EP2227383A2

EP2227383A2 - Process and machine for forming boxes

Info

Publication number: EP2227383A2
Application number: EP08870817A
Authority: EP
Inventors: Gino Bassi; Gabriele Vassura
Original assignee: Emmeci SpA
Current assignee: Emmeci SpA
Priority date: 2007-12-21
Filing date: 2008-12-19
Publication date: 2010-09-15
Anticipated expiration: 2028-12-19
Also published as: WO2009090481A3; WO2009090481A4; WO2009090481A2; EP2227383B1

Abstract

A process for forming boxes starting with a flat paper or cardboard blank (1) having at least two free edges (2) comprises the steps of folding the blank until the free edges (2) are drawn near and adjacent to each other and forming a reciprocal gluing bead (3), distributing a quantity of hot-melt glue (4) in the bead (3) and cooling the hot-melt glue until the free edges are stably joined together.

Description

Process and machine for forming boxes

Technical Field

The present invention relates to a process and a machine for forming boxes starting with an open paper or cardboard blank.

More particularly, the present invention relates to a process and a machine for making boxes having any shape, polygonal or curved in which the open ends of a blank must be joined to each other to obtain a stable box shape.

Background Art

Prior art systems for making boxes usually consist of machines which fold a paper or cardboard blank, drawing near each other the free edges of the blank to obtain the desired box shape.

The adjacent free edges of the blank are joined by applying an additional adhesive paper or heat-sealing paper tape which stably holds together, the edges of the blank, thus forming the box. A disadvantage of these systems is the need to use an additional material

(the adhesive or heat-sealing paper) which increases the thickness of some zones of the box, and which remains visible even after the formed box has been covered.

A second disadvantage is the need to apply a relatively high level of pressure on the strips of sealing paper applied on the edges to be closed, involving a relatively heavy structure for the machine supporting such equipment and a significant mechanical action on the material of which the box is made.

In this context, the technical purpose of the present invention is to propose a process and a machine which are free of the above-mentioned disadvantages.

The technical purpose indicated and the aims specified are substantially achieved by a process and a machine for making boxes with the technical characteristics described in one or more of the claims herein.

Disclosure of the Invention

Further characteristics and advantages of the present invention are more apparent from the non-limiting description which follows of a preferred, non- limiting embodiment of a process and a machine for making boxes, illustrated in the accompanying drawings, in which:

Figure 1 shows the free edges of a blank joined with a process in accordance with the present invention, to form a corner of the box, wherein the gluing bead is positioned between end surfaces of the two edges;

Figure 2 shows the free edges of Figure 1, for forming a linear stretch of the box;

Figure 3 shows the free edges of Figure 1, for forming a curved stretch of the box; Figure 3a shows the free edges of Figure 1, for forming a corner of the box with a rounded gluing bead;

Figure 3b shows the free edges of Figure 1, for forming a corner of the box with gluing bead positioned between an end surface of one edge and a lateral " surface of the other; Figures 4 to 6 are respectively a perspective view, a detail of the closing area, and a lateral view of a box having a curved base formed using a process in accordance with the invention;

Figure 7 illustrates the successive steps a) to e) of the process in accordance with the invention carried out by a machine for forming polygonal boxes; Figure 8 is a schematic top view of the heads for closing the open corners of a polygonal box in a machine in accordance with the invention;

Figure 9 is a perspective view of the closing heads of Figure 8; Figures 10 to 12 illustrate the series of steps of applying the glue, finishing, and final shaping of an open corner of a polygonal box closed with a process in accordance with the invention; Figure 13 is a schematic view of the use of pressers in accordance with the invention for closing a box;

Figure 13a is a top view of a preferred embodiment of a presser of Figure 13; Figure 14 is a detail of a preferred embodiment of a presser;

Figures 15a and 15b are respectively a plan view and a side view of a blank in accordance with the invention;

Figures 16a, 16b, 16c are respectively a view of a box formed with a blank according to Figure 15a positioned over a covering sheet, a side view of the covered box, and a top section detail of one corner of the covered box;

Figure 17 shows a detail of a box formed according to a preferred embodiment of the process in accordance with the invention;

Figures 18 and 19 illustrate a preferred embodiment of the invention.

