ES2933607T3 - Capsule for the preparation of infusion drinks with improved extraction - Google Patents

Description

DESCRIPTION

Capsule for the preparation of infusion drinks with improved extraction

The content of the present invention is a single-dose capsule for the preparation of infused or soluble beverages in an extraction device, comprising in particular infusion holes for optimal infusion of water into the substance to be infused.

As is known in the art, a wide variety of automatic or semi-automatic machines equipped with a preparation and dispensing group that can produce an infusion by passing water through a capsule containing the food substance to be infused, arranged inside a suitable infusion chamber.

In particular, the known type of capsules comprises a receptacle, usually made of plastic material, equipped with a circular perimeter edge adapted to obtain a sealed engagement with a relevant stop edge of the brewing chamber to prevent the leakage of hot water outside. of the infusion chamber itself. Examples of known capsules are disclosed in WO2011/154672 A1, WO2011/154666 A1 and WO2012/079959 A1.

Water is injected into the internal cavity of the capsule through special injection nozzles on the machine that dispense an appropriate amount of water at a given pressure and temperature.

Obtaining an adequate perfusion of water throughout the food substance to be infused, contained in the internal cavity of the capsule, is one of the most significant problems in the specific sector.

Indeed, some of the parameters that particularly influence the aroma and the organoleptic properties of the infused drink reside precisely in the times and the way in which the water flows through the food substance from the moment it is dispensed by the nozzles of the extraction machine until the moment it exits through the exit opening of the capsule.

In particular, an excessively fast flow of water through the substance does not allow the water to optimally pick up the aroma of the substance, generating a drink with a less intense taste; conversely, an excessively slow flow of water into the substance can result in a drink flavor that is too strong or a failure to dispense the drink in the desired time.

In particular, in the field of coffee dispensing, the problems mentioned above are particularly significant, since in the case of extraction machines with predetermined dispensing parameters (times and temperatures) (and therefore not variable at will) , the need is felt to be able to obtain adequate times and modes of passage of water through the food product in order to obtain an extracted beverage with the optimum desired flavor.

In addition, it is extremely important to be able to create a capsule that allows to obtain an optimal extraction of the food substance while maintaining a simple geometry from the manufacturing point of view, especially for capsules in which the receptacle is made by means of a thermoforming process that, such as it is known, it does not allow complex geometries to be achieved and often requires additional processing steps after thermoforming.

The object of the present invention is to manufacture a capsule that overcomes the aforementioned drawbacks.

This object is obtained with a capsule and a manufacturing method according to the attached independent claims; the claims dependent thereon describe preferred variant embodiments.

The characteristics and advantages of the capsule and the method according to the present invention will become evident from the description provided below, given as a non-limiting example, according to the attached figures, in which:

figure 1 shows an axonometric perspective view of a capsule according to the present invention;

figure 2 shows an axonometric perspective view of the capsule according to the present invention, without a bottom cover;

figure 3 shows a plan view from above of the capsule of figure 2;

figure 3a shows a sectional view of the capsule in figure 3 along the sectional plane AA, including the bottom cover and the dispensing cover;

figure 3b shows a sectional view of the capsule in figure 3 along the sectional plane B-B, including the bottom cover and the dispensing cover;

figure 4 shows an enlarged detail of figure 3b, without the lower cover;

figure 5 shows a section of an enlarged detail of a variant embodiment of the capsule according to the present invention;

figure 6 shows a manufacturing step of the capsule according to a variant embodiment of the present invention, in which the capsule is inserted between a punch and a punching head of a lower wall of the receptacle for the creation of holes;

figure 7 shows an axonometric perspective view in partial section of a receptacle for a capsule according to a variant embodiment of the present invention;

figure 7a shows an enlargement of a detail of figure 7 close to the bottom wall;

- Figure 8 shows a capsule manufacturing step according to a variant embodiment of the present invention, in which the capsule is inserted between a punch and a head for cutting and folding a part of the bottom wall of the receptacle for the creation of holes and respective receptacle wings.

With reference to the attached figures, a single-dose capsule of the type for the preparation of a beverage, for example, coffee, infusion, decoction or the like, normally by extraction within an extraction device, is collectively indicated by the reference number 10.

