AU5227600A

AU5227600A - Case and cardboard blank with tearaway wall

Info

Publication number: AU5227600A
Application number: AU52276/00A
Authority: AU
Inventors: Jean-Yves Bacques; Gerard Mathieu
Original assignee: DS Smith Packaging France SAS
Current assignee: DS Smith Packaging France SAS
Priority date: 1999-06-15
Filing date: 2000-05-29
Publication date: 2001-01-02
Anticipated expiration: 2020-05-29
Also published as: WO2000076856A3; WO2000076856A2; DE60000814D1; ATE228086T1; ES2184717T3; EP1093433B1; EP1093433A1; AU763170B2; PT1093433E; CA2374569A1; NZ516586A; JP2003502220A; DE60000814T2

Abstract

The invention concerns a case, a blank and a cardboard or corrugated cardboard sheet package blank. The case is formed from one single blank and comprises a side wall (2) arranged to be entirely torn away manually by a user.

Description

CARDBOARD CASE AND BLANK WITH TEAR-OFF WALL The present invention relates to a packing case made of cardboard or corrugated cardboard formed from a one 5 piece blank and comprising a tear-off wall. It also relates to a blank for obtaining such a packing case and to a perforating blade for partially precutting the join lines for joins to such a tear-off 10 wall. It finds a particularly important, although not exclusive, application in the field of packing for rigid products (jar, tins, etc.) or semirigid products 15 (bags, etc.), allowing the products to be displayed easily outside their transport packing immediately, in a clean and attractive way, particularly on the shelves of superstores. 20 Packing cases allowing swift detachment of the upper part of the case from the lower part that forms a tray, allowing the contents of the packing to be displayed quickly in said tray are already known (EP 0 637 548). 25 Such a case is, however, obtained from two different blanks stuck together and has the disadvantage of not AMENDED SHEET -2 allowing all the products in the packing to be removed quickly, easily and fully so that they can be lined up on a shelf. 5 A box formed of a blank with an opening at the top which is obtained by manually tearing off the lid, and with a reinforced handle, is also known (US-A 3,533,549). Such a rigid box does not allow the product it contains to be removed easily so that it can be 10 placed on shelves. The present invention aims to provide a blank and a case which are better than previously known ones at meeting the requirements of common practice 15 particularly in that it allows complete removal of the packing through a few simple movements allowing impeccable display on shelves in stores. In addition, the invention allows automatic 20 construction at a high rate (in excess of twenty cases/min) , the cases obtained being very robust and also being easy to stack on pallets. It also makes it possible better than previously to 25 guarantee cutting which is perfectly controlled, easy and 100% reliable, while at the same time allowing AMENDED SHEET - 2a optimized strength in the tear region so as to prevent any accidental risk of tearing the attachment points, for example as the result of an impact on the weakened region or a violent movement of the products inside the 5 packing. This improvement proves particularly beneficial in the case of perforations made on the periphery of one full face of the packing, for which the risk of initiating AMENDED SHEET WO 00/76856 PCT/FROO/01468 -3 the precut parts is high, especially on the middle of the edges of the face where the load is highest. To this end, the present invention proposes in 5 particular a case made of material in the form of a sheet of cardboard or corrugated cardboard, characterized in that it is formed from a single blank and in that it comprises a side wall designed so that it can be fully torn off by hand by a user. 10 To do this, join lines are provided between the wall formed by a tear-off panel and the other adjacent panels (bottom, lid, and adjacent side walls), which are fully precut. 15 A precut join line between two panels, a panel being formed by a leaf or by one or more flaps of the blank, is to be understood as meaning a join line consisting of a few attachment points or parts attaching the two 20 panels together, which makes the two panels easy to detach from one another by tearing along the join line, combining pulling at right angles to the line with progressive detachment of the attachment points one after the other. 25 WO 00/76856 PCT/FROO/01468 - 4 The precut join lines are thus designed to offer good resistance in the direction of the line and/or as long as tearing has not been begun. 5 Advantageously, a hard point makes it possible to avoid starting the tear on each side of the line and/or at the middle. Likewise, and in that which follows, a precut frangible 10 portion is to be understood as meaning a frangible portion which is held only by a few points or attachment parts to the remainder of the blank and which can therefore be easily detached from the blank by pulling at right angles to the plane of the blank (a 15 pulling force of a few newtons, for example from 5 to 10 N). Thus, the precut portion and/or the precut lines are designed to offer good resistance in the vertical 20 direction as long as the forces are exerted essentially in the plane of the walls. This resistance is, in particular, high enough to allow the products to be transported even if the packing is grasped by the upper part. 25 Conventionally, the precut lines are obtained by perforating the cardboard in a dotted line using WO 00/76856 PCT/FROO/01468 -5 cutting blades known as "perforating rules". The dotted lines are therefore defined by a regular alternation of perforated lines known as "cuts" and unperforated lines known as "attachment points". 5 The distance separating two attachment points, in other words the length of the cut, is termed D1, while the distance separating two perforated cutting lines, in other words the length of an attachment point, is known 10 as D2. A perforating profile is thus commonly denoted by a series of two figures corresponding to D1 and D2, separated by a dot. The values D1 and D2 are always 15 constant and on one and the same cutting line. For example, an 8.3 perforated line will consist of an alternation of cuts 8 mm long and of attachment points 3 mm long. 20 In this instance, as the path followed by the dotted lines has also to act as a fold line, the perforating rules also have a scoring function, that is to say that between the perforations, the attachment points are 25 crushed by deeper perforating rules so as to make subsequent folding about the line concerned easier.

