EP3509805A1

EP3509805A1 - Cutting and ejection method for a cardboard blank and ejection strip for such a method

Info

Publication number: EP3509805A1
Application number: EP17755537.2A
Authority: EP
Inventors: Nicolas Meyer
Original assignee: Lagora
Current assignee: Lagora
Priority date: 2016-09-09
Filing date: 2017-08-25
Publication date: 2019-07-17
Anticipated expiration: 2037-08-25
Also published as: LU93201B1; WO2018046317A1; US20190240942A1; ES2862308T3; EP3509805B1

Abstract

The invention proposes a method for cutting an opening in a flat cardboard blank (10, 12) intended for producing a packaging, which involves clamping a first portion (18) of the blank (10, 12) and an ejection strip (34) facing each other between a support tool (24) and an activation tool (26) that are facing each other in such a way as to bond the ejection strip (34) only with the first portion (18) of the blank (10, 12). The invention also concerns an ejection strip for such a method.

Description

CUTTING AND EJECTING METHOD FOR A CARDBOARD FLANK AND EJECTION TAPE FOR SUCH A METHOD

The invention relates to the field of packaging obtained from a sheet of cardboard.

Such packages are obtained by cutting, in a sheet of cardboard, a blank which is then folded along fold lines to form a three-dimensional packaging or packaging element. The cartons used for these packages generally have a basis weight of between 180 g per square meter and 2000 g per square meter, but most often between 220 and 350 grams per square meter.

For aesthetic or utilitarian reasons, it is sometimes provided in these packages one or more openings, or windows, made in the cardboard sheet. These openings, which are characterized by a closed contour, may have a complex geometry and may for example form a pattern, for example a letter or part of a letter. These openings may therefore in some cases have, in at least one direction, at least a very small dimension, less than 5 mm, or even less than 3 mm between two opposite edges of the opening.

It is known to make openings by practicing in the cardboard sheet, before or after cutting the blank, a cutting line closed on itself, the cutting contour defining a first portion of the blank relative to a second portion of the blank located outside the cutting line. Such cutting can be achieved by various means. In all cases, it is generally necessary to provide specific means for ejecting the portion of the cardboard sheet corresponding to the opening, that is to say to separate this part of the remainder of the sheet. In the state of the art, this is generally done by needle devices that push mechanically on the part to be ejected.

However, current techniques do not make it possible to achieve, under acceptable economic conditions, very small openings, in particular having at least one dimension less than 5 mm, or even less than 3 mm.

Indeed, the considered packaging are usually produced at high speed, so on high speed machines along which the cardboard sheets move quickly. It is therefore particularly difficult to ensure a very precise positioning of the sheet along its path in the machines. It follows that, without having a perfect positioning of the sheet, the needle systems can not be used because they are likely in this case to impact the sheet outside the opening.

JP-2016-30.318 discloses a method using a heat-sensitive adhesive tape applied to a complex comprising a base layer and an adhesive layer.

The steps of cutting and activating the adhesive by heat are simultaneous. The cutting and activation tool does not provide a radial shift activation.

JP-H04-170489 discloses an adhesive tape.

The purpose of the invention is to propose a manufacturing method that allows an opening in a flat cardboard blank, including an opening having at least a dimension of less than 5 mm, or even less than 3 mm, with sufficient reliability and at an economic cost acceptable in the context of mass production packaging, especially with machines working at more than one thousand strokes per hour, thus producing at least one thousand blanks per hour and per machine, or a thousand sets of blanks, arranged side by side in a sheet, per hour and per machine.

For this purpose, the invention provides a method of cutting an opening in a flat carton blank for the manufacture of a package and having a first face and a second opposite face.

In such a process:

a cut line closed on itself is practiced in the cardboard blank, the cutting line delimiting a first portion of the blank and a second portion of the blank outside the cutting line. - facing the first face of the blank is brought an ejection tape having a layer of adhesive, the ejection tape being arranged with its adhesive layer on the side of the first face of the blank and facing the first part flan;

the blank and the ejection tape facing the one of the other are brought between a support tool and an activation tool which are facing each other;

the activation tool has an active face in relief, turned towards the ejection tape and the blank, and whose relief is delimited by a peripheral edge;

a perpendicular projection of the peripheral edge on an extension plane of the blank is inscribed inside the cutting line with a radial activation offset inwardly with respect to the cutting line;

- Inside the peripheral edge, the active face has a recessed impression;

- The support tool has a protruding boss towards the blank with respect to a peripheral surface facing the blank, the boss having a contour relative to the peripheral surface;

a perpendicular projection of the contour of the boss on the plane of extension of the blank is inscribed inside the perpendicular projection of the peripheral edge of the activation tool on this plane with a radial offset of support towards the inside; ;

the first part of the blank and the ejection tape facing each other are clamped between the support tool and the activation tool which are facing each other in such a manner to stick the ejection tape exclusively on the first part of the blank.