With reference to the accompanying drawings, a process is described for forming boxes starting with a flat paper or cardboard blank 1 having at least two free edges 2 to be joined to each other. According to the process, the blank is folded until the free edges 2 are drawn near and adjacent to each other to form an intermediate area between the edges 2 available for the creation of a reciprocal gluing bead 3 by distributing a quantity of hot-melt glue intended to stably join the end surfaces of the edges 2. In different embodiments, schematically illustrated in

Figures 1 to 3, the free edges can be drawn near each other to form a corner 6 in contact (Figure 1) with the two edges forming an angle of amplitude (alpha), for example equal to 90° in the case of boxes having a rectangular base. Figure 3 a shows the same corner configuration of the edges 2 with a rounded bead 3. Figure 3b shows the same corner configuration of the edges 2 with a bead 3 formed between the end surface 5 of one edge 2 and a lateral portion of the adjacent edge

2.

Alternatively, the free edges may have a straight geometry and may be drawn near each other at a predetermined distance (h) with the respective end surfaces 5 opposite each other (Figure 2). Also, the free edges may have a curved geometry and may be drawn near each other at a predetermined average distance (h) with the respective end surfaces 5 substantially opposite each other.

In all of the cases, the dimensions of the bead 3, and in particular the length h must be such that they allow sufficient flexibility in subsequent use of the box.

This feature is particularly significant in the case of round boxes (Figures 4 to 6) in which case the geometry of the box entails a state of tension in the bead 3 which, if too fragile, would result in breakage of the join line.

By way of example only, without limiting the scope of the invention, the dimension h of the bead 3 is between 2 and 5 mm.

Once the glue has been distributed, it is allowed to cool until the free edges are stably joined together, or it is subjected to forced cooling for example using air jets directed onto the beads 3.

With reference to the accompanying drawings, the process in accordance with the invention may involve feeding (a) blanks having a polygonal base 8 joined to a plurality of lateral faces 9.

In this case, there is a step of folding (b) the lateral faces to form a polygonal box with a plurality of open corners 10 at the free edges of the faces.

Preferably, the lateral faces can be folded by imparting to the box 15 a movement relative to the folders 18 so that the free edges of the faces 9 are brought into the configuration shown in Figure 1.

Once folding is complete, the distribution step (c) is preferably carried out by glue dispensing nozzles 11 positioned at the open corners of the box 15 and able to move relative to the box in the direction parallel with the corners 10. Once the glue has been distributed in the beads 3 formed by the corners 10 of the box, a step of finishing the shape of the beads may preferably be carried out, for example using scrapers 16 having the shape to be given to the beads, followed by cooling with jets of air or nitrogen 14.

Advantageously, this step guarantees the perfect regularity of the walls of the finished box and the absence of thickened zones and shape defects. It will then also be possible to carry out a step of moving away the finished box 15, for example using a conveyor belt 17.

The advantages obtained are basically the fact that the box obtained in this way has a high level of regularity, since it does not have raised, additional sealing paper elements.

This regularity allows an extremely good appearance to be achieved once the box has been covered, and it also allows the use of thinner, less opaque coverings. Further advantages consist of the strong mechanical seal and simultaneously the high level of flexibility of the hot-melt glue gluing beads. Therefore, with reference to the accompanying drawings, a process is described for forming boxes starting with a flat paper or cardboard blank 1 having at least two free edges 2 to be joined to each other.

According to the process, the blank is folded until the free edges 2 are drawn near and adjacent to each other to form a reciprocal gluing bead 3 with the distribution of a quantity of hot-melt glue intended to stably join the edges 2.

In different embodiments, schematically illustrated in Figures 1 to 3, the free edges can be drawn near each other to form a corner 6 in contact (Figure 1) with the two edges forming a predetermined angle of amplitude (alpha), for example equal to 90° in the case of boxes having a rectangular base. Alternatively, the free edges may have a straight geometry and may be drawn near each other at a predetermined distance (h) with the respective end surfaces 5 opposite each other (Figure 2).

Also, the free edges may have a curved geometry and may be drawn near each other at a predetermined average distance (h) with the respective end surfaces 5 substantially opposite each other.

In all of the cases, the dimensions of the bead 3, and in particular the length h must be such that they allow the necessary flexibility in subsequent use of the box.

This feature is particularly significant in the case of round boxes (Figure 4) in which case the geometry of the box entails a state of tension in the bead 3 which, if too fragile, would result in breakage of the join line.

Once the glue 4 has been distributed, it is allowed to cool until the free edges are stably joined together, or it is subjected to forced cooling for example using air jets directed onto the beads 3. With reference to Figures 5 to 12, the process in accordance with the invention may involve feeding (a) blanks having a polygonal base 8 joined to a plurality of lateral faces 9.

