1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION STANDARD PATENT "Fold-Up Container" The following statement is a full description of this invention, including the best method of performing it known to me: 2 FOLD-UP CONTAINER 5 Field of the Invention This invention relates to collapsible container constructions. In a particular non limiting aspect the invention relates to collapsible container constructions which may be used as outers for holding flexible inner liners such as plastic bags containing 10 flowable materials. It is particularly applicable to containers having a capacity in the range of 500 to 1,500 litres. Background of the Invention 15 One of the ways in which flowable materials have been packaged in bulk has involved the use of a rigid outer container to lend support and security for a flexible liner bag containing the material. The outer container should be strong enough to provide maintenance of the physical integrity of the container while the inner liner is sufficiently impermeable to avoid spillage and waste. However, when the product 20 material held in the liner has been emptied, it is desirable that the outer container be re useable because it may represent a substantial proportion of the cost of the package. Where re-useability is an important consideration, if a large amount of space is taken up by an empty outer container, the cost of transporting the container can be so high 25 as to reduce the economic advantages associated with reusing the outer container. Thus it is desirable that the outer container be demountable or collapsible in order to reduce its volume and hence reduce the cost of transporting the container to a location where it may be reused. 30 Apart from the stresses applied to outer containers by the weight of flowable material held within the container, in some instances it is also necessary to provide that such 3 containers be stackable even when they are filled with material. In order to provide for stackability, such containers need to be reinforced to enable them to safely cope with the weight of one or more filled containers stacked on top of them. 5 Thus there is a need for a container design which may be used as an outer container for bags of flowable materials, which is sufficiently strong as to be stackable and is collapsible to facilitate easy and economic transport of the container for reuse. As the manual labour involved in assembly or erection of a container can become a 10 significant cost factor in the overall cost of using the container, it should also be simple to assemble or erect. Disclosure of the Invention 15 The invention provides in one aspect a collapsible container comprising, a base, atop, a plurality of vertically extending side walls intermediate the base and top, the side walls being joined at vertical edges between adjacent pairs of side walls, and 20 vertically extending struts arranged to span across the inside of the vertical edges between adjacent pairs of side walls when the container is in an erected state, wherein the side walls and base are foldable so that the container can be collapsed to a flattened configuration and each of the struts are attached by a hinge to one of each of the respective adjacent pairs of side walls in such a manner that they may be folded flat 25 against the side wall to which they are attached when the container is collapsed. Suitably the side walls and struts are constructed in such a fashion that, with the container assembled and filled, they have sufficient rigidity to bear weight. For example, they may bear the weight of a filled similar container stacked above them. 30 Whilst the invention is applicable to container constructions having three or more side walls, it is anticipated that containers having four side walls will be more commonly 4 used. The side walls may be curved or planar although it is anticipated that planar side walls will mostly be used. The top of the container may have a lid which is also foldable so it may be included 5 within the container's said collapsed flattened configuration. In a particularly suitable form of the invention, there may be four side walls forming a container having a rectangular, and preferably square, horizontal cross section. 10 The edge joins between side walls are preferably flexible in order that the side walls may be folded down upon each other about these joins. Thus the side walls themselves may be relatively rigid. It is even possible that the side walls may themselves have bendable portions in order to allow the side walls to be bent or folded with respect to themselves. However, in most instances, it is anticipated that each side is . wall will be fully rigid, the flexible edge joins being the main feature which allows them to be folded upon themselves. The side walls may comprise a composite of different materials. For example, the side walls may comprise flexible material. The flexible material may be a fabric such as 20 either woven polypropylene which is stitchable or a material which is weldable. The material may have a hot melt coating adhered to one or both sides to give an impermeable barrier to contaminants and water. The flexible material in the side walls may form pockets. The pockets may be adapted to receive stiffening means to lend rigidity to the side walls. The stiffening means may be planar material such as panels 25 of stiff flat sheet. Particle board or plywood may be suitable for this purpose. Five-ply plywood about 15 to 25mm in thickness has been found to be particularly suitable for a container of approximately 1100mm square and 950mm high in outside dimensions. The flexible material of the side walls may be formed with openings to allow insertion 30 and removal of the stiffening means to the pockets in the side walls. The openings may be provided near the base of the container to prevent the boards being pushed-out of the pockets when the containers are stacked one on top of