NL2026891B1

NL2026891B1 - a cardboard tray, an assembly of the cardboard tray and a foil, a sheet of cardboard arranged for being folded into the cardboard tray

Info

Publication number: NL2026891B1
Application number: NL2026891A
Authority: NL
Inventors: Richardus Van Der Does Cornelis
Original assignee: Schut Systems B V
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2022-06-30
Also published as: WO2022103261A1; EP4244147A1

Abstract

A cardboard tray folded from a sheet of cardboard, an assembly of a cardboard tray and a foil and a sheet of cardboard arranged for being folded into a cardboard tray, wherein said cardboard tray comprises sheet portions defining a bottom wall and side walls defining a receiving space of said cardboard tray, said side walls being connected, via respective first folding lines, to said bottom wall, wherein said cardboard tray further comprises flange parts connected, via respective second folding lines, to said side walls at a side of said side walls facing away from said bottom wall, wherein neighbouring flange parts of said flange parts are connected to each other via a locking sheet portion of one of said neighbouring flange parts, wherein said locking sheet portion is connected, via a third folding line, to said one of said neighbouring flange parts and extends at least partly through a locking opening provided in said sheet of cardboard, which locking opening is preferably provided in the other of said neighbouring flange parts, for said connecting of said neighbouring flange parts and realizing an uninterrupted flange along a circumference of said cardboard tray.

Description

Title: a cardboard tray, an assembly of the cardboard tray and a foil, a sheet of cardboard arranged for being folded into the cardboard tray Description According to a first aspect, the present disclosure relates to a cardboard tray folded from a sheet of cardboard.

According to a second aspect, the present disclosure relates to an assembly of a cardboard tray according to the first aspect of the present disclosure and a foil.

According to a third aspect, the present disclosure relates to a sheet of cardboard arranged for being folded into a cardboard tray according to the first aspect of the present disclosure.

Foldable cardboard trays are available in a lot of types, for example re-usable or disposable, composite or single-ply structured and with small or large dimensions. Cardboard trays are suitable for packaging and/or displaying materials and goods, such as vegetables or other kind of food. Cardboard trays have the property that the top of the tray is open, but in some cases, for example during transportation, there is a need for the ability to efficiently close the top of the tray.

A disadvantage of known cardboard trays available in the market is that there is a need for additional means, either mechanical, like tacks and strings, or chemical, like an adhesive, in order to ensure sufficient strength of the cardboard tray. In terms of recycling, environment and cost efficiency this is undesired. Therefore, there is furthermore a need for a foldable cardboard tray with improved strength, without additional adhering means.

It is therefore an objective of the present disclosure to provide a cardboard tray folded from a sheet of cardboard with improved strength, without additional adhering means. In particular, it is an objective of the present disclosure to provide a cardboard tray folded from a sheet of cardboard which can be closed at an upper side of the cardboard tray.

In a first aspect, there is provided a cardboard tray folded from a sheet of cardboard, wherein said cardboard tray comprises sheet portions defining a bottom wall and side walls defining a receiving space of said cardboard tray, said side walls being connected, via respective first folding lines, to said bottom wall, wherein said cardboard tray further comprises flange parts connected, via respective second folding lines, to said side walls at a side of said side walls facing away from said bottom wall, wherein neighbouring flange parts of said flange parts are connected to each other via a locking sheet portion of one of said neighbouring flange parts, wherein said locking sheet portion is connected, via a third folding line, to said one of said neighbouring flange parts and extends at least partly through a locking opening provided in said sheet of cardboard, which locking opening is preferably provided in the other of said neighbouring flange parts, for said connecting of said neighbouring flange parts and realizing an uninterrupted flange along a circumference of said cardboard tray.

The term cardboard may refer to a variety of heavy paper-like materials, including but not limited to, card stock, corrugated fibreboard or paperboard. Cardboard is a recyclable and/or reusable material. Producing the cardboard tray from a single sheet of cardboard prevents unnecessary waste of materials of which the cardboard is produced.

Preferably, the sheet of cardboard consists of one piece. Because the sheet of cardboard comprises folding lines, the sheet of cardboard can easily by folded into its final shape of the cardboard tray, either manually by hand or with the use of machinery. It was the insight of the inventor to design the bottom wall, side walls and flange parts according to the invention for improved strength of the cardboard tray, while waste of materials is minimized.

