FR2847555A1 - Carton comprises tubular sleeve which has top flap with lip which cooperates with two side flaps with locking edges hold carton shut, top flap having perforated lines extending to its upper corners - Google Patents

Abstract

The carton comprises a tubular sleeve (2 - 4) which has a top flap (32) with a lip (17) which is folded down. This cooperates with two side flaps (23, 24) with locking edges (35) which hold the carton shut. The top flap has perforated lines (32, 33) extending to its upper corners. An Independent claim is included for a blank for making the carton.

Description

The present invention relates to the technical field of packaging and,

  more particularly, packaging cases which are intended to package,

  preferably but not exclusively, products of a unitary nature, either by themselves or by a pre-conditioning imposed on them.

  The invention relates, more specifically, to packaging cases which are produced from a blank of pre-cut raw material and then mounted by

  folding to form the actual packaging.

  As a preferred application, the invention relates to packaging cases made from a cardboard blank, preferably compact, without this precision excluding corrugated cardboard or similar products, such as

  plastic sheets laminated or not.

  In the above technical field, it is widely known to produce a packaging package from a blank of suitable material cut flat, then mounted to form a case in which the product or products must be packaged. Generally, these are compact cardboard blanks which are produced to define, after assembly, a tubular envelope constituting a case body and having bottom and top closure systems. The design of these blanks can be ensured so that the case body of the tubular envelope has a shape, most generally, parallelepiped, without it being a question of excluding the case bodies of different shapes, such than of pentagonal or hexagonal, even octagonal or even triangular cross section. Such cases are used to ensure the packaging of different types of products, such as, for example but not exclusively, cosmetic products or, again, pharmaceutical products, which should be guaranteed against the risks of opening.

untimely at the point of sale.

  Thus, when the product or products to be packaged are considered to have a certain value and it is advisable to protect them against fraudulent openings, it is known to surround the packaging case, once the product to be packaged disposed of. inside the latter, of a transparent plastic sheet which prevents any opening of the packaging case and which thus ensures an opening control function, insofar as the destruction attests to an attempt to open , or even an opening of the packaging case, and,

  possibly the content of the latter.

  The use of such a tamper-evident envelope makes it possible to effectively guarantee the integrity of the contents of the packaging case. However, the establishment of this envelope requires an additional manufacturing step after filling the packaging case and substantially increases the cost of packaging the product to be marketed, both due to the hand

  additional work, than the material used.

  Thus, there appears to be a need for a packaging case which offers the possibility of preserving the integrity of its contents or of being able to attest attempts to open it effectively, without substantially encumbering the cost of the product. packaging case and this more particularly by presenting a lower cost than that which would result from the implementation of the additional tamper-evident envelope. In order to achieve this objective, the invention relates to a packaging case with an opening indicator, obtained from a precut blank and mounted, by folding, to include: * a tubular envelope with articulated panels provided with two ends, of which at least one first end is open, * at the level of the first end of the envelope, a closing panel articulated on a panel of the envelope, and at least one closing flap

  folding hinged on another panel of the envelope.

  According to the invention, the packaging case is characterized in that it comprises, at least at the level of the first end of the envelope, locking means comprising: * at the level of the closure panel: on the one hand , at least one locking flap which is separated from the closure panel by a fold line and which comprises, facing the closure panel, at least one locking edge, - and, on the other hand, at least one zone of lower resistance extending from the edge of the closure panel situated opposite the locking edge, over at least part of the closure panel, * and, at the closure flap, an edge intended to form a surface of 'stop for the locking edge in the closed position of the closing panel. The implementation of such locking means makes it possible to oppose an untimely, even fraudulent, opening of the packaging case followed by replacing the closure panel, so as to conceal this opening. Indeed, insofar as the locking edge of the locking flap comes to a stop on the closing flap when the packaging case is closed for the first time. When an opening of the latter is attempted, the force exerted on the zone of weakest resistance leads to a rupture of the latter, so that any attempt to open or open the packaging case is directly signaled , whether this opening is fraudulent or, on the contrary,

  voluntary, to access the contents of the packaging case.

  According to a characteristic, preferred but not strictly necessary of the invention, each end of the envelope is open and the packaging case comprises, at each end of the envelope, a closure panel and at least one shutter of closing. Preferably but not strictly necessary, the case then comprises locking means in accordance with the invention, at the level

  from each of the open ends of the envelope.

