ES2986607T3 - Cardboard box template and gable top cardboard box produced from the same - Google Patents

Abstract

The present invention relates to a carton comprising a plurality of panels configured to form a gable-top carton by folding, each of the plurality of panels comprising a wall section subpanel and a top closure subpanel. The carton comprises a longitudinal fold line section defining an edge between two neighboring top closure subpanels, in which longitudinal fold line section there is an upper corner position configured to form an upper corner of the carton when the carton is folded. The carton also comprises a transverse fold line forming an edge between one of said neighboring top closure subpanels and a neighboring wall section subpanel of the carton, wherein said edge ends at the upper corner position. The carton further comprises a diagonal fold line disposed in said one of said neighboring top closure subpanels, which diagonal fold line defines a fold line ending at the upper corner position. When finished at the top corner position, the folding line forms an angle of at least 70° with the longitudinal folding line section. (Automatic translation with Google Translate, not legally binding)

Description

DESCRIPTION

Cardboard box template and gable top cardboard box produced from the same

The present invention relates to a cardboard box template for producing a paper or cardboard-based packaging of a type commonly referred to as gable top cardboard. The present invention also relates to a gable top cardboard box produced from such a template.

Gable top cartons are commonly used to distribute pourable products, such as bulk pourable products and liquid consumable products, for example dairy products, such as milk or fruit juices, see for example EP1584563A1. Gable top cartons are produced from a laminated packaging material, typically comprising a multi-layered sheet of paper or paperboard onto which one or a plurality of barrier layers are laminated to contain liquid and/or prevent migration of air and flavour-degrading substances through the carton. A barrier layer may typically comprise a polyethylene or aluminium layer.

In the production of the cardboard box, the laminated packaging material is cut to form a substantially rectangular template, which is folded, filled and sealed to form the cardboard box.

To facilitate folding of the cardboard box template, the template comprises fold lines. As is known in the art, a fold line is a stamped or embossed depression on one side of the cardboard with a corresponding raised ridge or ridge on the other side that forms a line along which the cardboard is structurally weakened and along which the cardboard will bend or fold in a controlled manner when pressure is applied.

When drawing the fold lines on the cardboard, attention must be paid to the corner positions, i.e. the positions on the template that form the corners of the cardboard box when the template is folded. In particular, to obtain well-defined corners, special attention must be paid to how the fold lines approach and connect with the corner positions. This is especially the case for cardboard boxes that have a geometry that is more complex than the strict rectangular block-shaped geometry.

The present invention addresses this problem and provides a carton template having fold lines which have been found to provide well-defined top corners, especially the top corners of the front side of the carton.

In the following description, “longitudinal” will be used to designate a direction that is substantially parallel to the side edges of the carton template, and “transverse” will be used to designate a direction that is substantially parallel to the top and bottom edges of the carton template. “Diagonal” will be used to designate a direction that forms an angle of substantially 45° with respect to the bottom, side and top edges.

The present disclosure relates to a carton template comprising a plurality of panels configured to form a gable-top carton by folding, wherein each of the plurality of panels comprises a wall section subpanel and a lid closure subpanel, wherein the carton template comprises a longitudinal fold line section defining an edge between two neighboring lid closure subpanels, in which longitudinal fold line section a lid corner position configured to form a lid corner of the carton is located when the carton template is folded, wherein the carton template also comprises a transverse fold line forming an edge between one of said neighboring lid closure subpanels and a neighboring wall section subpanel of the carton template, wherein said edge terminates at the lid corner position, and wherein the carton template further comprises a diagonal fold line disposed on said one of said lid closure subpanels. neighboring cover, whose diagonal fold line defines a fold line ending at the cover corner position.

In such carton templates, it may be difficult to convert the lid corner position into a well-defined lid corner on the folded carton. This may especially be the case when the edge defined by the transverse fold line, when terminated at the lid corner position, forms an obtuse angle with the section of the longitudinal fold line.

However, it has been found that a well-defined lid corner position can be obtained by arranging the fold line defined by the diagonal fold line so that the fold line, when terminated at the lid corner position, forms an angle of 70°, more preferably at least 80°, and even more preferably at least 90°, for example 90°, with the longitudinal fold line section.

Thus, according to a first exemplary aspect, the present invention provides a carton template comprising a plurality of panels configured to form a gable-top carton by folding, each of the plurality of panels comprising a wall section subpanel and a lid closure subpanel.

The carton template comprises a longitudinal fold line section defining an edge between two neighboring lid closure subpanels, in which longitudinal fold line section there is located a lid corner position configured to form a lid corner of the carton when the carton template is folded.

The carton template also comprises a transverse fold line forming an edge between one of said neighboring lid closure subpanels and a neighboring wall section subpanel of the carton template, wherein said edge ends at the lid corner position.

The carton template further comprises a diagonal fold line disposed on said one of said neighboring lid closure subpanels, which diagonal fold line defines a fold line terminating at the position of the lid corner.

When finished at the lid corner position, the fold line forms an angle of at least 70° with the longitudinal fold line section.

In alternative embodiments, the angle formed between the longitudinal fold line section and the fold line defined by the diagonal fold line at the lid corner position may be any one of: at least 80°, at least 90°, for example, 90°.