The capsule 10 comprises a hollow body called receptacle 1, which contains an internal cavity 11 therein to contain at least one food substance to be infused or extracted by means of a pressurized liquid, such as coffee or tea, normally in the form granular or powder

The receptacle comprises a lower wall 4, intended to be traversed by a liquid injected by the extraction device, normally hot water or another liquid food (for example, milk), and a front end 6, opposite the lower wall 4, which defines a dispensing opening 5, intended to be traversed by the extracted drink.

The receptacle 1 comprises a side wall 2, which extends around a central axis X and in height along said central axis X between the lower wall 4 and the front end 6.

The front end 6 comprises a collar 7, protruding radially outwards from the side wall 2, normally arranged at the free end of the side wall 2, with a rear face 7a facing the bottom wall 4 and suitable for creating a seal when the capsule 10 is inserted into the extraction device.

The bottom wall 4 comprises a recessed region 41 towards the internal cavity 3. In particular, the recessed region is housed at least partially or totally in the internal cavity 3 of the capsule.

Capsule 10 further comprises a pierceable or yielding bottom cover 9 closing recessed region 41 and a pierceable or yielding dispensing cover 8 closing dispensing opening 5.

The central axis X is perpendicular to this bottom cover 9.

Preferably, the central axis X coincides with the axis of symmetry of the receptacle 1 and extends in the dispensing direction of the beverage. For example, when the receptacle is in the shape of a solid of rotation, the central axis X is the axis of rotation of the solid of rotation.

The recessed region 41 is defined by at least a first wall 420 and a second wall 430 facing towards each other and spaced apart along a radial direction Y perpendicular to the central axis X. This first wall 420 and this second wall 430 are joined by a connecting wall 410 that does not cross the central axis X. In addition, it defines an imaginary plane P1 tangent to at least part of the first wall 420 and a second imaginary plane P2 tangent to at least part of the second wall 430, this first imaginary plane P1 and this second imaginary plane P2 being inclined to intersect the central axis X.

In addition, first wall holes 421 and second wall holes 431 respectively are formed in said first wall 420 and second wall 430 for the passage of the liquid injected by the extraction device into the internal cavity 11 of the capsule 10.

It is clear that the term "holes" or "hole" means any type of opening, of any shape, for example, also a hole, a cut, a notch or, in any case, a perforation of any suitable type to allow the passage of the liquid injected into the interior of the internal cavity 11.

Preferably, the side wall 2 has a substantially frustoconical shape on the outside, formed for example by the succession of frustoconical surfaces having various angular openings.

According to a variant embodiment, the bottom cover 9 is a thin film, preferably a thin aluminum film or a plastic material, for example a multilayer plastic material. According to a further variant embodiment, the lower cover is a wall that yields under the action of the dispensing nozzles of the extraction device to create passages for the water towards the recessed region 41.

At the front end 6, the receptacle 1 comprises a collar 7, normally arranged at the free end of the side wall 2, which protrudes radially outwards.

The collar 7 has a front face 7b facing the opening 5 of the receptacle 1, opposite the rear face 7a.

The front face 7b of the collar 7 is intended to join with the annular peripheral region of the dispensing cover 8 that closes the receptacle 1 at the front end 6.

On the other hand, the rear face 7a of the collar 7 is intended to engage with a stop edge of the brewing chamber of the extraction device.

In this sense, for the extraction of the beverage, the capsule 10 is inserted in the extraction device in an infusion chamber adapted to accommodate at least part of the receptacle 1 of the capsule 10.

The brewing chamber is movable between an open position, which allows insertion and removal of the capsule 10, and a closed position. When the brewing chamber is in the closed position, it forms a closed chamber around capsule 10 when pressurized water is fed into capsule 10 (through bottom 4 and recessed region 41) to carry out carry out the stage of infusion and extraction of the drink.

The brewing chamber has at least one opening to allow the beverage to flow into the final container, eg a cup of coffee.

The watertight seal in the brewing chamber is obtained at the collar 7 of the capsule 10 by means of a compression edge of the extraction device which rests butt-sealed against the rear face 7a of the collar 7 of the capsule 10.

Due to the simultaneous presence of first wall holes 421 and second wall holes 431, a proper distribution of the infusion liquid (water) within the internal cavity 11 and thus through the contained food product is ensured.

A preferred variant embodiment of the receptacle 1 provides that, being defined as an imaginary horizontal plane P3 tangent to at least a part of the connecting wall 410, this imaginary horizontal plane is perpendicular to the central axis X; moreover, in this connecting wall 410 there are holes formed in the lower part 411 for the passage of the liquid injected by the extraction device into the internal cavity 11. The additional presence of the lower holes 411 further contributes to an improved diffusion of the extraction liquid. infusion into the internal cavity.