  According to another characteristic of the invention, the zone of least resistance is disposed laterally on the closure panel and is delimited by a line of least resistance arranged in the closure panel to extend from the fold line of the locking flap to the hinged panel carrying the

closure panel.

  According to the invention, the line of least resistance can be made in any suitable way, such as, for example, in the form of a cutting line executed over only part of the thickness of the blank constituting the case. conditioning. According to a preferred but not exclusive embodiment, the line of least resistance consists of a pre-cut or cut line

with dots.

  Preferably but not strictly necessary, the pre-cut line then extends from one end of the fold line, separating the locking flap from the closure panel, to the fold line separating the panel.

closing the hinged panel.

  According to another characteristic of the invention, the edge of the locking flap,

  located opposite the closure panel, is convex.

  According to yet another characteristic of the invention, preferred but not strictly necessary, in order to ensure better locking of the closure panel, the locking flap comprises two locking edges disposed on either side of the fold line separating the locking flap of the closing panel. In an embodiment which is preferred but not exclusive, the locking means then comprise, at the level of the closing flap, two pre-cut lines which delimit two opposite lateral zones of lesser resistance and which each extend from the two ends of the fold line separating the locking flap from the closure panel and up to the fold line separating

  the hinged shutter closing panel.

  According to another characteristic of the invention, which is not strictly necessary, the locking means then comprise two closing flaps which are articulated on opposite panels of the envelope and which each define a

  stop surface for a locking edge of the locking flap.

  According to yet another characteristic of the invention, the locking means comprise a locking notch which is arranged in the closing flap and in which the locking flap is intended to engage and

  at least one edge of which forms the stop surface for the locking edge.

  The implementation of such a locking notch makes it possible to reinforce the inviolability of the system and obliges to exert a relatively large force during the first opening, thus guaranteeing the rupture of the zone or zones of least

  resistance fitted on the closing flap.

  According to a characteristic of the invention, the case comprises two other flaps of

  closing, in addition to the closing flap provided with the locking notch.

  Preferably, the closing flap, comprising the locking notch, is articulated on the envelope panel opposite to the envelope panel carrying the closing panel and the locking notch is

  fitted on the closing flap at the edge of the hinged panel.

  The invention also relates to a precut blank for making a packaging case according to the invention. This precut blank comprises at least: ò a series of articulated panels, arranged one after the other, being separated by parallel fold lines, and intended to form the tubular envelope, * two closure panels, having each in the extension of an articulated panel from which they are each separated by a fold line, and being located on either side of the alignment of the articulated panels, * and at least one folding closing flap extending in the extension of an articulated panel of the tubular envelope from which it is separated by a fold parallel to and substantially aligned with the fold line of the closure panel located on the same side of the alignment of the

  hinged panels as the folding closing flap.

  According to the invention, this precut blank is characterized in that it comprises, on the same side of the alignment of the articulated panels as the folding closing flap, locking means comprising: * at the closing panel: - d firstly, at least one locking flap which extends opposite the hinged panel and is separated from the closure panel by a fold line, and which comprises, opposite the closure panel, at least one edge for locking, and, on the other hand, at least one zone of weakest resistance extending from the edge of the closure panel situated opposite the locking edge, over at least part of the closure panel, * and , at the closing flap, an edge intended to form a stop surface for the locking edge in the closed position of the panel

closing.

  Various other characteristics of the invention emerge from the description below, made with reference to the drawings which illustrate non-limiting forms

  for producing a packaging case according to the invention.

  Fig. 1 is a perspective view, partially broken away, of a case

packaging according to the invention.

  Fig. 2 is a flat view of a precut blank for obtaining the case, such

as illustrated in fig. 1.

  Fig. 3 is a perspective, substantially similar to FIG. 1, showing a

  another embodiment of a packaging case according to the invention.

  Fig. 4 is a plan view of a precut blank for obtaining a case,

as illustrated in fig. 3.

  Fig. 5 is a perspective view, partially broken away, showing a variant of

  realization of the case, as illustrated in fig. 1.

  Fig. 6 is a plan view of a precut blank for obtaining the case

as illustrated in fig. 5.

  A packaging case, according to the invention, as illustrated in a semi-constituted state in FIG. 1, is obtained from a flat precut blank, as illustrated in FIG. 2. Such a blank, generally designated by the reference 1, can be produced from compact cardboard, corrugated cardboard or, again, from suitable plastic sheets, the nature of the material constituting the blank being not a

characteristic of the invention.