According to a first aspect, the present invention provides a carton template configured to form a gable-top carton by folding, the carton template comprising a first, a second, a third, a fourth and a fifth panel, each of which comprises:

- a first subpanel configured to form part of a lower closure of the cardboard box;

- a second subpanel adjacent to the first subpanel and configured to form a wall section of the cardboard box; and

- a third subpanel adjacent to the second subpanel and configured to form part of a lid closure of the cardboard box,

wherein the cardboard box template comprises:

- a first longitudinal fold line section defining an edge between the third subpanel of the first panel and the third subpanel of the second panel;

- a second longitudinal fold line section defining an edge between the third subpanel of the second panel and the third subpanel of the third panel;

- a third longitudinal fold line section defining an edge between the third subpanel of the third panel and the third subpanel of the fourth panel; and

- a fourth longitudinal fold line section defining an edge between the third subpanel of the fourth panel and the third subpanel of the fifth panel,

in which the second panel comprises:

- a transverse fold line defining an edge between the second subpanel and the third subpanel of the second panel, the edge extending across the second panel between a first lid corner position located at the first longitudinal fold line section and a second lid corner position located at the second longitudinal fold line section, which first lid corner position is configured to form a first lid corner of the carton, and which second lid corner position is configured to form a second lid corner of the carton; and

- a first diagonal fold line of the second panel defining a fold line in the third subpanel of the second panel ending at the second fold corner position;

and in which the fourth panel comprises:

- a transverse fold line defining an edge between the second subpanel and the third subpanel of the fourth panel, the edge extending across the fourth panel between a third lid corner position located at the third longitudinal fold line section and a fourth lid corner position located at the fourth longitudinal fold line section, which third lid corner position is configured to form a third lid corner of the carton, and which fourth lid corner position is configured to form a fourth lid corner of the carton; and

- a first diagonal fold line of the fourth panel defining a fold line in the third subpanel of the fourth panel ending at the third fold corner position;

wherein the fold line defined by the first diagonal fold line of the second panel, when terminated at the second lid corner position, forms an angle of at least 70° with the second longitudinal fold line section, and wherein the fold line defined by the first diagonal fold line of the fourth panel, when terminated at the third lid corner position, forms an angle of at least 70° with the third longitudinal fold line section.

Each of the angles formed between the first diagonal fold line of the second panel and the second longitudinal fold line section and the angle formed between the first diagonal fold line of the fourth panel and the third longitudinal fold line section, may be any one of: at least 80°, at least 90° and 90°.

The angle formed between the first diagonal fold line of the second panel and the second longitudinal fold line section may be equal to the angle formed between the first diagonal fold line of the fourth panel and the third longitudinal fold line section.

The first diagonal fold line of the second panel may comprise a diagonal fold line section having a convex side facing the transverse fold line of the second panel, and the first diagonal fold line of the fourth panel may comprise a diagonal fold line section having a convex side facing the transverse fold line of the fourth panel.

The second panel may comprise a gable transverse fold line defining an edge between a lid gusset sub-subpanel and a gable seal sub-subpanel of the third sub-panel of the second panel, and the fold line defined by the first diagonal fold line of the second panel may extend between the gable transverse fold line of the second panel and the second lid corner position. Furthermore, the fourth panel may comprise a gable transverse fold line defining an edge between a lid gusset sub-subpanel and a gable seal sub-subpanel of the third sub-panel of the fourth panel, and the fold line defined by the first diagonal fold line of the fourth panel may extend between the gable transverse fold line of the fourth panel and the third lid corner position.

The edge defined by the transverse fold line of the second panel, when terminated at the second lid corner position, may form an obtuse angle with the second longitudinal fold line section, and the edge defined by the transverse fold line of the fourth panel, when terminated at the third lid corner position, may form an obtuse angle with the third longitudinal fold line section.

The transverse fold line of the second panel may terminate at the second lid corner position in an arc having a first radius of curvature, the transverse fold line of the fourth panel may terminate at the third lid corner position in an arc having said first radius of curvature, the first diagonal fold line of the second panel may terminate at the second lid corner position in an arc having a second radius of curvature, the first diagonal fold line of the fourth panel may terminate at the third lid corner position in an arc having said second radius of curvature, and said second radius of curvature may be less than said first radius of curvature.

The second radius of curvature can be any one of: 20%-80% of the first radius of curvature; 40%-60% of the first radius of curvature; and 45%-55% of the first radius of curvature.

Said arc of the first diagonal fold line of the second panel may have a center of curvature located at said second longitudinal fold line section, and said arc of the first diagonal fold line of the fourth panel may have a center of curvature located at said third longitudinal fold line section.

Said arc of the transverse fold line of the second panel may have a center of curvature located in the second panel at a lateral distance from said second longitudinal fold line section, and said arc of the transverse fold line of the fourth panel may have a center of curvature located in the fourth panel at a lateral distance from said third longitudinal fold line section, wherein said lateral distance may be within the range of 40% to 90% of the first radius of curvature.

The second panel may comprise a second diagonal fold line defining a fold line in the third subpanel that ends at the first lid corner position and forms an angle of at least 70° with the first longitudinal fold line section, and the fourth panel may comprise a second diagonal fold line defining a fold line in the third subpanel that ends at the fourth lid corner position and forms an angle of at least 70° with the fourth longitudinal fold line section.

The second diagonal fold line of the second panel may comprise a diagonal fold line section having a convex side facing the transverse fold line of the second panel, and the second diagonal fold line of the fourth panel may comprise a diagonal fold line section having a convex side facing the transverse fold line of the fourth panel.

The angle formed between the second diagonal fold line of the second panel and the first longitudinal fold line section may be equal to the angle formed between the second diagonal fold line of the fourth panel and the fourth longitudinal fold line section.

According to a second aspect, the present invention provides a gable top carton produced from a carton template as disclosed above.

The preferred and/or optional features discussed above of each aspect may be used, alone or in appropriate combination, in the other aspects of the invention.

The following drawings are attached to facilitate understanding of the invention:

Fig. 1 is a plan view of an embodiment of a carton template according to the first aspect of the invention.

Figs. 2a, 2b, 3a and 3b are detailed views of the cardboard box template according to Fig. 1.

Figs. 4 and 5 are detailed views of a carton template according to an embodiment of the invention.

Fig. 6 is a perspective view of a carton according to a first embodiment of the present invention.

Figs. 7 and 8 are side views of the cardboard box according to Fig. 6.

Figs. 9-11 are plan views of other embodiments of carton preforms according to the invention.

Figs. 12a and 12b are detailed plan views of another embodiment of a carton template according to the invention.

Figs. 13a and 13b are detailed plan views of yet another embodiment of a carton template according to the invention.