In this case, there is a step of folding (b) the lateral faces to form a polygonal box with a plurality of open corners 10 at the free edges of the faces. Preferably, the lateral faces can be folded by imparting to the box 15 a movement relative to the folders 18 so that the free edges of the faces 9 are brought into the configuration shown in Figure 1.

Once folding is complete, the distribution step (c) is preferably carried out by glue dispensing nozzles 11 positioned at the open corners of the box 15 and able to move relative to the box in the direction parallel with the corners 10.

Once the glue has been distributed in the beads 3 formed by the corners 10 of the box, a step of cooling with air jets 14 may preferably be carried out, then finishing the shape of the beads, for example using scrapers 16 having the shape to be given to the beads. Advantageously, this step guarantees the perfect regularity of the walls of the finished box and the absence of thickened zones and shape defects.

After the glue cooling, it will also be possible to carry out a step of moving away the finished box 15, for example using a conveyor belt 17.

With reference to Figures 13 and 14, pressers 20 are described which can be used instead of (or in addition to) the scrapers 16, which in a preferred embodiment of the invention consolidate box closing after glue application and contain the glue distributed.

The pressers 20 are shaped with a pressing surface 21 which forms an angle corresponding to the corner of the box to be closed, and they can move horizontally in alternate directions relative to the box. The number and distribution of the pressers 20 depends on the number of box corners to be closed, similarly to the use of pressers used in "quadrangular" machines for seaming boxes with heat-sealing strips of the type well-known in the sector. Advantageously, the pressers 20 in accordance with the invention can be used in the same machine in place of the pressers traditionally used to apply heat- sealing strips.

In this case, the pressers are not cooled but may be heated if necessary, and in place of one or more of the glue distribution nozzles a heat-sealing strip dispensing unit is removably applied.

The pressing surfaces 21 of the pressers 20 may advantageously have a predetermined shape, for example rounded, so as to give a desired shape to the glue bead. In light of this, it should be noticed that the shaped pressers 20 form means 16 for finishing the shape of the gluing bead 3. It was also found that a pressing surface 21 having an angle αl slightly less than the angle α of the box corner to be closed allows the achievement of an effect of spreading a film of glue 24 on the adjacent sides of the box. Advantageously, once cooled, the film 24 gives greater strength to box closing, and does not cause thickened areas which have a negative impact on the appearance of the box. Figure 17 illustrates a detail of a corner of a box closed by a film of glue 24 which partly covers the surfaces of the adjacent sides 25 and 26.

Advantageously, in this case the action to contain and compress the glue applied during the pressure applied by the pressers 20 on the box allows the glue to partly penetrate along the contact surface between the sides 25 and 26. Consequently, to form a sufficiently stable glue bead there is no need for an intermediate area to be left between the two sides 25, 26 in which to distribute the glue. Instead the sides can be directly in contact with each other, the edge 27 of one side being abutted directly against the inner surface 28 of the adjacent side.

Figure 13 schematically illustrates a system for cooling the pressers 20, comprising a cold generating unit 24 thermally connected to the pressers 20 by lines 25 and which allows elimination of the use of separate cooling devices such as the air jets described above.

When using cooled pressers 20, the step of distributing glue already described is followed by drawing the pressers near to the open corners of the box for a time long enough to cool the glue and consolidate box closing.

Figure 14 shows a preferred embodiment of a presser, having at the top an upper plate 22 fixed with removable means 23, and designed to contain at the top any glue which may leak out during the step of drawing near and pressing the pressers 20 on the box. The advantages achieved are basically the fact that the box obtained in this way has a high level of regularity, since it is without additional sealing paper elements, yet it guarantees a strong mechanical seal and at the same time a high level of flexibility of the hot-melt glue gluing beads.

This regularity in particular allows an extremely good appearance to be achieved once the box has been covered, and it also allows the use of thinner, less opaque coverings.

With regard to this, and with reference to Figures 15a and 15b, a cardboard blank 29 is illustrated for making packing boxes and which is designed to render the outside appearance of the covered box even more uniform. The blank 29 has a base section 33 having a polygonal shape, for example square, although it could be triangular, pentagonal, hexagonal, octagonal or another shape, and a plurality of lateral sections 30 (forming the lateral faces 9 of the box 15) which are joined to the base by fold lines 34 in such a way as to be able to form the lateral walls of the box. The process of folding the lateral sections 30 and forming the box S is not described in detail because it is not the subject matter of the invention.

