GB2367054A - A One-piece Moulded Watertight Collapsible Container - Google Patents

Abstract

A collapsible container (10), in the form of a box, of integral construction is moulded in erected state from plastics material to have panels defining four relatively rigid side walls (11) and a square base (10) interconnected by linear zones (13) of weakening forming film hinges (14). The panels defining the base (12) and two opposite ones of the side walls (11) have further linear zones (15) of weakening forming further film hinges (16) arranged to permit collapse of the container into a flattened state. In erected state, the container is self-supporting and liquid-tight and in collapsed state, with the panels folded inwardly, has compact dimensions.

Description

COLLAPSIBLE CONTAINER The present invention relates to a collapsible container and to a method of producing such a container.

Collapsible boxes, bags, cases and other containers exist in diverse forms. Collapsible bags and the like are often made of stiff paper, flexible plastics material or light card and produced from an essentially two-dimensional blank which is folded and joined by gluing, heat-welding or other suitable form of seaming to produce a three-dimensional structure able to be collapsed by folding along fold lines. The finished product is supplied in erected state capable of collapsing or, more usually, in folded state capable of erection.

Collapsible boxes can be assembled from discrete rigid panels, for example of plastics material, metal or wood, interconnected by hinges which can be separately provided and fitted or formed as interconnectible complementary parts integral with the panels.

Collapsible containers of these forms of construction can be economical to produce and are suitable for many purposes, but are also subject to constraints with respect to use, for example they are generally not liquid-tight due to porosity of the constituent material or leakage zones at the hinge points. In addition, containers produced from blanks folded into three-dimensional form and joined at edges or assembled from discrete panels connected together by hinges necessarily require additional handling to produce a finished article.

It is therefore the principal object of the invention to provide a multi-purpose collapsible container which is relatively simple to construct and does not oblige production steps beyond defining an initial shape in the constituent material. A further object is the provision of a collapsible container which is liquid-tight. Other objects and advantages will be apparent from the following description.

According to a first aspect of the invention there is provided a collapsible container of integral construction moulded in erected state from plastics material to have panels defining side walls and a base interconnected by linear zones of weakening forming film hinges, a plurality of the panels having further linear zones of weakening forming further film hinges arranged to permit collapse of the container into a flattened state. Such a container can be produced in a simple moulding process which results in a finished product without the need for any of the joining steps associated with containers constructed from blanks or the need for an assembly stage to interconnect separately produced panels by means of hinges. Due to the entirely integral construction, preconditions exist for the container to be liquid-light without requiring further sealing measures. The linear zones of weakening permit the container to be folded into a substantially flat state after production, so that it can be supplied in a compact form convenient for transport and storage. The container is capable of repeated erection and collapsing for as long as the integrity of the film hinges is preserved.

The container typically has four side walls, although other wall numbers can be possible depending on appropriate arrangement of the film hinges. Thus, in erected state, the container can represent a four-sided box open at the top and with a square, oblong, trapezium-shaped or rhombic plan. The open end could be closable by an integral lid of any desired suitable shape and connected with one of the side panels by another linear zone of weakening forming a film hinge.

The constituent plastics material is preferably substantially rigid in the areas between the film hinges so that the container in erected state is self-supporting and has no tendency to sag or distort. The rigidity of the panels and the flexibility of the hinges can be achieved simply by choice of an appropriate thickness of a suitable plastics material, such as polypropylene. The material can be selected to have specific rheological properties which impart a degree of memory assisting restoration of the collapsed container to its originally moulded, i. e. erected, state without permanent distortion in fold regions.

Preferably, the panels with the further film hinges are foldable inwardly of the container for collapsing thereof, so that in the flattened state the container has compact dimensions.

The panels with the further film hinges are preferably those defining the base and two mutually opposite ones of the side walls. The particular arrangement of the further film hinges depends on the number of sides and on the plan shape of the container. In the case of, for example, a container with four side walls the further film hinges preferably extend on a path bisecting the base and on continuation paths bisecting the two mentioned opposite side walls. In one preferred disposition of the further film hinges, these additionally extend on paths so linking each corner of the base with the path bisecting the base as to form two divided triangular gussets in the base. If the container base is, for example, square, the paths in the base can intersect in its centre. In the case of an oblong shape, the divided triangular gussets may be spaced apart, rather than contiguous, at their apices. In another possible disposition of the further film hinges, these additionally extend on paths so linking corners of the base with paths bisecting the two mentioned opposite side walls as to form divided triangular gussets in those walls. The principle of folding is essentially the same regardless of whether the gussets are in the base or in the side walls, but the former disposition has the aesthetic advantage of minimising the number of film hinges normally exposed to view.

In order to facilitate collapsing of the container and to prolong the life of the hinges under repeated folding, the container can comprise an area zone of weakening disposed at at least one junction of linear zones of weakening and forming a region of flexure in three dimensions. The area zone of weakening can have the form of, for example, a circular area of reduced thickness allowing the material to flex without formation of sharp creases and eventual splits. The afore-mentioned rheological character can allow the material to flow in the or each area zone of weakening so as to permit expansion and contraction for accommodation of three-dimensional bending during folding and unfolding. This not only avoids creasing, but may also prevent formation of bulges.

According to a second aspect of the invention there is provided a method of producing a collapsible container, comprising the step of moulding the container in one piece and in erected state from plastics material to have panels defining side walls and a base interconnected by linear zones of weakening forming film hinges, a plurality of the panels having further linear zones of weakening forming further film hinges arranged to permit collapse of the container into a flattened state.