According to other optional features of the invention:

The support tool contacts the second face of the blank preferably before the ejection tape is clamped against the first face of the blank by the activation tool. - The radial activation offset between the projection of the peripheral edge of the relief of the active face of the activation tool and the cutting line is at least 0.1 mm, preferably at least 0.2 mm on the extent of this peripheral edge.

- The radial support offset between perpendicular projections on the plane of extension of the blank of the contour of the boss of the support tool and the peripheral edge of the relief of the active face of the activation tool is preferably at least 0.1 mm, more preferably at least 0.2 mm over the extent of this peripheral edge.

The maximum depth of the impression in the active face of the activation tool is preferably between 0.1 and 0.5 mm.

- The maximum height of the boss relative to the peripheral surface of the support tool is preferably greater than 0.5 mm.

- The maximum height of the boss relative to the peripheral surface of the support tool is between 0.8 and 1.2 mm.

- An elastic abutment may be arranged, relative to the support tool, the opposite side of the assembly formed by the blank and the ejection tape.

- The resilient against-support is preferably arranged outside the perimeter line cutting which defines the opening.

- At least one of the activation tool or the support tool may be, at least during the clamping step, heated to a temperature greater than 80 ° C, more preferably greater than 120 ° C.

- Cutting the cutting line can be practiced in two successive steps comprising a first step of cutting a first portion of the cutting line and a second step of cutting a second portion of the cutting line.

Both cutting operations of the first and second portions of the cutting line can be carried out by means of a first and a second cutting knife respectively having the shape of the first and the second part of the cutting line. the cutting line. - Cutting the cutting line can be done in one operation.

The cutting line preferably forms a continuous and integral cut of the thickness of the blank over the entire length of the cutting line.

The first part of the blank is for example located inside the closed cutting line and the second part of the blank is located outside the cutting line.

- The flat blank extends in an extension plane, and it can be brought flat, in a machine translation direction parallel to its extension plane, between the support tool and the activation tool which are opposite one another, and the clamping can be obtained by relative displacement between the support tool and the activation tool in a directional translation perpendicular to the extension plane.

- The adhesive layer of the ejection tape may comprise a heat-reactive adhesive.

- The adhesive layer of the ejection tape may comprise a hot melt adhesive based on EVA copolymers.

The ejection tape may comprise a support layer which supports the adhesive layer of the ejection tape.

- The support layer of the ejection tape may comprise a paper layer.

The ejection tape may have a thickness of between 0.05 and 0.3 millimeters, preferably between 0.1 and 0.15 millimeters.

- After having tightened the first part of the blank and the ejection tape between the support tool and the activation tool, the ejection tape can be separated from the second part of the blank, the first part of the blank thus being separated from the second part of the blank by being glued to the activation tape.

The method may comprise the production of several cutouts of apertures offset from one another in a direction perpendicular to the direction of machine translation, and may comprise the implementation of several separate ejection ribbons offset one by one. on the other in the direction perpendicular to the direction of machine translation. The invention also relates to an ejection tape for a method of cutting and ejecting an opening in a cardboard blank, the ejection tape having an adhesive layer supported by a backing layer, the backing layer. adhesive comprising a heat-reactive adhesive, for example a hot melt adhesive based on EVA copolymers. The support layer which supports the adhesive layer of the ejection tape may comprise a layer of paper, for example a layer of kraft paper. Such an ejection tape may have a thickness of between 0.05 and 0.3 millimeters, preferably between 0.1 and 0.15 millimeters.

Various other characteristics appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention.

Figure 1 schematically illustrates a sheet of cardboard in which is defined a blank comprising an opening.

Figure 2 illustrates the realization of a cutting line in two successive steps.

Figures 3A-3D illustrate four successive steps of a method according to the invention.

Figure 4 schematically illustrates in section an ejection tape and a blank usable in a method according to the invention.

The invention is applicable in the field of cardboard packaging, for example in cardboard packaging for food or cardboard packaging of cigars or cigarettes, produced in very large numbers. However, it can also be applied to cardboard packaging for cosmetics.

These packages are manufactured by folding and assembling one or more blanks (s) pre-cut (s). This plane is usually provided with pre-marked fold lines. This blank is precut in a sheet of cardboard.

The invention aims to propose a method of cutting an opening in such a blank. The process can be implemented in the blank before it is cut from the cardboard sheet, or on the contrary after this blank has been cut from the cardboard sheet.