WO 00/76856 PCT/FROO/01468 - 6 Just like the simple cutting blades or rules or scoring rules, the perforating blades are generally made of steel, and are driven over part of their height into a wooden form which gives them rigidity against lateral 5 deformation as they are pressed onto the cardboard that is to be cut. The difficulty in choosing a perforating rule consists in selecting the one that makes it possible to obtain 10 tearing that is easy, quick and clean for the operator while at the same time avoiding accidental rupture of the attachment points for any other reason. Thus, it is as a function of the nature of the grammage 15 of the papers and of the thickness of the corrugated cardboard that the person skilled in the art will vary the values D1 and D2 until he finds the best possible compromise. 20 The higher the value of D2, the more energy will be required for tearing. Likewise, the lower the value of D1, the more tear points there will be over a defined distance, and the 25 greater the energy will be.

WO 00/76856 PCT/FROO/01468 - 7 However, beyond a certain value of D2, there is a risk that the tearing will not follow the anticipated path but will, on the other hand, diverge from it, to the considerable detriment of the appearance of the cut. 5 The graph in Figure 1 for example depicts the variation in tear force for an attachment point as a function of the length of the attachment point in millimeters for a given type of cardboard. 10 The tear regions of the prior art did not always manage to reach a satisfactory compromise between ease of tearing and resistance. 15 In one advantageous embodiment, the present invention therefore proposes to create join lines that can vary over one and the same length of perforated line, this being by taking advantage of the fact that the tearing moment applied to the region that is to be torn varies 20 according to the angle between the force applied and the wall bearing the attachment points, and that the energy transmitted to the attachment point is dependent on the speed at which the movement is applied. 25 These regions of variable resistance are obtained by varying the distances D1 and D2 along one and the same line.

WO 00/76856 PCT/FROO/01468 - 8 Thus, it is possible to start one end of a dotted line with a long distance Dl and a short distance D2 so that the cut can be begun easily and a high speed can be achieved toward the middle of the dotted line, then, as 5 the middle is approached, D1 is gradually reduced while D2 is increased so as to obtain greater resistance to tearing, then finally D1 is increased again while D2 is decreased as the other end of the dotted line is approached. 10 The invention thus also proposes a packing case made of a sheet of cardboard or corrugated cardboard comprising a tear-off wall equipped with partially precut join lines forming a perforated line exhibiting cut portions 15 of length Dl separated each from the next by attachment points of length D2, characterized in that at least one of the lengths D1 and D2 varies along said perforated line. 20 The invention also proposes a packing case formed from a single blank of material in the form of a sheet of cardboard or corrugated cardboard, comprising a first vertical wall connected by join lines to the bottom wall, top wall and adjacent side walls of the case, 25 characterized in that said join lines are precut and in that the vertical wall opposite the first wall is secured to the bottom wall via at least one precut WO 00/76856 PCT/FROO/01468 frangible portion that can be detached simply' by pulling and/or one or more spots of adhesive that can be unstuck manually simply by pulling. 5 The expression "detachable simply by pulling" is to be understood as being detachable by separating by hand, this being obtained by exerting a force at right angles to the walls. 10 As already mentioned, the partially precut portion or portions and/or the spots of adhesive are arranged so that they exhibit good resistance in the vertical direction, that is to say as long as the forces are exerted essentially in the plane of the walls. 15 If, on the other hand, the separating force exerted between the walls is very much at right angles to the walls, these can then easily be detached by hand, without peeling of the cardboard, for example with a 20 force of the order of 5 to 10 newtons, advantageously and for example after passing through a hard point involving an additional effort of a few newtons on the part of the user, for example using his thumb to push back and/or exert leverage to pass through this hard 25 point.

