FR2743779A1 - CUTTER ASSEMBLY FOR PACKAGING BAG FORMING DISPLAY AND BOX OBTAINED WITH SUCH A SET - Google Patents

Abstract

The unit is made from two cut-out panels of sheet material such as cardboard or corrugated cardboard, the first folded and glued to make a display unit (23) and container base, and the second folded and glued to form an insert which fits inside the base forming the side walls (24) and flaps (25) which make the top. After use for transporting/storing articles such as bottles. the main portion of the container is removed from the base, leaving the latter to act as a display unit.

Description

CUTTING ASSEMBLY FOR PACKAGING BOX FORMING

  DISPLAY AND CASE OBTAINED WITH SUCH A SET

  The present invention relates to a set of blanks for forming a carton display case, the box being of the type comprising two elements manually separable from one another and inserted into one another, respectively formed to from blanks made of cardboard or corrugated cardboard material belonging to said set, the first element forming a display tray, the second element forming an upper part of the box that can be removed so as to give access

  the products contained in the cash register.

  It also relates to such a packing box and a method of manufacturing the box

  from the set of cuts.

  The present invention finds a particularly important, although not exclusive, application in the field of rigid product packaging of the cylindrical jars type making it easy to present the products in their packaging.

  transportation in an immediate, clean and attractive way.

  It is already known (EP 0 637548 A1) packaging boxes of the type described above allowing a quick disconnection of the upper part of the

  box in relation to the lower part.

  Such a box, although satisfactory, however, has the disadvantage of not being easily

Formable in automatic.

  The present invention aims to provide a set of blanks and a box better than those previously known to the requirements of the practice including that it allows automatic assembly at a high rate (greater than twenty boxes min), while presenting a high strength and a rate of malformed crates almost zero, the boxes thus obtained by the invention being more

easily stacked on pallets.

  For this purpose the present invention provides a set of blanks for the constitution of a two-part packing case comprising two blanks made of cardboard sheet or corrugated cardboard material, namely a first cut to form a display tray and a second cutout adapted to form the upper part of the body, each cut comprising a sequence of four main parts terminated by a fastening tab, said main flaps and said tongue being connected to each other via first fold lines parallel to each other; other, directly or through secondary flaps, and a set of first side flaps disposed on one side of said sequence of main flaps and connected thereto by second fold lines perpendicular to said first fold lines and for to form at least partially for one the bottom of the tray and for the other the top of the upper part of the box, the two cutouts being interconnected by at least one pre-cut flap portion in one of said main flaps of the first cut to form the container, said outer flap, and secured to the corresponding wall of the second cutting to form the top of the box, said inner flap, characterized in that the first fold lines of the first blank are parallel and offset laterally with respect to the first fold lines of the second blank to allow winding around a mandrel of said blanks previously secured to each other at least in part by said portion by catching the extra thicknesses of the cardboard sheets, to form the box, and in that said pre-cut portion and the inner flap are secured to one another by means arranged to allow the relative movement between inner and outer flap during training

of the fund.

  By pre-cut portion is meant a frangible portion which has only a few attachment points with the remainder of the flap and is therefore easily tearable in the plane and / or

  perpendicular to the plane of said flap.

  In advantageous embodiments, one and / or the other of the following provisions is also used: the means arranged to allow the relative movement comprise a recess in the extant outer flap, and of complementary shape with , the pre-cut portion which is fixed immovably to the inner flap, to allow the catching of the extra thicknesses by sliding of said portion in the plane and in said recess of said outer flap, when the cuts of said first and second elements are simultaneously wound around the mandrel ; the means arranged to allow the relative movement comprise slidably securing means in the plane of the pre-cut portion on the inner flap, to enable the overthickness to be compensated when the cuts of said first and second elements are simultaneously wound around the mandrel when the formation of the fund; the securing means are constituted by cold-setting glue, for example dots or lines of glue offset to allow their spreading without leaving the surface of the

portion during winding.

  274377g Progressive glue adhesive is understood to mean an adhesive which remains pasty for a few seconds, for example of the order of 30 seconds, thereby permitting a sliding in the plane of the pre-cut portion on the inner flap during winding around the mandrel, before said portion is permanently fixed, that is to say without it is then possible to detach it from the inner flap without destroying the carton; the pre-cut shutter portion is cut according to

a closed line.