Embodiments of the invention will now be described in more detail with reference to the drawings. However, it is specifically intended that the invention not be limited to the embodiments and illustrations contained herein, but to include modified forms of the embodiments including portions of the embodiments and combinations of elements of different embodiments which fall within the scope of the following claims.

In the drawings, similar reference numerals have been used to indicate common parts, elements or features unless otherwise explicitly indicated or implied by the context.

An embodiment of a carton template 10 according to the invention is shown in Fig. 1. The template 10 is shown with the surface configured to form the outer surface of the carton facing the viewer.

The template 10 is made of a suitable packaging material, such as a multi-layered sheet of paper or cardboard onto which one or a plurality of barrier layers are laminated to contain the contents, for example a liquid, and/or prevent migration of air and flavour-degrading substances through the sheet. At least parts of the template may be coated with a layer of thermoplastic material which enables a cardboard box formed from the template to be sealed by plastic welding.

The template 10 is substantially rectangular and comprises a first bottom edge 11, a second top edge 12 and third and fourth parallel side edges 13, 14. The side edges 13 and 14 are rectilinear, while the top and bottom edges 11 and 12 have an irregular shape. The template 10 also comprises a plurality of fold lines defining fold lines along which the template 10 is configured to be folded when the carton is formed.

In this description, “longitudinal” will be used to designate a direction that is substantially parallel to the side edges 13 and 14, i.e., substantially vertical in Fig. 1, and “transverse” will be used to designate a direction that is substantially parallel to the top and bottom edges 11 and 12, i.e., substantially horizontal in Fig. 1. “Diagonal” will be used to designate a direction that is at an angle of substantially 45° to the top, side and bottom edges 11-14.

The template 10 comprises five panels, P1-P5, separated by longitudinal fold lines 20, 21, 22 and 23 defining fold lines extending across the panel 10 from the bottom edge 11 to the top edge 12. Accordingly, the longitudinal fold lines 20, 21, 22 and 23 divide the bottom and top edges 11, 12 into subsections 11a, 11b, 11c, 11d, 11e and 12a, 12b, 12c, 12d, 12e, respectively.

Each panel P1-P5 comprises a first subpanel 110, 210, 310, 410, 510 forming a bottom closure subpanel, a second subpanel 120, 220, 320, 420, 520 forming a wall section subpanel, and a third subpanel 130, 230, 330, 430, 530 forming a lid closure subpanel. The bottom closure subpanels 110, 210, 310, 410, and 510 are configured to form a bottom closure of the carton and the lid closure subpanels 130, 230, 330, 430, 530 a lid closure of the carton. The wall section subpanel 120 of the first panel P1 is configured to form a rear wall of the carton and the wall section subpanel 320 of the third panel P3 a front wall. The wall section subpanels 220 and 420 of the second and fourth panels P2, P4 are configured to form side walls of the carton. The fifth panel P5 is configured to be attached to an interior surface of the first panel P1 adjacent the side edge 13 when the carton is formed.

Template 10 shows positions TC1, TC2, TC3, TC4, BC1, BC2, BC3 and BC4 that define the top and bottom corners of the carton when formed (see Figs. 6-8).

Each longitudinal fold line 20, 21, 22 and 23 comprises a first longitudinal fold line section 20a, 21a, 22a, 23a extending between the bottom edge 11 and the bottom corner position BC1, BC2, BC3 and BC4, respectively. Each longitudinal fold line 20, 21, 22 and 23 also comprises a second longitudinal fold line section 20b, 21b, 22b, 23b extending between the bottom corner position BC1, BC2, BC3, BC4 and the lid corner position TC1, TC2, TC3 and TC4, respectively, and a third longitudinal fold line section 20c, 21c, 22c, 23c extending between the lid corner position TC1, TC2, TC3, TC4 and the top edge 12. In the present embodiment, the longitudinal fold lines 20, 21, 22 and 23 are continuous, i.e., uninterrupted, and extend vertically across the template 10 between the bottom edge 11 and the top edge 12. However, in alternative embodiments, the longitudinal fold lines 20, 21, 22 and 23 may be continuous, i.e., uninterrupted, and extend vertically across the template 10 between the bottom edge 11 and the top edge 12. 21, 22, 23 need not be continuous or rectilinear, and/or the longitudinal fold line sections 20b, 21b, 22b, 23b may be arranged to accommodate corner panel sections between the subpanel section wall 120, 220, 320, 420 and 520.

The first panel P1 comprises a lower fold line 140 extending from position BC1 to a position on the side edge 13 level with BC1. In other words, the lower fold line 140 extends transversely across the panel P1 in a direction that is orthogonal to the side edge 13 and the longitudinal fold line 20. The lower fold line 140 forms an edge between the lower closure subpanel 110 and the wall section subpanel 120 of the panel. Furthermore, the first panel P1 comprises an upper fold line 150 extending from position TC1 to a position on the side edge 13 that is level or substantially level with respect to TC1. Accordingly, in the present embodiment the upper fold line 150 extends transversely across the panel P1 in a direction that is substantially orthogonal to the side edge 13 and the longitudinal fold line 20, i.e. parallel to the bottom fold line 140. However, in alternative embodiments the upper fold line 150 need not be parallel to the bottom fold line 140. The upper fold line 150 forms an edge between the wall section sub-panel 120 and the lid closure sub-panel 130.

The lower closure subpanel 110 comprises a flap 111 which helps to ensure a secure closure of the bottom of the carton. Within the art of carton production, the function of such flaps is known as such and the flap 111 will not be discussed further here.

The lid closure subpanel 130 comprises an upper flap fold line 131 extending transversely across the panel P1 parallel to the upper flap fold line 150, i.e. in a direction that is orthogonal to the side edge 13 and the longitudinal fold line 20. The upper flap fold line 131 defines a fold line forming an edge between a roof subpanel 132 and an upper flap subpanel 133 of the lid closure subpanel 130. In the present embodiment, the upper edge subsection 12a is slightly convex, thus providing a curved and convex upper flap on the carton folded from the template 10. However, the upper edge subsection 12a may be rectilinear, concave, or any other shape.