According to the invention, at least one lateral section 30 has, on the outer surface at the lateral ends, lowered zones 31 obtained for example by compression of the cardboard of which the blank is made. Figures 16a, 16b, 16c show a box S obtained by folding the blank 29 and positioned over (Figure 16a) a glued covering sheet F whose shape matches that of the blank 29 and whose dimensions are slightly larger to allow the box to be completely covered and the sheet F to be tucked over the inner sides of the box.

In particular, prior art covering sheets F have on at least one side 32 excess end flaps L, over which once covering is complete (Figure 16b) the sides 32 for covering the adjacent lateral sections 30 of the box overlap (Figure 16c).

Advantageously, in the covered box configuration the lowered zones 31 correspond to the area of the lateral sections 30 on which the end flap L is applied and they therefore compensate for the increase in thickness caused by overlapping the covering sheet.

Advantageously, thanks to the blank 29 of the invention, particularly in combination with boxes formed using a process in accordance with the invention, it is therefore possible to obtain a covered box covering which is completely uniform and regular. With reference to Figures 18 and 19 a preferred embodiment of the invention is described, in which to close an open corner of the box a distribution of glue 330 (forming the bead 3) is applied, dispensed by means of an injection system 300 connected to the glue distribution area by a pipe 320 communicating with a hole 310 made through the presser 20. In this case, the glue is injected when the presser 20 is resting against the corner to be closed, and a forming profile 350 (positioned inside the box, according to a technique known in the box forming sector) closes the inside of the distribution area 330.

Again, the pressers 20 may advantageously be of the cooled type. Therefore, the present invention provides a machine for forming boxes starting with a flat paper or cardboard blank 1 with a polygonal base 8 joined to a plurality of lateral faces 9.

Said machine comprises, in combination:

- means 18 for folding the lateral faces relative to the base 8 to form a polygonal box 15 with a plurality of open corners 10 at the free edges of the faces; - means 11 for distributing a quantity of hot-melt glue 4 in a reciprocal gluing bead 3 at the open corners 10.

Said box can preferably move relative to the distribution means in a direction parallel with the corners 10. In particular, the distribution means can move relative to the box in a direction parallel with the corners 10.

Moreover, the present invention makes available a process for forming a box S starting with a flat paper or cardboard blank 1 having at least two free edges 2.

Said process comprises the following steps:

- folding the blank until the free edges 2 are drawn near and adjacent to each other, forming an intermediate area between the edges 2 available for the creation of a reciprocal gluing bead 3;

- distributing a quantity of hot-melt glue 4 to create said bead 3;

- cooling the hot-melt glue until said free edges are stably joined together. The process preferably also comprises the following steps: - preparation of the blank 29, before the folding step, in such a way that it comprises a base section 33 having a polygonal shape and a plurality of lateral sections 30 intended to constitute the lateral walls of the box, in which at least one lateral section 30 has, on the outer surface at its lateral ends, lowered zones 31 with reduced thickness; - a step of covering the box, after the cooling step, in which a covering sheet

F whose shape matches that of the blank 29 and whose dimensions are slightly larger to allow the box to be completely covered and the sheet F to be tucked over the inner sides of the box is positioned over the box, in such a way that the excess end flaps L of the sheet F overlap the sides 32 covering the adjacent lateral sections 30 of the box at the lowered zones 31, thus compensating for the increase in thickness caused by overlapping the covering sheet F.

The advantages obtained are basically the fact that the box obtained in this way has a high level of regularity, since it does not have raised, additional sealing paper elements. This regularity allows an extremely good appearance to be achieved once the box has been covered, and it also allows the use of thinner, less opaque coverings.

Further advantages consist of the strong mechanical seal and simultaneously the high level of flexibility of the hot-melt glue gluing beads.

The invention is described above with reference to a preferred embodiment, but it shall be understood that equivalent modifications may be made without thereby departing from the protective scope of this patent.

Claims

1. A process for forming boxes (S) starting with a flat paper or cardboard blank (1) having at least two free edges (2), characterised in that it comprises the following steps:

- folding the blank until the free edges (2) are drawn near and adjacent to each other and forming an intermediate area between the edges (2) available for the creation of a reciprocal gluing bead (3);

- distributing a quantity of hot-melt glue (4) to create said bead (3);

- cooling the hot-melt glue until said free edges are stably joined together.

2. The process according to claim 1, wherein the free edges are drawn near each other with a corner (6) in contact, the two edges forming a predetermined angle of amplitude (alpha).

3. The process according to claim 2, wherein the blank has a polygonal base (8) joined to a plurality lateral faces (9) and the folding step comprises a step (b) of folding the lateral faces to form a polygonal box with one or more open corners (10) at the free edges of said faces, the distributing step comprising a distribution (c) of hot-melt glue by glue dispensing nozzles (11) positioned at the open corners and able to move relative to the box in a direction parallel with the corners (10).

