GB2165217A - Packaging box - Google Patents

Abstract

A box made of expanded foam material has a base panel 11 and four side panels, 20, 26, 30 and 40. The side panels are joined by interlocking tongue-and-groove joints e.g. 21, 27 and the base panel 11 has a central raised plinth 12 provided on three sides with grooves 13 and tongues 14 and on the fourth side with a groove 15. The tongues 13 and grooves 14 engage with corresponding grooves and tongues in the side panels 20, 26 and 30 which prevent these panels from moving vertically. The fourth panel 40 has a tongue that fits into groove 15 to lock the four side panels rigidly onto the central plinth 12. The panel 40 is prevented from moving by the friction in the joints between adjacent side panels or by mechanical fixing devices or by glue. A lid may be provided, as may partitions 50, 51. <IMAGE>

Description

SPECIFICATION Packaging box The present invention relates to a box made from expanded foam material that can be assembled out of component panels for the purpose of packaging.

The use of expanded foam material, particularly expanded polystyrene, is well known in the packaging industry since it is cheap, light, strong and most importantly, because it is resilient and hence can absorb knocks without damagning the packaged goods It can also be made fire-retarding. Recently, high-density expanded polystyrene has been introduced which is stronger than previously known expanded polystyrene and so is an even more valuable packaging material.

Expanded polystyrene can be formed into any desired shape by cutting, typically with a hot wire, drilling, routing or indeed by any standard mechanical shaping process. However, this leads to a great waste in the basic expanded polystyrene since the material removed during shaping cannot usually be re-used. In particular, when scopping a cavity out of a large block of expanded polystyrene in order to make a box for a large item, which may for example be 1m3, it can happen that the amount of material removed and discarded is larger than the amount used in the box. In the past this problem has been overcome by placing two expanded polystyrene panels against opposed sides of the goods concerned and packing this in a large cardboard box.However this is not wholly satisfactory because of the well-known limitation of cardboard as a packing material: for example if the package gets wet, the strength of the cardboard can deteriorate and if the package is struck by a thin object mid-way between the two expanded polystyrene panels, this can penetrate the cardboard and damage the goods.

It is known that expanded polystyrene boxes can be made without wasting material by moulding but this is only economic if the boxes are relatively small and/or if they are produced in large numbers. Also, each mould can produce only one size of box.

There is thus a need to make rigid boxes of expanding foam material that do not involve great wastage of material, that do not require expensive moulding equipment and that can be produced in a variety of shapes and sizes.

According to the present invention, there is provided a box made of expanded foam material, which box has a base panel and two or more, preferably four, side panels that together form an open-topped box, the side panels being held together by inter-locking tongue-and-groove joints and the side panels being secured to the base panel by tongue and groove joints.

By "interlocking tongue and groove joints", I mean tongue-and-groove joints that do not permit the tongue to be pulled out of the groove other than by sliding the tongue longitudinally along the groove. Preferably such tongue and groove joints are T-shaped or dove-tailed in cross-section.

It is not necessary and in some cases it is undesirable for the tongue-and-groove joints between any side panel and the base panel to be of dovetail or similar interlocking profile and it is preferred for the tongues and grooves of the joints between the base panel and each of the side panels to be such a cross-section e.g. of rectangular cross-section, that permit the tongue to be inserted laterally into the groove, i.e. the tongue does not need to be slid longitudinally down the groove but the tongue can be inserted directly into the groove as in a mortise and tenon joint.

Since expanded foam is a resilient material and also because the coefficient of friction between two pieces of expanded foam is high, it is possible, by making the tongues fit tightly within the grooves, to avoid the use of fixing elements or material, e.g.

screws, plugs, dowels, pins or glue. Indeed a tight joint has proved to be so strong that it is in some cases very difficult to dismantle a box made in accordance with the invention. However, fixing elements or materials may be used if desired.

The box may also be provided with a lid that can be secured to the rest of the box by one or more plugs, screws or dowels extending through a side panel into the lid. If the plug is made of expanded foam, it can be push-fitted into a hole through a side panel into a blind hole in the lid and this has proved to be a very satisfactory method of securing the lid. Alternatively, the lid may push fit onto the rest of the box and be held in place by friction or the lid can be held in place by straps or bands encircling the box.

The side and base panels may be of any desired shape or cross-section. For example, the outside surface of one side panel may be curved in order to fit against the curved wall of an aircraft fuselage.

Since expanded foam can be very easily worked, it is not only straightforward to form the tongueand-groove joints of the side and base panels by conventional methods, but also it is easy to shape the insides of the panels to fit any desired goods, which may for example be a television set, a computer or other electronic equipment. It is also simple to divide the inside of the box into sections so that several, small items may be packed together, for example bottles of wine.