Preferably, the recessed region 41 is an annular groove, arranged annularly with respect to the central axis X, as shown, for example, in Figures 1 to 8.

In this variant, this annular groove is defined at least partially or totally by the first wall 420 and by the second wall 430.

In a variant embodiment, for example, shown in Figures 2-4 and 6-8, the first wall 420 is an annular inclined flat wall such that an imaginary extension of the same forms an acute intersection angle a with a parallel plane a y passing through the central axis X. The second wall 430 is an annular inclined plane wall such that the angle of intersection a', which forms an imaginary extension of it with the plane parallel to y passing through the central axis X, is an obtuse angle. The intersection angle a' is understood to be measured in the same measurement direction as the intersection angle a.

The first wall 420 and the second wall being 430 storey walls, it is clear that the first imaginary plane P1 and the second imaginary plane P2 are located respectively in the first wall 420 and in the second wall 430.

Preferably, "annular inclined flat wall" means not only flat walls, but also means that this inclined flat wall, in a sectional view thereof along a plane passing through the central axis X, is a straight segment . In other words, for example, in a preferred embodiment shown in figures 2 to 4 and 7, 7a, the first wall 420 has a frustoconical shape that develops around the central axis X and the second wall 430 has a frustoconical shape that it develops around the central axis X at a distance from the first wall 420 and preferably with an inverted tapering section.

In a variant embodiment, shown for example in Figure 5, the first wall 420 and the second wall 430, although they are not annular walls, are not flat walls, but are rather curved walls or are sometimes curved or sometimes flat walls. . In this case, therefore, as clarified in figure 5, there will be at least one point or region of the first wall 420 or of the second wall 430, in which the first imaginary plane P1 or the second imaginary plane P2 will be each tangent to such a point or region of the first wall 420 or the second wall 430. In this variant, therefore, the extension of the first imaginary plane P1 forms an acute angle of intersection a with a plane parallel to y passing through the axis central axis X, while the extension of the second imaginary plane P2 forms with the plane parallel to and passing through the central axis X an obtuse angle of intersection a'. As already mentioned, the intersection angle a' means measured in the same measurement direction as the intersection angle a.

In a preferred embodiment, the connecting wall 410 is a flat annular wall perpendicular to the central axis X and forming the lower part of the annular groove.

Preferably, each of the first wall holes 421 is arranged in front of a respective second wall hole 431, preferably in such a way that an imaginary plane P4 parallel to the central axis X and passing through the center of each first wall hole 421 and the center of a second wall hole 431 also passes through the central axis X, as shown, for example, in Figures 2 and 3.

Referring by way of example to figure 3, in an advantageous variant embodiment, the first wall holes 421 are arranged along a first imaginary circumference C3 around the central axis X and are circumferentially equidistant from each other, and the holes of second wall 431 are arranged along a second imaginary circumference C1 around the central axis X and are circumferentially equidistant from each other. In particular, preferably, the circumference C1 is spaced from and coaxial to the circumference C2 about the axis X.

Preferably, the lower holes 411 are arranged interleaved with respect to the first wall holes 421 and the second wall holes 431. In other words, by drawing an imaginary line I joining the center of a first wall hole 421 and the center of a second wall hole 431, this imaginary line I does not intersect the center of a lower hole 411 and preferably does not intersect the entire lower hole 411, and even more preferably does not intersect any lower hole 411.

In a variant embodiment, the lower holes 411 are arranged along a third imaginary circumference C2, which is concentric and is interposed between the first imaginary circumferences C3 and second C1, as shown, for example, in figure XX.

Preferably, the lower holes 411 are circumferentially equidistant from each other at an angle in the center p equal to the angle in the center y from which the first wall holes 421 and/or the second wall holes 431 are spaced circumferentially from one another.

In one embodiment, all of the first wall holes 421, second wall holes 431, and bottom holes 411 have a circular shape. This embodiment is preferred for receptacles 1 obtained by thermoforming.

In another variant embodiment, the holes in the first wall 421 and the holes in the second wall 431 have a square shape, while the holes in the bottom 411 have a circular shape. This embodiment is preferred for receptacles 1 obtained by injection molding.

