FIELD OF THE INVENTION

The present invention relates to the technical sector concerning realisation of a cardboard sheet for packaging, making folding lines in the cardboard sheet and the following folding of the cardboard sheet, for example for obtaining a cardboard box. In particular, the invention relates to a cutting apparatus of a cardboard sheet strip for packaging, to a method for cutting a cardboard sheet strip for packaging, to a cutting station of cardboard sheets for packaging, to a method for realising a folding line in a cardboard sheet for packaging, to a cardboard sheet for packaging with a folding line, and to a method for folding a cardboard sheet for packaging.

DESCRIPTION OF THE PRIOR ART

A cardboard sheet for packaging can be used for various ends, for example for forming a cardboard box or a cardboard folder. In this case folding lines must first be made, also known as score lines, about which portions of the cardboard sheet can easily be folded, preventing the formation of poorly aesthetic deformations and tearing of the cardboard sheet: at present these folding lines are made by exerting a predetermined pressure along a line, for example by means of a crushing roller. A folding line is therefore defined by a narrow and crushed strip of cardboard sheet, and identifies a joint axis of the cardboard sheet.

SUMMARY OF THE INVENTION

The aim of the present invention consists in identifying an alternative way of realising a folding line.

The above aim has been attained by means of a method for realising a folding line in a cardboard sheet for packaging according to claim 1 , and by means of a cardboard sheet for packaging with a folding line floor according to claim 6.

The first cut and second cut interrupt the continuity of the first external surface: if it is attempted to fold two portions of the cardboard sheet arranged on opposite sides with respect to the first cut and the second cut, the folding will take place with respect to a joint axis which is arranged in the region of space of the cardboard sheet which is comprised between the first cut and the second cut. A folding line is defined in this region of space. The folding is particularly easy and there are no more visible tears or deformations at the folding line than there are in a folding line obtained in a traditional way.

The first cut and second cut define a joint axis, comprised in the region of space of the cardboard sheet which is comprised between the first cut and the second cut: the folding of the cardboard with about this joint axis is particularly easy.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the accompanying tables of drawings, in which:

- figure 1 is a perspective view of the cutting apparatus of a cardboard sheet strip for packaging, object of the present invention;

- figure 2 is a perspective view of the cardboard sheet for packaging with a folding line, object of the present invention;

- figures 3 and 4 are perspective views respectively of detail K and detail J of figure 2;

- figure 5 is a perspective view of the cardboard sheet for packaging with a folding line, during an intermediate step of folding;

- figure 6 is a view of a transversal section of the cardboard sheet. DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the appended tables of drawings, reference numeral (1 ) denotes in its entirety a cardboard sheet for packaging having a folding line (2), that is the object of the present invention, comprising: a first external surface (3) and a second external surface (4) which are opposite one another, the distance between the first external surface (3) and the second external surface (4) identifying the thickness (5) of the cardboard sheet (1 ); a first cut (6) made on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than the thickness (5) of the cardboard sheet (1 ) (figures 3, 4); a second cut (7) made on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than the thickness (5) of the cardboard sheet (1 ) (figures 3, 4); the first cut (6) and the second cut (7) being parallel to one another and neared so as to define the edges of the folding line (2).

The first cut (6) and the second cut (7) are preferably mutually arranged at a distance that is equal to or greater than the thickness (5) of the cardboard sheet (1 ) (see figure 3).

The cardboard sheet (1 ) preferably comprises: a first external wall (8) which comprises in turn the first external surface (3); a second external wall (9) which comprises in turn the second external surface (4); an internal wall (10) which is interposed between the first external wall (8) and the second external wall (9) and which is corrugated, see for example figure 6; the first cut (6) and the second cut (7) are carried out at a depth that is equal to or greater than (see for example figures 3 and 4) the thickness (5) of the first external wall (8).

