GB2471268A

GB2471268A - Stackable box

Info

Publication number: GB2471268A
Application number: GB0910449A
Authority: GB
Inventors: Stephen Clarke
Original assignee: TRI PACK PLASTICS Ltd
Current assignee: TRI PACK PLASTICS Ltd
Priority date: 2009-06-17
Filing date: 2009-06-17
Publication date: 2010-12-29
Anticipated expiration: 2029-06-17
Also published as: GB0910449D0; GB2471268B; NO20100843L

Abstract

A stackable box 1 has upstanding tabs 8 on the tops of respective end panels 4, and holding tabs 10 at the bottoms of side panels 3, and an indentation 9 proximate the centre of the base 2 of the box 1. Such a configuration allows an overlapping stack (fig.2) of boxes 1 to be formed in which the upstanding tabs 8 of a first box engage in the holding tabs 10 of a second box and / or the indentation 9 of the second box, when the second box is place on top of the first. The box 1 is made of twin walled olefin plastics sheeting, which may allow for ease of cleaning prior to melting down of the boxes 1 during recycling. A strap 6, may provide additional structural rigidity to each individual box 1. The box 1 may be used in the transportation of fish.

Description

STACKABLE FISH BOX

Field of the Invention

This invention relates to stackable boxes for the transportation of fish and the like.

Background to the Invention

Fish are typically transported from port to market in boxes formed from expanded plastics such as polystyrene. The use of such materials permits the boxes to have sufficient strength to enable stacking on a pallet in an overlap- ping or interlocking manner so that the pallet can be transported without addi-tional wrapping. However, these materials also have disadvantages. Firstly, because they are moulded into shape, the volume of the boxes when unused makes transport from the factory to the fish-packing place costly, particularly as transport fuel costs rise. Secondly, because of contamination by fish protein and the impossibility of sterilising for re-use, the boxes are scrapped after a sin- gle use. Recycling of the plastics is difficult because of the nature of the plas-tics and the relatively large volume of material involved for the small amount of plastics recoverable. Breaking up of the boxes is difficult, and fish blood and protein absorbed into the box material requires removal, reducing the value of the recycled material. Transporting the boxes for recycling is also increasingly costly because of the high volume relative to mass.

In order to overcome these disadvantages, the use of extruded fluted double-walled polypropylene sheet materials has been adopted for some fish boxes. The sheet material can be cut and creased to form a blank which can be transported to the packing place and then readily assembled into a box for use. After use, the boxes can be converted back into flat blanks for transport to the recycling place. Since the material is smooth and impervious, it can readily be washed before being melted down to produce reusable plastics materials.

The boxes are configured for stacking into columns by providing up- standing tabs at each end of the box arranged to co-operate with spaced hori-zontal tabs at the lowermost part of the end panel to prevent lateral movement of the boxes relative to each other. However, there is a disadvantage in relation to boxes used for larger fish such as salmon, since if these are simply stacked vertically one upon another, additional support is required to hold the stacks to-gether on a pallet during transportation of the fish. The additional support may involve wrapping the stacks together in plastic film, which creates additional work at the packing station and at the market, and additional packaging material to be disposed of or recycled.

Conventionally, the larger expanded polystyrene boxes are stacked on pallets in a brick-stacking pattern, that is with overlapping to bind the layers of boxes together for greater stability during transport. Since the polystyrene ma-terial has an adequate coefficient of friction, the stacks hold together during transport without the need for external support or wrapping. However, with the polypropylene materials, which have a low coefficient of friction, there is a risk of sliding of one layer relative to another during transport.

Summary of the Invention

According to the invention, there is provided a stackable box for fish and the like, the box having a length which is twice the width of the box, the box be-ing formed from twin-wall olefin plastics sheet cut and creased to provide side and end walls upstanding from a base with a central upstanding positioning tab at the top centre of each end wall thereof and two pairs of holding tabs extend-ing outwardly of the box from the lowermost part of each side wall of the box, the holding tabs in each pair being spaced apart so as to receive therebetween as a close fit a positioning tab from another of said boxes in a stacked layer immediately below, when said other box extends in a transverse direction rela- tive to the box above, and wherein each box is provided at the centre of the un-derside of the base with an indentation for engaging a positioning tab from an underlying box in a stack whereby to hold the boxes in the stack together.

Preferably, the sheet is configured to provide in the assembled box a re-inforcement at each end wall thereof. The reinforcement may comprise a strap connected to the end wall and secured to the side walls. Alternatively, the rein- forcement comprises corner flaps depending from the sides of the end wall, at-tached to the adjacent side walls, and folded diagonally to attach to the end wall, thereby forming a triangular-section vertical supporting pillar at each cor-ner of the box.

The positioning tabs suitably have a width of no more than 20% of the width of the box. The holding tabs preferably extend from the side of the box by a distance of at least twice the thickness of the sheet.

A separate lid or cover may be used, adapted to leave the positioning tabs projecting above the lid, in use.

The boxes of the invention are capable of being transported in stacked pallet loads that remain stable under the stresses occurring in transport while protecting the fish from any damage that might reduce their value. The boxes can readily be economically recycled after use.

Brief Description of the Drawings

In the drawings, which illustrate an exemplary embodiment of the inven-tion: Figure 1 is a plan view of a cut and creased blank for forming into a box in accordance with the invention; and Figure 2 is a perspective view of a plurality of boxes formed from blanks as illustrated in Figure 1, stacked on a pallet.