Panel P1 comprises removal fold lines 160a, 160b extending transversely across the bottom of wall section subpanel 120. As known in the art, the removal fold lines are not activated when the carton is folded from template 10 during filling, but are activated by a user during removal of the carton when empty. In particular, as known in the art, the removal fold lines are configured to facilitate folding of the empty carton into a flat shape, thereby ensuring space efficient removal.

The second panel P2 comprises a bottom fold line 240 extending transversely across the panel P2 between positions BC1 and BC2. BC1 and BC2 are flush, i.e. arranged along a line that is orthogonal to the longitudinal fold lines 20 and 21. Accordingly, the bottom fold line 240 extends transversely across the panel P2 in a direction that is orthogonal to the longitudinal fold lines 20 and 21. The bottom fold line 240 forms an edge between the bottom closure subpanel 210 and the wall section subpanel 220.

The second panel P2 further comprises a transverse upper fold line 250 extending across the panel P2 between positions TC1 and TC2 and defining a fold line forming an edge between the wall section subpanel 220 and the lid closure subpanel 230. The upper fold line 250 is not rectilinear like the corresponding fold line 150 of the panel P1 but curved. Starting from position TC1, the upper fold line 250 initially extends generally orthogonally from the longitudinal fold line 20 and then curves towards the bottom edge 11 of the carton template. Approximately halfway between the longitudinal fold lines 20 and 21, the upper fold line 250 transitions from a downward fold to an upward fold, terminating at position TC2 in an arc 250' having a radius of curvature R1 and a convex side facing the second subpanel 220, which arc 250' forms an obtuse angle a with the longitudinal fold line section 21c, i.e. an angle within the range of 90° to 180° (see Figs. 2a and 3a). Accordingly, the transverse upper fold line 250 comprises a first section 250a having a convex side facing the upper edge 12, i.e. upwards, and a second section 250b having a convex side facing the lower edge 11, i.e. downwards, which first section 250a connects to the longitudinal fold line 20 at a right angle, and which second section 250b connects to the longitudinal fold line 21 by sloping upwards.

The lower closure subpanel 210 comprises a first diagonal fold line 211 extending between position BC1 and a position adjacent to the lower edge subsection 11b midway between the longitudinal fold lines 20 and 21. The lower closure subpanel 210 also comprises a second diagonal fold line 212 extending between position BC2 and said position adjacent to the lower edge subsection 11b midway between the longitudinal fold lines 20 and 21, thereby intercepting the first diagonal fold line 211 at this position. The diagonal fold lines 211 and 212 form fold lines that assist in folding the lower closure subpanel 210 when forming the lower closure of the carton.

The lid closure subpanel 230 comprises a transverse gable fold line 231 extending transversely across the panel P2 defining a fold line forming an edge between a lid bellows subsubpanel 232 and a gable seal subsubpanel 233 of the lid closure subpanel 230.

The lid gusset sub-subpanel 232 comprises a second diagonal fold line 234 extending between the position TC1 and a position on the gable transverse fold line 231 midway between the longitudinal fold lines 20 and 21. The lid gusset sub-subpanel 232 also comprises a first diagonal fold line 235 extending between the position TC2 and said position on the transverse fold line 231 midway between the longitudinal fold lines 20 and 21, thereby intercepting the second diagonal fold line 234 at this position.

The second diagonal fold line 234 is rectilinear. However, the first diagonal fold line 235 is curved and comprises a first section 235a having a convex side facing the longitudinal fold line section 21c and a second section 235b having a concave side facing the longitudinal fold line section 21c. The first diagonal fold line 235 makes a transition from said first section 235a to said second section 235b adjacent to the position TC2, ending at the position TC2 in an arc 235' having a convex side facing the transverse fold line 250 and a radius of curvature R2 (see Figs. 2a and 3a).

The gable sealing sub-subpanel 233 comprises a longitudinal gable fold line 236 extending between the transverse gable fold line 231 and the upper edge subsection 12b parallel to and equidistant from the longitudinal fold lines 20 and 21. In other words, the longitudinal gable fold line 236 extends vertically from the position on the transverse gable fold line 231 where the diagonal fold lines 234 and 235 intersect each other.

As a first panel P1, the second panel P2 comprises removal fold lines 260a-260e that are configured to be activated by a user during removal of the carton when it is empty.

The third panel P3 comprises a bottom fold line 340 extending transversely across the panel P3 between positions BC2 and BC3. BC2 and BC3 are flush, i.e. arranged along a line that is orthogonal to the longitudinal fold lines 21 and 22. Accordingly, the bottom fold line 340 extends transversely across the panel P3 in a direction that is orthogonal to the longitudinal fold lines 21 and 22. The bottom fold line 340 defines a fold line that forms an edge between the bottom closure subpanel 310 and the wall section subpanel 320 of the panel P3. The third panel P3 is free of a fold line defining a fold line forming an edge between the wall section subpanel 320 and the lid closure subpanel 330. Therefore, in the carton resulting from the folding of the template 10 there is no distinct edge between the wall section subpanel 320 and the lid closure subpanel 330. Instead, the wall section subpanel 320 and the lid closure subpanel 330 will seamlessly transition into each other and merge at an edge region.

The lid closure subpanel 330 comprises an upper flap fold line 331 extending transversely across the panel P3 in a direction that is orthogonal to the longitudinal fold lines 21 and 22, i.e., parallel to the lower fold line 340. The upper flap fold line 331 defines a fold line forming an edge between a roof subpanel 332 and an upper flap subpanel 333 of the lid closure panel 330. The roof subpanel 332 is provided with a circular through opening 334 for receiving a pouring spout attachment. As in panel P1, the upper edge subsection 12c is slightly convex, thus providing a curved, convex upper flap on the carton folded from the template 10.