It will be appreciated that the box according to the invention does not give rise to large amounts of waste material in its production, does not require expensive moulding equipment, and can be made in a variety of shapes and sizes. Furthermore, the box is easy and quick to assemble. Also, the panels can be stacked and transported, prior to assembly and use, which represents a considerable saving in storage and transport space as compared to an assembled box or a moulded box or a box formed by scooping the centre from a single block of expanded foam.

The invention will be illustrated, by way of example only, with reference to the accompanying drawings, in which: Figures la, b and c are perspective, plan and side views (respectively) of a base panel of a box, Figure 2 is a perspective view of a side panel of a box, Figure 3 is a detailed perspective view of the joint between two side panels, Figure 4 is a side view of a partly-assembled box, Figure 5 is a side view of the box shown in Figure 4 but at a more advanced stage of assembly, Figure 6 is a perspective view of the box of Figures 4 and 5 when fully assembled, Figures 7 and 8 are perspective views of two alternatively-shaped side panels, Figure 9 is a perspective view of an alternative base panel, Figures lOa, b and c are perspective, plan and side views (respectively) of a lid, and Figures 71a and b show two alternative side panels.

Referring to Figures 1a to there is shown a base panel 11 made of expanded polystyrene, and having a central, raised plinth 12, the faces on three sides of which have been undercut to form grooves 13 and tongues 14. Also, there is a further groove 15 cut into the base panel along the fourth side of the panel and two blind holes 16 are formed in the fourth side of the plinth which are designed to receive plugs to fix a side panel to the base panel as will be described in greater detail below.

Figure 2 shows an expanded polystyrene side panel 20 that is designed to be fixed to one of the three sides of base 11 that is provided with a groove 13 and a tongue 14. The side panel 20 has two tongues 21 along each side edge and is cut just above its bottom edge to form a groove 22 and a tongue 12. A vertical groove 25 is also cut in the panel to accommodate dividers as will be explained in greater detail below. When assembled, the tongue 14 of panel 11 fits into groove 23 and the tongue 24 of panel 20 fits into groove 13; this will be described in greater detail in connection with Figures 4 and 5 below.

Referring to Figure 3, this shows the way two side panels 20 and 26 fit together. Panel 20, which is shown in Figure 2, is made of expanded polystyrene and has a T-shaped tongue 21 that can slide lengthways into a corresponding shaped T-shaped groove 27 in panel 26. Because of the profile of the tongue 21 and the groove 27, the two panels cannot be pulled apart except by sliding longitudinally with respect to each other. The fit of the tongue into the groove is preferably tight so that such longitudinal sliding will not readily occur. In addition, the tongue 21 may be glued into groove 27 but this is not generally necessary if the fit is tight enough.

It does not matter which panels have tongues and which panels have grooves but it is of course necessary for the abutting side edges of two adjacent panels to have one tongue and one groove.

Figure 4 is a side view of a partly-assembled box; in this state, it has a base 11 and three side walls 20, 26 and 30. Also visible in this Figure is the plinth 12 with its tongues 14 located in grooves 23 and 33 of panels 20 and 30 and also the tongues 24 and 34 of the panels 20 and 30 located in the grooves 13 of base panel 11.

In Figure 4 there can be seen the tongue 21 of panel 20 and a corresponding tongue 31 in panel 30. Panel 30 is also made of expanded polystyrene and is identical to panel 10. Figure 4 also shows groove 15 in base 11.

In order to complete the box, the fourth side 40 shown in Figure 5 is added (Figure 5 is identical to Figure 4 except for the addition of panel 40). Panel 50 has two grooves (not shown in Figure 5 but shown in Figure 6 by the reference number 41) into which tongues 21 and 31 project in the way shown in Figure 3. Thus, panel 40 can be slid into position by engaging the ends of both tongues 21 and 31 in the ends of grooves 41 (see Figure 6) in panel 40 and pushing panel 40 downwardly; Figure 5 shows panel 40 part of the way down to its final position. Panel 40 differs from panels 20, 26 and 30 in having no groove 23 or 33 but instead has a tongue 42 that engages in groove 15 when panel 40 is slid downwardly from the position shown in Figure 5.

Because of the interengagement of the tongues and grooves on the base and side panels, the resulting box is rigid. If the tongues 21 and 31 are tightly held in grooves 41, there is no need for elements preventing panel 40 from sliding upwardly because the friction preventing movement of the tongues along the grooves is very high, particularly when the joints are so tight that the tongues have to be compressed slightly to fit into the grooves. However, if it is desired to fix panel 40 in place mechanically then plugs can be inserted into holes 42 passing through panel 40 so that they engage in holes 16 in the base panel.

The box assembled from the components shown in Figures 1 to 5 is illustrated in Figure 6. In addition, the inside of the box is divided into four sections by partitions 50 and 51, the edges of which engage in grooves 25 in the side panels. However, the partitions need not be used, in which case grooves 25 need not be provided.

