Cardboard tray

Abstract

The present invention relates to a cardboard tray formed by folding an unfolded cardboard sheet, the cardboard tray comprising: a bottom wall having a peripheral portion composed of a plurality of linear edges; a plurality of wall portions each provided along the linear edges of the bottom wall; and a plurality of first flange portions provided on at least the wall portions facing each other along the peripheral portion, the first flange portions being provided on the edges of the wall portions located on the opposite side to and preferably arranged parallel to the corresponding linear edges of the bottom wall, the first flange portions being elongated first, second and third flange portion sections connected to be arranged parallel and adjacent to each other. and in each of the first flanges, the first flange section is disposed along the corresponding wall, the second flange section is double folded against the first flange section, and the third flange section is connected to the second flange section, and in each of the first flanges, the third flange section is glued to the corresponding wall on the inside of the cardboard tray, and the second flange section slopes downward from the third flange section towards the first flange section.

Description

[Technical field]

[0001] The present invention relates to a cardboard tray formed by folding an unfolded cardboard sheet, in particular, the cardboard tray comprises a bottom wall having a peripheral edge formed of a plurality of straight edges, a plurality of wall sections each provided along the straight edges of the bottom wall, and a plurality of first flange sections provided on at least the opposing wall sections along the peripheral edge, the first flange sections being provided on edges of the wall sections located opposite to and preferably parallel to the corresponding straight edges of the bottom wall, the first flange sections comprising first, second and third elongated flange sections connected to each other so as to be arranged parallel and adjacent to each other, the first flange sections being arranged along the corresponding wall sections, the second flange section being double folded with respect to the first flange section, and the third flange section being connected to the second flange section. [Background technology]

[0002] Such a cardboard tray is known from WO 2019-179930. In this known cardboard tray, the elongated second and third flange sections are folded outward, and the third flange section is glued to the outer surface of the wall of the cardboard tray. As a result, the outer surface of the wall is at least partially covered by the third flange section, and the surface of the wall is not fully available for printing. It is not always possible to solve the above problem by printing on both sides of the unfolded (unfolded) cardboard sheet, because in this case one of the printed sides may come into contact with the product transported in the cardboard tray. Furthermore, the cost of the cardboard tray increases if double-sided printing is performed.

[0003] Another drawback of known corrugated trays is that in in-line applications, the outward folding of the flange sections prevents or at least severely limits the possibility of folding the trays from an unfolded (unfolded) corrugated sheet. Typically, known corrugated trays need to be folded individually before being fed into an in-line application, such as a conveyor belt with an in-line filling station and an in-line sealing station.

[0004] The object of the present invention is to mitigate or even eliminate the above mentioned drawbacks. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019-179930 Summary of the Invention

[0006] This object is achieved by a cardboard tray according to the invention, as mentioned in the opening paragraph, characterized in that for each first flange, the third flange section is glued to the corresponding wall section on the inside of the cardboard tray, and the second flange section slopes downwards from the third flange section towards the first flange section.

[0007] According to the present invention, the third flange section is folded inwards and glued to the wall on the inside of the cardboard tray, so that the outer surface of the wall is not partially covered, thereby allowing printing over the entire surface of the wall.

[0008] Additionally, the third flange section is located on the inside of the cardboard tray, allowing the cardboard tray to be folded for in-line applications. Because the third flange section is folded inward, the cardboard tray can be supported on one side, the outside side, when the wall and flange section are folded and the third flange section is bonded to the wall on the inside of the cardboard tray.

[0009] The downwardly inclined second flange section makes it possible to provide a top seal foil under tension by forcing the second flange section into a horizontal position when sealing the top seal foil (top seal film), which then allows the second flange section to bend into an inclined position.

[0010] In a preferred embodiment of the cardboard tray according to the present invention, A fold line between the second flange section and the third flange section is spaced relative to a bottom wall above a fold line between the first flange section and the wall.

[0011] The resulting first flange has a triangular cross-section, which provides strength to the first flange, allowing heavier products to be carried in the cardboard tray and thinner cardboard sheets to be used.