WO 00/76856 PCT/FROO/01468 - 10 In addition, it should be noted that as long as the first side wall of the case has not been torn off manually by the user, the case maintains its rigidity, which means there can be no parting or gaping 5 encouraging a risk of beginning tearing, this risk being moreover advantageously also allayed through the hard point mentioned hereinabove. Advantageously, the invention also proposes a cutting 10 blade for a material in the form of a sheet of cardboard or corrugated cardboard, comprising a perforating rule having cutting portions of length Dl separated each from the next by recessed portions of length D2, characterized in that at least one of the 15 lengths D1 and D2 varies along said perforating rule. Advantageously, the perforating rule has a first region with cutting portions of a first length D1 known as a long length, followed by a second region of length Dl' 20 shorter than Dl. Also advantageously, the cutting blade is designed to allow the formation of precut lines of the type described hereinabove. 25 In some advantageous embodiments, recourse is also had to one and/or other of the following provisions: WO 00/76856 PCT/FROO/01468 - 11 - the side walls adjacent to the first wall are secured to the bottom wall via at least one, for example essentially rectangular, precut frangible portion that can be detached simply by pulling and/or one or more 5 spots of adhesive that can be unstuck manually simply by pulling; - the walls of the case being formed by leaves and/or flaps of the blank, the precut frangible portions are cut along a line which is open with respect to the edge 10 of the corresponding leaf and/or flap. The invention also proposes a blank making it possible to obtain the case as described hereinabove. 15 The invention also proposes a blank made of material in the form of a sheet of cardboard or corrugated cardboard for manufacturing a parking case of the type comprising at least four rectangular leaves, said rectangular leaves comprising a first leaf intended to 20 form a first side wall of the case connected by a first join line to a second leaf intended to form the bottom of the case and, respectively, by second, third and fourth join lines to adjacent panels formed by one or more flaps and at least a third leaf, and a rectangular 25 fourth leaf intended to form a second side wall of the case opposite the first wall, characterized in that the second leaf comprises two side flaps and an end flap, WO 00/76856 PCT/FROO/01468 - 12 in that the first, second, third and fourth join lines are precut and in that the fourth leaf or the end flap of the second leaf comprise at least one precut frangible portion. 5 In some advantageous embodiments, recourse is further had to one and/or other of the following provisions: - the second and third join lines are fold lines connecting the first leaf to adjacent flaps intended at 10 least partially to form side walls of the case and the fourth join line is a line connecting the first leaf to a third leaf intended to form the top of the case; - the second and third join lines are fold lines connecting the first leaf to two adjacent leaves 15 intended to form the walls of the case and the fourth join line is a line connecting the first leaf to a top flap intended at least partially to form the top of the case; - the side flaps of the second leaf are each 20 respectively equipped with a, for example roughly rectangular, precut frangible portion; - the precut frangible portions of the two side flaps of the second leaf are cut along an open line with one side completely open to the outside of said flaps; 25 - the precut frangible portions of the two side flaps of the second leaf lie on the same side as the first leaf; WO 00/76856 PCT/FROO/01468 - 13 - each of the side flaps of the second leaf comprises at least one additional precut frangible portion; - the fourth join line is in the form of a cap astride the fold line between the first leaf and the adjacent 5 panel; - at least one of the precut frangible portion of the fourth leaf and of the fourth precut join line, is respectively associated with grasping means, for example comprising a hollowed-out part in the blank 10 allowing a user to perform the tearing-off. The invention will be better understood from reading the description which follows of some embodiments which are given by way of nonlimiting examples. The 15 description makes reference to the accompanying drawings in which: - Figure 1 is a plan view of a blank according to a first embodiment of the invention. - Figure 2 is a plan view of another embodiment of the 20 flaps of the second leaf of the blank of figure 1. - Figure 3 is a plan view of another embodiment of the flaps of the second leaf of the blank of figure 1. - Figure 4 is a skeleton diagram of the forming then opening out of a packing case using the blank of figure 25 1, prejoined. - Figure 5 is a plan view of a width of cardboard continuously cut to form blanks according to figure 1.