  Such an arrangement facilitates the lateral separation between first and second elements during tearing of said pre-cut portion perpendicular to the plane of, and with respect to, the outer flap; the fastening tab of the second element extends along only a portion of the lateral edge of the adjacent flap to which it is connected, above the fastening tab of the first element; - the main shutters are separated from each other by secondary shutters to form a box to eight

sides, with cut corners.

  The invention also proposes a method of manufacturing cash from a set of

  cutouts, of the type described above.

  The present invention also proposes a packing case, comprising two elements that are manually separable from each other and inserted into one another, respectively formed from blanks made of corrugated cardboard or corrugated board material, namely a first display tray element and a second element forming the upper part of the body, each element comprising a sequence of four main components terminated by a fastening tongue, said main flaps and said tongue being connected to each other via first folding lines parallel to each other, directly or via secondary flaps, and a set of first side flaps arranged on one side of said sequence of main flaps and connected thereto by perpendicular second fold lines said first fold lines and intended to form at least partially for one the bottom of the first el forming the tray and for the other the top of the second element, the two elements being interconnected by at least one pre-cut flap portion in one of said main flaps of the first element, said outer flap, said portion being fixed to the corresponding main flap opposite the second element, said inner flap, characterized in that the first fold lines of the first element are parallel and offset laterally with respect to the first fold lines of the second element to allow the winding around a mandrel of first and second elements previously secured to each other at least in part by said portion by catching the extra thicknesses of the cardboard sheets, and in that said pre-cut portion and the inner flap are secured to each other via means arranged to allow the relative movement between flap internal and external component during training

of the fund.

  In advantageous embodiments, the various arrangements described above are furthermore used with reference to the set of blanks according to the invention. The present invention will be better understood in

  reading of the following description of modes of

  realization given by way of non-limiting examples.

  The description refers to the drawings which

  accompany it, in which: - Figure 1 is a perspective view of an embodiment of a set of cutouts according to

  the invention in four parts, before assembly.

  - Figure 2 is a longitudinal sectional view II-

  II of the assembly of Figure 1 assembled.

  FIG. 3 is a perspective view of the box, lid and open bottom obtained with the cutouts of

Figure 1.

  - Figure 3 'is a partial view on a large scale

  an angle of the box of Figure 3.

  FIGS. 4A, 4A 'and 4B, 4B' are cross-sectional views, respectively of the second and first cutouts of the type of FIG. 1 taken in isolation, on the one hand box-shaped and on the other hand flattened, making appear the differences in the width of the shutters or panels and the

offsets between fold lines.

  FIG. 5 is a perspective view of another body embodiment according to the invention,

eight sides.

  - Figure 6 shows the box of Figure 5 as

  that display, the lid part has been removed.

  FIG. 7 schematically shows, in section, the winding of the two cutouts of FIG. 5 around

a mandrel.

  - Figures 8 and 9 show the two cutouts for obtaining a packing box of the type shown in Figure 5, respectively separated and assembled before winding around a mandrel. FIGS. 1, 2, 3, 3 ', 4A, 4B, 4A' and 4B 'show an assembly 1, or various elements of an assembly, of blanks made of corrugated sheets

  double face, for example 2 mm thick.

  For these figures, the same reference numbers will be used to designate the body elements and / or cutouts that are identical or occupy the same

position.

  This set 1 comprises a first cut 2 own to form the tray and a second cut

  3 to form the lid of the box.

  - The second cut is superimposed, flat, the first cut, and fit to form a belt

  internal of the box, once it formed.

  The first cutout 2 comprises a series of four shutters, namely two so-called lateral flaps 4 and 4 'arranged alternately with two so-called facial flaps 4' 'and 4' '', the shutters being interconnected by first folding lines. 5 parallel to each other and represented in phantom in Figure 1, the flap sequence being adapted to form the outer walls of the tray 4 with four sides (cf.

Figure 3).

  More precisely, shutters 4 and 4 'are of shape

trapezoidal rectangle.

  They are symmetrical with respect to the rectangular facial flap 4 '', which forms the rear face of the tray and which is taller than the rectangular facial flap 4 '' 'which forms the face

before the tray.

  The flaps 4 and 4 'thus comprise an upper peripheral edge 7 and 7' obliquely downwards,

  directed in the opposite direction of the 4 '' shutter.