The fact that the first cut (6) and the second cut (7) extend over the whole thickness (5) of the first external wall (8) makes folding the first portion (14) of the cardboard sheet (1 ) and of the second portion (15) of the cardboard sheet (1 ) with respect to one another easier, in particular as illustrated in figure 5 (for reasons that will be explained in the following): in fact, an end (21 ) of the first external wall (8) of a third portion (22) of cardboard sheet (1 ), which third portion (22) of cardboard sheet (1 ) is defined between the first cut (6) and the second cut (7), can partially slide, during the folding step of the first portion (14) of cardboard sheet (1 ) and of the second portion (15) of cardboard sheet (1 ) with respect to one another, above or below the first external wall (8) of the first portion (14) of cardboard sheet (1 ) or above or below the first external wall (8) of the second portion (15) of cardboard sheet (1 ). This partial sliding reduces the degree of compression of the first external wall (8) of the third portion (22) of cardboard sheet (1 ) during the folding step with respect to the case in which the first cut (6) and the second cut (7) extend only for a part of the thickness (5) of the first external wall (8). As a consequence, the force necessary for carrying out the folding step is reduced.

The first cut (6) and the second cut (7) are preferably carried out by means of a laser. The laser determines a removal of material at the cutting zone (23) (see for example figure 3): so that there are defined: a first empty space (24) at the first cut (6), between the first portion (14) of cardboard sheet (1 ) and the third portion (22) of cardboard sheet (1 ), and a second empty space (25) at the second cut (7), between the third portion (22) of cardboard sheet (1 ) and the second portion (15) of cardboard sheet (1 ). The first empty space (24) and second empty space (25) are occupied by the third portion (22) of the cardboard sheet (1 ) during the step of folding, illustrated in figure 5: as a consequence, the degree of compression of the third portion (22) of cardboard sheet (1 ) (in particular the relative first external wall (8)) is reduced during the folding step with respect to a case in which the first cut (6) and the second cut (7) are carried out by cutting elements.

The cardboard sheet (1 ) is preferably folded with respect to a joint axis (Z1 or Z2 or Z3) which is arranged substantially in the region of space of the cardboard sheet (1 ) which is comprised between the first cut (6) and the second cut (7), in such a way that a first portion (14) of cardboard sheet (1 ) and a second portion (15) of cardboard sheet (1 ), which are separated from one another by the first cut (6) and by the second cut (7), are mutually arranged in such a way that the first external surface (3) of the first portion (14) of cardboard sheet (1 ) and the first external surface (3) of the second portion (15) of cardboard sheet (1 ) are reciprocally positioned at an angle of less than one hundred and eighty degrees. See for example figures 2 and 5. In general, the folding of a cardboard sheet (1 ) has the consequence that a first layer at one of the two external surfaces (in the case of the example, the first external surface (3)) compresses while a second layer at the remaining external surface (in the example the second external surface (4)) is placed in traction. The fact that the layer subjected to compression is the one in which the first cut (6) and the second cut (7) are made, i.e. the layer at the first external surface (3), facilitates the folding because it fills the empty spaces (24, 25) defined by the first cut (6) and the second cut (7), for the reasons set down in the foregoing.

Differently, a folding such that the first external surface (3) of the first portion (14) of cardboard sheet (1 ) and the first external surface (3) of the second portion (15) of cardboard sheet (1 ) are reciprocally positioned at an angle of less than one hundred and eighty degrees is to be avoided, as it might increase the depth of the first cut (6) and the second cut (7), up to determining the tearing of the cardboard sheet (1 ).

The present invention further relates to a method for realising a folding line (2) in a cardboard sheet (1 ) for packaging, comprising steps of: providing a cardboard sheet (1 ) comprising a first external surface (3) and a second external surface (4) which are opposite one another, the distance between the first external surface (3) and the second external surface (4) identifying the thickness (5) of the cardboard sheet (1 ); carrying out a first cut (6) on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than the thickness (5) of the cardboard sheet (1 ); carrying out a second cut (7) on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than the thickness (5) of the cardboard sheet (1 ); the first cut (6) and the second cut (7) being parallel to one another and neared so as to define the edges of the folding line (2) (see figures 2 and 5).

In a case in which the cardboard sheet (1 ) comprises the first external wall (8), the second external wall (9) and the internal wall (10), then the first cut (6) and the second cut (7) are preferably carried out at a depth that is equal to or greater than the thickness (5) of the first external wall (8).

The first cut (6) and the second cut (7) are preferably carried out by means of a laser.

