Food containers

Abstract

A blank 1 foldable to form a tray (3, fig 2) for carrying food. The blank comprises a base 2, where the base comprises a plurality of edges 4a, 4b, 4c, 4d and a plurality of wall elements 6a, 6b, 6c,

Description

The invention relates to blanks which are foldable to form a tray for carrying food, to a tray formed from such a blank and to a box for carrying food which is formed from two such trays. Blanks are planar pieces of material (typically cardboard) which are shaped such that they can be folded to form a three-dimensional object. Trays used for carrying food are often formed from blanks. This is particularly common for disposable trays. To better protect the food carried in such trays, it can be advantageous to cover such trays and, in particular, to secure such a cover to the tray to form a box around the food. A first aspect of the invention is a blank foldable to form a tray for carrying food, wherein the blank comprises: a base comprising a plurality of edges; a plurality of wall elements extending from the edges of the base, wherein each of the plurality of wall elements comprise: a wall portion; and an extension, and the wall portions comprise: a proximal end joined to the base along one of the plurality of edges at a wall fold line; a proximal part extending from the proximal end; a distal part extending from the proximal part; and a distal end from which the extension extends, wherein, when a tray is formed by folding the blank along the wall fold lines to form an enclosure for carrying food, the plurality of distal parts and extensions together form a circumferential tray interface, the tray interface is configured such that a second tray having a second tray interface which is substantially identical to the tray interface can couple with the tray interface to form a box, the extension of each wall element of the tray interface crosses an extension of a wall element of the second tray interface, respectively, at an intersection such that each extension of the tray interface can be arranged outside a distal part of the second tray interface. A second aspect of the invention is a tray formed by folding the blank of the first aspect of the invention along the wall fold lines such that the plurality of distal parts and extensions together form a circumferential tray interface, wherein the base is in a base plane, and the plurality of wall portions project out of the base plane to form a circumferential wall, thereby forming an enclosure for carrying food. Accordingly, the blank according to the first aspect of the invention forms a tray for carrying food according to the second aspect of the invention having a tray interface which is readily coupleable to an identical tray interface of a second tray to form a box for carrying food. The trays are configured such that they can be coupled together by engaging the tray interface with the identical second tray interface, and crossing each extension of the tray interface with a corresponding extension of the second tray interface at an intersection such that each extension of the tray interface can be arranged outside a distal part of the second tray interface and vice versa. It should be noted that although each extension of the tray interface can be arranged outside a distal part of the second tray interface as described, each extension of the tray interface is not necessarily arranged outside a distal part of the second tray interface when a box is formed. The resulting box forms a substantially closed container which can be readily opened and closed. Such a box may be formed from two identical trays which can reduce the number of components required at point of sale. Food can be provided to a consumer in a single tray or, if more environmental protection is required, a second tray can be connected to the first tray to form a box. This can simplify the delivery of the food at the point of sale as the food can be provided in a tray and an identical tray can be issued with the tray, either as a formed box or separately for the customer to assemble the box themselves. When formed into a box, the extensions overlap the distal part of the wall portion of the opposing tray, and therefore cover the joint where the two trays meet. This may reduce exposure of the food therein to contaminants external to the box. The overlapping of the extensions and the distal parts may also provide enhanced structural support for the box. This may reduce the risk or crushing the box during transport. The extensions may overlap along substantially the entire length of a wall element, for example at least 90% of the length of a wall element. The blank may be formed by any suitable process, for example by cutting the blank from a sheet of material. A plurality of blanks may be cut from a single sheet of material. The fold lines may comprise lines of weakness in the blank to ease folding. The fold lines may comprise score lines, pre-formed folds, and I or lines of perforations. Cutting and defining the fold lines may be performed at separate times, or simultaneously, and may be formed using a single machine. The machine may be controlled manually or automatically under instruction from a computer program. Similarly, the blank may be folded along the fold lines and secured to form the tray either manually or automatically using a machine controlled under instruction from a computer program. The blank may be made of any foldable material which is suitable for carrying food. The material may be modified, for example, by laminating or coating, to