  The flap 4 'is connected to its small end side via a fold line 5, to a rectangular tongue 4a, bonding, which extends over the entire

height of said small side.

  The continuation of shutters 4, 4 ', 4' ', 4' '' is also provided on its lower side, a first suite 8 of rectangular flaps, via second

fold lines 9.

  The flaps 8 are intended to form the bottom 8 '(see Figure 3) of the tray, in known manner, two of said flaps coming for example in contact by

  their outer edge to form an airtight bottom.

  The second cutout 3 has four rectangular flaps, which will be referred to below as panels to better differentiate them from the flaps of the first

cutting.

  This is a first central rectangular panel 10 and three secondary rectangular panels 11, 12 and 13, interconnected by third fold lines 14, namely two panels 12 and 13 connected on both sides to central panel 10 and a connected 11 end panel

at the other side of the panel 12.

  The cutout 3 comprises a second flap continuation 15, identical to the first flap continuation 8, connected to the adjacent panels by fifth fold lines 16, perpendicular to the first lines 14, and intended to form the cover 15 '.

the box.

  An end tongue 13a is also provided, connected to the end panel 13 on only a part of the height of the latter, situated

on the side of the folding lines 16.

  The tongue 13a is placed on the same side as the tongue 4a, and its length is equal to the height 11 of the panel 13, minus an equal length or a

  little greater than the length of the tongue 4a.

  The tongues 4a and 13a are also provided and arranged to close on the walls facing the cutouts formed, without overlapping each other

  although they are on the same side (see Figure 3).

  According to the invention, the fold lines 14 and 5 of the two blanks are parallel and offset (cf.

Figure 2).

  More specifically, FIGS. 4A, 4A ', 4B and 4B' show the respective dimensions or the width between the folding lines of blanks 2 and 3 according to the embodiment of the invention.

particularly described here.

  The fold lines according to the invention are simple, that is to say suitable to form an edge whose peak is one-sided as shown in Figure 3 '. These are arranged to catch up with

  cardboard overthickness during folding.

  Let: Li,: distance between the internal faces of two opposite walls with respect to the first cut of the

box formed.

  The: distance between the outer faces of said

walls of the first cut.

  lil: distance between the internal faces of the two other walls opposite the first cut of

the box formed.

  le1: distance between the outer faces of said

  other walls of the first cut.

  el: thickness of the first blank P1: width of the end fixing tab 4a of the first blank. Li2: distance between the internal faces of two walls facing the second cut of the box formed. Le2: distance between the outer faces of said

walls of the second cut.

  ! 2: distance between the inner faces of the two other walls opposite the second cut of

the box formed.

  le2: distance between the outer faces of said

walls of the second cut.

  e2: thickness of the second cut.

  P2: width of the end fixing tab

13a of the second cut.

  In the embodiment of the invention more particularly described here, there are the following relations: Li1 = Li2 + 2e2 lil = li2 + 2e2 The distances between the first or third fold lines are furthermore indicated in FIGS. 4B 'and 4A ', and are respectively for the first blank (FIG. 4B'): * between the edge 17 of the first flap 4 '' 'and the first fold line 5: Li1 + 0.5e, * between the two fold lines 5 of the second flap 4: li1 + e1 * between the two fold lines 5 of the third flap 4 '': Li1 + e1 and * between the two fold lines 5 of the fourth flap 4 ': li1 + 2e1 - for the second blank ( FIG. 4A '): * between the edge 18 of the second panel 11 and the third fold line 14: Li2 + 0.5e2 = Li1 - 1.5e2 * between the two fold lines 14 of the panel 12 li2 + e2 = li1 - e2 * between the two fold lines 14 of the first panel 10: Li2 + e2 = Li, -e2 and * between the two fold lines of the second panel 13: li2 + 2e2 = li 1 Folding lines 14 of the first panel 10, located under the mandrel and which remains fixed relative to the latter during the formation of the body, are also placed at equal distance x folding lines 5 of the panel 4 '' with

x e + e2 (see Figure 2).

  Other distances between the fold lines

  are obtained simply by stacking the odds.

  As has been seen, the panel 10 is thus extended on each side by two second panels 12 and 13 covering the flaps 4 and 4 'facing each other, the series of panels being terminated by a last secondary panel 11 substantially coinciding with the last

  end flap 4 '' 'of the first cut.

