mechanical weakening, such as perforations, for example, that is inclined relative to the edge 29 shared by the flap and a face. According to the embodiments, this inclination of the zone 10 of weakening may take the form of a curved line or of a straight line inclined at a given angle.

Two surfaces are thus defined on the flap 9: a first surface 11 delimited by the edge 29 shared by the flap and a face and by the zone 10 of weakening, and a second surface 12 delimited by the zone 10 of weakening and by the end border of the flap 9 opposite the edge 29. In particular, the first surface 11 is larger than the second surface 12, and this second surface 12 is designed to be pinched between the tab 8 and the lid 7 and torn away by tearing of the zone 10 of weakening when the tab 8 is unfolded from its position against the first face of the box.

According to a first embodiment, illustrated in FIG. 3, the zone 10 of weakening extends in a curved line from a lateral border of the flap 9. The lateral borders of the flap 9 are defined as the borders extending from the edge 29 shared by the flap and a face.

According to the embodiment illustrated in FIG. 3, the curve of the zone 10 of weakening extends from one lateral border to the other of the flap 9 in a concave shape along the first surface 11. This concavity of the side of the first surface 11 gives this first surface 11 a greater surface area as compared to the second surface 12.

In such an embodiment, the curve of the zone 10 of weakening defines an arc of a circle of which the diameter is greater than or equal to the edge 29 shared by the flap 9 and a face. For example, the diameter of the arc of the circle of the curve 10 is between 100% and 150% of the length of the edge 29.

The curve of the zone 10 of weakening may also extend from a lateral border to the end border opposite the edge 29 in a concave or convex shape along the first surface 11. The diameter of the arc of the circle defined by the curve of the zone 10 of weakening may then be smaller than the edge 29 shared by the flap and a face.

The diameter of the arc of the circle of the curve 10 is chosen as a function of the box model. It must be sufficiently small to guarantee a curved-in shape for the zone of weakening, and sufficiently large to guarantee tearing-away of the second surface 12 of the flap 9 by the tab 8, which generates a force perpendicular to the lateral border of the flap when it is unfolded.

According to a second embodiment, illustrated in FIG. 4, the zone 10 of weakening extends in a straight line from a lateral border of the flap 9. The zone 10 of weakening is inclined at an angle Î± relative to the edge 29 shared by the flap and a face. The angle Î± must be sufficiently large to guarantee that a first surface 11 is larger than the second surface 12 of the flap, allowing folding of the flap 9 without altering the zone of weakening at the time of industrial packing, and sufficiently small to guarantee satisfactory tearing of the zone of weakening, the tab generating a force perpendicular to the lateral border of the flap when it is unfolded. An angle Î± of between from about 10Â° and about 80Â°, and preferably between from about 20Â° and about 60Â°, may fulfill such conditions in the example of a four-face box.

Other zones of weakening may be provided on the box according to the invention in order to enhance detection of first opening of the box.

According to one embodiment, the first face 1 of the box, called the â€œfront faceâ€ , may have a zone 15 of weakening. This zone 15 is arranged opposite the tab 8 when it is in the position in which it is folded against this first face 1. For example, this zone 15 of weakening of the first face 1 may be formed by an arc of a circle of which the ends are arranged on an edge of the first face.

According to one embodiment, the lid 7 of the box may also have one or more zones 16, 17 of weakening (see FIG. 3). For example, a zone 16 of weakening of the lid 7 may be formed by an arc of a circle of which the ends are arranged on an edge 18 shared by the lid 7 and the tab 8. A zone 17 of weakening may also be formed by a line extending from the edge 18 shared by the lid 7 and the tab 8 toward a lateral border of the lid 7 extending from said edge 18.

FIGS. 3, 5, and 6 are diagrammatic views of the apical surface of the box according to the first embodiment of the invention. These figures show, respectively, the box in three successive states, namely open before packing, closed, and after first opening by a user.

Before packing (FIG. 3), the box is as described previously. Zones 10, 15, 16, 17 of mechanical weakening, which may, for example, include perforations or thin sections of the material of the box, are provided, respectively, on the flaps 9, at the front face 1, and the lid 7.

During packing, the zone 10 of mechanical weakening of the flaps 9 will not be damaged. In fact, the inclination of this zone 10 of weakening is such that the bearing point of the mechanical arm of the packing machine on the flap 9 will be located on the first surface 11 of the flap, which is mechanically rigid.

When the box is closed (FIG. 5), the tab (not visible) is slid against the internal wall of the first face 1. The flaps (not visible) are covered by the lid 7.

At the time of first opening (FIG. 6), the tab is designed to give rise to tearing of the zone 10 of weakening of the flaps 9 when it is unfolded from its position against the first face 1 of the box.

This tearing of the zone 10 of weakening is inevitable because the tab 8 is slightly folded under the flaps 9 by the finger of a user wishing to hold the border of the lid in order to open the box. The tab 8 will therefore pinch the second surface 12 of the flap 9 against the lid 7 and give rise, when it is pulled out of its folded position against the first face 1 of the box, to the irreversible tearing-away of this second surface 12 by tearing of the zone 10 of weakening.

Furthermore, when the border of the lid is grasped, a user is able to push in the zone 15 of weakening arranged, as appropriate, on the front face 1 of the box, and to cause it to be torn irreversibly. This tearing will be supplemented, as appropriate, by tearing of the zone 16 of weakening of the lid 7 arranged on a median portion of the edge 18 shared by the lid 7 and the tab 8.

If, in order to prevent such tearing, the user pulls the border of the lid 7, another zone 17 of weakening, as appropriate, may be torn irreversibly.

These tears 15, 16, 17 of the front face 1 and/or of the lid 7 supplement the tearing of the zone 10 of weakening of the flaps 9.

Thus, regardless of the precautions taken when opening the box according to the invention, at least one zone 10, 15, 16, 17 of weakening will inevitably tear. First opening of the box may thus be detected, and its tamperproof state before its first use guaranteed.

The invention also relates to a pre-cut-out blank for manufacturing the box according to the invention. This blank is illustrated in FIG. 7 and comprises fold zones designed to form edges of the box according to the invention and at least one zone 10 of weakening on a portion of the blank designed to form a flap 9, this zone extending in a line that is inclined relative to an edge shared by the flap and a face of the box according to the invention.

This blank is composed mostly of cardboard. The material of the blank is preferably anisotropic, i.e. it has greater tensile strength in one given direction as compared with the direction perpendicular to this direction.

The anisotropic axis may be parallel to the edges 29 shared by the flaps 9 and the lateral faces 2, 3. This arrangement may promote initiation of the tearing of the zone 10 of weakening, while reducing the risk of tearing in other zones.

Of course, the present invention is not limited to the embodiments described by way of example. A four-face box has therefore been described and illustrated, but the invention equally applies to a triangular box and to a polygonal box having more than four faces. In particular, irrespective of the number of flaps with which the box is provided, this number depending partly on the number of faces, at least one flap has a zone of mechanical weakening extending in a line inclined relative to the edge shared by the flap and a face.