enhance the suitability for carrying food, for example to reduce the penetration of liquids, oils or the like. For example, the material may be card or paperboard and a surface thereof, particularly a surface to become an interior of the tray, may be covered by a plastic film or other coating. The plastic film or coating may be applied by any suitable technique, for example by laminating, heat sealing or otherwise applying. The blank may have a substantially constant thickness; for example, between 0.1mm to 0.7mm, for example, between 0.2mm to 0.6mm, for example, 0.3mm. The blank may have a surface area of any size; for example, between 100cm2 and 900cm2, for example, between 200cm2 and 800cm2, for example 500cm2. The base may be any suitable shape depending on the intended tray shape. The edges of the base may be substantially straight. For example, the base may have three or more edges, for example, four edges. The length of the edges may be different (for example, the edges of the base may define a rectangular base) or the length of the edges may be the same (for example, the edges of the base may define a square base). The length of the edges may be between 5cm to 20cm; for example, 10cm. The base may have a surface area of any suitable size; for example, between 9cm2 and 400cm2, for example, between 25cm2 and 225cm2, for example, 100 cm2. A wall element may extend from each of the edges of the base. The plurality of wall elements may be any suitable shape depending on the intended tray shape. The components of each wall element, the wall portion and the extension, may be any suitable shape depending on the intended tray shape. The edges of the wall portion and the extension may define a quadrilateral shape, for example a trapezium or a rectangle. As the tray is formed from a single blank, the proximal end, proximal part, distal part, and distal end of each wall portion, and the extension of each wall element, are all formed from the same piece of material. The length of a wall portion may be between 5cm to 20cm, and the length of the extensions may be less than half (for example, less than a quarter or less than an eighth of the length of its respective wall portion). The wall portion may have a surface area of between 9cm2 and 100cm2, for example, 25cm2. The extension may have a surface area of less than half (for example, less than a quarter or less than an eighth) of the surface area of the wall portion. Each of the wall elements may have a length parallel to the base. The length of the wall element may vary, for example increase, with distance from the base. Accordingly, the wall portion and extension of each wall element may also have a length parallel to the base. The length of each extension may be any length less than the length of its respective wall portion. For example, at the connection between the wall portion and extension of each wall element, the length of each extension may be half or less than, a third or less than, or a quarter or less than, the length of its respective wall portion. The wall portions of the tray may taper outwardly from the proximal end to the distal end, such that an area defined by the plurality of distal ends is greater than an area defined by the plurality of proximal ends. This may be achieved by configuring the wall portions such that have a trapezoidal shape. This may enable the trays to be stacked in a nested manner which may facilitate storage and I or shipping. The base of the tray may be rectangular or square, and the plurality of wall elements may include a first end wall element and a second end wall element, wherein the first end wall element and the second end wall element are at opposite ends of the base. Further, the plurality of wall elements may include a first side wall element and a second side wall element, wherein the first side wall element and the second side wall element are at opposite sides of the base. When the tray is formed, the first end wall element and the first side wall element may meet at a first wall edge, the first side wall element and the second end wall element may meet at a second wall edge, the second end wall element and the second side wall element may meet at a third wall edge, and the second side wall element and the first end wall element may meet at a fourth wall edge. When formed into a tray, the wall elements may be affixed to one another at the first, second, third, and fourth wall edges to form the circumferential wall. The wall elements may be fixed to one another by any suitable means. A tab may extend from one of the wall portions at each of the first, second, third, and fourth wall edges, and each tab may be configured to overlap an adjacent wall portion and be affixed thereto to secure the circumferential wall. A web may extend between the wall portions at each of the first, second, third, and fourth wall edges, and each web may be configured to fold onto an adjacent wall portion and be affixed thereto to secure the circumferential wall. The circumferential wall may have any height away from the base; for example, between 3cm to 10cm, for example, 5cm. Wall elements may have a single extension from the distal end of the wall portion. Wall elements may include a plurality of extensions distributed along the length of the distal ends of the wall portion, for example there may be two extensions, or three extensions. Two extensions from a wall element may linked by a bridge. The bridge may extend across one or more other extensions. The plurality of wall elements may each have only one extension. When