A particularly advantageous variant embodiment provides that the receptacle 1 comprises at least six lower holes 411, at least six first wall holes 421 and at least six second wall holes 431.

A further variant embodiment of the capsule 10 comprises at least one flap 50, 51 close to at least one first wall hole 421 and/or at least one second wall hole 431.

In particular, from an edge 421', 431' of at least one first wall hole 421 and/or at least one second wall hole 431, a flap 50, 51 protrudes into the internal cavity 11.

This tab is obtained by folding along the edge 421', 431' of the hole in the first wall 421 and/or the hole in the second wall 431. In other words, the edge 421', 431' is the only anchoring region of the fin 50, 51 to the first wall 420 or to the second wall 430.

In particular, since the flap is obtained by partially cutting the first wall 420 or the second wall 430, this flap 50, 51 has a complementary shape to the shape of the first wall hole 421 or the second wall hole 431.

Preferably, the flap 50, 51 is inclined at an angle between 80 and 100° with respect to the first imaginary plane P1 if it projects from the first wall 420 or with respect to the second imaginary plane P2 if it projects from the second wall 430.

In one embodiment, the receptacle 1 is obtained by thermoforming starting from a multi-layer sheet comprising an internal barrier-like layer arranged between two external layers.

Preferably, the multilayer sheet is of the PP/EVOH/PP type, ie the barrier layer is composed of ethylene vinyl alcohol (EVOH) material sandwiched between two outer polypropylene (PP) layers.

Also, the content of the present invention is a manufacturing method of a receptacle 1 of a capsule 10 described herein, for example, as shown in Figures 6 and 8.

The method comprises the steps of:

- mold a receptacle 1 made of plastic material in one piece, preferably by thermoforming, as described in the previous paragraphs,

- inserting the receptacle 1 into a cutting or punching machine comprising a punch 100 resting on the lower wall 4 on the side of the internal cavity 11 of the receptacle 1;

- by means of cutting or punching head 101, cutting or punching, preferably simultaneously, the first wall 420 and the second wall 431 to create first wall holes 421 in said first wall 420 and second wall holes 431 in said second wall 430.

In a variant embodiment, in the step of cutting or punching the first wall 420 and the second wall 431, a part of said first wall 421 and/or of said second wall 431 is folded so that at least one flap 50, 51 protrudes of said first 420 and/or second 430 walls towards the internal cavity 11.

This is achieved by a cutting head comprising cutting or punching elements 101', 101'' suitable for cutting the first or second walls 420, 430 to create the first or second wall holes 421, 431 and, at the same time, folding a part of this first or second wall towards the inside of the receptacle 1 in the internal cavity 11 and obtain the flap 50, 51.

In particular, each cutting or punching element 101', 101", comprises an inclined wall 101b, located on an inclined plane that intersects the central axis X of the receptacle 1, so that this inclined wall 101b, in its approach movement and crossing the lower wall 4 of the receptacle 1, folds a part of the first 420 or second 430 walls of the receptacle to create the flap 50, 51 and guide it towards the final tilt position.

In addition, each cutting or punching element 101', 101", preferably also comprises at least one vertical wall, substantially parallel to the central axis X of the receptacle, attached to the inclined wall 101b, to form a point in the joining region suitable for cut the first wall 420 or second wall 430 to obtain the first wall hole 421 or the second wall hole 431.

Preferably, regardless of whether a first wall hole 421 or a second wall hole 431 provided with a fin 50, 51 or without a fin 50, 51, i.e. a simple through hole, is made in the cutting or punching step , the cutting elements 101', 101", in their movement through the lower wall 4 of the receptacle 1, are each housed at least partially in a punch seat 100a, 100b, 100c, obtained in the punch 100. From In this way, it is guaranteed that the punch performs its function of supporting the lower wall 4 of the receptacle during punching in an adequate manner, while at the same time ensuring a proper stroke of the cutting and punching elements inside the receptacle.

Preferably, the receptacle 1 of the capsule 10 is obtained by thermoforming. In particular, the receptacle is made of a multi-layered sheet comprising a barrier-type inner layer. Preferably, this barrier layer is completely wrapped within the adjacent layers of the multilayer sheet. In other words, the inner layer as a barrier never comes into contact with the outside.

Preferably, the inner layer is an oxygen barrier layer and is composed of ethylene vinyl alcohol (EVOH) material.