WO 00/76856 PCT/FROO/01468 - 14 - Figure 6 is a plan view of another embodiment of a blank according to the invention. - Figure 7 is a skeleton diagram of the formation of a packing case from the blank of figure 1, by wrapping 5 the blank around the load. - Figure 8 is a plan view of another embodiment of the blank according to the invention. - Figure 9 is a skeleton diagram of the formation of a case from a blank of the type described with reference 10 to figure 8. - Figure 10 is a curve showing the variation of the tear force of an attachment point for a particular type of cardboard. - Figure 11 shows a cutting blade according to one 15 embodiment of the invention and a wall of packing after cutting. - Figure 12 shows a cutting blade with a progressive profile in another embodiment of the invention. 20 In the remainder of the description, the same reference numerals will be used to denote the same elements. Figure 1 shows a blank 1 made of double-sided corrugated cardboard, for example 3 mm thick. The blank 25 is formed of a succession of four rectangular leaves 2, 3, 4 and 5 connected together by fold lines.

WO 00/76856 PCT/FROO/01468 - 15 More specifically, the succession comprises a first leaf 2 intended to form a side wall of the case, connected by a first join line 6, coincident with a 5 fold line between leaves, to a second leaf 3 intended to form the bottom of the case and, respectively, by a second join line 7 and a third join line 8 which also form fold lines to two rectangular or roughly rectangular adjacent flaps 10 and 11. 10 The first leaf 2 is also connected to a third rectangular leaf 4 by a fourth join line 9 consisting of a line in the form of a hat. The line 9 straddles the fold line 12 parallel and on the opposite side to 15 the fold line 6, to form the opposite edge of the case. The remainder comprises a fourth rectangular leaf intended to form the wall of the case opposite the first wall 2. 20 Each of the first, second, third and fourth join lines (6, 7, 8, 9) are precut according to the invention. The join line 9 makes it possible to determine two 25 rectangular or trapezoidal leaf parts 13 and 14 lying one on each side of a central portion 15 of trapezoidal shape straddling the line and comprising a part WO 00/76856 PCT/FROO/01468 - 16 situated on the third leaf 4, ending in an aperture or opening 16 made in said third leaf intended to form the top of the case. 5 The line 15 therefore has the shape of an Q or of a hat. The opening is, for example, rectangular and/or triangular and allows the user to slip in one or more 10 fingers so as to tear off the first wall formed by the first leaf 2. Each of the leaves 3, 4, and 5 also has, on each side of and in the continuation of the two flaps 10 and 12 15 of the first leaf 2, rectangular or roughly rectangular flaps 17, 18; 19, 20 and 21, 22 respectively able to collaborate once the case has been made up, with the flaps of the first leaf so as to form open-work opposed side walls of the case. 20 The second leaf 3 comprises, on the opposite side to the first leaf, a set 23 of three rectangular or roughly rectangular flaps, namely a central flap 24 connected to the second leaf via a fold line 25 and two 25 small end flaps 26 connected respectively by fold lines 27 lying in the continuation or roughly in the WO 00/76856 PCT/FROO/01468 - 17 continuation of the fold line 25, to the two side flaps 17 and 18 of the second leaf 3. These two side flaps 17 and 18 each respectively and 5 for its own part comprises, on the same side as the first leaf 2, a precut frangible portion 28, 29 precut along an open line with a side 30, 31 entirely open toward the outside of the flaps on the one hand and toward the first leaf on the other. 10 The fourth leaf 5 for its part comprises, on its outer edge 32 lying on the opposite side to the third leaf 4, a precut frangible portion 33 which is, for example, rectangular or trapezoidal, capable of collaborating 15 with the central flap 24 of the second leaf 3. This precut portion 33 is continued toward the leaf 5 by a recessed part 34 in said fourth leaf 5, for grasping the wall, to allow easy tearing once the blank 20 has been made up to form packing. Figures 2 and 3 depict other embodiments of the flaps of the second leaf 3 according to the invention. 25 Figure 2 thus shows a second leaf 3 equipped with two side flaps 17' and 18' each equipped with an end flap 26. The two flaps 17' and 18' are each equipped with WO 00/76856 PCT/FROO/01468 - 18 two rectangular or essentially rectangular partially precut portions 35 and 36, 37 and 38 which are symmetric in pairs with respect to the longitudinal axis 39 of the blank. 5 The portions 35 and 37 lie at the end of the flaps directed toward the first leaf 2 and are free on three sides. 10 The portions 36 and 38 lie on the same side as the other end of the flaps and are free on two sides, making it possible to form a part 39, 40 which is set back in the flap 17', 18' toward the leaf 3. 15 Figure 3 shows another embodiment of the flaps 17'', 18'' of the second leaf 3 according to the invention. Each flap is equipped with two precut portions 28' and 29' of the same type as the parts 28 and 29 described 20 with reference to figure 1, and two other precut parts 41 and 42 which are free only on the side coincident with the outer edge of the flap. In this embodiment, the flaps 17'', 18'' are not 25 equipped with small end flaps.