forming a box, the first end wall element of the first tray may engage with the first end wall element of the second tray and this would mean that the first side wall element of the first tray engages with the second side wall element of the second tray. In other examples, the first end wall element of the first tray may engage with the second end wall element of the second tray and this would mean that the first side wall element of the first tray engages with the first side wall element of the second tray. For a tray with a square base, a side wall element may engage with an end wall element. The end wall elements may be shorter than the side wall elements, but this need not be the case. The extension of the first end wall element may meet the extension of the first side wall element at the first wall edge and the extension of the second end wall element may meet the extension of the second side wall element at the third wall edge. A first end wall element may have one first end wall extension. The first end wall extension may be located at any location along the length the first end wall portion between the fourth wall edge and the first wall edge. For example, the first end wall extension may be located substantially centrally between the fourth wall edge and the first wall edge. The second end wall element of that blank may have two second end wall extensions. One of the two second end wall extensions may be located at an end of its respective wall portion nearest the second wall edge and the other may be located at an end of its respective wall portion nearest the third wall edge. The second end wall extensions may be immediately adjacent the second and third wall edges, or there may be a space between the second end wall extensions and the second and third wall edges. The first end wall extension of a first tray may be able to fit between the second end wall extensions of a second tray when forming a box. Such an arrangement of wall element extensions will be referred to as a one-two arrangement and this could be on side or end wall elements. A first side wall element may have one first side wall extension. The first side wall extension may be located at an end of the first side wall portion nearest the first wall edge or the second wall edge. The second side wall element of the blank may have one second side wall extension. The second side wall extension may be located at an end of the second side wall portion nearest the fourth wall edge or the third wall edge. For example, the first side wall extension may be located an end of the first side wall portion nearest the first wall edge and the second side wall extension may be located at an end of the second side wall portion nearest the fourth wall edge, such that the first and second side wall extension are opposite each other. Similarly, the first side wall extension may be located an end of the first side wall portion nearest the second wall edge and the second side wall extension may be located at an end of the second side wall portion nearest the third wall edge, such that the first and second side wall extension are opposite each other. Such an arrangement of wall element extensions will be referred to as an opposite one-one arrangement and this could be on side or end wall elements. Two substantially identical trays having an end wall one-two arrangement and a side wall opposite one-one arrangement as described above may be coupled together by inverting a second tray over a first tray; engaging the first side wall extension of the first tray with the first side wall extension of the second tray and the second side wall extension of the first tray with the second side wall extension of the second tray such that they cross at an intersection and each extension is arranged outside a distal part of the opposing tray; and slotting the first end wall extension of the first tray between the second end wall extensions of the second tray, and vice versa, such that they cross at an intersection and each extension is arranged outside a distal part of the opposing tray. To further secure trays having a one-two arrangement together, the first end wall extension may have a retention bulge at a first end nearest the first wall edge and / or a retention bulge at a second end nearest the fourth wall edge. Alternatively, or additionally, the one or both of the two second end wall extensions may each have a retention bulge at an end opposite the second wall edge and the third wall edge, respectively. The first and second wall extensions may be sized so that a length of the first wall extension substantially equals the space between the second wall extensions. In this way, retention bulges may allow overlapping along the length of the wall element between the first end wall extension and the two second end wall extensions. Retaining bulges may be included on extensions of any arrangement to enhance the securing of one tray to the other. The first end wall element may have two first end wall extensions connected by a first end wall bridge. One of the two connected first end wall extensions may be located at an end nearest the first wall edge and the other may be located at an end nearest the fourth wall edge. The first end wall extensions may be immediately adjacent the first and fourth wall edges, or there may be a space between the first end wall extensions and the first and fourth wall edges. The first end wall element may also have a central first end wall extension, wherein the central first end wall extension is located substantially centrally