  The flaps 4 and 4 'are each fixed, by gluing, on their panels opposite 12 and 13 via a detachable portion 20, 20', half-oval, open on the edge 7, 7 'of the flap, of small size compared to the shutter, the rest of the surface of the shutters 4 and 4 'and the shutters 4' 'and 4' '' not being

attached to the second cut.

  Each portion 20, 20 'is extended on the opposite side of the panel 4' 'by a recess 21, 21' of the same transverse width as said portions, and of sufficient length to catch the slippage portions torn in the plane of the flaps when

  the formation of the box (see Figure 3).

  In other words, the portions 20, 20 'tearing in the plane of the cut during winding, are embedded in the recesses 21, 21' in the extension of said portions. Thanks to the portions as provided, the cutouts of the tray and the lid can also be detached from one another after forming the body, by pressure exerted perpendicularly to the walls of a formed cutout

compared to each other.

  FIG. 5 shows an eight-sided box 22 according to the invention comprising a first tray-forming element 23 and a second element 24 forming the upper part of the box, the flaps 25 of which are open to allow filling

of the crate formed.

  This is, according to the invention, rigid and non-foldable once the tongues glued to the

walls facing.

  A recess 26 is for example provided on both sides in the panels of the second element 24, at the level and a little above the upper part of the tray, which facilitates the extraction of said second element, after disconnection from that by

compared to the first element.

  FIG. 6 shows the box 22 of FIG. 5 after removal of the cover, which makes it possible to

  present the product 27 in a pleasant and simple way.

  Figure 7 shows the winding of the blanks 28

  and 29 around an eight-sided mandrel 30.

  In the case shown in this figure the two end tabs 31 and 32 of the first and second cutouts are located on the same side, and will respectively cover the end flaps 33 and 34 opposite with which they are bonded for example by hot gluing with glue of the type known under the name "hot

melt "in the Anglo-Saxon language.

  The device and the method used for forming the box are of the type described in documents FR-A-2 629 012 or FR-A-2 665 137. Assuming that the flaps that are not movable with respect to the mandrel during the formation of the box are those of the large face 35, there will be sliding on the other faces and pulling in the plane of the flap on the opposite face 36, of the portion 37 secured to the inner flap 38 and belonging to the

external flap 39.

  Portion 37 then comes to fit into

the recess 40 of the shutter.

  FIGS. 8 and 9 show an embodiment of the first cutout 41 and the second cutout 42 of an assembly according to the invention making it possible to obtain an eight-sided box of the type of that

  appearing in Figures 5 and 6.

  The first blank 41 comprises a series of eight flaps 43 and a rectangular gluing tab 44, the flaps and the tongue being interconnected by parallel folding lines 45 to one another, namely four main flaps 46, 47, 48 and 49, and four intermediate flaps 50, 51, 52 and 53. The main flaps 46, 47, 48 and 49 are each connected by second fold lines 54 to a succession of flaps 55, said second fold lines being perpendicular to the first lines of folding. Each pair of flaps is substantially rectangular in shape and has its two lateral sides at least partly obliquely outwardly of said flap from the second fold lines, said second fold lines 54 being substantially

  aligned or aligned with each other.

  The other two flaps are themselves

rectangular.

  More specifically, the main flaps are constituted by two rectangular flaps namely a first rectangular small flap 47, central, and a second rectangular flap 49, located on the side of one end, and two main flaps of substantially trapezoidal rectangular shape namely a first flap 46 and a second flap 48 both symmetrical relative to the small flap 47 and having an oblique side 46 ', respectively 48', directed outwards and upwards from the

small rectangular shutter 47.

  The main flaps are separated by rectangular or substantially rectangular secondary flaps, as indicated above, said

  secondary flaps being devoid of flaps.

  According to the embodiment of the invention more particularly described here, the main flap 46 comprises a detachable portion 56 extended by a recess 57 as described above making it possible to make up for the extra thicknesses during the formation of the tray around the element upper body, upper element corresponding to the second

cutting 42.

  The flap 48 also has a detachable portion 56 ', but which in this embodiment is not necessarily extended recess. The cutout 42 comprises a series of eight rectangular flaps 60, 61, 62, 63, 64, 65, 66 and 67 terminated by a rectangular fastening tab 68. The flaps are connected to each other and to the tongue by third lines. folding 69

parallel to each other.