  The blank 1 comprises four articulated panels 2, 3, 4 and 5 which are intended to define a tubular envelope E, of generally parallelepiped shape, as shown in FIG. 1. According to the example illustrated, the tubular envelope E is open at its first end El, as well as at its second end E2, although in FIG. 1 this second end appears closed by means of a system

  closure forming an integral part of the packaging case.

  The purpose of this tubular envelope E is to constitute a case body, that is to say, within the meaning of the concept of packaging, a container. The invention could find an identical application with a tubular envelope E having a different shape and, for example, having a pentagonal, hexagonal, even octagonal or, again, triangular section. In such a case, the number of hinged panels is chosen in correspondence with the number of sides of the section of the tubular casing. Fig. 2 shows that the panels 2, 3, 4 and 5 extend one after the other, being each delimited with respect to the next by means of fold lines, respectively 6, 7 and 8 which are parallel between them and perpendicular to the alignment of the hinged panels 2, 3, 4 and 5. It should be noted that the fold lines appear in fig. 2 in dashed lines, while solid or continuous lines

  represent lines of cutouts.

  The articulated panel 5 has, in addition, opposite the articulated panel 4, a connecting strip 9, separated from the panel 5 by a fold line 10 parallel to the lines 6 to 8. The connecting strip 9 is intended to be counter-fixed on the inner face of the articulated panel 2 during the shaping of the case, as will appear later. This fixing of the connecting strip 9 can be carried out by any suitable means, such as, for example but not exclusively,

by laminating.

  Conventionally, the panel 4 is bordered, beyond fold lines 11 and 12 parallel to each other and perpendicular to the lines 7 and 8, by two closure panels, respectively top 13 and bottom 14. These closure panels 13 and 14 have in plan a shape corresponding to the section of the envelope

  tubular E, in this case rectangular.

  1 5 In accordance with an essential characteristic of the invention, each closure panel 13, 14 is provided, beyond a fold line 15 or 16 substantially parallel to the fold lines 11 and 12, with a flap 17 or 18, said to be locked for reasons which will become apparent later. Furthermore, the articulated panels 3 and 5, arranged on either side of the panel 4 are each provided beyond a fold line 19 or 20, with a folding closing flap 21 or 22 extending in the same direction as the closure panel 14. It should be noted that the fold lines 19 and are perpendicular, respectively, to the fold lines 6 and 7, as well as 8 and 10. Similarly, the hinged panels 3 and 5 have, opposite the bottom closing flaps 21 and 22, high closing flaps, respectively 23 and 24 extending beyond fold lines 25 and 26 in the same direction as the top closing panel 13. The fold lines 25 and 26 are then parallel

  substantially at fold lines 19 and 20.

  In accordance with an essential characteristic of the invention, the packaging case, and therefore the blank 1, comprises at least at the level of the first end El of the envelope E and, according to the example illustrated, at the level of the two ends E1 and E2 of the envelope E, locking means which are arranged, on the one hand, at the level of each of the closure panels 13 and 14 and, on the other hand, at the level of at least one, according to the illustrated example, of the two closing flaps of

  each of the ends, respectively 21, 22 and 23, 24.

  Thus, the locking means comprise, at each closure panel 13, 14, the locking flap 17, 18 separated from the closure panel by the fold line 15, 16. This flap then comprises, opposite the panel closure 13, 14, at least one and, according to the illustrated example, two locking edges arranged on either side of the fold line 15, 16. According to the illustrated example, each locking edge 30 is defined by a notch cut in the locking panel 17, 18, so that the edge 30 is, in the assembled configuration and

  closed from the case, at a distance from the edge 31 opposite the closure panel 13, 14.

  The locking means also comprise, still at the level of the closure panel 13, 14, at least one and, according to the example illustrated, two zones of weaker resistance 33 extending from the edge 31 of the closure panel located opposite the locking edge 30 on at least part of the closure panel and, according to the example illustrated, along the two lateral edges of the closure panel 13. Each zone of lower resistance 32 can be produced in any suitable manner and, for example, but not exclusively, correspond to an area

  thinned material constituting the blank 1.

  According to the example illustrated, the zones of least resistance 32 are each delimited by a line of least resistance 33 arranged in the closure panel 13, 14 to extend, from each end of the fold line, 16 of the locking flap, towards the articulated panel 4 carrying the closure panel 13, 14 and, according to the example illustrated, up to the fold line 12. Each line of least resistance 33 can, according to the example illustrated, be formed by a dotted precut line. However, each line of least resistance 33 could consist of a continuous precut made on a part

  only of the thickness of material constituting the blank 1.