The fourth panel P4 is essentially a mirror image of the second panel P2. Accordingly, the fourth panel P4 comprises a bottom fold line 440 extending transversely across the panel P4 between positions BC3 and BC4. BC3 and BC4 are flush, i.e. arranged along a line that is orthogonal to the longitudinal fold lines 22 and 23. Accordingly, the bottom fold line 440 extends transversely across the panel P4 in a direction that is orthogonal to the longitudinal fold lines 22 and 23. The bottom fold line 440 forms an edge between the bottom closure subpanel 410 and the wall section subpanel 420.

The fourth panel P4 further comprises a transverse upper fold line 450 extending across the panel P4 between positions TC3 and TC4 and defining a fold line forming an edge between the wall section subpanel 420 and the lid closure subpanel 430. The upper fold line 450 is curved in the same manner as the upper fold line 250 of the panel P2. Accordingly, starting from position TC4, the upper fold line 450 initially extends generally orthogonally from the longitudinal fold line 23 and then curves towards the bottom edge 11 of the carton template. Approximately midway between longitudinal fold lines 22 and 23, upper fold line 450 transitions from bending downward to bending upward, terminating at position TC3 in an arc 450' having a radius of curvature R1 and a convex side facing second subpanel 420, which arc 450' forms an obtuse angle a with longitudinal fold line section 22c (see Figs. 2b and 3b). Accordingly, the transverse upper fold line 450 comprises a first section 450a having a convex side facing the upper edge 12, i.e. upwards, and a second section 450b having a convex side facing the lower edge 11, i.e. downwards, which first section 450a connects to the longitudinal fold line 23 at a right angle, and which second section 450b connects to the longitudinal fold line 22 by sloping upwards.

The lower closure subpanel 410 comprises a first diagonal fold line 411 extending between position BC3 and a position adjacent to the lower edge subsection 11d midway between the longitudinal fold lines 22 and 23. The lower closure subpanel 410 also comprises a second diagonal fold line 412 extending between position BC4 and said position adjacent to the lower edge subsection 11d midway between the longitudinal fold lines 22 and 23, thereby intercepting the first diagonal fold line 411 at this position. The diagonal fold lines 411 and 412 form fold lines that assist in folding the lower closure subpanel 410 when forming the lower closure of the carton.

The lid closure subpanel 430 comprises a transverse gable fold line 431 extending transversely across the panel P4 defining a fold line forming an edge between a lid bellows subsubpanel 432 and a gable seal subsubpanel 433 of the lid closure subpanel 430.

The lid bellows sub-subpanel 432 comprises a second diagonal fold line 434 extending between position TC4 and a position on the gable transverse fold line 431 midway between the longitudinal fold lines 22 and 23. The lid bellows sub-subpanel 432 also comprises a first diagonal fold line 435 extending between position TC3 and said position on the gable transverse fold line 431 midway between the longitudinal fold lines 22 and 23, thereby intercepting the second diagonal fold line 434 at this position.

The second diagonal fold line 434 is rectilinear. However, the first diagonal fold line 435 is curved and comprises a first section 435a having a convex side facing the longitudinal fold line section 22c and a second section 435b having a concave side facing the longitudinal fold line section 22c. The first diagonal fold line 435 makes a transition from said first section 435a to said second section 435b adjacent to the position TC3, ending at the position TC3 in an arc 435' having a convex side facing the transverse fold line 450 and a radius of curvature R2 (see Figs. 2b and 3b).

The gable sealing sub-subpanel 433 comprises a longitudinal gable fold line 436 extending between the transverse gable fold line 431 and the upper edge subsection 12d parallel to and equidistant from the longitudinal fold lines 22 and 23. In other words, the longitudinal gable fold line 436 extends vertically from the position on the transverse gable fold line 431 where the diagonal fold lines 434 and 435 intersect each other.

As a second panel P2, the fourth panel P4 comprises removal fold lines 460a-460e that are configured to be activated by a user during removal of the carton when it is empty.

In the fifth panel P5, two collinear bottom fold lines 540a, 540b define a fold line extending across panel P5, which fold line is collinear with the bottom fold lines 140, 240, 340, and 440 in panels P1-P4, and forms a border between the bottom closure subpanel 510 and the wall section subpanel 520 of panel P5. In addition, two collinear top fold lines 550a, 550b define a fold line that is generally collinear with the top fold line 150 of the first panel P1, which fold line forms a border between the body subpanel 520 and the lid closure subpanel 530. Furthermore, two collinear top fin fold lines 531a, 531b define a fold line that is generally collinear with the top fin fold lines 131 and 331 of panels P1 and P3, which fold line forms an edge between a roof sub-subpanel 532 and a top fin sub-subpanel 533 of lid closure sub-panel 530.

In the present embodiment, the edge defined by the transverse fold line 250 of the second panel P2, when terminated at the second lid corner position TC2, forms an obtuse angle a of approximately 140° with the second longitudinal fold line section 21c. Furthermore, the edge defined by the transverse fold line 450 of the fourth panel P4, when terminated at the third lid corner position TC3, forms an obtuse angle a of approximately 140° with the third longitudinal fold line section 22c. The fold line defined by the first diagonal fold line 235 of the second panel P2, when terminated at the second lid corner position TC2, forms an angle p of approximately 90° with the second longitudinal fold line section 21c. Likewise, the fold line defined by the first diagonal fold line 435 of the fourth panel P4, when terminated at the third lid corner position TC3, forms an angle p of approximately 90° with the third longitudinal fold line section 22c. In alternative embodiments, the angle p formed between the first diagonal fold line 235 of the second panel P2 and the second longitudinal fold line section 21c and the angle p formed between the first diagonal fold line 435 of the fourth panel P4 and the third longitudinal fold line section 22c, may be any one of at least 80° and at least 90°, for example, 90° as in the embodiment shown in Fig. 1.

It has been found that by using this diagonal fold line configuration, predictable and accurate folding of the carton template can be achieved in the area surrounding the top corner positions TC2 and TC3.