along the length of its respective wall portion between the two connected first end wall extensions. Such an arrangement of wall element extensions will be referred to as a bridged extension arrangement and this could be on side or end wall elements. Further, the second end wall element may have a similar bridged extension arrangement with two connected second end wall extensions. One of the two connected second end wall extensions may be located at an end nearest the second wall edge and the other may be located at an end nearest the third wall edge. The second end wall extensions may be immediately adjacent the second and third wall edges, or there may be a space between the second end wall extensions and the second and third wall edges. The two connected second end wall extensions may be connected by a second end wall bridge. The second end wall element may also have a substantially central second end wall extension, wherein the central second end wall extension is located centrally along the length of its respective wall portion between the two connected second end wall extensions. The bridged extension arrangement on the first end wall and the second end wall may be identical. Two substantially identical trays having end wall bridged extension arrangements and side wall one-two arrangements may be coupled together by inverting a second tray over a first tray; rotating the second tray in the to align the first side wall element of the first tray with the second side wall element of the second tray; slotting the first side wall extension of the first tray between the two second side wall extensions of the second tray and the first side wall extension of the second tray between two second side wall extensions of the first tray, such that they cross at intersections on each side of the first side wall extensions and each extension is arranged outside a distal part of the opposing tray; and either slotting the central first end wall extension of the first tray between the two connected second end wall extensions of the second tray such that the extensions cross at intersections on each side of the central first end wall extension of the first tray and the central first end wall extension of the first tray is arranged outside a distal part of the second end wall portion of the second tray and the two connected second end wall extensions of the second tray can be arranged outside a distal part of the first end wall portion of the first tray, or slotting the central second end wall extension of the second tray between the two connected first end wall extensions of the first tray such that the extensions cross at intersections on each side of the central second end wall extension of the second tray and the central second end wall extension of the second tray is arranged outside a distal part of the first end wall portion of the first tray and the two connected first end wall extensions of the first tray can be arranged outside a distal part of the second end wall portion of the second tray. As discussed above, to further secure the trays together, the first side wall extension may have a retention bulge at a first end nearest the first wall edge and / or a retention bulge at a second end nearest the second wall edge. Alternatively, or additionally, one or both of the two second side wall extensions may each have a retention bulge at an end opposite the third wall edge and the fourth wall edge, respectively. Such retention bulges allow the first side wall extension to hook with the two second side wall extensions. The invention also provides a box comprising two trays, wherein the box is formed by inverting one tray over the other such that the tray interfaces face one another, and coupling them together by crossing the extensions of each corresponding wall element at an intersection such that each extension of one of the trays is arranged outside a distal part of the corresponding wall element. The two trays may be substantially identical, or the two trays may differ, with only the tray interfaces being identical. The tray may be used to carry any food. For example, foods served heated (such as burgers or chips) or foods served cold (such as salad or sandwiches). The tray may also be used as a cover by coupling the tray to a tray carrying food, as explained in greater detail below. The invention will now be described by way of example only with reference to the following figures in which: Figure 1 shows a blank for forming a tray according to a first example; Figure 2 shows two trays each formed from the blank shown in Figure 1 prior to coupling the two trays together to form a box; Figure 3 shows two trays each formed from the blank shown in Figure 1 after coupling the two trays together to form a box; Figure 4 shows a blank for forming a tray according to a second example; Figure 5 shows two trays each formed from the blank shown in Figure 4 prior to coupling the two trays together to form a box; and Figure 6 shows two trays each formed from the blank shown in Figure 4 after coupling the two trays together to form a box. Figure 1 shows a blank 1 for forming a tray 3 shown in Figures 2 and 3. Figure 2 shows an exploded view of a box 5 comprising two trays 3. Figure 3 shows a view of the box 5. The blank 1 has a rectangular base 2 having four edges: a first base edge 4a, a second base edge 4b, a third base edge 4c, and a fourth base edge 4d. The first base edge 4a is opposite the third base edge 4c and the second base edge 4b is opposite the fourth base edge 4d. In this example, the base 2 has