For example, the multilayer sheet is of the PP/EVOH/PP type in which polypropylene (PP) forms the outer layers of the sheet, ie, the layers that surround and contain the inner barrier layer.

In a further exemplary embodiment, at least one outer layer of the multilayer sheet is made of polyethylene (PE), and this layer forms the rear face 7a of the collar 7, which is intended to engage with a stop edge of the sheet. infusion chamber of the extraction device. Advantageously, this technical solution improves the seal of the collar 7.

For example, the multilayer sheet is of the PP/EVOH/PP/PE type.

In a variant embodiment, the receptacle is obtained by injection molding of a plastic material, for example, composed of PBT.

In an innovative way, the capsule according to the present invention overcomes the drawbacks mentioned with reference to the prior art, since it makes it possible to create a capsule that, due to the presence of holes arranged both on the first wall 420 and on the second wall 430, allows that the infused water is distributed in an optimal way in the food product to be infused and, therefore, allows a drink with an improved taste to be obtained with respect to the capsules of the prior art without this solution.

In particular, surprisingly, comparative taste tests carried out with respect to prior art capsules for making espresso coffee have shown that a capsule having holes arranged in both the first 420 and second 430 inclined walls, allows a quality to be obtained. and improved flavor persistence, especially for the variant embodiments that also comprise the lower holes 411.

Furthermore, in an innovative and advantageous way, the solution according to the present invention maintains a constructive geometry that is easy to obtain. Indeed, the plurality of holes obtained directly in the receptacle with the surprising effect of improving the quality of the extracted beverage, especially with regard to coffee, does not require additional components in the receptacle (such as filters or microperforated spray elements). and does not require special measures during the receptacle molding stage.

Advantageously, therefore, the capsule according to the present invention can be used in different types of extraction machines guaranteeing an improved quality of the extracted beverage, regardless of the type of extraction machine.

Advantageously, the capsule according to the present invention can be easily obtained through a thermoforming process.

Furthermore, advantageously, a variant embodiment provides for the presence of fins that can direct at will, depending on the inclination of the fin, the flow of liquid inside the interior cavity of the receptacle and further improve the diffusion of the liquid. This variant is also simple to implement and does not require additional components to the receptacle or additional material. Furthermore, advantageously, the fins are obtained at the same stage as the holes are obtained, thereby allowing for improved production efficiency of the individual capsule in terms of production time.

Claims (15)