As discussed above, arc 250' of the transverse fold line 250 of the second panel P2 and arc 450' of the transverse fold line 450 of the fourth panel P4 both have a radius of curvature R1 (see Figs. 2a, 2b, 3a, and 3b). In addition, arc 235' of the diagonal fold line 235 of the second panel P2 and arc 435' of the diagonal fold line 435 of the fourth panel P4 both have a radius of curvature R2. The radius of curvature R2 of arcs 235' and 435' is smaller than the radius of curvature R1 of arcs 250' and 450'.

The second radius of curvature R2 may be within the range of 20%-80% of the first radius of curvature R1, for example within the range of 40%-60% of the first radius of curvature R1, or 45%-55% of the first radius of curvature R1. In one embodiment, shown in Figs. 4 and 5, R1 is 14 mm and R2 is 6 mm.

The arc 235' may have a center located at the longitudinal fold line section 21c, and the arc 435' may have a center located at the longitudinal fold line section 22c, as shown in Figs.

4 and 5. This will cause the diagonal fold lines 235 and 435 to connect to the lid corner position TC2 and TC3, respectively, at a right angle, which has been found to result in particularly accurate folding of the carton template.

The arc 250' may have a center located on the second panel P2 at a lateral distance D from the longitudinal fold line section 21c, and the arc 450' may have a center located on the fourth panel P4 at the same lateral distance D from the longitudinal fold line section 22c. The lateral distance D may be within the range of 40%-90% of the first radius of curvature R1. In the embodiment shown in Figs. 4 and 5, the center of the arc 250' and 450' is located at a lateral distance D of approximately 11 mm from the longitudinal fold line section 21c and 22c respectively.

One method of forming a carton from the carton template 10 discussed above is as follows. After the template of Fig. 1 has been produced, the fifth panel P5 is sealed to the inner wall of the panel P1 to form a sleeve open at both ends. This sleeve is then bottom sealed by folding inward the first subpanels 110, 210, 310, 410 and 510 and sealing them to produce an open-top, bottom-sealed carton. A pouring spout attachment (see Figs. 6 and 7) is lowered into the open top of the carton and inserted into the opening 334 from the inside of the carton until a flange thereof contacts the inner surface of the subpanel 330 around the opening 334, whereupon the flange is sealed to the innermost layer of the subpanel 330 around the opening. The still open carton is then filled with the liquid to be packaged.

The subpanels 130, 230, 330, 430, and 530 are then folded and sealed together to provide a sealed lid closure of the carton.

Figs. 6-8 show a carton 600 formed from the template 10 illustrated in Fig. 1. The carton 600 comprises top and bottom corners TC1', TC2', TC3', TC4', BC1', BC2', BC3', and BC4' defined by the corresponding top and bottom corner positions TC1, TC2, TC3, TC4, BC1, BC2, BC3, and BC4 of the template 10 (see Fig. 1). Between the top corners TC1', TC2', TC3', TC4' and the bottom corners BC1', BC2', BC3', BC4', the carton 600 has a generally rectangular or square cross section.

The carton 600 comprises a bottom closure 602 formed from subpanels 110, 210, 310, 410, and 510. The carton 600 further comprises a rear wall section 610 formed from subpanel 120 and a front wall section 606 formed from subpanel 320. The carton 600 also comprises a first side wall section 604 formed from subpanel 220 and a second side wall section 608 formed from subpanel 420.

The carton 600 also comprises a lid closure 612 formed from subpanels 130, 230, 330, 430, and 530. The lid closure 612 comprises a rear roof section 614 formed from subsubpanel 132 and a front roof section 616 formed from subsubpanel 332. The lid closure 612 also comprises a first gable section 618 formed from a subsubpanel section 232 delimited by fold lines 234 and 235, and a second gable section 620 formed from a subsubpanel section 432 delimited by fold lines 434 and 435. The lid closure 612 further comprises a top flap 622 where the subpanels 130, 230, 430, and 530 are positioned. 330, 430 and 530 are sealed together and a pour spout 624 disposed in the through opening 334 in the sub-subpanel 332.

Since there is no fold line between the subpanels 320 and 330 of the third panel P3 (see Fig. 1), the front wall section 606 is continuous with the front roof section 616 through a T-curved transition area. In such embodiments, it may be difficult to obtain a distinct formation of the second and third top corners TC2' and TC3' since folding of the cardboard material along unwanted fold lines may occur. However, by designing each diagonal fold line 235 and 435 so that it ends at the corner position TC2, TC3 in an arc 235', 435' having a convex side facing the transverse fold line 250, 450 and a radius of curvature R2 that is larger than the radius of curvature R1 of the transverse fold line 250, 450 (see Figs. 2 and 3), accurate folding of the paperboard material can be achieved. It should be understood, however, that this design of the diagonal fold line 235 and 435 is equally suitable for cartons having a fold line separating the front wall section 606 and the front roof section 616. Accordingly, in alternative embodiments, the front wall section and the front roof section may be separated by a transverse fold line, for example, by a transverse fold line as shown in Fig. 9.

Another embodiment of a carton template 30 according to the invention is shown in Fig. 9. The carton template 30 differs from the carton template 10 of Fig. 1 only in that the third panel P3 of the template 30 comprises a transverse fold line 350 extending across the panel P3 between positions TC2 and TC3 and defining a fold line forming an edge between the wall section subpanel 320 and the lid closure subpanel 330.

A further embodiment of a carton template 40 according to the invention is shown in Fig. 10. The carton template 40 differs from the carton template 10 of Fig. 1 in that the transverse fold lines 250 and 450 terminate at corner positions TC1 and TC4, respectively, in the same manner as they terminate at corner positions TC2 and TC3. Furthermore, the carton template 40 differs from the carton template 10 of Fig. 1 in that the diagonal fold lines 234 and 434 terminate at lid corner positions TC1 and TC4 in the same manner as the diagonal fold lines 235 and 435 terminate at lid corner positions TC2 and TC3, respectively. Accordingly, the transverse fold line 250 terminates at TC1 in an arc 250'' having a radius of curvature R1 and a convex side facing the second subpanel 220. Furthermore, the diagonal fold line 234 terminates at the position of the lid corner TC1 in an arc 234' having a convex side facing the transverse fold line 250 and a radius of curvature R2 that is greater than the radius of curvature R1 of the arc 250” (see also Figure 2). Furthermore, the transverse fold line 450 terminates at the lid corner positions TC4 in an arc 450'' having a radius of curvature R1 and a convex side facing the second subpanel 420. Furthermore, the diagonal fold line 434 terminates at the lid corner position TC4 in an arc 434' having a convex side facing the transverse fold line 450 and a radius of curvature R2 that is greater than the radius of curvature R1 of the arc 450” (see also Figure 3).