The blank material will preferably be a conventional material for this type of packaging. It may for example be a carton having a basis weight greater than or equal to 180 g per square meter. Generally, the cardboard used for such packages has a basis weight less than or equal to 2000 g per square meter. It has been found that grammages of between 220 and 350 grams per square meter are particularly advantageous.

It is illustrated in FIG. 1 schematically a sheet of cardboard 10 in which it is possible to define a blank 12 for forming a package. The blank 12 is a flat blank which extends in an extension plane defined in the figures by the perpendicular axes X and Y. In the example illustrated, the blank 12 is not yet precut. It may be delimited in the cardboard sheet 10 by a peripheral trace 14, but this peripheral trace may very well not exist physically in the sheet 10 and be revealed only when the blank 12 is actually cut from the sheet 10.

According to the invention, the blank 12, and thus the sheet 10, has a cut line 16 closed on itself which delimits the opening that is to be formed in the blank 12, thus in the sheet 10.

The cutout 16 may be made in any manner known to those skilled in the art. In some embodiments it will be performed using one or more punches or knives.

For example, as shown in FIG. 2, the cutting of the closed cutting line 16 can be practiced in two successive steps comprising a first step of cutting a first portion 161 of the closed cutting line 16 and a second cutting step of a second portion 162 of In this case, the two cutting operations of the first and the second part 161, 162 of the cutting line 16 can be carried out by means of a first and a second knife respectively. cutting having respectively the shape of the first and second part of the cutting line. However, the cutting of the closed cutting line 16 can be performed in a single operation, for example by means of a punch whose cutting portion has the entire shape of the closed cutting line 16.

The cutout 16 thus delimits in the blank 12 a first portion 18 of the blank 12, for example located inside the cutout 16, and a second portion 20 of the blank 12, which is therefore in this example located outside the blank. In the example considered, the first portion 18 of the blank 12 is considered as a material drop, while the second portion 20 will be an integral part of the final package. However, one could quite consider that the part of interest would be the inner part and that the fall would be the part outside the cut.

In the example shown, the cutout 16 has a completely different geometry. It has been illustrated that the opening delimited by this cutout 16 has a transverse dimension D in the extension plane of the blank 12. For the entire cut, the transverse dimension changes according to the points considered, but it is still possible to define for the opening defined by the cutout 16, a minimum transverse dimension of the opening between two opposite points of the cut where two opposite edges of the opening have their greatest proximity.

Preferably, in a single operation or in several operations, the cutting of the closed cutting line 16 is performed using a cutting tool, with contact between the cutting tool and the blank. Preferably, the blade wire of the cutting tool is of small thickness to ensure a clean cut without trace. The disadvantage of these cutting tools, particularly those whose blade wire is thin, in that in the case of a cutting of a carton, the cutting chute, here the first part 18 of the blank 12, does not necessarily evacuate itself by simple gravity.

The closed cutting line 16 preferably forms a continuous and integral cut of the thickness of the blank 12 over the entire length of the cutting line 16. However, even in this case, it is known that it is common that after the cutting operation, the inner portion 18 of the blank defined by the blank 16 remains stuck by its edges at its location in the center of the opening, in the same plane as the outer portion 20 of the blank.

Also, in a step subsequent to the cutting step of the cutting line 16, the invention provides an ejection operation during which the first portion 18 and the second portion 20 of the blank 12 are separated one of the other. In the illustrated example, it will be sought more particularly to remove the first portion 18 by extracting it from the extension plane in which extends the second portion 20 of fian 12.

Of course, these operations are advantageously automated and implemented on a production line comprising for example a cutting station (not shown) and an ejection station 22 which is illustrated schematically in FIGS. 3A to 3D. It will be assumed here that the blank 12, in this case the cardboard sheet 10, is brought flat, in a direction of machine translation parallel to its extension plane, in this case the longitudinal direction X.

By way of example, to simplify the description, it will be considered that the extension plane defined by the X and Y directions is horizontal, without this having to be interpreted as a limitation of the invention insofar as other Blank orientations 12 may be provided for the ejection operation. In this way, the blank 12 has a first face 11, which can arbitrarily be described as an upper face with reference to the figures, and a second opposite face 13, which can therefore be arbitrarily described as a lower face.

The blank 12, in this case the cardboard sheet 10, can thus be transported along this extension plane X, Y, for example by means of gripping tongs gripping the longitudinal edges of the cardboard sheet 10.

In the example illustrated, the ejection is actually performed by means of a support tool 24 and an activation tool 26 which are, in this example, integrated into the ejection station 22. The tool 24 and the activation tool 26 are facing each other. Means are provided to ensure relative movement between the support tool 24 and the tool activation 26 according to a Z direction translation perpendicular to the extension plane X, Y of the blank 12.