It was further the insight of the inventor to add and design the locking mechanism provided in the flange parts for improved strength of the cardboard tray.

Neighbouring flange parts are adhered to each other by means of the locking mechanism comprising the locking sheet portion and the locking opening, for realizing an uninterrupted flange along a circumference of the cardboard tray, which is both advantageous for improved strength and provides a sufficient area for connecting a foil for closing the cardboard tray at an upper side. With closing the cardboard is meant that the bottom wall, the side walls and the foil bound the receiving space of the cardboard tray.

A further advantage of the cardboard tray is that there is no need for additional means, either mechanical, like tacks and strings or the like, or chemical, like an adhesive or the like in order to retain the cardboard tray in its folded position, while maintaining improved strength. This is environmentally beneficial, cost efficient and less time-consuming and labour-intensive during manufacturing of the cardboard tray from the sheet of cardboard. Furthermore, this allows for a more simple and less error- prone automated manufacturing process.

A further advantage of the cardboard tray according to the present disclosure is that the cardboard tray is formed of a single sheet of cardboard. This is beneficial for realising a relative cost effective cardboard tray by using a relative little amount of material. In addition, using only a relative little amount of material is beneficial for realising a cardboard tray having a relative low weight. A relative low weight is advantageous for realising relative low cost for distributing cardboard trays according to the present disclosure.

Preferably, the uninterrupted flange are of such dimensions, that the area of the uninterrupted flange is large enough for receiving the foil. Preferably the uninterrupted flange has a width in the range of minimal 4 — 15 mm, more preferably in the range of 8 — 15 mm. This is beneficial for realising a relative strong cardboard tray while using only a relative little amount of cardboard and while providing a relative large surface area for attachment of the foil.

In an example, said neighbouring flange parts of said flange parts are only connected to each other via said bottom wall, said side walls and said locking sheet portion of said one of said neighbouring flange parts. This is beneficial for realising a relative strong cardboard tray while using only a relative little amount of cardboard.

In an example, said one of said neighbouring flange parts is provided with a further locking opening and said other of said neighbouring flange parts is provided with a further locking sheet portion, wherein said further locking sheet portion extends at least partly through said further locking opening for said connecting and realizing an uninterrupted flange along said circumference of said cardboard tray. This is beneficial for arriving at a cardboard tray having an increased strength.

In an example, said connection to each other of said neighbouring flange parts of said flange parts is free of an adhesive. This is environmentally beneficial and more cost efficient. Furthermore, this allows for a more simple and less error-prone automated manufacturing process.

In an example, said locking sheet portion and said locking opening of said neighbouring flange parts are connected via form locking. This is beneficial, as there is no need for additional means, either mechanical, like tacks and strings or the like, or chemical, like an adhesive or the like in order to retain the cardboard tray in its folded position In an example, said one of said neighbouring flange parts comprises at least two of said locking sheet portions, preferably three or more of said locking sheet portions, and wherein said other of said neighbouring flange parts comprises a corresponding number of locking openings. Preferably, each side wall is connected to each of its neighbouring side wall via one of said locking sheet portion and one of said locking opening.

In an example, said locking sheet portion comprises an extension part extending through said locking opening.

The extension part is produced of the same sheet of cardboard, resulting in efficient use of the sheet of cardboard, minimizing waste of cardboard material and resulting in additional strength of the resulting cardboard tray.

In an example, said extension part is connected to a main sheet part of said locking sheet portion via a fourth folding line thereof.

In an example, said side walls are only connected to each other via said first folding lines and via said second folding lines. In other words, neighbouring side walls are not directly mutually connected, for instance via a further locking arrangement that may be applied for locking the neighbouring side walls to each other.

5 The neighbouring side walls are maintained in a position relative to each other only via the bottom wall and the uninterrupted flange. This is beneficial for realising a relative strong cardboard tray while using only a relative little amount of cardboard.

In an example, first flange parts of said flange parts are connected to opposite side walls of said side walls, wherein said first flange parts comprise a centre flange part, and wherein said locking sheet portions are provided at opposite sides of said centre flange part, wherein a length of said centre flange part corresponds substantially to a length of said second folding line and wherein said locking sheet portions are extensions of said centre flange part beyond said second folding line.

Preferably, said connecting flange parts are connected to said second folding line via said centre flange part.