A further embodiment of a carton template 50 according to the invention is shown in Fig. 11. The carton template 50 differs from the carton 40 of Fig. 10 in that the first panel P1 does not have a transverse fold line separating the wall section subpanel 120 and the lid closure subpanel 130. Accordingly, in the carton formed from the template 50, the rear wall will be continuous with the rear roof section through a curved transition area in the same manner as is the case for the front wall 606 and front roof section 616 of the carton 600 shown in Figs. 6-8.

It is understood that the above-discussed curved sections 235a, 435b, 250b and 450b of the diagonal fold lines 235, 435 and the transverse fold lines 250, 450 (see Figs. 2a and 2b) do not have to extend to the respective upper corner positions. Figs. 12a and 12b show such an embodiment of a carton template in which the diagonal fold lines 235, 435 and the transverse fold lines 250, 450 each comprise a rectilinear section 235c, 435c, 250c, 450c disposed between the curved section 235b, 435b, 250b, 450b and the respective lid corner positions TC2, TC3, which rectilinear sections 235c, 435c, 250c, 450c connect to the lid corner positions TC2 and TC3, respectively.

It is also understood that the diagonal fold lines 235, 435 and the transverse fold lines 250, 450 do not have to extend to the respective top corner positions. Figs. 13a and 13b show such an embodiment of a carton template where the diagonal fold lines 235, 435 and the transverse fold lines 250, 450 end before reaching the respective lid corner position TC2, TC3, but close enough, i.e. within 0-5 mm, to define a fold line extending to the lid corner position. For example, ending the diagonal fold lines 235, 435 and the cross fold lines 250, 450, say, 2 mm from the respective top corner positions TC2, TC3 can still provide accurate folding of the carton template, although it may be preferable to extend the fold lines 235, 435, 250 and 450 to the top corner positions TC2, TC3.

Although the subject matter of the present invention, i.e., the design of the diagonal fold lines of the lid closure subpanels of panels two and four, has been discussed based on specific carton template and carton embodiments, it is understood that the present invention may be implemented in other types of carton templates and cartons. For example, the design of the diagonal fold lines according to the invention may be implemented in templates and cartons having bottom closure configurations other than those shown in the illustrative embodiments, or in templates and cartons having dispensing means other than the illustrated pouring spout.

In the foregoing specification, various aspects of the invention have been described and discussed with reference to illustrative embodiments. For purposes of explanation, specific numerals, systems, and configurations have been set forth to provide a thorough understanding of the closure device and its operation. However, this specification is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the closure device, which are apparent to those skilled in the art to which the disclosed subject matter pertains, may be within the scope of the present invention as defined in the following claims.

Claims (14)