a rectangular shape, and the first and third base edges 4a,4c have a shorter length than the second and fourth base edges 4b,4d. In other examples, the firstand third base edges 4a,4c have a longer length than the second and fourth base edges 4b,4d. In other examples, the base 2 has a square shape, and accordingly the first base edge 4a, second base edge 4b, third base edge 4c, and fourth base edge 4d are the same length. The blank 1 has a plurality of wall elements: a first end wall element 6a, a first side wall element 6b, a second end wall element 6c, and a second side wall element 6d. The first end wall element 6a, first side wall element 6b, second end wall element 6c, and second side wall element 6d are each joined to the base 2 along the first base edge 4a, second base edge 4b, third base edge 4c, and fourth base edge 4d, respectively. Each of the wall elements 6a,6b,6c,6d are joined to the base 2 at the edges 4a,4b,4c,4d via a fold line 5 and have a length which runs parallel to the base. Each of the wall elements comprise a wall portion 8a,8b,8c,8d and an extension 10a, 10b, 10c, 10d. The first end wall element 6a has a first end wall portion 8a and a first end wall extension 10a. The first end wall portion 8a has a length which runs parallel to the first edge 4a between two ends 32a, and the first end wall extension 10a is located substantially centrally between the two ends 32a. The first side wall element 6b has a first side wall portion 8b and a first side wall extension 10b. The first side wall portion 8b has a length which runs parallel to the second edge 4b between two ends 32b, and the first side wall extension 10b is located adjacent the end 32b nearest the first end wall element 6a. The second end wall element 6c has a second end wall portion 8c and two second end wall extensions 10c. The second end wall portion 8c has a length which runs parallel to the third edge 4c between two ends 32c, and one of the two second end wall extensions 10c is located adjacent one of the ends 32c and the other of the two second end wall extensions 10c is located adjacent the other of the ends 32c. The second side wall element 6d has a second side wall portion 8d and a second side wall extension 10d. The second side wall portion 6d has a length which runs parallel to the fourth edge 4d between two ends 32d, and the second side wall extension 10d is located adjacent the end 32d nearest the first end wall element 6a, such that it is opposite the first side wall extension 10b. Although in this example the first and second side wall extensions 10b,10d are located adjacent the ends 32b,32d nearest the first end wall element 6a, in other examples the first and second side wall extensions 10b,10d may be located adjacent the ends 32b,32d nearest the second end wall element 6c. In this example, the length of the first end wall extension 10a, first side wall extension 10b, and second side wall extension 10d is approximately half the length of their respective wall portion, and the length of each of the two second end wall extensions 10c is approximately a quarter the length of its respective wall portion. Tabs 12 extend from both ends 32b of the first side wall portion 8b and both ends 32d of the second side wall portion 8d such that, upon folding the wall elements 6a,6b,6c,6d along the fold lines 5 at the base edges 4a, 4b, 4c and 4d, the tabs 12 overlap with, and can be affixed to, the first and second end wall portions 8a,8c to affix the first side wall element 6b to the first end wall element 6a and the second end wall element 6c, and the second side wall element 6d to the first end wall element 6a and the second end wall element 6c, to form a circumferential wall 14 (as shown in Figures 2 and 3) extending from the base 2 to define a tray 3. When the tabs are affixed to the first and second end wall portions 6a,6b, end 32a and end 32b meet to form a first wall edge 16a, end 32b and end 32c meet to form a second wall edge 16b, end 32c and end 32d meet to form a third wall edge 16c, and end 32d and end 32a meet to form a fourth wall edge 16d (as shown in Figures 2 and 3). In this example, the tabs 12 are affixed to the inside of the first end wall portion 8a and the second end wall portion 8c. In other examples, the tabs 12 may be affixed to the outside of the first end wall portion 8a and the second end wall portion 8c. Furthermore, the tabs 12 may be present on any of the ends 32a, 32b, 32c, 32d. Each of the wall portions 8a,8b,8c,8d comprise a proximal end 18, wherein the proximal end 18 is joined to the base 2 along a respective base edge 4a,4b,4c,4d at the fold line; a proximal part 20, wherein the proximal part 20 extends from the proximal end 18; a distal part 22, wherein the distal part 22 extends from the proximal part 18; and a distal end 24, from which the extension 10a,10b,10c,10d extends. Figures 2 and 3 show these features in the second side wall portion 8d in both trays: proximal end 18 is joined to edge 4d; proximal part 20 extends from proximal end 18; distal part 22 extends from the proximal part 20; and second side wall extension 10d extends from distal end 24. As can be more clearly seen in Figure 3, the distal part 22 is an area of the second side wall portion 8d over which the extension 10d of the other tray 3 extends when the two trays 3 are coupled together to form a box 5. Although not expressly shown, it will be understood that proximal end 18, proximal part 20, distal part 22, and distal end 24 are present in each of the wall portions 8a,8b,8c,8d. As such the distal part 22 of