In an example, each of said respective first folding lines is interrupted by cut-outs provided in said bottom wall and said side walls.

Preferably, the dimensions of the cut-outs are adapted to the size of the products, for which the specific cardboard tray is arranged. More preferably, the dimensions of the cut-outs are substantially smaller than the dimensions of the products, for which the specific cardboard tray is arranged.

The cut-outs ensure supply of fresh air which is particular advantageous the product, for which the specific cardboard tray is arranged, is food, for example vegetables or the like.

In an example, said uninterrupted flange is directed away from said receiving space. This maximizes the dimensions of the open end of the receiving space.

Preferably, said side walls define a height of said cardboard tray. Preferably, said sheet of cardboard has mass per unit area in the range of 200 gram/m? to 500 gram/m?, wherein said mass per unit area is determined according to ISO 536:2019. A mass per unit area in this range is beneficial for In addition, using only a relative little amount of material is beneficial for realising a cardboard tray having a relative low weight while being relative strong. A relative low weight is advantageous for realising relative low cost for distributing cardboard trays according to the present disclosure.

Preferably, a stiffness of said sheet of cardboard in a first cardboard direction is in a range of 8 mNm and 190 mNm, wherein said stiffness is determined according to DIN 53121:2014.

Preferably, a stiffness of said sheet of cardboard in a second cardboard direction, perpendicular to said first cardboard direction, is in a range of 8 mNm and 330 mNm, wherein said stiffness is determined according to DIN 53121:2014.

In this regard, it is beneficial if said stiffness of said sheet of cardboard in said first cardboard direction is lower than said stiffness of said sheet of cardboard in said second cardboard direction.

Preferably, said second cardboard direction is substantially perpendicular, preferably perpendicular, to said third folding line and/or substantially parallel, preferably parallel to said locking opening. This is beneficial for realising a relative reliable connection between said neighbouring side walls.

Preferably, a thickness variation of said sheet of cardboard is in the range of 200 um to 750 um, wherein said thickness variation is determined according to ISO 534:2011.

Preferably, a ratio of a width of said uninterrupted flange and said height of said cardboard tray is in the range of 0.2 to 0.4, more preferably in the range of 0.25 to 0.35. A ratio in this range is beneficial for realising a relative strong cardboard tray while using only a relative small amount of cardboard. Preferably, a ratio of a surface area of the uninterrupted flange and the bottom wall is in the range of 0.3 to 0.45, more preferably in the range of 0.35 to

0.4. A ratio in this range is beneficial for realising a relative strong cardboard tray while using only a relative small amount of cardboard. In a second aspect, there is provided an assembly of a cardboard tray as described above and a foil, wherein said foil is adhered to said uninterrupted flange, such that said bottom wall, said side walls and said foil bound said receiving space of said cardboard tray. Abovementioned embodiments of the cardboard tray according to the first aspect can be applied mutatis mutandis to embodiments of the assembly according to the second aspect of the present disclosure. Advantages of the cardboard tray according to the first aspect presented previously can be applied mutatis mutandis to advantages of the assembly according to the second aspect of the present disclosure.

Preferably, the foil is adhered to the uninterrupted flange after addition of products. Closing the upper side of the box prevents the products to unintentionally leave the tray, for example during transport. In an example, said foil is adhered to said uninterrupted flange } by heating and pressing said foil to said uninterrupted flange. Friction welding is a solid-state welding process that generates heat through mechanical friction between the foil and the uninterrupted flange in relative motion to one another in order to fuse the materials. This ensures strong connection between the foil and uninterrupted flange. Preferably, the foil is produced of a transparent material, enabling visibility of the products contained in the closed cardboard tray.

In a third aspect, there is provided a sheet of cardboard arranged for being folded into a cardboard tray as described above, said sheet of cardboard comprising a bottom wall sheet portion, side wall sheet portions connected, via first folding lines, to said bottom wall sheet portion, and wherein said sheet of cardboard further comprises flange part sheet portions connected, via second folding lines, to said side wall sheet portions at a side of said side wall sheet portions facing away from said bottom wall sheet portion, wherein first flange part sheet portions of said flange part sheet portions are provided with a locking sheet portion and wherein second flange part sheet portions of said flange part sheet portions are provided with a locking opening.