  According to the invention, the locking means further comprise, at at least one and, according to the illustrated example, two closing flaps 21, 22 and 23, 24 of each end E1 and E2, a edge 35 intended to form a stop surface for the locking edge in the closed position of the closure panel 13, 14, as will appear later. According to the example illustrated, each stop surface 35 extends, from the corresponding fold line 19, 20, 25 and 26, over a distance d less than the length L of the corresponding locking edge 30. In addition, the stop surface 35 extends, from the closing flap 24, over a width I strictly greater than the thickness e of the blank 1 at the locking flap. Preferably, the width l is greater than two or three times the thickness e of the blank 1. The blank 1 thus formed is used in the following manner to form the case, as illustrated in FIG. 1. First of all, the fold lines 6, 7, 8 and 10 are formed and the connecting strip 9 is fixed on the articulated panel 2, so as to impart its parallelepiped shape to the case body E. Then, the second end E2 of the case is closed by folding the closing flaps 21 and 22 towards the inside of the case. After folding the locking flap 18 along the fold line 16, the closing flap is raised, so as to engage the locking flap 18 in the space existing between the panel 2 and the closing flaps 21 and 22 Once this engagement is completed, the closure panel 14 is then substantially perpendicular to the articulated panels 2, 3, 4, 5, while

  that the flap 18 is then in the locked position, as illustrated in FIG. 1.

  In this closed position, the surfaces 35 of the closing flaps 21 are

  then placed opposite the locking edges 30 of the flap 18.

  In this pre-assembled state, the case according to the invention can then be loaded and the closure of the first end E1 will be carried out as explained

  previously for the second end E2.

  It should be noted that, in the locked state of the bottom closure panel 14, as illustrated in FIG. 1, when a traction is exerted on the latter, the edges 30 abut on the stop surfaces 35 of the closing flaps 21 and 22. Thus, it is necessary to exert a greater traction on the panel 14 to open. However, this traction, most often exerted on the lateral edges of the closure panel 14, is applied at the level of the zones of least resistance 32, so that this force leads to a rupture of the precut line 33 then attesting to a attempt to open. Thus, the use of the locking means according to the invention makes it possible to guarantee the inviolability of the case 1 or, at least, to attest that it is not open by the integrity of the zones of least resistance. According to the invention, the stopping of the locking flaps 17 and 18 of the closure panels 13 and 14 is not necessarily ensured by the edges of two flaps of

side closures.

  Thus, figs. 3 and 4 illustrate another embodiment of a packaging case according to which the stopping of the locking flaps 17 and 18 is ensured by the insertion of the latter in a locking notch 40, like this

will appear later.

  According to this exemplary embodiment, the closure panels 13 and 14 are carried by the last articulated panel 5, while the closure flaps 23, 24 and

  21, 22 are carried by the first and third articulated panels.

  In addition, according to this example, the second articulated panel carries, at each of its two ends and beyond fold lines 41 perpendicular to fold lines 6 and 7, another closing flap 42 which could be considered as a third closing flap for each end E1 and E2 of the tubular casing E. Each locking notch 40 is arranged in the corresponding closing flap 42, from the fold line 41 to present, first of all, a width 140 greater than the distance D separating the ends of the two locking edges 30 of each of the locking flaps 17, 18. The notch 40 then has a "V" shape, the two edges of which converge to define an opening having a smaller width at distance D and greater than length

L15 from fold line 15.

  The blank thus formed is implemented in the following manner.

  After the connecting strip 9 has been fixed to the first articulated panel 2, the second end E2 of the tubular casing E is closed by folding the closing flaps 21 and 22 towards the inside of the case and then by folding the

  third closing flap 42 against flaps 21 and 22.

  Then, the closure panel is also folded down and the flap 18 is engaged in the locking notch 40. It should be noted that, in order to facilitate this insertion, the edge 45 of the flap 18, located opposite the panel 14 , is convex. Once this insertion has been completely carried out, the locking edges of the flap 18 are then disposed beyond the edges of the notch 40 which define two

  stop surfaces for the edges 30 of the locking flap 18.