In the illustrated example, the ejection station 22 comprises a lower plate 30 and an upper plate 32 which are both parallel to the extension plane of the blank 12, so here horizontal. An actuating mechanism, not shown, comprising for example an electric, pneumatic or hydraulic actuator, with a possible transmission mechanism, makes it possible to ensure a relative displacement of the two plates 30, 32 in a direction perpendicular to the extension plane X , Y of the blank 12, so in the direction Z, considered by convention to be in this vertical example. The bottom plate 30 has an upper face on which the support tool 24 can be fixed and the upper plate 32 has a lower face on which the activation tool 26, the two tools 24, 26 can be fixed. being arranged facing each other and being brought towards one another by the plates 30, 32 to, as will be seen later, operate a clamping operation of an ejection strip 34 against the blank 12.

Indeed, the cutting and ejection method according to the invention implements an ejection tape 34. This ejection tape is intended to be presented parallel to the blank 12, that is to say in a plane parallel to the extension plane X, Y of the blank 12. As illustrated in FIG. 4, the ejection tape 34 has an adhesive layer 38 which, in the exemplary embodiment, is supported by a support layer 36.

The adhesive layer 38 of the ejection tape 34 comprises, for example, a reactivatable adhesive, for example a heat-reactivatable adhesive. In known manner, such an adhesive requires, to adhere against a surface, to be brought to a temperature above an activation temperature. Below this activation temperature, its adhesion power when brought into contact with a surface is very limited, or zero. On the contrary, above the activation temperature, it adheres to the surface and this adhesion is then retained even when the temperature of the adhesive falls below the activation temperature. Such an adhesive heat-reactivatable may comprise a hot melt adhesive based on EVA copolymers. By way of example, the inventors have successfully implemented the invention by using an ejection tape comprising an adhesive layer formed by a layer of adhesive sold by Henkel Technologies France, 161 rue de Silly, France. -92100 Boulogne Billancourt, France, under the reference "Technomelt Q 3656 FR". Such glues generally have an activation temperature which is between 80 and 120 degrees. However, other adhesives may be used, including other reactivatable adhesives. Depending on the application, the adhesive may be selected to have a higher or lower activation temperature.

Alternatively, instead of a heat-reactive adhesive, a pressure-reactive adhesive may be used.

The ejection tape may comprise between 10 and 50 grams per square meter of adhesive, preferably between 15 and 35 grams per square meter, more preferably between 20 and 25 grams per square meter.

In the illustrated example, the ejection tape 34 has a support layer 36 which supports the adhesive layer 38 of the ejection tape. Such a support layer 36 facilitates the handling of the ejection tape and facilitates the implementation of the method. For example, the support layer 36 of the ejection tape 34 may comprise a paper layer. The inventors have successfully implemented the invention using, in particular, as a support layer 36, a layer of kraft paper, for example a natural kraft paper sold by the company Gascogne Papier, Bel Air District, 40200 Mimizan , France, under the reference "086 - ADOUR® 2000", in its version of weight 90 g per square meter. However, other types of paper could be used. Likewise, a backing layer 36 may be formed of, or comprise, other materials. For example, it is conceivable to use, for the production of a support layer 36 for the ejection tape 34, a polymeric material, for example a polyethylene terephthalate (PET). In the illustrated example, the ejection tape 34 has a thickness of between 0.05 and 0.3 millimeters, for example between 0.1 and 0.15 millimeters.

The ejection tape 34 is arranged to be with its adhesive layer 38 on the side of the first face 11 of the blank 12 and opposite the first portion 18 of the blank 12.

For the ejection operation, the ejection tape 34 is brought continuously over the cardboard sheet 10, hence the blank 12. This is therefore done after the cutting operation of the cutting line 16. The ejection tape 34 may be in the form of a roll that is unwound and guided to be brought into position in the ejection station 22, above the first portion 18 of the blank 12 that is desired eject.

Thus, the blank 12, provided with the cutting line 16, and the ejection strip 34, facing each other, are brought between the support tool 24 and the activation tool 26. which are themselves facing each other in the direction perpendicular to the extension plane X, Y of the blank 12.