WO 00/76856 PCT/FROO/01468 - 19 However, the central flap 43 of the leaf 3 has' two small end flaps or tabs 44 which will be able to be folded down to form a case according to the invention. 5 This will now be described more particularly with reference to figure 4, which gives a skeleton diagram 45 of a first embodiment of the forming of the case obtained using the blank 1 described above. 10 Starting out from the blank 1 which is prejoined using the central flap 24 to the precut portion 33 of the fourth leaf 5, the blank is opened out at 46, then squared (step 47). 15 The load 48 is introduced sideways into the packing, as shown at 49, then the side flaps intended to form the side walls of the case are folded down having been previously coated for example with hot-melt adhesive, particularly the partially precut portions 28, 29, so 20 as to form the case as shown at the end of formation at 50. The case is then conveyed then taken, for example, into a supermarket. 25 The wall formed by the first leaf 2 is then torn off (step 51) manually by a user, something which the WO 00/76856 PCT/FROO/01468 - 20 latter can easily do given the precut join lines, then the packing is placed on the shelf (not depicted). The lower part 52 forming the bottom is detached at the 5 precut portions 28, 29 by pulling outward in the direction of the arrow 53 (step 54). The shovel-shaped bottom 52 is then extracted from beneath by the user who pulls it, pushing the top or 10 upper part 55 of the case and the load 48 back. Finally, the upper part 55 of the case is removed so as to completely uncover the load 48 on the shelf. 15 Figure 5 shows a collection 56 of blanks 1, 1', 1'' as described with reference to figure 1, which can easily be manufactured from the same width of cardboard, continuously. 20 The precut join lines 6, 7, 8, 9 or connecting lines for precut portions 28, 29, 33 are obtained by perforating the cardboard in dotted lines using perforating cutting blades. 25 The dotted lines are therefore defined by an alternation of perforated lines and unperforated lines known as attachment points.