[0012] Preferably, the width of the second flange section is greater than the width of the first flange section.

[0013] In another embodiment of the cardboard tray according to the present invention, the third flange section extends to the bottom wall to cover the corresponding wall section.

[0014] The third flange section extends to the bottom wall to provide a smooth inner surface with no thickness variations.

[0015] In a further preferred embodiment of the cardboard tray according to the present invention, the multiple wall portions are provided with second flange portions in addition to the first flange portions, and the first flange portions and the second flange portions are alternately arranged circumferentially along the peripheral edge portion so as to form a circumferential flange.

[0016] This allows the first flange portion to apply tension to the top seal foil (top seal film), while the circumferential flange allows the top seal foil to be hermetically sealed.

[0017] In yet another preferred embodiment of the cardboard tray according to the present invention, a longitudinal end of the second flange portion overlaps a longitudinal end of the first flange portion section of the first flange portion.

[0018] The overlapping portions may be bonded together to further strengthen the circumferential flange and to allow the second flange section of the first flange to be aligned with the second flange in a horizontal plane, thereby providing a flat, continuous sealing surface for the top seal foil (top seal film).

[0019] The adhesive for bonding the overlapping longitudinal ends may be a glue, a hot melt or a sealing lacquer. If a sealing lacquer is used, the heat from the heating element, which warms the sealing lacquer, may be relaxed by the cardboard. In such a case, the longitudinal end in direct contact with the heating element may be provided with holes or slits, which facilitate the transfer of heat from the heating element towards the sealing lacquer present at the interface between the two longitudinal ends. Preferably, the edge of the longitudinal end of the second flange portion abuts the edge of the longitudinal end of the second flange portion section of the first flange portion.

[0020] In another embodiment of the cardboard tray according to the present invention, the angle combination of the two abutting longitudinal end edges is greater than 90 degrees, such that the abutting longitudinal end edges support the downwardly inclined second flange section, thereby removing all tension from the third flange section.

[0021] In yet another embodiment of the cardboard tray of the present invention, the second flange section and the third flange section are removed from each of the first flange portions, and the longitudinal end edges of the second flange portions abut against longitudinal end edges of the first flange section of the first flange portion, and the combined angle of the two abutting longitudinal end edges is greater than 90 degrees.

[0022] Because the combination of angles is greater than 90 degrees, the edges of the two abutting longitudinal ends securely support the downwardly inclined first flange section, so that tension in the top seal foil (top seal film) can be maintained without further support from the second and third flange sections.

[0023] Preferably, a foil (film) is applied (laminated) to the inner surfaces of the bottom and wall portions of the cardboard tray and to the first and second flange portions. The foil (laminating foil, laminating film) thus applied maintains the edges of the longitudinal ends in abutting position and the first flange portion in a downwardly inclined position. This ensures that the flange portion is maintained in the desired position before the placement of the top seal foil (top seal film). [Brief description of the drawings]

[0024] These and other features of the present invention are described below in conjunction with the accompanying drawings.