The outer and inner shape of the side and base panels may be varied. For example, side panel 60 shown in Figure 7 has a curved outer wall 61 and a curved inner wall 62. This panel can be combined with the base panel 11 in exactly the same way as described above. The curved shape of outer wall 61 is intended to make packing of boxes into an aircraft fuselage efficient since the curved wall 61 can lie against the curved surface of a fuselage. It is not necessary to have the outer surface of all four panels identically shaped.

A panel similar to that shown in Figure 7 is illustrated in Figure 8; the only difference between these two panels is that the inner wall 71 of the Figure 8 panel is flat and not curved. The shape of the panels can thus be made to accommodate the desired goods.

The base panel may also be shaped as shown in Figure 9 according to the goods to be conveyed; in this case, four recesses 80 are provided to hold bottles.

The boxes may be open-topped but it is, of course, preferred for them to be closed if they are to be used for transporting goods. To this end, a lid 90 shown in Figures 10a to 10c may be provided which push fits onto the box shown in Figure 6, the central part 91 of the lid fitting into the cavity in the box with the outer part 92 abutting the tops of the side panels 20, 26, 30 and 40. The lid may be secured by pins or dowels passing through holes 55 (see Figure 4) in panels 20, 26, 30 and 40 into blind holes 93 in the lid. These pins or dowels are preferably held by friction in the holes.

It is not necessary for the tongues and grooves to be straight (although any pair of connecting tongues and grooves must be of the same shape) For example, the side panels may be as shown in Figures lia and lib in which the tongues and grooves are curved.

It will be appreciated that panels 20, 26 and 30 can be made as a single unit rather than joined by tongue and groove joints although it is less advantageous than the box illustrated and described above.

Also, it is not necessary for the base to be square; round, rectangular or hexagonal bases may also be used, but square or rectangular boxes are preferred.

The tongue 42 is not necessary and can be dispensed with if desired, since the abutment of panel 40 against plinth 12 serves to lock panels 20, 26 and 30 in place.

Finally, it is not necessary for the base and side panels to be made wholly of expanded foam material. For example the panels may be covered in plastics or paper bearing printed material. Also, the tongues and/or the grooves (or the rest of the panels) may be coated with an outer layer that provides greater stiffness to the underlying expanded foam, and we have found that this can be achieved using water-based (emulsion) paint for example.

Claims (15)

1. A box made of expanded foam material, which box has a base panel and at least two side panels that together form an open-topped box, the side panels being connected together by interlocking tongue-and-groove joints and the side panels being secured to the base panel by tongue-andgroove joints.

2. A box as claimed in claim 1, wherein the tongues and grooves of the locking tongue-andgroove joints are of dove-tail or T-shaped crosssection.

3. A box as claimed in any one of claims 1 or 2, wherein the base panel has a central plinth against which the bottom of the inner face of each side panel abuts, wherein the plinth and all except one side panel are joined by a tongue extending from the plinth into a groove in the abutting side panel(s) and/or by a tongue extending from the or each side panel into a groove in the side of the plinth, the said one last side panel being connected to the part of the base panel around the central plinth by a tongue-and-groove joint.

4. A box as claimed in claim 3, wherein the said one last side panel is mechanically joined to the base panel.

5. A box as claimed in claim 4, wherein the said one last panel is joined to the base panel by glue or by one or more pins, screws or dowels.

6. A box as claimed in any one of claims 1 to 5, wherein the tongues of the locking tongue-andgroove joints are prevented from sliding longitudinally within their respective grooves by friction.

7. A box as claimed in any one of claims 1 to 5, wherein the tongue of the locking tongue-andgroove joints are prevented from sliding within their respective grooves by glue or by one or more pins, screws or dowels.

8. A box as claimed in any one of claims 1 to 7, wherein the box is cube or cuboid in shape.

9. A box as claimed in any one of claims 1 to 8, which has four side panels each joined to its neighbouring side panels by locking tongue-andgroove joints.

10. A box as claimed in any one of claims 1 to 9, wherein the expanded foam material is expanded polystyrene.

11. A box as claimed in any one of claims 1 to 10, which includes a lid.

12. A box as claimed in claim 11, wherein the lid is held on the side panels by friction or by one or more pins, dowels or screws.

13. A box comprising a base panel provided with a central raised area, the box further including two or more side panels joined together by interlocking tongue-and-groove joints, the bottom region of the side panels being so shaped that together they abut against the sides of the central raised area of the base panel around the whole perimeter thereof and wherein the side panels are joined to the base by one or more tongue and groove joints.

14. A box substantially as hereinbefore described in connection with and as illustrated in Figures 1 to 11.

15. A kit of parts comprising a base panel and two or more side panels and optionally a lid, the side and base panels being made of expanded foam material and being capable of being joined together to form a box as claimed in any one of claims 1 to 14.