the first end wall portion 8a is the part of the wall portion which overlaps with second end wall extensions 10c when the two trays 3 are coupled together to form a box 5. Similarly, distal part 22 of the second end wall portion 8c is the part of the wall portion which overlaps with first end wall extension 10a, and distal part 22 of the first side wall portion 8b is the part of the wall portion which overlaps with the first side wall extension 10b, when the two trays 3 are coupled together to form a box 5. As shown in Figures 2 and 3, when each tray 3 is formed by folding the blank 1 along the wall fold lines 5, the distal parts 22 and extensions 10a, 10b, 10c, 10d together form a circumferential tray interface 9. The circumferential tray interface 9 of each of the two trays 3 are coupled together by inverting one of the trays 3, placing it over the other tray 3, and then arranging the extensions 10a, 10b, 10c, 10d of each tray 3 to cross one another at an intersection 26 such that each extension is arranged outside a distal part 22 of the other tray 3. The first end wall extension 10a and the two second end wall extensions 10c each have retention bulges 28 to secure the first end wall elements 6a and the second end wall elements 6c of each tray 3 together, and thereby further secure the trays 3 together. In this example the trays 3 are identical, but in other examples, only the circumferential tray interface 9 of each of the trays 3 is identical. The extensions 10a, 10b, 10c, 10d of the trays cover substantially all of the joint between the two trays 3. Figure 4 shows a blank 101 for forming a tray 103 (shown in Figures 5 and 6) according to a second example. The blank 101 has a base 102 having a plurality of edges: a first base edge 104a, a second base edge 104b, a third base edge 104c, and a fourth base edge 104d. The first base edge 104a is opposite the third base edge 104c and the second base edge 104b is opposite the fourth base edge 104d. In this example, the base 102 has a rectangular shape, and the first and third base edges 104a, 104c have a shorter length than the second and fourth base edges 104b,104d. In other examples, the first and third base edges 104a,104c have a longer length than the second and fourth base edges 104b,104d. In other examples, the base 102 has a square shape, and accordingly the first base edge 104a, second base edge 104b, third base edge 104c, and fourth base edge 104d are the same length. The blank 101 has a plurality of wall elements: a first end wall element 106a, a first side wall element 106b, a second end wall element 106c, and a second side wall element 106d. The first end wall element 106a, first side wall element 106b, second end wall element 106c, and second side wall element 106d are each joined to the base 102 along the first base edge 104a, second base edge 104b, third base edge 104c, and fourth base edge 104d, respectively. Each of the wall elements are joined to the base 102 at the edges via a fold line 105 and have a length which runs parallel to the base 102. Each of the wall elements comprise a wall portion and an extension. The first end wall element 106a has a first end wall portion 108a and three first end wall extensions 110a, 110a’. The first end wall portion 108a has a length which runs parallel to the first edge 104a between two ends 132a. One of the first end wall extensions 110a is located at or adjacent an end 132a and one of the first end wall extensions 110a is located at or adjacent the other end 132a, and these two first end wall extensions 110a are connected by a first end wall bridge 30a to form a flap 34. The extensions 110a are connected to the wall portion 108a by a flap fold 36. The other end wall extension 110a’ is located centrally along the length of the first end wall portion 108a between the connected first end wall extensions 110a. The first side wall element 106b has a first side wall portion 108b and a first side wall extension 110b. The first side wall portion 108b has a length which runs parallel to the second edge 104b between two ends 132b, and the first side wall extension 110b is located substantially centrally along the length of the first side wall portion 108b between ends 132b. The second end wall element 106c has a second end wall portion 108c and three first end wall extensions 110c. The first end wall portion 108c has a length which runs parallel to the third edge 104c between two ends 132c. One of the second end wall extensions 110c is located at or adjacent an end 132c and one of the second end wall extensions 110c is located at or adjacent the other end 132c, and these two first end wall extensions 110c are connected by a second end wall bridge 30c to form a flap 38. The extensions 110a are connected to the wall portion 108a by a flap fold 40. The other end wall extension 110c’ is located centrally along the length of the second end wall portion 108c between the connected second end wall extensions 110c. The second side wall element 106d has a second side wall portion 108d and two second side wall extensions 110d. The second side wall portion 106d has a length which runs parallel to the fourth edge 104d between two ends 132d, and one of the second side wall extensions 110d is located adjacent the end 132d nearest the first end wall element 106a, and the other of the second side wall extensions 110d is adjacent the end nearest the second end wall element 106c. In this example, the length of all of the extensions is approximately a third the length of their respective wall portion. Tabs 112 extend from