As can be seen in Figs. 3A-3D, the activation tool 26 has an active face 40 in relief relative to a base 42. In the example shown, the base 42 is an integral part of the activation tool 26 and serves as interface with the upper plate 32. However, the base 42 could be a separate part, or be further formed by the upper plate 32. The active face 40 of the activation tool 26 is turned towards the ejection tape 34 and the blank 12. Its relief is delimited by a peripheral edge 44 whose projection perpendicular to a plane of extension of the blank is inscribed inside the closed cutting line 16 with a radial shift of activation "drl" towards the interior with respect to the cutting line 16 which defines the opening. The radial activation offset drl between the projection of the peripheral edge 44 of the relief of the active face 40 of the activation tool 26 and the closed cutting line 16 is preferably at least 0.1 mm. more preferably at least 0.2 mm over the extent of this peripheral edge. Inside the peripheral edge 44, the active face 40 has a hollow recess 46. This hollow recess forms a concavity with respect to the peripheral edge 44 in the active face 40. The depth of this recess 46 relative to the peripheral edge 44, in a direction perpendicular to the extension plane of the blank 12, is preferably between 0.1 mm and 0.5 mm. In an exemplary embodiment, for a blank of cardboard 12 having a thickness of between 0.2 and 0.4 mm, for example about 0.3 mm, the impression 46 may thus have a depth of between 0.1 and 0.3 mm, for example 0.2 mm with respect to the peripheral edge 44.

The active face 40 of the activation tool 26 is intended to press the ejection tape 34 against the first face 11 of the first portion 18 of the blank 12.

The active face 40, delimited by its peripheral edge 44, is therefore inscribed in perpendicular projection on the extension plane of the blank 12, inside the cutout 16. In FIG. 3A, it is illustrated that, in section by a plane perpendicular to the plane of extension, the dimension D1, which separates the two opposite points in this section, from the peripheral edge 44 of the active face 40, is smaller than the dimension D between the two opposite points, in this section, of the opening delimited by the closed cutting line 16. Preferably, the active face 40 is centered with respect to the opening and, as illustrated in FIG. 1, the radial activation offset dr1 is preferably constant over the entire contour of the opening 16 and the active face 40. In such a case, these dimensions are connected by the relation D = D1 + 2 x drl.

In embodiments in which an ejection tape having a heat-reactive adhesive is used, at least one of the activation tool 26 or the support tool is, at least in the case of clamping step, heated to a temperature above the activation temperature of the adhesive, for example at a temperature above 80 ° C, more preferably above 120 ° C. For example, the activation tool 26 comprises means for heating the active face 40, or at least a portion thereof, in particular its peripheral edge 44. The heating means may for example be made in the form of a resistor integrated or contiguous to the tool 26 or to the upper plate 32, while providing for Preferably, the platen and the tool are made of materials having a good conductivity of heat, for example of metal. The activation tool 26 is for example made of brass. The heating means could use induction heating. The heating means may comprise a circulation circuit of a hot fluid, integrated or attached to the activation tool 26 or to the upper plate 32. It may also provide indirect heating means, external, providing heating the active face 40 from the outside, for example an infrared heater or a hot air flow.

In the method according to the invention, the activation tool 26 cooperates with the support tool 24 to clamp the ejection tape 34 against the blank 12.

The support tool 24 has a projection 48 protruding towards the blank 12 relative to a peripheral surface 50 facing the blank. In the example shown, the peripheral surface 50 is that of a flat flange surrounding the boss, belonging to the support tool 24, and forming a fixing interface of the tool 24 on the bottom plate 30. However, the flat flange could be a separate part of the tool 24. According to yet another variant, the peripheral surface 50 could be a surface element of the bottom plate 30.

The boss 48 of the support tool 24 has a contour 52 with respect to the peripheral surface 50. A perpendicular projection of the contour 52 of the boss 48 on the extension plane of the blank 12 is inscribed inside the projection. perpendicular to the peripheral edge 44 of the activation tool 26 on this plane, with a radial offset support "dr2" inwardly. The radial support offset dr2 between perpendicular projections on the plane of extension on the one hand of the blank of the contour 52 of the boss 48 of the support tool 24 and secondly of the peripheral edge 44 of the relief of the active face 40 of the activation tool 26, is preferably at least 0.1 mm, more preferably at least 0.2 mm over the range of this peripheral edge 44. In the example shown, the contour 52 is a lower contour defined at the foot of the boss 48, at its junction with the peripheral surface 50. The relations below are in any case respected if one considers the upper contour of the boss which corresponds to the peripheral edge of the upper surface of the boss which actually comes into contact with the blank 12. In the example shown, this surface is flat.

In FIG. 3A, it is illustrated that, in section by a plane perpendicular to the plane of extension, the dimension D2 which separates, in a section, the two opposite points of the contour 52 of the boss 48 of the support tool is less than the dimension D1 which separates, in the same section, the two opposite points of the peripheral edge 44 of the active face 40 of the activation tool 26. Preferably, the boss 48 is centered with respect to the active face 40 and, as illustrated in FIG. 1, the radial shift activation "dr2" is preferably constant over the entire contour of the boss 48 and the active face 40. In such a case, these dimensions are connected by the relationship Dl = D2 + 2 x dr2.