  Thus, as has been described above, when an opening of the panel 14 is sought, it is necessary to carry out a relatively large traction on the latter, traction which results in partial destruction of the zones of least resistance 32 or, at the very least. least, a break in the precut line 33 delimiting them. According to the example illustrated in FIGS. 3 and 4, the precut lines 33 are substantially parallel and perpendicular to the fold line separating the closure panel of the articulated panel from the body of the tubular casing E. However, a

  such configuration of the precut lines 33 is not strictly necessary.

  Thus, according to the example illustrated rig. 1 and 2, the precut lines 33

  converge towards each other to the fold line 11 or 12.

  According to another alternative embodiment, more particularly illustrated in FIG. 5 and 6, the lines of least resistance have a broken shape and extend from the edges of the fold line 15 separating the closure flap from the corresponding closure panel, first towards the interior of the panel, to then join the ends of the fold line 11 separating the closure panel from the

hinged panel carrying it.

  Thus, according to this example, the precut lines 33 have a "V" shape. Of course, it could also be envisaged to give them a form

arcuate.

  The invention is not limited to the examples described above because various modifications can be made without departing from its scope. Thus, according to the examples described above, the two ends E1 and E2 of the envelope

  tubular are provided with locking means according to the invention.

  However, only the first end E1 of the case could be equipped with such locking means, the second end E2 being equipped with a system of

  different closure or vice versa.

Claims (20)