Abovementioned embodiments of the cardboard tray according to the first aspect can be applied mutatis mutandis to embodiments of the sheet of cardboard according to the third aspect of the present disclosure. Advantages of the cardboard tray according to the first aspect presented previously can be applied mutatis mutandis to advantages of the sheet of cardboard according to the third aspect of the present disclosure.

The term cardboard may refer to a variety of heavy paper-like materials, including but not limited to, card stock, corrugated fibreboard, or paperboard. The sheet of cardboard arranged for being folded into a cardboard tray prevents unnecessary waste of materials of which the cardboard is produced. Because cardboard furthermore is a recyclable material, the resulting tray is beneficial for the environment.

Providing the sheet of cardboard according to the third aspect enables efficient transport of a plurality of the sheets of cardboard and furthermore reduces cost of manufacturing, transportation, manipulation by a middle- or end-user, as well as other costs. The sheets of cardboard can efficiently be stacked on for example a flat transport structure like a pallet. The sheets of cardboard are transported to intermediate or end users, where the sheet of cardboard is folded into its final shape of the cardboard tray according to the first aspect, either manually by hand or with the use of machinery. Eventually, preferably after products are added to the cardboard tray, the cardboard tray is closed at an upper side, by adhering a foil to the uninterrupted flange, such that the bottom wall, the side walls and the foil bound a receiving space of the cardboard tray. This prevents, that the products unintentionally leave the tray, for example during transport to a further user, like a distributor, a shop, or the like.

The present disclosure will now be explained by means of a description of embodiments of a cardboard tray in accordance to the first aspect of the present disclosure and embodiments of a sheet of cardboard according to the third aspect of the present disclosure, in which reference is made to the following schematic figures, in which: Fig. 1 — Fig. 6 disclose the manufacturing of a cardboard tray from a sheet of cardboard in subsequent steps in accordance to an embodiment of the present disclosure; Fig. 7 — Fig. 10 disclose the manufacturing of a cardboard tray from a sheet of cardboard in subsequent steps in accordance to another embodiment of the present disclosure; Fig. 11 — Fig. 15 disclose the manufacturing of a cardboard tray from a sheet of cardboard in subsequent steps in accordance to yet another embodiment of the present disclosure.

Figure 1 to figure 6 disclose in subsequent steps the manufacturing of a cardboard tray 1 from a sheet of cardboard 301.

Figure 1 discloses the sheet of cardboard 301, comprising a bottom wall 3 and side walls 5. The side walls 5 are connected to the bottom wall 3 via first folding lines 7. The cardboard tray 1 further comprises flange parts 9, 11, connected to the side walls 5 via second folding lines 13 and are positioned at a side of the side walls 5 facing away from the bottom wall 3. The folding lines 7 are interrupted by cut- outs 35 provided in the bottom wall 3 and the side walls 5.

The flange parts 9 of two side walls 5 are provided with a locking sheet portion 15, connected via third folding lines 17. The locking sheet portion 15 comprises an extension part 23, connected to a main sheet part 25 of the locking sheet portion 15 via a fourth folding line 27. The flange parts 9 are further provided with a further locking opening 29. The flange parts 11 are provided with a locking opening 19 and a further locking sheet portion 31. By folding the side walls 5 about the first folding lines 7 relative to the bottom wall 3, the cardboard receptacle of figure 2 is obtained, thereby defining a receiving space 2. By folding the two flange parts 9 about the second folding lines 13, the cardboard receptacle of figure 3 is obtained. By folding the two flange parts 11 about the second folding lines 13, the cardboard receptacle of figure 4 is obtained. By subsequently folding the extension parts 23 about the fourth folding line 27 and locking sheet portions 15 about the third folding lines 17, the cardboard receptacle of figure 5 is obtained.

By pressing the locking sheet portions 15 such that the extension parts 23, provided in the flange parts 9, extend through the locking opening 19, provided in the flange parts 11, and the further locking sheet portions 31, provided in the flange parts 11, extend through the further locking opening 29, provided in the flange parts 9, the flange parts 9, 11 are firmly connected and the cardboard tray 1 of figure 8 is realized.

The bottom wall 3 and side walls 5 define the receiving space 2 of said cardboard tray 1. By connecting the neighbouring flange parts 9, 11 an uninterrupted flange 21 along a circumference of the cardboard tray 1 is realized.

