The present invention generally relates to an arrangement in a box, and more specifically concerns a corner structure in an open-top, stackable box, especial¬ ly intended for vegetables.

In recent years, the trend in agriculture has been towards increased automatisation when sowing or planting as well as harvesting vegetables. When harvesting vege- tables, modern farms thus use reapers with packing sta¬ tions, where the vegetables are directly packed in bags or boxes of various sorts. Mostly, the vegetables are then taken directly to a cold storage, to be distributed later on to wholesale or retail dealers. In harvesting, many vegetables, such as iceberg let¬ tuce, are handled manually, i.e. the vegetable is manually handled and placed in a box. Usually, the boxes are open at the top and of such dimensions that four corner-to-cor¬ ner boxes cover the surface of a loading pallet. The boxes are in addition stackable, so that a loading pallet holds about 40 boxes filled with vegetables, such as iceberg lettuce.

When harvesting e.g. iceberg lettuce, one therefore has to use many loading pallets and a great number of boxes. Conveniently, the boxes are in the form of blanks which are successively erected and filled with vegetables. Since a high and even harvesting rate is desirable, the vegetable boxes have to be erected fairly quickly, and the number of operations required for doing this should there- fore be limited. At the same time, however, the vegetable box, usually made of environment-friendly paperboard, has to be st ^' able and stackable to a considerable height. Al¬ ternatively, a plurality of machine-erected boxes can be brought along and successively filled and placed on the loading pallet supporting the boxes.

GB-A-2,185,964 teaches such a box, in which tri¬ angular vertical corner areas are obtained when erecting the box, a stabilising triangular plastic part being applied on the upper ends of the corner areas. Apart from the fact that a great many plastic parts have to be brought to the harvesting site (about 160 plastic parts are required for a loading pallet with iceberg lettuce), several drawbacks are associated with this box structure. Moreover, the use of plastic materials should be restrict- ed for environmental reasons.

The GB box structure with mounted plastic parts or knobs is very stable when loaded in the vertical direc¬ tion. However, if the box is exposed to transverse forces, as is usually the case when the filled vegetable box is lifted to be placed on the loading pallet or on another box, the bottom and the side walls of the box are deform¬ ed, frequently causing the plastic knob to slide upwards and fall off. Should two or more plastic knobs fall off, which is not uncommon, the erected vegetable box becomes unstable and runs the risk of collapsing.

Apart from this serious disadvantage impairing the GB vegetable box, applying the plastic knobs out in the fields means extra work. It should also be observed that the container for the plastic parts takes up quite a lot of space in the fairly restricted packing station.

Another aspect is that plastic parts may be lost, either when erecting the box and applying the plastic knobs or when the box is unevenly loaded, as described above. Usually, the plastic knobs fall to the ground and are, for various reasons, seldom picked up after the har¬ vest to be reused or destroyed. Instead, there is a con¬ siderable risk that the plastic parts be ploughed into the ground, where they remain. Not being degradable, or only slowly so, the plastic parts constitute an environ- mental hazard. The plastic knobs are a problem also when the used vegetable boxes are to be destroyed, since they then have to be removed and somehow taken care of.

In addition to the serious drawbacks mentioned above, prior-art vegetable boxes suffer from other disadvantages. The box disclosed in US-A-5,016,814 is unsuitable for use in a cold storage owing to the design of its side walls, the boxes preventing the cooling air from circulating between the stacked boxes.

Also the box taught in FR-A1-2,548,626 is unsuitable for use in a cold storage where cold air is passed between the stacked boxes. If cooled air is passed across the long-side walls, it is a disadvantage if the air can pass out via the short-side walls of the boxes.

The stackable container known from DE-A1-34 39 185 is interesting in many ways. This container has the advan¬ tage of a stable structure. However, a serious drawback is that,_in order to obtain the aimed-at stacking stability, it implies the use of plastic materials, such as polyethy¬ lene, polyester and polypropylene, i.e. the container and the corner structure described in the DE specification cannot be durably made of paperboard or corrugated board. As indicated in the foregoing, the use of plastic mate¬ rials should, however, be avoided whenever possible. To become sufficiently strong, the DE container is, in addi¬ tion, provided with substantially horizontal panels extending inwards towards the erected container, which however makes it more difficult to put the vegetables in the container.

One object of the present invention is, therefore, to provide an open-top box of paperboard or corrugated board, or some other degradable material, which is intend- ed primarily for vegetables and has a corner structure imparting a high degree of stability to the box, also when unevenly loaded.

Another object of the invention is to provide a box of paperboard or corrugated board, or some other degrad- able matarial, which is primarily intended for vegetables and can be rapidly erected when the vegetable at issue is harvested.

A further object of the invention is to provide a box of paperboard or corrugated board, or some other degrad- able material, which is primarily intended for vegetables and is made in one piece and to which no loose parts, such as metal staples and plastic knobs, have to be applied to impart the desired stability.