[0025] [Figure 1] 1 shows a sheet of a cardboard tray in an unfolded state according to a first embodiment of the present invention. [Diagram 2] 2 shows a cross-sectional view of the cardboard tray of FIG. 1 in a folded state. [Diagram 3] 2 is a bottom perspective view of the cardboard tray of FIG. 1 in a folded state. FIG. [Figure 4] FIG. 2 is a top perspective view of the cardboard tray of FIG. 1 in a folded state. [Diagram 5] 13 shows a sheet of a cardboard tray in an unfolded state according to a second embodiment of the present invention. [Figure 6] 6 shows a perspective view of the cardboard tray of FIG. 5 in a folded position. [Figure 7] 13 shows a sheet of a cardboard tray according to a third embodiment of the present invention in an unfolded state. [Figure 8] 8 shows a cross-sectional view of the cardboard tray of FIG. 7 in a folded state. [Figure 9] 13 shows a sheet of a cardboard tray in an unfolded state according to a fourth embodiment of the present invention. [Figure 10] 10 shows a perspective view of the cardboard tray of FIG. 9 in a folded position. [Figure 11A] 13 shows details of a cardboard tray according to a fifth embodiment of the present invention. [Figure 11B] The details of the cardboard tray are shown. [Figure 11C] The details of the cardboard tray are shown. [Figure 12] FIG. 13 is a cross-sectional view of a cardboard tray according to a sixth embodiment of the present invention. [Figure 13] 10A and 10B show diagrammatically a first method of bonding the third flange section to the wall; [Figure 14] 13A and 13B show diagrammatically a second method of bonding the third flange section to the wall. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] FIG. 1 shows a sheet (cardboard tray 1) in an unfolded state (unfolded state) of a cardboard tray according to a first embodiment of the present invention. The sheet (cardboard tray 1) has a bottom wall 2 and four walls 3 attached to the bottom wall 2. The four walls 3 are provided with a number of adhesive flaps 4 that are used to position the four walls 3 relative to one another. These adhesive flaps 4 can be folded over the outer or inner surface of the adjacent wall 3. Note that the adhesive flaps 4 may be omitted, particularly when a foil (film) is attached (laminated) to the inner surface of the cardboard tray (sheet) 1.

[0027] First flange portions 5, 6, 7 are disposed on two mutually opposing side portions of the bottom wall 2, and second flange portions 8 are disposed on the other two mutually opposing side portions of the bottom wall 2.

[0028] 2 shows a cross-sectional view of a sheet (corrugated tray 1) folded into a corrugated tray according to the present invention. The first flanges 5, 6, 7 have an elongated first flange section 5 extending outwardly from the corrugated tray, an elongated second flange section 6 that is double-folded onto the first flange section 5, and an elongated third flange section 7 that is folded onto the inner surface of the corrugated tray over the wall 3.

[0029] The width w1 of the first flange section 5 is smaller than the width w2 of the second flange section 6, and the second flange section 6 is inclined downward. The folds 9 are spaced apart above the folds 10 such that a triangular cross section is formed in the first flanges 5, 6, 7. By varying the ratio of the width w1 to the width w2, the inclination angle of the second flange section 6 can be defined (changed). Preferably, the inclination angle of the second flange section 6 is greater than or equal to about 20 degrees and less than or equal to about 30 degrees. However, the inclination angle of the second flange section 6 may be close to 0 degrees.

[0030] FIG. 3 shows the cardboard tray 1 in a folded state, seen from below. The longitudinal end 11 of the second flange section 6 overlaps with the longitudinal end 12 of the second flange section 8. As shown in FIG. 3, the longitudinal end 12 is located below the longitudinal end 11 (see also FIG. 4). Further strength is obtained by gluing the two longitudinal ends 11, 12 together. An adhesive, e.g. glue, hot melt or sealing lacquer, may be provided on the longitudinal ends 11, 12 to attach the flanges to each other when folding them. The flanges may also be attached to each other during a top sealing process that is applied after the cardboard tray 1 is filled.

[0031] 5 shows a sheet (cardboard tray 20) in an unfolded state (unfolded state) of a cardboard tray according to a second embodiment of the present invention. The cardboard tray (sheet) 20 has a bottom wall 21, a wall portion 22, first flange portions 23, 24, 25, and second flange portions 26, 27, 28. The first flange portions 23, 24, 25 and the second flange portions 26, 27, 28 are alternately arranged in the circumferential direction of the bottom wall 21.

[0032] Each of the first flange portions 23, 24, 25 and the second flange portions 26, 27, 28 has a first flange portion section 23, 26 extending outward from the cardboard tray 20 in the folded state, a second flange portion section 24, 27 that is double-folded relative to the first flange portion section 23, 26, and a third flange portion section 25, 28 that is folded inwardly of the cardboard tray 20 relative to its corresponding wall portion 22 (see also Figure 6).