Figure 7 to figure 10 disclose in subsequent steps the manufacturing of a cardboard tray 101 from a sheet of cardboard 401.

Figure 7 discloses the sheet of cardboard 401, comprising sheet a bottom wall 3 and side walls 5. The side walls 5 are connected to the bottom wall 3 via first folding lines 7. The cardboard tray 1 further comprises flange parts 9, 11, connected to the side walls 5 via second folding lines 13 and are positioned at a side of the side walls 5 facing away from the bottom wall 3. The folding lines 7 are interrupted by cut-outs 35 provided in the bottom wall 3 and the side walls 5.

The flange parts 11 of two side walls 5 are provided with a locking sheet portion 15, connected via third folding lines 17. The flange parts 9 are provided with a locking opening 19.

By folding the side walls 5 about the first folding lines 7 relative to the bottom wall 3, the cardboard receptacle of figure 8 is obtained, thereby defining a receiving space 2. By folding the two flange parts 9 about the second folding lines 13, the cardboard receptacle of figure 9 is obtained.

By folding the two flange parts 11 about the second folding lines 13, and subsequently folding the locking sheet portions 15 about the third folding line 17, such that the locking sheet portions 15, provided in the flange parts 11, extend through the locking opening 19, provided in the flange parts 9, the flange parts 8, 11 are firmly connected and the cardboard tray 101 of figure 10 is realized.

The bottom wall 3 and side walls 5 define the receiving space 2 of said cardboard tray 101. By connecting the neighbouring flange parts 9, 11 an uninterrupted flange 21 along a circumference of the cardboard tray 101 is realized.

Figure 11 to figure 15 disclose in subsequent steps the manufacturing of a cardboard tray 201 from a sheet of cardboard 501.

Figure 11 discloses the sheet of cardboard 501, comprising sheet a bottom wall 3 and side walls 5. The side walls 5 are connected to the bottom wall 3 via first folding lines 7. The cardboard tray 1 further comprises flange parts 9, 11, connected to the side walls 5 via second folding lines 13 and are positioned at a side of the side walls 5 facing away from the bottom wall 3. The folding lines 7 are interrupted by cut-outs 35 provided in the bottom wall 3 and the side walls 5.

The flange parts 9 of two side walls 5 are provided with a locking sheet portion 15, connected via third folding lines 17. The flange parts 9 are further provided with a further locking opening 29. The flange parts 11 are provided with a locking opening 19 and a further locking sheet portion 31. The locking sheet portion

15 is provided with a cut 37 for allowing a part of the locking sheet portion 15 to extend through the locking opening 19. By folding the side walls 5 about the first folding lines 7 relative to the bottom wall 3, the cardboard receptacle of figure 12 is obtained, thereby defining a receiving space 2. By folding the two flange parts 9 about the second folding lines 13, the cardboard receptacle of figure 13 is obtained.

By folding the two flange parts 11 about the second folding lines 13, the cardboard receptacle of figure 14 is obtained.

By subsequently folding the locking sheet portion 15 about the third folding line 17 and pressing the locking sheet portions 15 such that the locking sheet portions 15, provided in the flange parts 9, extend through the locking opening 19, provided in the flange parts 11, and the further locking sheet portions 31, provided in the flange parts 11, extend through the further locking opening 29, provided in the flange parts 9, the flange parts 9, 11 are firmly connected and the cardboard tray 201 of figure 15 is realized.

The bottom wall 3 and side walls 5 define the receiving space 2 of said cardboard tray 201. By connecting the neighbouring flange parts 9, 11 an uninterrupted flange 21 along a circumference of the cardboard tray 201 is realized.

It is noticed that the above description of the figures describe one variation of many embodiments of the present disclosure.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article, “a” or “an” does not exclude a plurality.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CONCLUSIONS

A cardboard tray (1, 101, 201) folded from a sheet of cardboard (301, 401, 501), the cardboard tray (1, 101, 201) comprising sheet parts defining a bottom wall (3) and side walls (5) defining a receiving space (2) of the cardboard tray (1, 101, 201), the side walls (5) being connected, via respective first fold lines (7), to the bottom wall (3), the cardboard tray (1 , 101, 201) further comprises flange portions (9, 11) connected, via respective second fold lines (13), to the side walls (5) on one side of the side walls (5) facing away from the bottom wall (3), adjacent flange portions ( 9, 11) of the flange portions (9, 11) are connected to each other via a locking field portion (15) of one of the adjacent flange portions (8, 11), the locking field portion (15) being connected via a third fold line {17) with one of the adjacent flange portions (9, 11) and extending at least partially through a locking opening (19) provided in the paperboard sheet (301, 401, 501), which locking opening (19) is preferably provided in the other of the adjacent flange portions (8, 11), for connecting the adjacent flange portions (9, 11) and for creating a continuous flange (21) along a periphery of the carton tray (1, 101, 201).