  More specifically, they consist of four main flaps 60, 62, 64, 66, separated two by two by three secondary flaps 61, 63, 65, the last flap 66 is also provided with an end flap 67, disposed at the end of the flap suite when the flaps are flat and connected with the rectangular tab 68 on which it

  is glued when the box is formed.

  The tongue 68 is located on the side of the fold line 71, relative to the flap 60, its upper edge 71 'being in the extension of said

folding lines 71.

  The tongue 68 extends over a height arranged to not cover the tongue 44 when the cuts are assembled (Figure 9). It is for example equal to half the height of the flap 60, the tab 44 being of a height a little less than

this dimension.

  In the same way as for the cutout 41, the cutout 42 comprises, situated on the other side with respect to the continuation 55, a succession of flaps 70 connected to the principal shutters by fourth fold lines 71 perpendicular to the third lines of

folding 69.

  This series of flaps is for example identical to the following flaps 55 described with reference to the

cutting 41.

  In the embodiment described here, the reference flap is the flap 64 for the second cutout

and 48 for the first cut.

  These two flaps are immobile relative to each other and relative to the mandrel on which they are plated during the formation of the box, the direction of passage under the mandrel being that indicated

by the arrow 72 in FIG. 9.

  The fold lines 45 of the first blank are provided and placed progressively offset on the opposite side to the flap located under the mandrel with respect to the fold lines 69 of the second cutout to make up the extra thicknesses, as shown in FIG. 9, or the first blank. cutting is

represented in phantom.

  Offset calculations are done in the same way as previously described, adapting them to the case in

eight shutters.

  Only the portions 56 and 56 'are fixed by gluing (for example "hot melt") on the flaps 60 and

  64 of the second cut opposite.

  When the box is formed, the tongue 44 is glued to the flap 53, the tongue 68 on the outside of the flap 67, and the flaps 55 together, before ejection of the box thus formed around the mandrel. To form the display tray of Figure 6, the parts 56 and 56 'partly pre-cut to be frangible, are torn transversely relative to the body, which allows to move the lid member upwards. It goes without saying and as it follows from the foregoing, the present invention is not limited to the more

particularly described.

  On the contrary, it embraces all the variants and in particular that where the first cut and the second cut are secured together by two portions of the second cut, for example facing each other, or by three or four portions of the second cut.

Claims (15)