WO 00/76856 PCT/FROO/01468 - 21 The distance separating two attachment points or, in other words, the length of cut being termed D1 and the distance separating two perforated lines, or in other words, the length of the attachment point being termed 5 D2, a perforating profile is therefore defined by the two figures corresponding to Dl and D2. Depending on the nature and grammage of the paper, and on the thickness of the corrugated cardboard, it is 10 possible to vary the values of D1 and D2 until the best possible compromise is found to allow ease of tearing while at the same time keeping the packing sufficiently robust. 15 Advantageously, Dl and D2 are thus varied along the same precut line to create weaker points or hard points as indicated above. Figure 6 shows another embodiment of blanks 57, 57' 20 nestled together opposite ways round, manufactured continuously from the same width of cardboard. The first leaf 58 here comprises two flaps 59 and 60 which are symmetric with respect to the longitudinal 25 axis 61 of the blank and each of which is formed of a rectangular first part and of a trapezoidal or roughly triangular second part of greater height than the first WO 00/76856 PCT/FROO/01468 - 22 part located on the same side as the third leaf 62 and directed toward the outside of the blank. The flaps 63, 64 of the second leaf which is intended 5 to form the bottom of the packing, are small rectangular flaps located at the periphery of said second leaf. The two side flaps 63 are extended by a short tab 65, the central, end, flap 64 being, for example, of the same width as the side flaps 63. 10 The third leaf 62 and the fourth leaf 66 each comprise, on each side, two large rectangular or roughly rectangular flaps 67, 68 intended, when bonded together, and with the flaps of the first and second 15 leaves, to form the other two side walls of the case. Figure 7 depicts another way of forming packing from a blank 1 according to the invention. 20 In this case, the blank 1 is not prejoined as described with reference to figure 4, but is brought in flat (step 70). The load 71 may be air-driven (embodiment not 25 depicted), or conveyed from the side onto the blank (step 72) before the blank is folded up around the WO 00/76856 PCT/FROO/01468 - 23 package by wrapping, as depicted at 73, the load resting on the top of the packing or third leaf 4. The packing is then completed as shown at 74 in figure 5 7, the flaps 10, 11; 21, 22 then 17, 18, 19, 20 being coated with adhesive then folded over, the second leaf 3 capable of forming the bottom of the packing being folded down onto the load, its central end flap 24 being bonded to the precut portion 33 of the fourth 10 leaf 25 as indicated at 75. Figure 8 depicts another embodiment of a blank 80 according to the invention comprising a first leaf 81 connected by first, second, third and fourth precut 15 join lines 82, 83, 84, 85 respectively to a second leaf 86, a third leaf 87 and a fifth leaf 88, the second leaf 86 being intended to form the bottom of the case and being, for example, identical to the second leaf described with reference to figure 1. 20 The third and fifth leaves 87, 88 are, for their part, situated one on each side of the first leaf 81, to which they are connected by the second and third precut join lines which are coincident with the fold lines, 25 the fourth join line 85 for its part straddling a fold line 89 connecting with a rectangular flap 90 to form portions identical to the portions 13, 14, 15 and a WO 00/76856 PCT/FROO/01468 - 24 recess identical to the recess 16 of the blank of figure 1. A fourth leaf 91 is provided at the end of the fifth 5 leaf 88 and comprises the precut portion 92 identical to the portion 33 according to the invention, which will be bonded onto the end flap 93 of the second leaf. The fourth leaf additionally comprises an end tab 94 10 for bonding to the third leaf 87 (or conversely the tab may be on the third leaf and be bonded to the fourth), each of the third, fourth and fifth leaves comprising a roughly rectangular flap 95, 96, 97 of the same width as the flap of the first leaf and which are intended to 15 form the top of the case. The flaps 95 and 97 are symmetric with respect to the first leaf 81 and comprise, for example, a cut-out at the corner located on the same side as the flap 90 of the first leaf, of a shape that complements the portion 15. 20 Figure 9 depicts the forming of a case 98 according to the invention from a blank 80 of the type described with reference to figure 8. 25 The blank 'is first of all brought in flat then preformed into a ring, the tab 94 being bonded to the third leaf 87, the bottom 86 of the case being brought WO 00/76856 PCT/FROO/01468 - 25 up then bonded. The case is then tipped open (step 99), the load 100 then being introduced before the flaps 90, 96 then 95, 97 are closed to form the top of the case. 5 Figure 10 shows a curve 101 giving the variation in tear force of an attachment point for a profile 10.D2 namely with D1 = length of cuts of 10 mm, and D2 = length of the attachment point (mm) along the x-axis and the rupture force (N) along the y-axis, for a 10 corrugated cardboard of type PC 2T30C090 T140 and a total grammage for the cardboard of 410 g/mm 2 It can be seen that for D2 = 3 mm, the force is 9.3 N, for D2 = 4 mm, it is 12.6 N, etc. 15 From these values and from values from other similar curves, those skilled in the art will be able to meter the tearing force to suit the requirement. Figure 11 shows a panel 103 made of two-sided 20 corrugated cardboard, for example 3 mm thick according to one embodiment of the invention, with a partially precut line 104, comprising a first region 105 and a second region 106. 25 The region 105 comprises cut portions 107 of a first length Dl, and attachment points 108 of a first length D2. The second region 106 comprises cut portions 109 of WO 00/76856 PCT/FROO/01468 - 26 a second length Dl' shorter than D1, for example half as long, and attachment points 110 of the same length D2 as the attachment points 108. 5 Figure 11 also shows the straight cutting blade 111 comprising a perforating rule 112 of a shape designed to cut the partially precut line 104 and fixed to a rigid support 113 removably so that it can be changed easily. 10 Figure 12 gives an enlarged side view of another embodiment of the cutting blade 114 according to the invention. The blade comprises a straight perforating rule which 15 here comprises four regions, of progressive difficulty of tearing, namely a first region 115 which is easy to tear, a second region 116 which is not as easy to tear, a third and fourth region 117 and 117' which are difficult to tear without any impetus. 20 The first region 115 is equipped with cutting portions 118 of a length of, for example, 15 mm, and rectangular recessed portions 119 to form the attachment points, of length of 5 mm. 25 The second region 116 comprises cutting portions 118' of 10 mm and identical recessed portions 119.