[0033] The first flange section 23 has a longitudinal end 29 which overlaps a longitudinal end 30 of the second flange section 27. This provides a flat uninterrupted peripheral flange for hermetic sealing of, for example, a top foil.

[0034] 7 shows a sheet (cardboard tray 40) in an unfolded state (unfolded state) of a cardboard tray according to a third embodiment of the present invention. The cardboard tray (sheet) 40 has a bottom wall 41, a wall portion 42 having a plurality of adhesive flaps 43, first flange portions 44, 45, 46, and a second flange portion 47.

[0035] As shown in FIG. 8A , the first flange portions 44, 45, 46 have a first flange portion section 44 extending outward, a second flange portion section 45 folded double over the first flange portion section 44, and a third flange portion section 46 folded inwardly of the cardboard tray 40 over the wall portion 42.

[0036] Figure 8B shows a variation of Figure 8A, in which a foil 47 is further laminated onto the bottom wall 41, onto the wall 42 and onto the second flange section 45. The foil 47 helps to maintain the first flanges 44, 45, 46 in a downwardly inclined position.

[0037] FIG. 9 shows a sheet (cardboard tray 60) of a cardboard tray according to a fourth embodiment of the present invention in an unfolded (unfolded) state.

[0038] The cardboard tray (sheet) 60 has a bottom wall 61, a wall portion 62 having an adhesive flap 63, a pair of first flange portions 64, 65, 66 arranged opposite each other, and a pair of second flange portions 67 arranged opposite each other.

[0039] The second flange portion 67 has a longitudinal end 68. The longitudinal end 68 of the second flange portion 67 overlaps a longitudinal end 69 of the first flange portion section 64. An edge of the longitudinal end 68 of the second flange portion 67 abuts an edge 70 of the longitudinal end of the second flange portion section 65.

[0040] The combination of angle α of longitudinal end edge 70 and angle β of longitudinal end edge 68 is greater than 90 degrees, resulting in both second flange section 65 and second flange section 67 being biased to slope downward.

[0041] 11A to 11C show a cardboard tray 80 according to a fifth embodiment of the present invention. The cardboard tray 80 has a bottom wall 81 and a plurality of wall portions 82. First flange sections 83, 84 are provided on the upper surface of each wall portion 82 (the second flange section and the third flange section have been removed (not provided)).

[0042] A longitudinal end edge 85 of first flange section 83 has an angle α, and a longitudinal end edge 86 of first flange section 84 has an angle β.

[0043] When the cardboard tray 80 is placed in a mold (not shown), the longitudinal end edges 85, 86 are pressed together (see FIG. 11B). This position is fixed by laminating a foil 87 to the bottom wall 81, the walls 82, and the flanges 83. Furthermore, when the combination of angles α and β is greater than 90 degrees, the flanges 83, 84 slope downward to provide additional strength to the cardboard tray.

[0044] FIG. 12 shows a cross-sectional view of a sixth embodiment of a cardboard tray 90 according to the present invention. The cardboard tray 90 has a bottom wall 91 with an upstanding wall 92. A first flange section 93, 94, 95 is disposed on the top of the wall 92. The first flange section has a first flange section 93 extending outwardly, a second flange section 94 folded twice against the first flange section 93, and a third flange section 95 extending inwardly of the cardboard tray 90 along the entire height of the wall 92. This ensures that the cardboard tray 90 has an uninterrupted surface on both the outside and inside. A foil (film) 96 is attached to the bottom wall 91, the wall 92, and the second flange section 94 to help maintain the flanges in a downwardly inclined position.

[0045] Figure 13 shows diagrammatically a first method for bonding the third flange section 7 to the wall 3 of the cardboard tray 1 shown in Figures 1 and 2. A lower mould 100 and an upper mould 101 which is movable up and down are provided. The lower mould 100 is provided with a recess 102 and an edge 103 adjacent to the recess 102. The upper mould 101 has an inverse shape to the lower mould 100 and has a flange 104 which cooperates with the edge 103.