A further object of the present invention relates to a method for cutting a cardboard sheet strip (1 1 ) for packaging, see figure 1 , comprising: the step of feeding a cardboard sheet strip (1 1 ) for packaging; one or more cutting steps of the cardboard sheet strip (1 1 ), for separating, from the cardboard sheet strip (1 1 ), at least a cardboard sheet (1 ), so as to maintain the continuity of the cardboard sheet strip (1 1 ); the above-described steps for realising at least a folding line (2); the step of winding the cardboard sheet strip (1 1 ), from which the at least a cardboard sheet (1 ) has been separated, on a reel (12) for storing the scrap (13).

The cut enables maintaining the continuity of the cardboard sheet strip (1 1 ), in the sense that the strip is not divided into two or more parts during the cut, which enables winding the cardboard sheet strip (1 1 ) on the reel (12). The remaining part of the cardboard sheet strip (1 1 ), following the cutting steps aimed at separating cardboard sheets, is the scrap (13); storing the scrap (13) on a reel (12) is advantageous as it reduces to a minimum the volumes and facilitates elimination.

The cardboard sheet (1 ) can be a portion of a cardboard sheet strip (1 1 ), already separated from the cardboard sheet strip (1 1 ) by cutting, or still to be separated. In other words, the steps required to obtain a folding line (2) can be carried out on the cardboard sheet strip (1 1 ) before or following the cut necessary for separating the cardboard sheet (1 ) from the cardboard sheet strip (1 1 ) itself.

The one or more cutting steps can be carried out by means of a laser.

A further object of the present invention relates to a method for folding a cardboard sheet (1 ) for packaging, comprising: the above-defined steps relating to the realising of at least a folding line (2) in the cardboard sheet (1 ); a step of folding the cardboard sheet (1 ) with respect to a joint axis (Z1 or Z2 or Z3) which is arranged substantially in the region of space of the cardboard sheet (1 ) which is comprised between the first cut (6) and the second cut (7), in such a way that a first portion (14) of cardboard sheet (1 ) and a second portion (15) of cardboard sheet (1 ), which are separated from one another by the first cut (6) and by the second cut (7), are mutually arranged in such a way that the first external surface (3) of the first portion (14) of cardboard sheet (1 ) and the first external surface (3) of the second portion (15) of cardboard sheet

(I ) are reciprocally positioned at an angle of less than one hundred and eighty degrees.

A further object of the present invention is a cutting station (16) of a cardboard sheet strip (11 ) for packaging, comprising: first cutting means (17) which separate, from the cardboard sheet strip (11 ), at least a cardboard sheet (1 ) having the first external surface (3) and the second external surface (4) which are opposite one another, the distance between the first external surface (3) and the second external surface (4) identifying the thickness (5) of the cardboard sheet (1 ), so as to maintain the continuity of the cardboard sheet strip (1 1 ); second cutting means (18) which carry out the first cut (6) on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than the thickness (5) of the cardboard sheet (1 ), and for carrying out a second cut (7) on the first external surface (3) of the cardboard sheet (1 ), having a depth that is smaller than a thickness (5) of the cardboard sheet (1 ); the first cut (6) and the second cut (7) being parallel to one another and neared so as to define the edges of the folding line (2).

The cutting station (16) preferably comprises a fumes aspirating system (26) for aspirating the fumes produced by the laser cutting.

The first cutting means (17) can act before the second cutting means (18), i.e. before the cardboard sheet (1 ) is separated from the cardboard sheet strip

(I I ).

The first cutting means (17) and/or the second cutting means (18) are preferably of a laser type. A further object of the present invention relates to a cutting apparatus (19) of a cardboard sheet strip (1 1 ) for packaging, comprising: a store (20) for storing a cardboard sheet strip (1 1 ) for packaging: the above-described cutting station (16), which is arranged downstream of the store (20); a reel (12) which is arranged downstream of the cutting station (16) for winding the cardboard sheet strip (1 1 ), from which at least a cardboard sheet (1 ) has been separated, on a reel (12) for storing the scrap (13).

The reel (12) can be activated in rotation by motor means, not illustrated.

Lastly, the invention also relates to a computer program comprising instructions for causing the above-described cutting station (16) to carry out the method steps described in the foregoing in order to cut the cardboard sheet strip (1 1 ).

It is understood that the above has been described by way of non-limiting example and that any technical-functional variants are considered to fall within the protective scope of the present technical solution, as claimed in the following.