In the example shown, the contour 52 is a lower contour defined at the foot of the boss 48, at its junction with the peripheral surface 50. The relations below are in any case respected if we consider the upper contour of the boss corresponding to the peripheral edge of the upper surface of the boss that actually comes into contact with the blank 12. In the example shown, this upper surface is flat, but it could be curved.

The maximum height of the boss 48 relative to the peripheral surface 50 of the support tool 24 is preferably greater than 0.5 mm. Indeed, below such a distance, it appeared that the ejection of the first portion 18 of the blank 12 may not be completely ensured, including a risk of delamination of the carton. In an exemplary embodiment in which the cardboard blank 12 has a thickness of between 0.2 and 0.4 mm, for example about 0.3 mm, the maximum height of the boss 48 with respect to the peripheral surface 50 of the support tool 24 is for example between 0.8 and 1.2 mm, in particular about 1 mm. In the process, the first part 18 of the blank 12 is clamped and the ejection strip 34 facing each other between the support tool 24 and the activation tool 26, which are also in position. facing each other, so as to stick the ejection tape 34 exclusively on the first portion 18 of the blank 12.

This is ensured in particular by the fact that the support and activation tools 24 are dimensioned so that their respective active surfaces, which come into contact respectively with the second face 13, here below, of the blank 12, and with the ejection tape 34, are both smaller than the opening defined the cutting line 16, so smaller than the first portion 18 of the blank 12. Thus, the activation of the collage, whether it is by pressure or heat or a combination of the two, is only within the contour of the active face 40 of the activation tool, therefore only in contact with the first portion 18 of the blank 12.

Preferably, it is ensured that, as illustrated in FIG. 3B, the support tool 24 comes into contact with the second face 13 of the blank 12 before the ejection tape 34 is pressed against the first face 11 of the blank by the activation tool 26. This is ensured by controlling the relative displacement of the support tool 24, the activation tool 26 and the blank 12. In the example illustrated, the relative movement is thus, in a first step of the clamping step, ensured by a relative displacement between the tool 24 and the blank 12. It can be seen here that this is done in the form of a displacement in translation of the lower plate 30, in the direction perpendicular to the extension plane of the blank 12, in direction of the blank 12, the blank 12 and the upper plate 32 remaining stationary. However, the same relative movement can be obtained differently, for example by moving the blank towards the support tool.

When the support tool 24 comes into contact with the second face 13 of the first portion 18 of the blank 12, it causes a lifting start of this first portion 18 relative to the second portion 20 of the blank 12.

Even more preferably, it will be provided that, as illustrated in FIG. 3B, this contact between the support tool 24 and the second face 13 of the blank 12 occurs before the active face 40 of the activation tool 26 does not come into contact with the ejector strip 34. In particular, it is possible to provide an elastic abutment 54, arranged, with respect to the support tool 24, on the opposite side of the assembly formed by the blank 12 and the ejector strip 34, therefore on the side of the activation tool 26. This resilient abutment 54 is preferably arranged to be located outside the perimeter the closed cutting line 16 which delimits the opening, thus radially outwardly around the active face 40 of the activation tool 26. This resilient counter-support 54 can be carried by the upper plate 32, or by another part of the ejection station 22 This elastic counter-support 54 is arranged to come into contact with the assembly formed by the blank 12 and the ejection tape 34 before this assembly is clamped between the activation tool and the support tool. 24. Thus, in a state of rest of the elastic abutment 54, the active face 40 of the activation tool 26 is is set back, further from the blank 12, with respect to a lower face of the elastic abutment 54.

With such an arrangement, it can be seen that, moreover, the elastic abutment 54 tends to press the ejection tape 34 against the first face 11 of the blank 12, still outside the perimeter of the opening defined by the closed cutting line 16.

The resilient abutment 54 may be arranged to extend all around the activation tool 26, continuously. On the contrary, it can be provided that the elastic abutment is arranged in the form of point elements distributed around the activation tool 26.

The elastic abutment 54 can be made for example in the form of a ring or pads of cellular material, for example foam, in particular a polymeric foam, or in the form of a ring or rigid studs mounted on a spring .

The elastic abutment 54 is preferably made, at least in part, of thermally insulating material, in particular a material having a thermal conductivity of less than 1 Wm K.

Fig. 3C illustrates the moment when the first part 18 of the blank 12 and the corresponding part of the ejection ribbon 34 are clamped between the support tool 24 and the activation tool 26. This makes it possible to ensure close contact between the ribbon 34 and the first portion 18 of the blank 12. In addition, the contact of the ribbon 34 with the activation tool 26 makes it possible, if necessary, to reactivate the adhesive of the ejection ribbon 34. sufficient adhesion between the ejection tape 34 and the first part of the blank 12. Conversely, any possible contact between the tape 34 and the second portion 20 of the blank 12, outside the closed cutting line 16, at a pressure and / or temperature insufficient to allow adhesion of the ejection tape 34 to the second portion 20.