[0046] The edge 103 and flange 104 are sloped downwards so that when the cardboard tray 1 is pressed between the upper and lower halves 101, 100, the third flange section 7 is glued to the wall 3. Once the adhesive has cured, the cardboard tray 1 maintains its shape with the downwardly sloping flanges 5, 6, 7.

[0047] 14 shows diagrammatically a second way of gluing the third flange section 7 to the wall 3. For this purpose the same upper mould 101 as above is used in combination with two laterally movable support rails 105, 106. After the flanges 5, 6, 7 of the cardboard tray 1 are compressed between the flanges 104 and the support rails 105, 106 and the adhesive has hardened, the support rails 105, 106 are moved laterally so that the cardboard tray 1 can be dropped, for example onto a conveyor.

Claims

1. A cardboard tray formed by folding an unfolded cardboard sheet, a bottom wall having a periphery formed of a plurality of linear edges; A plurality of walls each provided along the linear edge of the bottom wall; a plurality of first flange portions provided on at least opposing wall portions along the peripheral edge portion; The first flange portion is provided on an edge of the wall portion that is located opposite and parallel to the corresponding linear edge portion of the bottom wall, the first flange portion comprises elongated first, second and third flange portion sections connected in a parallel adjacent arrangement to one another; In each of the first flanges, the first flange section is disposed along the corresponding wall, the second flange section is double-folded relative to the first flange section, and the third flange section is connected to the second flange section; In each of the first flanges, the third flange section is bonded to the corresponding wall on the inside of the cardboard tray, and the second flange section is inclined downward from the third flange section to the first flange section. Cardboard tray.

2. a fold line between the second flange section and the third flange section is spaced relative to the bottom wall above a fold line between the first flange section and the wall.

2. The cardboard tray according to claim 1.

3. The width of the second flange section is greater than the width of the first flange section. The cardboard tray according to claim 1 or 2.

4. The third flange section extends to the bottom wall to cover the corresponding wall portion. The cardboard tray according to any one of claims 1 to 3.

5. The plurality of wall portions are provided with second flange portions together with the first flange portions, and the first flange portions and the second flange portions are alternately arranged in a circumferential direction along the peripheral edge portion so as to form a circumferential flange. The cardboard tray according to any one of claims 1 to 4.

6. a longitudinal end of the second flange portion overlaps a longitudinal end of the first flange portion section of the first flange portion; 6. The cardboard tray according to claim 5.

7. an edge of a longitudinal end of the second flange portion abuts an edge of a longitudinal end of the second flange portion section of the first flange portion; 7. The cardboard tray according to claim 6.

8. a combination of angles between the edges of the longitudinal ends of the second flange portion and the edges of the longitudinal ends of the second flange portion section of the first flange portion that abut each other is greater than 90 degrees; 8. The cardboard tray according to claim 7.

9. A cardboard tray formed by folding an unfolded cardboard sheet, a bottom wall having a periphery formed of a plurality of linear edges; A plurality of walls each provided along the linear edge of the bottom wall; a plurality of first flange portions provided on at least opposing wall portions along the peripheral edge portion; The first flange portion is provided on an edge of the wall portion that is located opposite and parallel to the corresponding linear edge portion of the bottom wall, the first flange portion comprises an elongated first flange portion section; For each of the first flanges, the first flange section is disposed along a corresponding one of the walls; The plurality of wall portions are provided with second flange portions together with the first flange portions, and the first flange portions and the second flange portions are alternately arranged in a circumferential direction along the peripheral edge portion to form a circumferential flange, an edge of a longitudinal end of the second flange portion abuts an edge of a longitudinal end of the first flange portion section of the first flange portion; a combination of angles between the edges of the longitudinal ends of the second flange portion and the edges of the longitudinal ends of the first flange portion section of the first flange portion that abut each other is greater than 90 degrees; Cardboard tray.

10. A foil is attached to the inner surface of the cardboard tray at the bottom wall and the wall portion, and to the first flange portion and the second flange portion.

10. The cardboard tray of claim 9.

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