Cardboard Tray

Abstract

A cardboard tray may include a bottom wall part; arranged along the circumference of the bottom wall part, a number of upstanding side wall parts alternated with the same number of upstanding corner wall parts; a circumferential flange composed out of abutting circumferential flange parts, each circumferential flange part being arranged, along a fold line, to the upper edge of one of the upstanding side wall parts; strengthening flange parts arranged, along a fold line, to the upper edge of each upstanding corner wall part, wherein a strengthening flange part is adhered to both circumferential flange parts of the adjacent side wall parts; wherein the circumferential flange has a sealing zone, which extends along the circumferential flange and which spans at least part of the width of said circumferential flange, and wherein the strengthening flange parts at least partially overlap with the sealing zone, when viewed in a direction perpendicular to the sealing zone.

Claims

1. Cardboard tray comprising: a bottom wall part; arranged along the circumference of the bottom wall part, a number of upstanding side wall parts alternated with the same number of upstanding corner wall parts; a circumferential flange composed out of abutting circumferential flange parts, each circumferential flange part being arranged, along a fold line, to the upper edge of one of the upstanding side wall parts, wherein the circumferential flange has a sealing zone, which extends along the circumferential flange and which spans at least part of the width of said circumferential flange; wherein strengthening flange parts arranged, along a fold line, to the upper edge of each upstanding corner wall part, wherein a strengthening flange part is adhered to both circumferential flange parts of the adjacent side wall parts; wherein the strengthening flange parts at least partially overlap with the sealing zone, when viewed in a direction perpendicular to the sealing zone.

2. The cardboard tray according to claim 1, wherein the strengthening flange parts fully overlap the sealing zone in width direction of the circumferential flange.

3. The cardboard tray according to claim 1, wherein adjacent upper edges of an upstanding side wall part and adjacent upstanding corner wall part are under an angle of larger than 0 and smaller than 90, preferably larger than 35 and smaller than 55, more preferably 45.

4. The cardboard tray according to claim 1, wherein the combined angle of the abutting edges of two adjacent circumferential flange parts is smaller than the angle between the upper edges of the two upstanding side wall parts of said two adjacent circumferential flange parts.

5. The cardboard tray according to claim 1, wherein at least one longitudinal end of at least one of the circumferential flange parts extending along an adjacent upstanding corner wall part is provided with a glue flap, which is adhered to said upstanding corner wall part.

6. The cardboard tray according to claim 1, wherein at least one of the upstanding side wall parts is provided with a glue flap, which is adhered to the adjacent upstanding corner wall part.

7. The cardboard tray according to claim 1, wherein at least one of the circumferential flange parts comprise at least a first, a second and third elongate flange part section, which are connected parallel and along an elongate edge to each other, wherein the first elongate flange part section is arranged to the corresponding upstanding side wall part, the second elongate flange part section is double folded against the first elongate flange part section, and the third elongate flange part section is connected parallel and along an elongate edge to the second elongate flange part section, wherein the third elongate flange part section is adhered either on the inside or the outside of the corresponding upstanding side wall part.

8. The cardboard tray according to claim 1 further comprising a plastic film, which plastic film covers the cardboard tray and is sealed along the circumferential flange at the sealing zone.

9. The cardboard tray according to claim 1, wherein an amount of glue or adhesive is arranged between each strengthening flange part and both corresponding circumferential flange parts, wherein the amount of glue or adhesive extends between the abutting edges of the circumferential flange parts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

[0038] FIG. 1 shows a perspective view of a first embodiment of a cardboard tray according to the invention.

[0039] FIG. 2 shows the unfolded sheet for the cardboard tray according to FIG. 1.

[0040] FIG. 3 shows a cross-section along the line III-III in FIG. 1.

[0041] FIG. 4 shows a bottom view of a corner of the cardboard tray of FIG. 1.

[0042] FIG. 5 shows a part of an unfolded sheet for a second embodiment of a cardboard tray according to the invention.

[0043] FIG. 6 shows a cross-section of a cardboard tray folded out of the unfolded sheet of FIG. 5.

[0044] FIG. 7 shows a perspective view of part of a third embodiment of a cardboard tray according to the invention.

[0045] FIG. 8 shows a cross-section of the cardboard tray of FIG. 7.

[0046] FIGS. 9A and 9B show a cross-sectional view of a detail of a corner of a cardboard tray according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0047] FIG. 1 shows a perspective view of a first embodiment of a cardboard tray 1 according to the invention. The cardboard tray 1 has an eight-sided bottom wall part 2 along the circumference upstanding side wall parts 3 alternated with upstanding corner wall parts 4 are arranged.

[0048] Abutting circumferential flange parts 5 are arranged along a fold line 6 to the upper edge of one of the upstanding side wall parts 3. Each of the circumferential flange parts 5 extend on each longitudinal end beyond the fold line 6 to border part of an adjacent corner wall part 4.