Moreover, the concavity of the active face 40 of the activation tool 26, combined with the fact that, as explained above, the boss 48 of the support tool 24 is smaller than the active face 40, the projection of the contour 52 being inscribed within that of the peripheral edge 44 of the active face 40, tends to cause a deformation of the first portion 18 of the blank 12 which is clamped between the two tools 24, 26. This deformation , dome, tends to spread the edges of the first portion 18 of the blank 12 relative to the edges of the second portion 20 of the blank 12, which tends to release the two parts 18, 20 from one another.

It is illustrated in FIG. 3D that, after having tightened the first portion 18 of the blank 12 and the ejection tape 34 between the support tool 24 and the activation tool 26, the ejection tape 34 is separated from the second part 20 This separation is allowed in particular by the absence of adhesion between the ejection tape 34 and the second part 20 of the blank 12. On the other hand, by removing the ejection tape 34 from the blank 12, the first part 10 of the blank 12 is separated from the second portion 20 of the blank 12 while remaining stuck to the activation tape 34.

This separation is performed after separation of the support tool 24 relative to the activation tool 26. This separation can take place at the time of separation of the two tools or during or after moving the tape and the blank 12 with respect to the tools in the longitudinal direction X.

In the example, it has been shown the making of a cut and the ejection of the portion of the blank corresponding to this cut. In the case of making several cutouts of apertures offset from each other according to a direction perpendicular to the translation direction X of the machine, it can be provided to implement a plurality of separate ejection ribbons, offset from one another in the direction perpendicular to the machine translation direction, each ribbon being associated with a support tool 24 and an activation tool 26 arranged correspondingly.

The invention is not limited to the examples described and shown because various modifications can be made without departing from its scope.

Claims

1 - Process for cutting an opening in a flat cardboard blank (10, 12) intended for the manufacture of a package and comprising a first opposite face (11) and a second face (13), in which:

a cut line (16) closed on itself is formed in the cardboard blank (10, 12), the cutting line (16) delimiting a first portion (18) of the blank (10, 12) and a second part (20) of the blank (10, 12) outside the cutting line (16);

- facing the first face (11) of the blank (10, 12) is brought an ejection tape (34) having an adhesive layer (38), the ejection tape (34) being arranged with its layer adhesive (38) on the side of the first face (11) of the blank (10, 12) and facing the first portion (18) of the blank (10, 12);

the blank (10, 12) provided with the cutting line (16) is brought, and the ejection tape (34) faces one another between a support tool (24) and a activation tool (26) facing each other;

the activation tool (26) has an active face (40) in relief, turned towards the ejection tape (34) and the blank (10, 12), and whose relief is delimited by a peripheral edge (44). );

- a perpendicular projection of the peripheral edge (44) on an extension plane of the blank (10, 12) is inscribed inside the cutting line (16) with a radial activation offset (drl) towards the interior to the cutting line (16);

- Inside the peripheral edge (44), the active face (40) has a recess (46) recessed;

- the support tool (24) has a projection (48) protruding towards the blank (10, 12) with respect to a peripheral surface (50) facing the blank (10, 12), the boss (48) having an outline (52) with respect to the peripheral surface (50); - a perpendicular projection of the contour (52) of the boss (48) on the plane of extension of the blank (10, 12) is inscribed within the perpendicular projection of the peripheral edge (44) of the activation tool (26) in this plane with a radial radial support offset (dr2) inwards;

the first portion (18) of the blank (10, 12) and the ejection strip (34) are clamped against each other between the support tool (24) and the activation tool (26) which are facing each other so as to stick the ejection tape (34) exclusively on the first portion (18) of the blank (10, 12).

2 - Method according to claim 1, characterized in that the support tool (24) comes into contact with the second face (13) of the blank (10, 12) before the ejection tape (34) is tight against the first face (11) of the blank by the activation tool (26).

3 - Process according to any one of the preceding claims, characterized in that the radial activation offset (drl) between the projection of the peripheral edge (44) of the relief of the active face (40) of the activation tool (26) and the cutting line (16) is at least 0.1 mm, preferably at least 0.2 mm over the extent of this peripheral edge (44).

4 - Process according to any one of the preceding claims, characterized in that the radial support offset (dr2) between perpendicular projections on the plane of extension of the contour blank (52) of the boss (48) of the support tool (24) and the peripheral edge (44) of the relief of the active face (40) of the activation tool (24) is at least 0.1 mm, preferably at least 0.2 mm over the extent of this peripheral edge (44).