The inventive vegetable box should otherwise meet the requirements placed on known boxes, i.e. all the boxes should have the same outer dimensions and be stackable. In addition, the inventive box should permit the cooling air in a cold storage to flow more efficiently.

According to the invention, these and other objects are attained by an arrangement in a box, preferably a vegetable box, as defined in the characterising clause of appended claim 1.

Other features and advantageous embodiments appear from the appended subclaims.

Currently preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings, in which

Fig. 1 is a partial top plan view showing a corner of a box blank that, when erected, forms the inventive trans¬ portation box;

Fig. 2 is a partial top view showing a corner of the transportation box in Fig. 1 when erected;

Fig. 3 is a perspective view of the inventive trans¬ portation box when erected; and

Fig. 4 is a partial top plan view showing a corner of another blank that, when erected, forms the inventive transportation box.

Fig. 1 illustrates one of four corner areas of a sheet-like blank, i.e. whose vertical extent is negligible as compared with its horizontal extent, the blank forming, when erected, an inventive box, preferably for vegetables. Apart from the inventive corner structure to be described in more detail below, the box comprises, in known manner, a bottom 2, two long-side walls 4 which are substantially

vertical when erected and of which but one is partially illustrated, and two short-side walls 6 which are substan¬ tially vertical when erected and of which but one is par¬ tially illustrated. The short-side walls 6 are connected to the bottom 2 via fold lines 8 and 10. To make the erected box very stable, the invention provides a corner structure 12 which interconnects a long-side wall 4 and a short-side wall 6 of the erected box in stable and reli¬ able manner. The corner structure 12 comprises three panels, name¬ ly an inner panel 16 connected to one short side of the short-side wall 6 via a fold line 14, a second panel 20 connected to the inner panel 16 via a fold line 18 paral¬ lel to the fold line 14, and an outer panel 24 connected to the second panel 20 via fold lines 22A and 22B parallel to the fold lines 14 and 18. The length, or rather the height when erected, of these panels is substantially identical with that of the short-side wall 6 and exceeds that of the long-side wall 4, for reasons to be given fur- ther below. In the embodiment illustrated, the inner panel 16 and the outer panel 24 are substantially of equal width, whereas the width of the second panel complies with Pythagoras' theorem and thus equals the square root of the sum of the square of the width of the inner and outer panels 16 and 24, respectively. It should here be pointed out that the outer panel may alternatively be in the form of a flap, as in the embodiment described with reference to Fig. 4 further below.

To fix the corner structure and provide a stable con- nection to the long-side wall 4 and the short-side wall 6, provision is made of a plurality of flaps cooperating with slots. In the immediate vicinity of each outer corner of the long-side walls 4, there is provided a first flap 26 which is connected to the long-side wall 4 via a fold line 28. Preferably, the fold line 28 forms an angle of about 30° with the upper edge of the long-side wall 4. A first slot 30 is formed in the inner panel 16 at a corresponding

distance from the outer edge and correspondingly oriented. A second flap 32 is formed in the second panel 20 and is rigidly connected to the outer panel 24. The second flap 32 is provided by making a U-shaped slit 33 in the second panel 20 so that the ends of the slit 33 merge into the fold lines 24A and 24B, while being at substantially right angles to the branches of the U-shaped slit. A second slot 34 is formed in the short-side wall 6 at a corresponding distance from the fold line 14 and correspondingly orient- ed. In practice, the distance between the second slot 34 and the fold line 14 thus is substantially equal to the width of the outer panel 24, i.e. the width between the fold lines 24A, 24B and the outer edge of the outer panel 24 parallel thereto. To make the boxes stackable, the edge of the second panel 20 facing away from the long-side wall 4 is provided with a tab or extension 36, preferably with bevelled cor¬ ners, and a slot 38 is formed in the bottom 2, at a corre¬ sponding distance from the corner area of the bottom 2 and correspondingly oriented, and is intended to cooperate with a corresponding tab or extension 36 of the box below. As mentioned above, four boxes preferably form a tier on a loading pallet. The four adjoining corner areas are locked to one another by a ring (not shown) passed into a recess 40 in the short-side wall 6 of each box.

When harvesting e.g. iceberg lettuce, one brings along loading pallets and unfolded blanks which are suc¬ cessively erected and filled with vegetables. Then, the boxes are placed on a loading pallet or on top of one another. When erecting such a vegetable box, the outer panel 24 is first folded so far in towards the second panel 20 that it almost comes to rest on this panel. Then, the second flap 32 connected to the outer panel 24 is swung approximately 180° to be directed away from the short-side wall 6 in the end position. The second panel 20, on which the outer panel 24 is folded, is then folded in towards the inner panel 16, so that the outer panel 24

is placed substantially halfway between the second panel 20 and the inner panel 16. The second flap 32 has then been swung approximately another 180° and now occupies a position in the immediate vicinity of the second slot 34. By slightly pivoting the inner panel 16 along the fold line 14, the second flap 32 is pivoted a few degrees more and can easily be pushed through the slot 34, while at the same time the outer panel 24 is released and, owing to the properties of the material, springs back somewhat to be finally applied against the inside of the short-side wall 6 between the second slot 34 and the fold line 14. After this has been done to all the corners of the box, the short-side walls 6 are folded upwards. The first flap 26 of the long-side walls 4 is folded inwards or downwards and is, after the side-walls have been erected, pushed through the first slot 30 in the inner panel 16. The flap 26 is thus pressed downwards, and one panel 40 comes into engagement with the edge of the slot 30, locking the flap 26 in the end position and thus preventing any motion of the outer panel 24 in towards the second panel 20, while at the same time the flap 26 is clamped against the second panel 20.