The paperboard tray (1, 101, 201) according to claim 1, wherein the adjacent flange portions (9, 11) of the flange portions (9, 11) are connected to each other only through the bottom wall (3), the side walls (5) and the locking field portion (15) of the one of the adjacent flange portions (9, 11).

The paperboard tray (1, 201) according to claim 1, wherein one of the adjacent flange portions (9, 11) is provided with a further locking opening (29) and the other of the adjacent flange portions (9, 11) is provided with a further locking sheet portion (31), the further locking sheet portion (31) extending at least partially through the further locking opening (29) for connecting and creating a continuous flange (21) along the periphery of the carton tray (1, 201) .

The cardboard tray (1, 101, 201) according to any one of the preceding claims, wherein the connection of the adjacent flange parts (9, 11) and the flange parts (9, 11) to each other is free of an adhesive.

The cardboard tray (1, 101, 201) according to any one of the preceding claims, wherein the locking sheet portion (15) and the locking opening (19) of the adjacent flange portions (9, 11) are positively connected.

The cardboard tray (1, 101, 201) according to any preceding claim, wherein the one of the adjacent flange portions (9, 11) comprises at least two of the locking sheet portions (15), preferably three or more of the locking sheet portions (15), and wherein the other of the adjacent flange portions (9, 11) includes a corresponding number of locking apertures (19).

The cardboard tray (1) according to any one of the preceding claims, wherein the locking sheet portion (15) comprises an extension portion (23) extending through the locking opening (19).

The carton tray (1) according to claim 7, wherein the extension portion (23) is connected to a main field portion (25) of the locking field portion (15), via a fourth fold line (27) thereof,

The cardboard tray (1, 101, 201) according to any one of the preceding claims, wherein the side walls (5) are connected to each other only through the first fold lines (7) and through the second fold lines (13).

The cardboard tray (1, 101) according to any one of the preceding claims, wherein first flange portions (9) of the flange portions (9, 11) are connected to opposite side walls (5) of the side walls (5), the first flange portions (9) comprise a center flange portion (33), and wherein the locking sheet portions (15) are provided on opposite sides of the center flange portion (33), wherein a length of the center flange portion (33) substantially corresponds to a length of the second fold line (13) and wherein the locking sheet portions (15) are extensions of the center flange portion (33) beyond the second fold line (13).

The cardboard tray according to any one of the preceding claims, wherein each of the respective first fold lines (7) is interrupted by cutouts (35) provided in the bottom wall (3) and the side walls (5).

The carton tray according to any preceding claim, wherein the continuous flange (21) faces away from the receiving space (2).

An assembly of a cardboard tray (1, 101, 201) according to any one of the preceding claims and a film, wherein the film is fixed to the continuous flange (21) such that the bottom wall (3), the side walls (5 ) and the foil bounding the receiving space (2) of the cardboard tray (1,101, 201).

The assembly of claim 13, wherein the film is secured to the continuous flange (21) by heating and pressing the film against the continuous flange (21).

A paperboard sheet (301, 401, 501) arranged to be folded in a paperboard tray (1, 101, 201) according to any one of the preceding claims 1 to 12, wherein the paperboard sheet (301, 401, 501 a bottom wall sheet portion (3) comprising side wall sheet portions (5) connected via first fold lines (7) to the bottom wall sheet portion (3), and wherein the paperboard sheet (301, 401, 501) further comprises flange portion sheet portions (9, 11) connected, via second fold lines (13), with the sidewall sheet portion (5) on one side of the sidewall sheet portions (5) facing away from the bottom wall sheet portion (3), wherein first flange portion sheet portions (9) of the flange portion sheet portions (9,11) are provided with a locking sheet portion (15 ) and wherein second flange portion sheet portions (11) of the flange portion sheet portions (9,11} are provided with a locking opening (19).