5 - Process according to any one of the preceding claims, characterized in that the maximum depth of the cavity (46) in the active face (40) of the activation tool (26) is between 0.1 and 0.5 mm.

6 - Process according to any one of the preceding claims, characterized in that the maximum height of the boss (48) relative to the peripheral surface (50) of the support tool (24) is greater than 0.5 mm . 7 - Process according to any one of the preceding claims, characterized in that the maximum height of the boss (48) relative to the peripheral surface (50) of the support tool (24) is between 0.8 and 1.2 mm.

8 - Process according to any one of the preceding claims, characterized in that a resilient abutment (54) is arranged, relative to the support tool (24), on the opposite side of the assembly formed by the blank (10, 12) and the ejection tape (34).

9 - Process according to claim 8, characterized in that the elastic abutment (54) is arranged outside the perimeter of the cutting line (16) which defines the opening.

10 - Process according to any one of the preceding claims, characterized in that at least one of the activation tool (26) or the support tool is, at least during the step of clamping, heated to a temperature above 80 ° C, more preferably above 120 ° C.

11 - Process according to any one of the preceding claims, characterized in that the cutting of the cutting line (16) is performed in two successive steps comprising a first step of cutting a first portion (161) of the line of cutting (16) and a second cutting step of a second portion (162) of the cutting line (16).

12 - Process according to claim 11, characterized in that the two cutting operations of the first and second part of the cutting line are performed by means respectively of a first and a second cutting knife respectively having the shape of the first (161) and the second portion (162) of the cutting line (16).

13 - Process according to any one of claims 1 to 10, characterized in that the cutting of the cutting line (16) is performed in a single operation.

14 - Process according to any one of the preceding claims, characterized in that the cutting line (16) forms a continuous and integral cut of the thickness of the blank (10, 12) over the entire length of the cutting line ( 16). 15 - Process according to any one of the preceding claims, characterized in that the first portion (18) of the blank (10, 12) is located inside the closed cutting line (16) and the second part (20) ) of the blank is located outside the cutting line (16).

16 - Process according to any one of the preceding claims, characterized in that the flat blank extends in an extension plane (X, Y), in that it is brought flat, in a direction of machine translation parallel to its extension plane, between the support tool (24) and the activation tool (26) facing each other, and in that the clamping is obtained by displacement relative between the support tool (24) and the activation tool (26) according to a translation of direction (Z) perpendicular to the extension plane.

17 - Process according to any one of the preceding claims, characterized in that the adhesive layer (38) of the ejection tape (34) comprises a heat-reactive adhesive.

18 - Process according to any one of the preceding claims, characterized in that the adhesive layer (38) of the ejection tape comprises a hot melt adhesive based on EVA copolymers.

19 - Method according to any one of the preceding claims, characterized in that the ejection tape (34) comprises a support layer (36) which supports the adhesive layer (38) of the ejection tape (34) .

20 - Process according to claim 19, characterized in that the support layer (36) of the ejection tape (34) comprises a layer of paper.

21 - Process according to any one of the preceding claims, characterized in that the ejection tape (34) has a thickness of between 0.05 and 0.3 millimeter, preferably between 0.1 and 0.15 millimeter.

22 - Method according to any one of the preceding claims, characterized in that, after having tightened the first portion (18) of the blank (10, 12) and the ejection tape (34) between the support tool ( 24) and the activation tool (26), the ejection tape (34) is separated from the second part (20) of the blank, the first part (18) of the blank being thus separated from the second part (20). ) of the blank being glued to the activation tape (34). 23 - Method according to any one of the preceding claims, characterized in that it comprises the production of several aperture cutouts offset from each other in a direction perpendicular to the direction of machine translation, and in that it comprises the implementation of several separate ejection ribbons offset from each other in the direction perpendicular to the direction of machine translation.

An ejection tape for a method of cutting and ejecting an opening in a cardboard blank, the ejection tape (34) having an adhesive layer (38) supported by a backing layer (36). ), characterized in that the adhesive layer (38) comprises a heat-reactive adhesive.

25 - ejection tape according to claim 24, characterized in that the adhesive comprises a hot melt adhesive based on EVA copolymers.

26 - ejection tape according to any one of claims 24 or 25, characterized in that the support layer (36) which supports the adhesive layer (38) of the ejection tape comprises a layer of paper, for example a layer of craft paper.

27 - ejection tape according to any one of claims 24 to 26, characterized in that the ejection tape (34) has a thickness of between 0.05 and 0.3 millimeters, preferably between 0.1 and 0.15 millimeter.