[0049] As shown in FIG. 2, strengthening flange parts 7 are arranged, along a fold line 8, to the upper edge of each upstanding corner wall part 4. The strengthening flange parts 7 are adhered to the bottom side of the extending flange parts 5 to keep the cardboard tray 1 in the folded position.

[0050] FIG. 3 shows a cross section of the cardboard tray 1 according to the invention. Clearly shown is that the strengthening flange 7 is adhered to the bottom of the circumferential flange part 5. A sealing zone 9 is defined on the circumferential flange 5 to which a plastic sheet 10 is sealed. The strengthening flange 7 spans at least part of the width of said circumferential flange 9 such that the sealing zone 9 is at least partially and preferably, as shown, fully overlapped by the strengthening flange 7 (see FIG. 4).

[0051] FIG. 5 shows a part of an unfolded sheet for a second embodiment of a cardboard tray 20 according to the invention. The cardboard tray 20 has a bottom wall part 21 with upstanding side wall parts 22 and corner wall parts 23. The side wall parts 22 have each a circumferential flange part 24, 25. The circumferential flange part 24, 25 extends in longitudinal direction with an end 25 over the strengthening flange part 26 arranged to the corner wall part 23. This is similar to the embodiment 1 shown in FIG. 1.

[0052] The bottom edge 27, 28 of the side wall parts 22 is formed partially by a cut line 27 and partially by a fold line 28. When the unfolded sheet as shown in FIG. 5 is folded to a cardboard tray 20 as shown in FIG. 6, the cut line 27 will form a foot element which will space the bottom wall part 21 from any underground on which the cardboard tray 20 is placed.

[0053] The combined angle .sub.1 and .sub.2 of the abutting edges of the two adjacent circumferential flange parts 24, 25 is smaller than the angle between the upper edges of the two upstanding side wall parts 22 of said two adjacent circumferential flange parts 24, 25. When the cardboard tray 20 is folded into its shape, the circumferential flange parts 24, 25 need to slope down (see FIG. 6) in order for the longitudinal edges to abut and form a smooth circumferential flange. Because the circumferential flange slopes down, additional strength is provided to the cardboard tray 20.

[0054] FIG. 7 shows a third embodiment of a cardboard tray 30 according to the invention. The cardboard tray 30 has a bottom wall part 31 with upstanding side wall parts 32 and corner wall parts 33. To the upper edge of the side wall parts 32, a first 34, a second 35 and third 36 elongate flange part section are connected parallel and along an elongate edge to each other. (see also FIG. 8) The first 34, a second 35 and third 36 elongate flange part section are double folded with the third elongate flange part section 36 adhered to the side wall part 32. This provides a strong flange along the side wall part 32. Such a double folded flange could also be provided for the other side wall parts of the tray.

[0055] The second elongate flange part section 35 extends in longitudinal direction along the upper edge of the corner wall part 33. This corner wall part 33 is provided with a strengthening flange (not shown) similar to the embodiments 1 and 20. To further strengthen the corner, the elongate flange part section 35 is provided at the end with glue flaps 37 which are adhered to the corner wall part 33.

[0056] The side wall parts 32 are furthermore provided with glue flaps 38 along the side edges, which glue flaps 38 are adhered to the corner wall part 33.

[0057] As will be clear from this embodiment as well as the previous embodiments, only the corner wall part needs to be provided on one side with an adhesive for the full cardboard tray to be folded into its shape.

[0058] FIG. 9A and 9B show a detail of a corner of a cardboard tray 40 similar to any of the previous embodiments. The corner has a corner wall part 41 with a strengthening flange 42 adhered with a glue layer 45 to the bottom side of circumferential flange parts 43, 44.

[0059] If the circumferential flange parts 43, 44 would not fully abut, the glue could well up from the space between the flange parts 43, 44 to form a bulge 46.

[0060] When a plastic sheet 47 is laminated onto the circumferential flange parts 43, 44, the bulge 46 would be flattened (see FIG. 9B), such that a smooth sealing zone is formed and the seal of the plastic sheet 47 on the circumferential flange 43, 44 is airtight.

[0061] By designing the radius of the corners of the circumferential flange, the width of the circumferential flange and the width of the side wall parts and corner wall parts, a cardboard tray can be provided, which corresponds in dimensions to conventional plastic trays. This allows for a user to keep the existing top seal devices and tools, without any additional investments, and easily switch between plastic trays and cardboard trays and even handle both types through each other.

[0062] The strengthened corners of the cardboard tray according to the invention ensures that the elongate sides of the tray are sufficient strong that a cardboard tray, filled with for example fruit of vegetables, will hang into the tools of existing top seal devices, similar to a plastic tray. The elongate sides will not bend such that a filled cardboard tray falls from the top seal device.