both ends 132b of the first side wall portion 108b and both ends 132d of the second side wall portion 108d such that, upon folding the wall elements along the fold lines at the base edges 104a, 104b, 104c and 104d, the tabs overlap and can be affixed to the first and second end wall portions 108a, 108c to affix the first side wall element 106b to the first end wall element 106a and the second end wall element 106c, and the second side wall element 106d to the first end wall element 106a and the second end wall element 106c, to form a circumferential wall 114 (as shown in Figures 5 and 6). When the tabs 112 are affixed to the first and second end wall portions 106a, 106b, end 132a and end 132b meet to form a first wall edge 116a, end 132b and end 132c meet to form a second wall edge 116b, end 132c and end 132d meet to form a third wall edge 116c, and end 132d and end 132a meet to form a fourth wall edge 116d (as shown in Figures 5 and 6). In this example, the tabs 12 are affixed to the inside of the first end wall portion 108a and the second end wall portion 108c. In other examples, the tabs 12 may be affixed to the outside of the first end wall portion 108a and the second end wall portion 108c. Furthermore, the tabs 12 may be present on any of the ends 132a, 132b, 132c, 132d. Similarly to the first example, each of the wall portions comprise a proximal end, wherein the proximal end is joined to the base 102 along a respective base edge at the fold line; a proximal part, wherein the proximal part extends from the proximal end; a distal part, wherein the distal part extends from the proximal part; and a distal end from which the extension extends. Figures 5 and 6 show these features in the second side wall portion 108d in a bottom tray 103: proximal end 118 is joined to edge 104d; proximal part 120 extends from proximal end 118; distal part 122 extends from the proximal part 120; and second side wall extension 110d extends from the distal end 124. As can be more clearly seen in Figure 6, the distal part 122 is an area of the second side wall portion 108d over which the first side wall extensions 110b of the other tray 103 extend when the two trays 103 are coupled together to form a box 105. Figures 5 and 6 also show these features in the first side wall portion 108b in the top tray 103: proximal end 118 is joined to edge 104b; proximal part 120 extends from proximal end 118; distal part 122 extends from the proximal part 120; and the first side wall extensions 110b extend from distal end 124. As can be more clearly seen in Figure 6, the distal part 122 is an area of the second side wall portion 108b over which the first side wall extension 110d of the other tray 103 extends when the two trays 103 are coupled together to form a box 105. Similarly, the distal part 122 of the first end wall portion 108a is the part of the wall portion which can overlap with the connected second end wall extensions 110c, and the distal part 122 of the second end wall portion 108c is the part of the wall portion which can overlap with the central end wall extension 110a, when the two trays 103 are coupled together to form a box 105. As shown in Figures 5 and 6, when each tray 103 is formed by folding the blank 1 along the wall fold lines, the distal parts and extensions together form a circumferential tray interface. The circumferential tray interface of each of the two trays 103 may be coupled together by, beginning with a second tray 3 nested within a first tray 3, rotating the second tray 3 180 degrees about an axis which runs parallel to the second base edge 104b and the fourth base edge 104d, such that a first tray interface of the first tray meets a second tray interface of the second tray, and then arranging the extensions 110a, 110b, 110c, 110d of each tray 103 to cross one another at an intersection 126 such that each extension is arranged outside a distal part 122 of the other tray 103. In particular, the first side extension 110b of the first tray will sit between the two second side extensions 110d of the second tray 3, and the extensions will cross at intersections 126 such that the first side extension 110b overlaps distal part 122 of the second side wall portion 108d of the second tray. The two second side extensions 110d of the first tray 3 will receive the first side extension 110b of the second tray 3 therebetween, and the extensions will cross at intersections 126 such that the two second side wall extensions 110d of the first tray overlap distal part 122 of the first side wall portion 108b of the second tray. Furthermore, the first central extension 110a’ of the first tray will slot between the two second connected extensions 110a of the flap 34 of the second tray 3, and the extensions will cross at intersections 126 such that the first central extension 110a’ overlaps distal part 122 of the second end wall portion 108c of the second tray 3. Similarly, the second central extension 110c’ of the first tray will slot between the two second connected extensions 110c of the flap 38 of the second tray 3, and the extensions will cross at intersections 126 such that the second central extension 110c’ overlaps distal part 122 of the second end wall portion 108c of the second tray 3. Similarly to the first example, the central first end wall extension 110a and the central second end wall extensions 110c may have retention bulges to secure the trays 103 together. In this example the trays 103 are identical, but in other examples, only the circumferential tray interface of each of the trays 103 is identical.