WO 00/76856 PCT/FROO/01468 - 27 The third region 117 comprises cutting portions 118'' of a third length of 6 mm, and recessed portions 119 still of 5 mm, and finally, the fourth region 117' comprises cutting portions 118'' of 6 mm and recessed 5 portions 119' of 16 mm. As goes without saying and as is also evident from the foregoing, the present invention is not restricted to the embodiments more particularly described. On the 10 contrary, it encompasses all alternatives thereof, particularly those in which the precut portions belong, in part, to the flaps of the first rather than of the second leaf.

Claims

1. A case made of material in the form of a sheet of cardboard or corrugated cardboard, formed from a single 5 blank and comprising a panel at least partially forming a first side wall (2, 58, 81), said panel or said first wall being designed to be able to be torn off completely by hand by a user, being connected by precut join lines (6, 7, 8, 9; 82, 83, 84, 85) to the first 10 wall and/or to the adjacent walls of the case, said adjacent walls comprising two side walls or two parts of side walls and a wall known as the bottom wall of the case, characterized in that the side walls or portions of 15 side walls (10, 11; 59, 60; 87, 88) adjacent to the first wall (2, 58, 81) are secured respectively to the bottom wall (3, 86) or to flaps (17, 18) connected to the bottom wall, via at least one precut frangible portion (28, 29; 28', 29'; 35, 37; 41, 42) that can be 20 detached simply by pulling and/or one or more spots of adhesive that can be unstuck by hand, simply by pulling.

2. The case as claimed in claim 1, characterized in 25 that the precut join lines are at least partially formed by fold lines. AMENDED SHEET - 29

3. The case as claimed in any one of the preceding claims, characterized in that, the walls of the case being formed by leaves and/or flaps of the blank, the precut frangible portions are cut along a line which is 5 open with respect to the edge of the corresponding leaf and/or flap.

4. The case as claimed in any one of the preceding claims, characterized in that the wall opposite the 10 first wall is secured to the bottom wall (3, 86) or to a flap (24, 64, 93) connected to the bottom wall, via at least one precut frangible portion (33, 92) that can be detached simply by pulling and/or one or more spots of adhesive that can be unstuck manually simply by 15 pulling.

5. The case as claimed in claim 4, characterized in that the single blank comprises at least four rectangular leaves, namely a first leaf (2, 58, 81) 20 intended to form the first wall of the case connected by a first join line (6, 82) to a second leaf (3, 86) intended to form the bottom wall of the case and, respectively, by second, third and fourth join lines (7, 8, 9; 83, 84, 85) to adjacent panels forming one or 25 more flaps (10, 11; 90) and at least one rectangular third leaf (4; 62; 87; 88) and a rectangular fourth AMENDED SHEET - 30 leaf (5; 66; 91) intended to form the wall opposite the first wall of the case, and in that the second leaf (3) comprises two side flaps (17, 18; 17', 18'; 17'', 18''; 63) and an end 5 flap (24; 43; 64; 93), the fourth leaf (5; 66; 91) or the end flap (24; 43; 64; 93) of the second leaf comprising the precut frangible portion (33; 92).

6. The case as claimed in claim 5, characterized in 10 that the second and third join lines (7, 8) are fold lines connecting the first leaf (2) to adjacent flaps (17, 18) intended at least partially to form the adjacent side walls of the case and the fourth join line (9) is a line connecting the first leaf (2) to a 15 third leaf (4; 62) intended to form the top wall of the case.

7. The case as claimed in claim 5, characterized in that the second and third join lines (83, 84) are fold 20 lines connecting the first leaf (81) to two adjacent leaves (87, 88) intended to form the adjacent walls of the case and the fourth join line (85) is a line connecting the first leaf to a top flap (90) intended to at least partly form the top wall of the case. 25 AMENDED SHEET - 31

8. The case as claimed in any one of claims 5 to 7, characterized in that the precut frangible portions (28', 29'; 35, 37) are situated on the same side as the first leaf (2) and in that each of the said side flaps 5 (17', 18'; 17'', 18'') of the second leaf (3) comprises at least one additional precut frangible portion (36, 38; 41, 42).

9. The case as claimed in any one of the preceding 10 claims, characterized in that the fourth join line (9, 85) is in the form of a cap astride the fold line (12) between the first wall and the top wall of the case.