1. A carton blank (10, 30, 40, 50) configured to form a gable-top carton (600) by folding, the carton blank (10, 30, 40, 50) comprising a first (P1), a second (P2), a third (P3), a fourth (P4) and a fifth (P5) panel, each of which comprises: - a first subpanel (110, 210, 310, 410, 510) configured to form part of a lower closure (602) of the box (600); - a second subpanel (120, 220, 320, 420, 520) adjacent to the first subpanel (110, 210, 310, 410, 510) and configured to form a wall section (604, 606, 608, 610) of the cardboard box (600); and - a third subpanel (130, 230, 330, 430, 530) adjacent to the second subpanel (120, 220, 320, 420, 520) and configured to form part of a lid closure (612) of the cardboard box (600), wherein the cardboard box template (10, 30, 40, 50) comprises: - a first longitudinal fold line section (20c) defining an edge between the third subpanel (130) of the first panel (P1) and the third subpanel (230) of the second panel (P2); - a second longitudinal fold line section (21c) defining an edge between the third subpanel (230) of the second panel (P2) and the third subpanel (330) of the third panel (P3); - a third longitudinal fold line section (22c) defining an edge between the third subpanel (330) of the third panel (P3) and the third subpanel (430) of the fourth panel (P4); and - a fourth longitudinal fold line section (23c) defining an edge between the third subpanel (430) of the fourth panel (P4) and the third subpanel (530) of the fifth panel (P5) (P4), wherein the second panel (P2) comprises: - a transverse fold line (250) defining an edge between the second subpanel (220) and the third subpanel (230) of the second panel (P2), the edge extending across the second panel (P2) between a first lid corner position (TC1) located at the first longitudinal fold line section (20c) and a second lid corner position (TC2) located at the second longitudinal fold line section (21c), which first lid corner position (TC1) is configured to form a first lid corner (TC1') of the carton, and which second lid corner position (TC2) is configured to form a second lid corner (TC2') of the carton; and - a first diagonal fold line (235) of the second panel (P2) defining a fold line in the third subpanel (230) of the second panel (P2) ending at the second lid corner position (TC2); and in which the fourth panel (P4) comprises: - a transverse fold line (450) defining an edge between the second subpanel (420) and the third subpanel (430) of the fourth panel (P4), the edge extending across the fourth panel (P4) between a third lid corner position (TC3) located at the third longitudinal fold line section (22c) and a fourth lid corner position (TC4) located at the fourth longitudinal fold line section (23c), which third lid corner position (TC3) is configured to form a third lid corner (TC3') of the carton, and which fourth lid corner position (TC4) is configured to form a fourth lid corner (TC4') of the carton; and - a first diagonal fold line (435) of the fourth panel (P4) defining a fold line in the third subpanel (430) of the fourth panel (P4) ending at the third lid corner position (TC3); characterized by the fold line defined by the first diagonal fold line (235) of the second panel (P2), when it ends at the second position of the lid corner (TC2), forming an angle (p) of at least 70° with the second longitudinal fold line section (21c), and by the fold line defined by the first diagonal fold line (435) of the fourth panel (P4), when it ends at the third position of the lid corner (TC3), forming an angle (p) of at least 70° with the third longitudinal fold line section (22c). 2. The cardboard box template (10, 30, 40, 50) according to claim 1, wherein each of the angle (p) formed between the first diagonal fold line (235) of the second panel (P2) and the second longitudinal fold line section (21c) and the angle (p) formed between the first diagonal fold line (435) of the fourth panel (P4) and the third longitudinal fold line section (22c), is any one of: at least 80°, at least 90° and 90°. 3. The carton template (10, 30, 40, 50) according to any one of claims 1 and 2, wherein the angle (p) formed between the first diagonal fold line (235) of the second panel (P2) and the second longitudinal fold line section (21c) is equal to the angle (p) formed between the first diagonal fold line (435) of the fourth panel (P4) and the third longitudinal fold line section (22c). 4. The cardboard box template (10, 30, 40, 50) according to claim 1, wherein the first diagonal fold line (235) of the second panel (P2) comprises a diagonal fold line section (235b) having a convex side facing the transverse fold line (250) of the second panel (P2); and wherein the first diagonal fold line (435) of the fourth panel (P4) comprises a diagonal fold line section (435b) having a convex side facing the transverse fold line (450) of the fourth panel (P4). 5. The cardboard box template (10, 30, 40, 50) according to any one of the preceding claims, wherein the second panel (P2) comprises a gable transverse fold line (231) defining an edge between a lid bellows sub-subpanel (232) and a gable seal sub-subpanel (233) of the third sub-panel (230) of the second panel (P2); wherein the fold line defined by the first diagonal fold line (235) of the second panel (P2) extends between the transverse gable fold line (231) of the second panel (P2) and the second lid corner position (TC2); wherein the fourth panel (P4) comprises a gable transverse fold line (431) defining an edge between a lid bellows sub-subpanel (432) and a gable seal sub-subpanel (433) of the third sub-panel (430) of the fourth panel (P4); and wherein the fold line defined by the first diagonal fold line (435) of the fourth panel (P4) extends between the transverse gable fold line (431) of the fourth panel (P4) and the third lid corner position (TC3). 6. The cardboard box template (10, 30, 40, 50) according to any one of the preceding claims, wherein the edge defined by the transverse fold line (250) of the second panel (P2), when terminated at the second lid corner position (TC2), forms an obtuse angle (a) with the second longitudinal fold line section (21c); and wherein the edge defined by the transverse fold line (450) of the fourth panel (P4), when terminated at the third lid corner position (TC3), forms an obtuse angle (a) with the third longitudinal fold line section (22c). 7. The cardboard box template (10) according to any one of the preceding claims, wherein the transverse fold line (250) of the second panel (P2) ends at the second position of the lid corner (TC2) in an arc (250') having a first radius of curvature (R1); wherein the transverse fold line (450) of the fourth panel (P4) ends at the third lid corner position (TC3) in an arc (450') having said first radius of curvature (R1); wherein the first diagonal fold line (235) of the second panel (P2) ends at the second lid corner position (TC2) in an arc (235') having a second radius of curvature (R2); wherein the first diagonal fold line (435) of the fourth panel (P4) ends at the third lid corner position (TC3) in an arc (435') having said second radius of curvature (R2); and wherein said second radius of curvature (R2) is smaller than said first radius of curvature (R1). 8. The carton template (10) according to claim 7, wherein the second radius of curvature (R2) is any one of: 20%-80% of the first radius of curvature (R1); 40%-60% of the first radius of curvature (R1); and 45%-55% of the first radius of curvature (R1). 9. The carton template (10) according to claim 8, wherein said arc (235') of the first diagonal fold line (235) of the second panel (P2) has a center of curvature located at said second longitudinal fold line section (21c), and said arc (435') of the first diagonal fold line (435) of the fourth panel (P4) has a center of curvature located at said third longitudinal fold line section (22c). 10. The carton template (10) according to any one of claims 7-9, wherein said arc (250') of the transverse fold line (250) of the second panel (P2) has a center of curvature located in the second panel (P2) at a lateral distance (D) from said second longitudinal fold line section (21c), and wherein said arc (450') of the transverse fold line (450) of the fourth panel (P4) has a center of curvature located in the fourth panel (P4) at a lateral distance (D) from said third longitudinal fold line section (22c), wherein said lateral distance (D) is within the range of 40% to 90% of the first radius of curvature (R1). 11. The cardboard box template (40, 50) according to any one of the preceding claims, wherein the second panel (P2) comprises a second diagonal fold line (234) defining a fold line in the third subpanel (230) that ends at the first lid corner position (TC1) and forms an angle (p) of at least 70° with the first longitudinal fold line section (20c); and wherein the fourth panel (P4) comprises a second diagonal fold line (434) defining a fold line in the third subpanel (430) that ends at the fourth lid corner position (TC4) and forms an angle (p) of at least 70° with the fourth longitudinal fold line section (23c). 12. The cardboard box template (40, 50) according to claim 11, wherein the second diagonal fold line (234) of the second panel (P2) comprises a diagonal fold line section (234b) having a convex side facing the transverse fold line (250) of the second panel (P2); and wherein the second diagonal fold line (434) of the fourth panel (P4) comprises a diagonal fold line section (434b) having a convex side facing the transverse fold line (450) of the fourth panel (P4). 13. The cardboard box template (40, 50) according to any one of claims 11 and 12, wherein the angle (p) formed between the second diagonal fold line (234) of the second panel (P2) and the first longitudinal fold line section (20c) is equal to the angle (p) formed between the second diagonal fold line (434) of the fourth panel (P4) and the fourth longitudinal fold line section (23c). 14. A gable top carton produced from a carton template (10) according to any one of the preceding claims.