Claims

1. A blank foldable to form a tray for carrying food, wherein the blank comprises:a base comprising a plurality of edges;a plurality of wall elements extending from the edges of the base, wherein each of the plurality of wall elements comprise:a wall portion; andan extension, and the wall portions comprise:a proximal end joined to the base along one of the plurality of edges at a wall fold line;a proximal part extending from the proximal end;a distal part extending from the proximal part; and a distal end from which the extension extends,wherein, when a tray is formed by folding the blank along the wall fold lines to form an enclosure for carrying food, the plurality of distal parts and extensions together form a circumferential tray interface, the tray interface is configured such that a second tray having a second tray interface which is substantially identical to the tray interface can couple with the tray interface to form a box, the extension of each wall element of the tray interface crosses an extension of a wall element of the second tray interface, respectively, at an intersection such that each extension of the tray interface can be arranged outside a distal part of the second tray interface.

2. A tray formed by folding the blank of claim 1 along the wall fold lines such that the plurality of distal parts and extensions together form a circumferential tray interface, wherein the base is in a base plane, and the plurality of wall portions project out of the base plane to form a circumferential wall, thereby forming an enclosure for carrying food.

3. A tray as claimed in claim 2, wherein the wall portions taper outwardly from the proximal end to the distal end, such that an area defined by the plurality of distal ends is greater than an area defined by the plurality of proximal ends.

4. A tray as claimed in claim 2 or 3, wherein the base is rectangular or square, and the plurality of wall elements comprise:a first end wall element and a second end wall element, wherein the first end wall element and the second end wall element are opposite each another; anda first side wall element and a second side wall element, wherein the first side wall element and the second side wall element are opposite each another, wherein the first end wall element and the first side wall element meet at a first wall edge, the first side wall element and the second end wall element meet at a second wall edge, the second end wall element and the second side wall element meet at a third wall edge, and the second side wall element and the first end wall element meet at a fourth wall edge.

5. A tray as claimed in claim 4, wherein each of the plurality of wall elements have a length parallel to the base, wherein the length of each respective extension is no more than half the length of each respective wall portion.

6. A tray as claimed in claim 5, wherein the plurality of wall elements each have only one extension, wherein the extension of the first end wall element meets the extension of the first side wall element at the first wall edge and the extension of the second end wall element meets the extension of the second side wall element at the third edge.

7. A tray as claimed in claim 5, whereinthe first end wall element comprises one first end wall extension which is located centrally between the fourth edge and the first edge along the length of its respective wall portion;the second end wall element comprises two second end wall extensions, wherein one of the two second end wall extensions is located at an end of its respective wall portion nearest the second edge and the other is located at an end of its respective wall portion nearest the third edge;the first side wall element comprises one first side wall extension which is located at an end of its respective wall portion nearest the first edge; andthe second side wall element comprises one extension which is located at an end of its respective wall portion nearest the fourth edge.

8. A tray as claimed in claim 7, whereinthe first end wall extension comprises a retention bulge at a first end nearest the first wall edge and a retention bulge at a second end nearest the fourth wall edge; andthe two second end wall extensions each comprise a retention bulge at an end opposite the second wall edge and the third wall edge, respectively.

9. A tray as claimed in claim 5, whereinthe first end wall element comprisestwo connected first end wall extensions, wherein one of the two connected first end wall extensions is located at or adjacent the first wall edge and the other is located at or adjacent the fourth wall edge, wherein the two connected first end wall extensions are connected by a first end wall bridge, anda first end wall extension, wherein the first end wall extension is located centrally along the length of its respective wall portion between the two connected first end wall extensions;the second end wall element comprisestwo connected second end wall extensions, wherein one of the two connected second end wall extensions is located at or adjacent the first wall edge and the other is located at or adjacent the fourth wall edge, and the two connected second end wall extensions are connected by a second end wall bridge; anda second end wall extension, wherein the second end wall extension is located centrally along the length of its respective wall portion between the two connected second end wall extensions;the first side wall element comprises one first side wall extension which is located centrally between the first wall edge and the second wall edge along the length of its respective wall portion; andthe second side wall element comprises two second side wall extensions, wherein one of the two second side wall extensions is located at or adjacent the third wall edge and the other is located at or adjacent the fourth wall edge.

10. A tray as claimed in claim 9, whereinthe first side wall extension comprises a retention bulge at a first end nearest the first wall edge and a retention bulge at a second end nearest the second wall edge; andthe two second side wall extensions each comprise a retention bulge at an end opposite the third wall edge and the fourth wall edge, respectively.

11. A tray as claimed in claim 10, wherein the first end wall extensions and the second end wall extensions are identical.

12. A box comprising two trays, wherein each of the two trays are as claimed in any one of claims 2 to 11, wherein the box is formed by inverting one tray over the other such that the tray interfaces face one another, and coupling them together by crossing the extensions of each corresponding wall element at an intersection such that each extension is arranged 5 outside a distal part of the corresponding wall element.

13. A box as claimed in claim 12, wherein the two trays are substantially identical.

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