  1 - Packaging case with opening indicator, obtained from a blank (1) precut and mounted, by folding, to include: * a tubular envelope (E) with hinged panels (2, 3, 4, 5) provided with two ends (El, E2), at least one first end (El) of which is open, * at the first end (El) of the envelope, a closure panel (13) hinged on a panel (4 ) of the envelope (E), and at least one folding closing flap (23) articulated on another panel (3) of the envelope, characterized in that it comprises, at least at the level of the first end of the envelope, locking means comprising: * at the closure panel (4): - on the one hand, at least one locking flap (17) which is separated from the closure panel by a fold line (15 ) and which comprises, facing the closure panel (13), at least one locking edge (30), - and, on the other hand, at least one zone of lower resistance this (32) extending from the edge (31) of the closure panel (13) situated opposite the locking edge (30), over at least part of the closure panel (13), * and, at the level of the closing flap (23), an edge (35) intended to form a stop surface for the locking edge (30) in the closed position of the closure panel (13).   2 - packaging case according to claim 1, characterized in that each end (El, E2) of the envelope (E) is open and in that it comprises, at each end (El, E2) of the envelope, a closing panel (13, 14) and at   less a closing flap (23, 21).   3 - packaging case according to claim 2 characterized in that it comprises locking means at each end (El, E2) of the envelope (E).   4 - packaging case according to one of claims 1 to 3, characterized in   that the zone of least resistance (32) is disposed laterally on the closure panel (13) and is delimited by a line of least resistance (33) arranged in the closure panel (13) to extend, starting from the fold line (15) of the locking flap, towards the articulated panel (4) carrying the panel closure (13).   - Packaging case according to claim 4, characterized in that the line   of least resistance (33) is constituted by a precut line.   6 - packaging case according to claim 5, characterized in that the pre-cut line (33) extends from one end of the fold line (15), separating the locking flap (17) of the panel closure (13), to the line   folding (11) separating the closure panel (13) from the hinged panel (4).   7 - packaging case according to one of claims 1 to 6, characterized in   that the edge of the locking flap (17), located opposite the closure panel (13), is convex.   8 - packaging case according to one of claims 1 to 7, characterized in   that the locking flap (17) comprises two locking edges (30) arranged on either side of the fold line (15) separating the locking flap (17) of the closure panel (13).   9 - packaging case according to claim 8, characterized in that the locking means, at the closure panel (13), comprise two precut lines (33) which delimit two opposite lateral zones (32) of less resistance and which each extend from the two ends of the fold line (15) separating the locking flap (17) from the closure panel (13) and up to the fold line (11) separating the cover panel shutter (13) articulated (4).   - Packaging case according to claim 8 or 9, characterized in that the locking means comprise two closing flaps (13, 14) which are articulated on panels (3, 5) opposite the envelope (E) and which each define a stop surface (3, 5) for a locking edge (30) of the flap lock (17).   11 - packaging case according to one of claims 1 to 10, characterized in that the locking means comprise a locking notch (40) which is arranged in the closing flap (42) and in which the locking flap (17 ) is intended to engage and at least one edge of which forms the stop surface for the locking edge (30).   12 - packaging case according to claim 11 characterized in that it comprises two other closing flaps (23, 24) in addition to the closing flap (42)   provided with the locking notch.   13 - packaging case according to claim 1 1 or 12, characterized in that the closing flap (42) comprising the locking notch is articulated on the panel (3) of the envelope (E) opposite the panel (5 ) of the envelope (E) carrying the closure panel (13) and in that the locking notch (40) is provided   on the closing flap at the edge of the hinged panel (3).   14 - Pre-cut blank for making a packaging case according to one   claims 1 to 13, comprising at least:   * a series of articulated panels (2, 3, 4, 5), arranged one after the other, being separated by fold lines (6, 7, 8) parallel, and intended to form the tubular envelope ( E), X two closure panels (13, 14), each being in the extension of an articulated panel (5) from which they are each separated by a fold line (11, 12), and being located on the side and other of the alignment of the articulated panels (2, 3, 4, 5), * and at least one folding closing flap (23) extending in the extension of an articulated panel (2) of the tubular casing (E) from which it is separated by a fold (25) parallel to and substantially aligned with the fold line (11) of the closure panel (13) located on the same side of the alignment of the articulated panels (2, 3, 4, 5) as the folding closing flap (23), characterized in that it comprises, on the same side of the alignment of the articulated panels as the folding closing flap (2 3), locking means comprising: * at the closure panel (13): on the one hand, at least one locking flap (17) which extends opposite the articulated panel (4, 5) and is separated from the closure panel (13, 14) by a fold line (11), and which comprises, facing the closure panel (4), at least one locking edge (30), - and, d on the other hand, at least one zone of weakest resistance (32) extending from the edge (31) of the closure panel (13) situated opposite the locking edge (30), on at least part of the panel closure (13), * and, at the closure flap (23), an edge (35) intended to form a stop surface for the locking edge (30) in the closed position of the closure panel (13).   - Pre-cut blank according to claim 14 characterized in that it comprises, on either side of the alignment of the articulated panels (2, 3, 4, 5), at least at least one folding closing flap (23, 21) extending in the extension of an articulated panel (2, 3) of the tubular casing (E) from which it is separated by a fold line (19, 25) parallel to and substantially aligned with the fold line (11, 12) of the closure panel (13, 14) located on the same side of the alignment of the panels   articulated (2, 3, 4, 5) as said folding closing flap (21, 23).   16 - blank precut according to claim 15 characterized in that it comprises on either side of the alignment of articulated panels (2, 3, 4, 5) at least two   closing flaps (21, 22, 23, 24).   17 - precut blank according to claim 15 or 16 characterized in that it comprises on either side of the alignment of hinged panels of the means locking.   18 - precut blank according to one of claims 14 to 17 characterized in that the locking means comprises at least one locking notch (40) which is arranged in the closing flap (42) and in which the locking flap ( 17) is intended to engage and of which at least one edge forms the   stop surface for the locking edge (30).   19 - precut blank according to claim 18 characterized in that the notch (40) is arranged from the fold line (41) separating the closing flap   (42) of the articulated panel (3) which carries it.   - Pre-cut blank according to one of claims 14 to 19, characterized in that the zone of least resistance (32) is arranged laterally on the closure panel (13) and is delimited by a line of least resistance (33) arranged in the closure panel to extend, from the fold line (15) of the locking flap (17), to the articulated panel (4, 5) carrying the panel closure (13).   21 - precut blank according to claim 20, characterized in that the line of   least resistance (33) is formed by a precut line.   22 - Pre-cut blank according to claim 21, characterized in that the pre-cut line (33) extends from one end of the fold line (15), separating the locking flap (17) from the closure panel (13), up to the fold line   (11) separating the closure panel (13) from the articulated panel (4, 5).   23 - Pre-cut blank according to one of claims 14 to 22, characterized in that the edge of the locking flap (17), located opposite the closure panel (4, 5), is convex.   24 - precut blank according to one of claims 14 to 23, characterized in that the locking flap (17) comprises two locking edges (30) disposed on either side of the fold line (15) separating the locking flap (17) of the closure panel (13).   - Pre-cut blank according to claim 24, characterized in that the locking means, at each closure panel (13, 15), comprise two pre-cut lines (33) which delimit two opposite lateral zones of less resistance (32) and which each extend from the two ends of the fold line (15, 16) separating the locking flap (17, 18) from the closure panel (13, 14) and up to the fold line (11, 12) separating the panel from   closure (13, 14) of the articulated panel (4, 5) which carries it.