4. The process according to claim 2 or 3, comprising a step (d) of finishing the gluing bead (3).

5. The process according to any of the foregoing claims, wherein the cooling step is a forced cooling step (e).

6. The process according to any of the foregoing claims, wherein the cooling step comprises a step of applying cooled pressers.

7. The process according to any of the foregoing claims, wherein the free edges have a straight geometry and are drawn near each other at a predetermined distance (h) with corresponding end surfaces (5) opposite each other.

8. The process according to any of the claims from 1 to 6, wherein the free edges have a curved geometry and are drawn near each other at a predetermined average distance (h) with the respective end surfaces (5) substantially opposite each other.

9. The process according to claim 8, wherein the free edges are the two end edges of a rectangular blank (12) folded to form a box with a curved geometry (13).

10. The process according to any of the foregoing claims, wherein the bead (3) is formed between the end surface (5) of one edge (2) and a lateral portion of the adjacent edge (2).

11. The process according to any of the foregoing claims, wherein the free edges are sides (25, 26) drawn near and in contact with each other, the edge (27) of one side being abutted directly against the inner surface (28) of the adjacent side.

12. The process according to any of the foregoing claims, wherein the glue is distributed by injection.

13. The process according to any of the foregoing claims, also comprising:

- a step of preparing the blank (29), before the folding step, in such a way that it comprises a base section (33) having a polygonal shape and a plurality of lateral sections (30) intended to constitute the lateral walls of the box, wherein at least one lateral section (30) has, on the outer surface at its lateral ends, lowered zones (31) with reduced thickness;

- a step of covering the box, after the cooling step, wherein a covering sheet (F) whose shape matches that of the blank (29) and whose dimensions are slightly larger to allow the box to be completely covered and the sheet (F) to be tucked over the inner sides of the box is positioned over the box, in such a way that the excess end flaps (L) of the sheet (F) overlap the sides (32) covering the adjacent lateral sections (30) of the box at the lowered zones (31), thus compensating for the increase in thickness caused by overlapping the covering sheet (F).

14. A machine for forming boxes starting with a flat paper or cardboard blank (1) with a polygonal base (8) joined to a plurality of lateral faces (9), characterised in that it comprises, in combination: - means (18) for folding the lateral faces relative to the base (8) to form a polygonal box (15) with a plurality of open corners (10) at the free edges of the faces;

- means (11) for distributing a quantity of hot-melt glue (4) in a reciprocal gluing bead (3) at the open corners (10), said box being able to move relative to the distribution means in a direction parallel with the corners (10).

15. The machine according to claim 14, comprising means (14) for cooling the hot-melt glue until the free edges are stably joined together.

16. The machine according to claim 14 or 15, comprising means (16) for finishing the shape of the gluing bead (3).

17. The machine according to any of the claims from 14 to 16, comprising at least one presser (20) having a pressing surface (21) shaped for finishing the shape of the gluing bead (3).

18. The machine according to any of the claims from 14 to 16, comprising means (17) for removing the finished box (15).

19. The machine according to any of the claims from 14 to 18, comprising at least one cooled presser (20) which can be drawn near and in contact with a corresponding open corner (10) to cool the hot-melt glue until the free edges are stably joined together.

20. The machine according to any of the claims from 14 to 19, wherein the distribution means can move relative to the box in a direction parallel with the corners (10).

21. The machine according to any of the claims from 14 to 20, wherein the distribution means comprise an injection system (300) connected to the glue distribution area (330).

22. The machine according to any of the claims from 14 to 21, comprising at least one presser (20) for closing a corner (10) having an angle (α), wherein the surface (21) of the presser has a flare angle (αl) which is slightly less than the angle (α) of the corresponding corner (10).

23. The machine according to any of the claims from 14 to 22, comprising at least one presser (20) equipped with an upper plate (22) for glue containment.

24. A packing box comprising a polygonal base and corresponding lateral walls forming open corners (10) joined by a hot-melt glue bead (3).

25. The box according to claim 24, wherein the bead (3) comprises a film of glue (24) distributed on both of the adjacent sides (25, 26) forming the open corner (10).

26. A cardboard blank for forming packing boxes covered with a covering sheet (F), comprising a base section (33) having a polygonal shape and a plurality of lateral sections (30) intended to constitute the lateral walls of the box, wherein at least one lateral section (30) has, on the outer surface at its lateral ends, lowered zones (31) with reduced thickness.