10. The case as claimed in any one of the preceding 15 claims, characterized in that the first wall and the opposite wall are associated with a hollowed-out part of the blank allowing a user to perform the tearing off. 20

11. The case as claimed in any one of the preceding claims, characterized in that at least one precut join line forms a perforated line exhibiting cut portions of length D1 separated each from the next by attachment points of length D2, at least one of the lengths Dl and 25 D2 varying along said perforated line. AMENDED SHEET - 32

12. The case as claimed in claim 11, characterized in that the perforated line is of rectilinear shape.

13. The case as claimed in claim 11, characterized in 5 that the perforated line is of curved shape or has at least one corner.

14. The case as claimed in any one of claims 11 to 13, characterized in that the perforated line has a first 10 region with cut portions of a first length D1 said to be a long length, so that the cut can be begun easily and a high tearing speed can be achieved, followed by a second region of length D1', shorter than D1, so as to obtain greater resistance to tearing. 15

15. The case as claimed in any one of claims 11 to 14, characterized in that the perforated line has a first region with tear points of a first length D2 said to be a short length, so that the cut can be begun easily and 20 a high tear speed can be achieved, followed by a second region of length D2', longer than D2, so as to obtain greater resistance to tearing.

16. The case as claimed in any one of claims 11 to 15, 25 characterized in that the perforated line comprises a third region having cut portions of a length D1'' AMENDED SHEET - 33 longer than Dl';, and/or tear points of length D2'' shorter than D2', so as once again to reduce the resistance to tearing. 5

17. A blank (1, 1', 1''; 57, 57'; 80) made of material in the form of a sheet of cardboard or corrugated cardboard for manufacturing a case comprising at least four rectangular leaves, said rectangular leaves comprising a panel at least partially forming a first 10 leaf (2, 58, 81) intended to form a first side wall of the case, said panel being connected by a first join line (6, 82) to a second leaf (3, 86) intended to form the bottom of the case and, respectively, by second, third and fourth join lines (7, 8, 9; 83, 84, 85) to 15 adjacent panels formed by one or more flaps (10, 11; 90) and at least a third leaf (4; 62; 87, 88), and a rectangular fourth leaf (5; 66; 91) intended to form a second side wall of the case opposite the first wall, characterized in that the second leaf (3, 86) comprises 20 two side flaps (17, 18; 17', 18'; 17'', 18''; 63) and an end flap (24, 43; 64; 93), and in that the first, second, third and fourth join lines are precut, and in that the side flaps (17, 18; 63) of the second 25 leaf (3, 86) are each equipped respectively with a precut frangible portion (28, 29; 28', 29'; 35, 37) AMENDED SHEET - 34

18. The blank (1, 1', 1''; 57) as claimed in claim 17, characterized in that the second and third join lines (7, 8) are fold lines connecting the first leaf (2) to adjacent flaps (17, 18) intended at least partially to 5 form side walls of the case and the fourth join line (15) is a line connecting the first leaf (2) to a third leaf (4; 62) intended to form the top of the case.

19. The blank (80) as claimed in claim 17, 10 characterized in that the second and third join lines (83, 84) are fold lines connecting the first leaf (81) to two adjacent leaves (87, 88) intended to form the walls of the case and the fourth join line (85) is a line connecting the first leaf (81) to a top flap (90) 15 intended at least partially to form the top of the case.

20. The blank as claimed in any one of claims 17 to 19, characterized in that the fourth leaf (5; 66; 91) or 20 the end flap of the second leaf comprise at least one precut frangible portion (33; 92).

21. The blank as claimed in claim 20, characterized in that the precut frangible portions (28, 29; 28', 29'; 25 35, 37) of the two side flaps of the second leaf are AMENDED SHEET - 35 cut along an open line with one side completely open to the outside of said flaps.

22. The blank as claimed in either one of claims 20 and 5 21, characterized in that the precut frangible portions (28', 29'; 35, 37) lie on the same side as the first leaf (2) and in that each of said side flaps (17', 18'; 17'', 18'') of the second leaf (3) comprises at least one additional precut frangible portion (36, 38; 41, 10 42).

23. The blank as claimed in any one of claims 17 to 23, characterized in that the fourth join line (15, 18) is in the form of a cap astride the fold line between the 15 first leaf and the adjacent panel.

24. The blank as claimed in any one of claims 17 to 23, characterized in that the precut frangible portion (33, 92) of the fourth leaf (5, 91) and the precut fourth 20 join line (15, 85) are each respectively associated with a hollowed-out part (16, 34) in the blank allowing grasping so that a user can perform tearing. AMENDED SHEET