The step of moulding is preferably injection moulding.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a side view of a collapsible box embodying the invention, in erected state; Fig. 2 is a front view of the box of Fig. 1; Fig. 3 is an inverted plan view of the box of Fig. 1; Fig. 4 is a view similar to Fig. 1, but showing the box collapsed into flattened state; Fig. 5 is a view similar to Fig. 2, but showing the box in flattened state; Fig. 6. is a view similar to Fig. 3, but showing the box in flattened state; Fig. 7 is a perspective view from below, to enlarged scale, of the box in erected state; and Fig. 8 is a view similar to Fig. 7, but showing the box in partly collapsed state. Referring now to the drawings there is shown a collapsible box 10 composed of panels which in the erected state of the box define, by way of example, four oblong side walls 11 and a square base 12. The box 10 is integrally moulded from plastics material, such as polypropylene, to define the erected state at the outset. The walls 11 and base 12 are interconnected by linear zones 13 of weakening, in particular zones of reduced thickness of the plastics material, which form film hinges 14 to permit the panels or parts of the panels to be folded relative to each other for collapsing of the box. The capability of collapsing the box is imparted by further linear zones 15 of weakening forming further film hinges 16. In the illustrated embodiment, the further film hinges 16 extend on a path bisecting the base 12 and on continuation paths bisecting two mutually opposite ones of the side walls 11 as well as on paths connecting opposite corners of the base 12, i. e. the diagonals of the base. Due to the square format of the base, the film hinge paths in the base 12 intersect at its centre. The base 12 is thus provided with two mutually opposite, divided triangular gussets 17, in addition to two opposite, undivided triangular gussets.

Circular areas 18 of weakening are formed at the junctions of the linear zones 13 so as to provide regions permitting three-dimensional flexure without risk or immediate risk of formation of creases. The material can be selected to be of a kind undergoing selfrestoring flow when flexed in the linear and area zones 13,15 of weakening, so as to enhance pliability in these regions.

The material of the panels between the film hinges 14,16 is substantially rigid so that in the erected state of the box 10 as illustrated in Figs. 1 to 3 and 7 the box constitutes a selfsupporting, stable structure. By virtue of the integral hinges and the non-porous nature of the polypropylene, the erected box 10 provides a liquid-tight container.

Collapsing of the box 10 is achieved by pushing the base 12 inwardly at the centre so that the two halves of each of the divided triangular gussets 17 move towards each other at their inner faces with simultaneous inward folding of the undivided triangular gussets and the two halves of the bisected side walls 11, as apparent from Fig. 8 (partially collapsed state) and Figs. 4 to 6 (fully collapsed state). In the latter state, the two halves of each of the bisected side walls 11 lie against one another and each partially against a respective one of the other two side walls 11. Due to the gussets in the base 12, the layer thickness of the box 10 in the fully collapsed state is twice as great (eight adjacent layers) as that at the end opposite the base 12 (four adjacent layers), the panels having sufficient resilience, however, to tolerate this small difference and allow the collapsed box to adopt a relatively flat form.

The box 10 can be produced in an injection-moulding process with a mould configured to define the zones of weakening in the finished product. Consequently, no additional production steps are required. The erected box can serve various purposes, including, for example, use as an inexpensive and conveniently transportable receptacle for displaying flowers. The box 10 can be safely filled with water without risk of leakage. In the case of use for such purpose, the box can be supplemented near the top with slots or tongues for attachment of a card. For other uses, the container can, if desired, be provided with an integrally attached lid.

By contrast with conventional collapsible containers, the container embodying the present invention is not only of integral construction, but moulded in erected state. The container is easily collapsed by virtue of the film hinges and the inwardly folding panels result in a compact flattened form.

Claims (14)

1. CLAIMS 1. A collapsible container of integral construction moulded in erected state from plastics material to have panels defining side walls and a base interconnected by linear zones of weakening forming film hinges, a plurality of the panels having further linear zones of weakening forming further film hinges arranged to permit collapse of the container into a flattened state.
2. 2. A container as claimed in claim 1, wherein the plastics material is substantially rigid in the areas between the film hinges.
3. 3. A container as claimed in claim 1 or claim 2, wherein the container is liquid-tight.
4. 4. A container as claimed in any one of the preceding claims, wherein the panels with the further film hinges are foldable inwardly of the container for collapse thereof.
5. 5. A container as claimed in any one of the preceding claims, wherein the panels with the further film hinges define the base and two mutually opposite ones of the side walls.
6. 6. A container as claimed in claim 5, wherein the further film hinges extend on a path bisecting the base and on continuation paths bisecting the two side walls.
7. 7. A container as ciaimed in claim 6, wherein the further film hinges additionally extend on paths so linking each corner of the base with the path bisecting the base as to form two divided triangular gussets in the base.
8. 8. A container as claimed in claim 7, wherein the paths in the base intersect in the centre thereof.
9. 9. A container as claimed in claim 6, wherein the further film hinges additionally extend on paths so linking the corners of the base with the paths bisecting the two side walls as to form divided triangular gussets in those walls.
10. 10. A container as claimed in any one of the preceding claims, comprising an area zone of weakening disposed at at least one junction of linear zones of weakening and forming a region of flexure in three dimensions.
11. 11. A container as claimed in claim 10, wherein the at least one area zone of weakening is circular.
12. 12. A container as claimed in any one of the preceding claims, wherein the plastics material is polypropylene.
13. 13. A method of producing a collapsible container, comprising the step of moulding the container in one piece and in erected state from plastics material to have panels defining side walls and a base interconnected by linear zones of weakening forming film hinges, a plurality of the panels having further linear zones of weakening forming further film hinges arranged to permit collapse of the container into a flattened state.
14. 14. A method as claimed in claim 13, wherein the step of moulding comprises injection moulding.