  A set of blanks for forming a two-part packing case comprising two cut-outs (2, 3; 41, 42) of cardboard sheet or corrugated material, namely a first blank (2, 41) adapted to form a display tray and a second cutout (3, 42) adapted to form the upper part of the box, each cutout comprising a sequence of four main components (4, 4 ', 4' ', 4' ''; 11, 12, 13; 46, 47, 48, 49; 60, 62, 64, 66) terminated by a fastening tab (4a, 13a; 44, 68), said main flaps and said tongue being connected to each other. other via first fold lines (5, 14; 45, 69) parallel to each other, directly or through secondary flaps (50, 51, 52, 53; 61, 63, 65, 67), and an assembly (8, 15; 55, 70) of first side flaps arranged on one side of said sequence of main flaps and connected thereto by second fold lines (9, 16; 54, 71) perpendicularly said first fold lines and intended to form at least partially for one the bottom of the tray and for the other the top of the upper part of the box, the two cuts being interconnected by at least one portion ( 20, '; 56) pre-cut flap in one of said main flaps of the first cut proper to form the tray, said outer flap (4, 4 ', 46), said portion being fixed to the corresponding main flap opposite the second cut, said inner flap (12, 13; 60), characterized in that the first fold lines (5, 45) of the first cut are parallel and offset laterally with respect to the first fold lines (14, 69) of the second cut for allowing the winding around a mandrel of said blanks previously secured to each other by catching the extra thicknesses of the cardboard sheets, to form the box, and in that said pre-cut portion (20, 20 '; 56) and the inner flap (12 , 13; 60) are interconnected by means arranged to allow the relative movement between the inner flap and   outer flap when forming the crate.   2. Set of blanks according to claim 1, characterized in that the means arranged to allow relative movement comprise a recess (21, 21 ', 57) in the outer flap (4, 4' 46) extending, and complementary shape with the pre-cut portion (20, 20 ', 56) which is fixed immovably to the inner flap (12, 13; 60) to enable the slips to be compensated for by sliding of said detachable portion in the plane and in said recess of said outer flap when the cuts of said first and second elements are   simultaneously wound around the mandrel.   3. Set of blanks according to claim 1, characterized in that the means arranged to allow the relative movement comprises slidably securing means in the plane of the pre-cut portion on the inner flap, to allow the recovery of extra thicknesses when said first and second cuts are simultaneously wound around the mandrel during the formation of the body, before joining final.   4. Set of blanks according to claim 3, characterized in that the pre-cut portion is glued to the inner flap with cold glue. progressive setting.   5. Set of blanks according to any one   of the preceding claims, characterized in that   the pre-cut flap portion (56) is cut along a closed line.   6. Set according to any one of   preceding claims, characterized in that the   securing tongue (13a; 68) of the second blank (3, 42) extends along only a portion of the corresponding adjacent flap (13, 60), above the fastening tongue of the first cutting (2, 41).   7. Set of blanks according to any one   of the preceding claims, characterized in that   each cut has eight flaps, namely four principal flaps (46, 47, 48, 49, 60, 63,, 67) separated from each other by secondary flaps (50, 51, 52, 53, 61, 63, 65, 67) suitable for training cut corners of the box.   8. A method of manufacturing a packing case from a set of blanks according to   any one of the preceding claims.   Packing case, comprising two elements which are manually separable from one another and inserted into one another, respectively formed from blanks (2, 3; 41, 42) made of cardboard sheet material or corrugated cardboard, namely a first element (6, 23) forming a display tray and a second element (24) forming the upper part of the box, each element comprising a series of four main parts (4, 4 ', 4' ') , 4 '' '; 10, 11, 12, 13, 46, 47, 48, 49; 60, 62, 64, 66) terminated by a fastening tongue (4a, 13a; 44, 68), said main flaps and said tongue being connected to one another via first folding lines (5, 14; 45, 69) parallel to one another directly or via secondary flaps (50, 51, 52, 53; 61, 63, 65 , 67) and an assembly (8, 15; 55, 70) of first side flaps arranged on one side of said sequence of main flaps and connected thereto by second fold lines (9, 16; 54, 71) perpendicular to said first fold lines and intended to form at least partially for one the bottom (8 ') of the first tray member and for the other the top (15') of the second element, the two elements being interconnected by at least a portion (20, '; 56) in one of said main flaps of the first element, said outer flap (4, 4 ', 46), said portion being fixed to the corresponding main flap opposite the second element, said inner flap (12, 13; 60), characterized in that the first fold lines (5, 45) of the first element are parallel and offset laterally with respect to the first fold lines (14, 69) of the second element to allow winding around a mandrel (30) first and second elements previously secured together at least in part by said portion (20, 20 '; 56), catching the extra thicknesses of the cardboard sheets, and in that said pre-cut portion (20, 20'; 56) and the inner flap (12, 13; 60) are interconnected by means arranged to allow the relative movement between the outer flap and   internal component during the formation of the body.   10. Box according to claim 9, characterized in that the means arranged to allow relative movement comprise a recess (21, 21 ', 57) in the outer flap (4, 4' 46) extending, and complementary shape with the pre-cut portion (20, 20 '; 56) which is fixed irremovably to the inner flap (12, 13; 60) to enable retraction of the slippage thicknesses of said portion in the plane and in said recess of said outer flap, when the cutouts of said first and second elements are   simultaneously wound around the mandrel.   11. Box according to claim 9, characterized in that the means arranged to allow the relative movement comprises slidably securing means in the plane of the pre-cut portion on the inner flap, to allow the recovery of extra thicknesses when the cuts of said first and second elements are simultaneously wound around the mandrel during the formation of the fund.   12. Case according to claim 11, characterized in that the securing means are constituted by cold-setting glue. 13. Box according to any one of   Claims 9 to 12, characterized in that the   portion of the pre-cut flap (56) is cut according to a closed line.   14. Box according to any one of   Claims 9 to 13, characterized in that the   tongue (13a, 68) of the second element (3, 42) extends along only a part of the corresponding adjacent flap (13, 60), above the fixing tab (4a, 44) of the first element (2, 41). 15. Cash box according to any of the   claims 9 to 14, characterized in that   is eight-sided, the principal flaps (46, 47, 48, 49; 60, 63, 65, 67) being separated from each other by secondary flaps (50, 51, 52, 53; 61, 63, 65, 67) forming cut corners.