Detailed Description of the Illustrated Embodiment

A sheet of twin-walled fluted polypropylene is cut and creased by press-ing the sheet on to a suitable tool having a predetermined pattern of knives and heated creasing bars upstanding therefrom to form a box blank 1. In Figure 1, the cut edges are represented by solid lines, while the creases are represented by broken lines. The heated creasing bars serve to provide permanently in-dented lines along which creases can be formed when the box is erected. The blank 1 consists of a rectangular base panel 2 having along two opposed longer sides thereof side panels or walls 3. End walls or panels 4 are connected to the shorter ends of the base panel 2 through creases, and have side flaps 5 and an end strap 6 connected to it through a further crease 7. At the centre of each crease 7, a positioning tab 8 is cut out.

At the centre of the base panel 1 a series of short transverse indenta-tions 9 are formed on the underside by a pattern of short heated creasing bars.

Although the indentations 9 are shown in Figure 1, it will be appreciated that they will not actually be visible in a top plan view; they are shown in this Figure for convenience. The indentations 9 can either be formed by a second pressing operation on the blank using a second tool and flipping the blank, or by provid-ing the short heated creasing bars on the press tool that is used to form the blank on the first tool. In the creases separating the side walls 3 from the base panel 2, two pairs of holding tabs 10 are cut out so as to project outwardly of the side walls when the box is erected. The holding tabs 10 in each pair are spaced apart by a distance equal to the width of the positioning tab 8, and each pair is located centrally of a half of the length of the box so as to co-operate with the positioning tab 8 when the boxes are stacked in interlocking formation as hereinafter described with reference to Figure 2.

The box may be erected from the blank at the location at which it is to be used by folding up the side walls or panels 3 so as to extend at right angles to the base panel 2. The end walls or panels 4 are then folded up at right angles to the base panel, with the side flaps 5 inside the box, where they are secured to the side walls by adhesive or by spot welding using high frequency welding, for example. The straps 6 are then folded inwardly over the box with their free ends 6a then being folded down and secured to the outside of the side panels 3, again by adhesive or spot welding, leaving the tab 8 projecting upwardly of the box at each end. The strap forms a support for overlying boxes when stacked, as well as increasing the rigidity of the box, constraining the side pan-els from outward movement under load.

Referring now to Figure 2, the boxes are stacked, when filled, for exam-ple with large fish such as salmon, on a pallet 11 in an interlocking formation with each layer of boxes having two boxes extending side by side lengthways of the pallet and one box extending transversely of the pallet across the ends of the other two, with the arrangement being reversed in the next layer above so that the layers are bonded together to provide a very stable load for transport-ing. The positioning tabs of the longitudinal boxes engage, at the end of the pallet, with the holding tabs in the side of the transverse box in the next layer, while the positioning tabs at the ends of the transverse box engage with one of the pairs of holding tabs 10 at the side of the longitudinal boxes in the next layer above. The positioning tabs 8 upstanding from the longitudinal boxes adjacent to the transverse box in any layer are received in the indentations 9 in the long i-tudinal boxes in the next layer above. While a slight upward bowing of the base panels 2 may occur, the indentations ensure that the tabs 8 remain upright and do not penetrate the base panels, and so the tendency of the upper boxes to slide relative to the lower boxes during transport when subjected to forces aris- ing from braking or cornering of the transporting vehicle is overcome. The pal-lets can therefore be transported without the need for any additional packaging.

At the destination, after the fish have been removed from the boxes, the boxes can readily be flattened back into a blank for removal to a recycling plant where, after washing off of the residual fish materials, the blanks can be melted down to recover the plastics for re-use/re-cycling.

Claims

CLAIMS1. A stackable box for fish and the like, the box having a length which is twice the width of the box, the box being formed from twin-wall olefin plastics sheet cut and creased to provide side and end walls upstanding from a base with a central upstanding positioning tab at the top centre of each end wall thereof and two pairs of holding tabs extending outwardly of the box from the lowermost part of each side wall of the box, the holding tabs in each pair being spaced apart so as to receive therebetween as a close fit a positioning tab from another of said boxes in a stacked layer immediately below, when said other box extends in a transverse direction relative to the box above, and wherein each box is provided at the centre of the underside of the base with an indenta-tion for engaging a positioning tab from an underlying box in a stack whereby to hold the boxes in the stack together.
2. A box according to Claim 1, wherein the sheet is configured to provide in the assembled box a reinforcement at each end wall thereof.
3. A box according to Claim 2, wherein the reinforcement comprises a strap connected to the end wall and secured to the side walls.
4. A box according to Claim 2, wherein the reinforcement comprises corner flaps depending from the sides of the end wall, attached to the adjacent side walls, and folded diagonally to attach to the end wall, thereby forming a tri-angular-section vertical supporting pillar at each corner of the box.
5. A box according to any preceding claim, wherein each positioning tab has a width of no more than 20% of the width of the box.
6. A box according to any preceding claim, wherein the holding tabs extend from the side of the box by a distance of at least twice the thickness of the sheet.
7. A box according to any preceding claim, including a separate lid or cover adapted to leave the positioning tabs projecting above the lid, in use.
8. A stackable box, substantially as described with reference to, and/or as shown in, the drawings.