Fig. 4 illustrates another embodiment of one out of four corner areas of a sheet-like blank-which, when erect- ed, forms an inventive box, preferably for vegetables. Like details as in Figs 1-3 are identified by like refe¬ rence numerals.

Apart from the inventive corner structure described further below, the box comprises, in known manner, a bottom 2, two long-side walls 4 which are substantially vertical when erected and of which but one is partially illustrated, and two short-side walls 6 which are substan¬ tially vertical when erected and of which but one is par¬ tially illustrated. The short-side walls 6 are connected to the bottom 2 via fold lines 8 and 10. To make the erected box very stable, the invention provides a corner structure 12 which interconnects one long-side wall 4 and

one short-side wall 6 of the erected box in stable and reliable manner.

The corner structure 12 comprises three panels, name¬ ly an inner panel 16 connected to one short-side of the short-side wall 6 via a fold line 14, a second panel 20 connected to the inner panel 16 via a fold line 18 paral¬ lel to the fold line 14, and a rigid outer panel 24 con¬ nected to the second panel 20. Preferably, the fold lines 14 and 18 each form an angle with the fold line 8 to make the long-side and short-side walls 4, 6 incline slightly inwards when the box is erected, thereby increasing its stackability. The length, or rather the height when the box is erected, of the inner and outer panels 16 , 20 is substantially identical with that of the short-side wall 6 and exceeds that of the long-side wall 4, thereby improv¬ ing the flow-through of cooling air in a cold storage. In the embodiment illustrated here, the width and the length of the outer panel 24 are so reduced that there is formed a flap 32 which is fixedly connected to the second panel 20, whereas the width of the second panel 20 substantially equals the square root of the sum of the square of the double width of the inner panel 16.

In order to fix the corner structure and provide a stable connection to the long-side wall-4 and the short- side wall 6, provision is made of several slots and an additional flap. In the immediate vicinity of each outer corner of the long-side walls 4, there is provided a flap 26 which is connnected to the long-side wall 4 via a fold line 28. Here, the fold line 28 extends in the same direc- tion as the upper edge of the long-side wall 4. An elon¬ gate slot 30 is formed in the inner panel 16 at a corre¬ sponding distance from the outer edge and at an angle to the fold line 10. The outer panel 24 is intended to coope¬ rate with a second slot 34 which is formed in the short- side wall 6 at a corresponding distance from the fold line 14 and is correspondingly oriented.

To make the boxes stackable, the upper edge of the short-side wall 6 is provided with a tab or extension 36, preferably with bevelled corners, and a mating recess 37, cooperating with the tab or extension of a box below, is formed in the bottom 2 and the edge of the short-side wall 6 facing the bottom 2. A tab 42 is provided on the edge of the second panel 20 facing away from the upper edge and is intended to cooperate with a recess 38 formed in the bot¬ tom 2 at a corresponding distance from the corner area, thereby to stabilise this area.

Also in the embodiment illustrated in Fig. 4, the corner area has a substantially triangular cross-section. By inclining the long-side and short-side walls in towards the centre of the box, the forces acting on the box are directed inwards and the stackability of the box is increased.

The triangular cross-section of the corner structure according to the first and the second embodiment results in a very high stackability, while at the same time the interlocking of the flaps and the inclination of the walls in towards the centre of the box provide a high degree of stability, also for considerable lateral or transverse forces. Tests have shown that the corner structures locked as described above remain locked, also when subjected to extremely rough handling, and that it is the material itself that is ultimately destroyed.

Thus, the invention provides a box of high stability, also when subjected to considerable uneven load, without the use of any loose parts, such as metal staples. The inventive arrangement enables the box to be rapidly erect¬ ed by a few simple operations or with the aid of a simple device. Thus, the inventive arrangement is especially suitable for use in a mobile packing station when harvest¬ ing vegetables to be packed in boxes. Because two parallel side walls, in this instance the short-side walls, are higher than the other two side walls, the flow of cooling air in a cold storage is considerably improved.

It goes without saying that the embodiment described can be modified in certain ways. Thus, the corner struc¬ ture may be a polygon having more than three sides. How¬ ever, this solution has the disadvantage of requiring a larger material consumption without increasing the stabi¬ lity or the durability of the box. All variants and modi¬ fications encompassed by the inventive idea fall within the scope of the appended claims.