Yo. Capsule (10) for preparing a drink in an extraction device, said capsule (10) comprising a receptacle (1) housing an internal cavity (11) to contain a food substance, said receptacle (1) comprising: - a lower wall (4) intended to be traversed by a liquid injected by the extraction device, - a front end (6), opposite the lower wall (4), which defines a dispensing opening (5) intended to be traversed by the extracted drink, - a side wall (2) extending around a central axis (X) and in height along said central axis (X) between the bottom wall (4) and the front end (6); said front end (6) comprising a collar (7) protruding radially outwardly from the side wall (2); said collar (7) being provided with a rear face (7a) facing the bottom wall and adapted to provide a seal when the capsule (10) is inserted into the extraction device; said lower wall (4) comprising a recessed region (41) towards the internal cavity (3); said capsule (10) comprising a lower cover (9) that closes the recessed region (41) and a dispensing cover (8) that closes the dispensing opening (5), said central axis (X) being perpendicular to the lower cover (9), said capsule (10) being characterized in that the recessed region (41) is defined by at least a first wall (420) and a second wall (430) oriented towards each other and separated along a radial direction (Y) perpendicular to the central axis (X), said first wall (420) and said second wall (430) being connected to each other by a connecting wall (410) that does not cross the central axis (X), in which a first imaginary plane (P1) tangent to at least a part of the first wall (420) and a second imaginary plane (P2) tangent to at least a part of the second wall (430), said first imaginary plane (P1) being inclined and said second imaginary plane (P2) to cut the central axis (X), and wherein first wall holes (421) and second wall holes (431) are formed in said first wall (420) and in said second wall (430), respectively, for the passage of liquid injected by the extraction device. in the internal cavity (11). Capsule (1) according to claim 1, in which an imaginary horizontal plane (P3) tangent to at least a part of the connecting wall (410) is defined, said imaginary horizontal plane being perpendicular to the central axis (X) , and in which lower holes (411) are formed in said connecting wall (410) for the passage of the liquid injected by the extraction device into the internal cavity (11). Cap (10) according to claim 1 or 2, in which the undercut region (41) is an annular groove, arranged annularly with respect to the central axis (X). The capsule (10) according to claim 3, wherein the annular groove is defined at least partially or totally by the first wall (420) and the second wall (430), wherein said first wall (420) is a flat annular inclined wall such that an imaginary extension of the same form an acute intersection angle (a) with a parallel plane passing through the central axis (X) and in which said second wall (430) is a flat wall annular inclined in such a way that the angle of intersection (a) that forms an imaginary extension of it with the plane parallel to and that passes through the central axis (X) is an obtuse angle. Capsule (10) according to claim 3, in which the first wall (420) has a frustoconical shape that develops around the central axis (X) and the second wall (430) has a frustoconical shape that develops around the central axis (X) at a distance from the first wall (420), preferably with an inverted tapering section. Cap (10) according to claim 4 or 5, in which the connecting wall (410) is an annular flat wall perpendicular to the central axis (X) and forming the lower part of the annular groove. Cap (10) according to any one of the preceding claims, in which each hole of the first wall holes (421) is arranged in front of a respective second wall hole (431), preferably in such a way that an imaginary plane (P4) parallel to the central axis (X) passes through the center of each first wall hole (421) and the center of a second wall hole (431) also passes through the central axis (X). Capsule (10) according to any one of the preceding claims, in which the first wall holes (421) are arranged along a first imaginary circumference (C3) around the central axis (X) and are spaced circumferentially from each other. yes and the second wall holes (431) are arranged along a second imaginary circumference (C1) around the central axis (X) and are circumferentially spaced from each other. Cap (10) according to any one of claims 2 to 8, in which the lower holes (411) are arranged interposed with respect to the first wall holes (421) and the second wall holes (431). . Capsule (10) according to claim 9, in which the lower holes (411) are arranged along a third imaginary circumference (C2), concentric and interposed between the first (C3) and second (C1) imaginary circumferences. . Cap (10) according to any one of claims 2 to 10, comprising at least six lower holes (411), at least six first wall holes (421) and at least six second wall holes (431). Cap (10) according to any one of the preceding claims, in which from one edge (421', 431') of at least one first wall hole (421) and/or at least one second wall hole (431) ) a fin (50, 51) protrudes into the interior of the internal cavity (11). Capsule (10) according to any one of the preceding claims, in which the receptacle (1) is obtained by thermoforming starting from a multilayer sheet comprising an internal barrier-like layer arranged between two external layers. 14. Method of manufacturing a receptacle (1) for a capsule (10) according to any one of the preceding claims, comprising the steps of: - molding a receptacle (1) composed of plastic material in one piece, said molded receptacle comprising a lower wall (4), a front end (6), opposite the lower wall (4), which defines a dispensing opening (5) intended to be traversed by the extracted beverage, a side wall (2) that extends around a central axis (X) and in height along said central axis (X) between the lower wall (4) and the front end (6); said front end (6) comprising a collar (7) protruding radially outwardly from the side wall (2); said collar (7) being provided with a rear face (7a) facing the bottom wall and adapted to provide a seal when the capsule (10) is inserted into the extraction device; said lower wall (4) comprising a recessed region (41) towards the internal cavity (11), wherein the recessed region (41) is defined by at least a first wall (420) and a second wall (430) facing toward each other and spaced apart along a radial direction (Y) perpendicular to the central axis ( X), said first wall (420) and said second wall (430) being joined together by a connecting wall (410) that does not cross the central axis (X), wherein an imaginary first plane (P1) tangent to at least a part of the first wall (420) and a second imaginary plane (P2) tangent to at least a part of the second wall (430) are defined, said being inclined first imaginary plane (P1) and said second imaginary plane (P2) to cut the central axis (X); - inserting the receptacle (1) into a cutting or punching machine comprising a punch (100) resting on the lower wall (4) on the side of the internal cavity (3); - by means of cutting or punching head (101), cutting or punching, preferably simultaneously, said first wall (420) and said second wall (431) to create first wall holes (421) in said first wall (420 ) and second wall holes (431) in said second wall (430). The method of claim 14, wherein in the step of cutting or punching said first wall (420) and said second wall (431), a portion of said first wall (421) and/or said second wall (431) ) is folded so that at least one flap (50, 51) protrudes from said first and/or second walls (420, 430) towards the internal cavity (11).