the other. To assist with 5 retaining the stiffening boards in the pockets, flaps may be provided to cover the openings. The flaps may include fastening means to fasten them to the flexible material in order to close off the openings when the stiffening boards have been inserted. The material of the four side walls may be one sheet, doubled over to create 5 pockets, then joined end to end. Similarly, the struts may be in the form of stiff planar members. They may comprise a combination of flexible material encasing stiffening boards as generally the case for the side walls. Thus each strut may comprise a pocket of flexible material in which is held 10 a narrow panel of stiff flat sheet material as hereinbefore described. The struts may be joined at one edge to the side walls by stitching or otherwise joining the flexible material to the flexible material forming the interior layer of flexible material of the respective side walls. 15 Each join at the vertical edges of the container may be in the form of a hinge. The hinge may comprise an extension of the flexible material of the side walls. The extension may form a hollow region at the vertical edge which forms a pocket for an elongate rigid member. The elongate rigid members may be shaped so as to facilitate hinging or flexing of the flexible material on either side of each elongate rigid member. 20 The rigid members which fit in the hollow may comprise a length of timber dowel or similar material. The base of the container may be formed of flexible material. The flexible material may comprise the same type of flexible material as the side walls. A fabric such as 25 polypropylene or reinforced polypropylene may be suitable for this purpose. The flexible material forming the base may comprise more than one piece of flexible material. For example, it may comprise two triangular pieces joined by a diagonally extending region of joining in the base. The diagonally extending region of joining 30 may comprise a slide fastener, Velcro, hook and eyelet, or other suitable fastening means.
6 The lid may also be formed of a flexible material. The flexible material may be the same material as the flexible material used for the side walls and base. The lid may be permanently joined to one of the four side walls. Thus it may be releaseably joined to the other three side walls. It may be joined by a slide fastener. Alternatively the lid 5 may be made to have the same general structure as the base, namely with two triangular pieces joined by a slide fastener. The container may have a liner. The liner may be a liquid impermeable liner. It may be formed from a plastic film. The liner may conform to the interior configuration of 10 the container. When the liner is placed in the collapsible container after erection, it may subsequently be filled with liquid such that the walls of the liner then press out against the side walls of the container. At the same time, the liner will push against the struts provided at 15 the inside of the vertical edges to hold the struts rigidly in place across the inside of the vertical edges. This can act to distribute the pressure from the filled liner over a distance across the inside of the vertical edges. The struts which act as rigid members should also assist with resisting crushing of the container when the containers are stacked on top of each other. 20 One of the side walls of the collapsible container may be provided with an opening to allow a bung or tap provided on the liner to protrude therethrough. Thus it may be possible to periodically withdraw liquid from the liner through the tap or bung as is required. 25 The invention provides in another aspect a method of storing liquid comprising stacking a filled first container on top of a similar filled second container, each container being as described above, such that the side walls of said first container are generally aligned with the corresponding side walls of said second container. 30 Preferred aspects of the invention will now be described with reference to the accompanying drawings.
7 Brief Description of the Drawings Figure 1 is an oblique schematic view of an erected container according to the 5 invention, and shown with its lid fully fastened into place; Figure 2 is a plan view looking down on the top of the container of Figure 1; Figure 3 is a plan view of the base of the container of Figure 1; Figure 4 is a plan view of the top of the container of Figure 1 with the lid unfastened and folded back away from the top of the container and a liner in the 10 container; Figure 5 is a partial isometric view of the container of Figure 1 with its lid and struts arranged prior to collapsing of the container; Figure 6 is a plan view of the container of Figure 5 after folding flat; and Figure 7 is a horizontal cross section through portion of the container of Figure 15 4 with the liner removed. Detailed Description of the Preferred Embodiment In Figures 1 to 4 and 7 of the accompanying drawings the container generally 20 designated 1 is shown in the erected condition. The container 1 has four vertically standing side walls 3. These are joined together at vertical edges 17 of the container to define a wall outline having a square horizontal cross-section. Whilst the illustrated embodiment shows a square cross-section, it is to 25 be appreciated that a container having a different rectangular or other cross section is also usable. A base 5 formed of flexible material joins the bottom edges 6 of the side walls 3 and a lid 7, having the form of a flap, also formed of flexible material covers the open top 10 30 of the container defined by the side walls 3.
8 Struts 9 span the furrow 20 formed between adjacent side walls 3 in the container on the inside of the vertical edges 17. The struts 9 are arranged so that they form an angle of approximately 45* with the side walls 3. In this specification the terms "furrow" and "inside of the vertical edge" are used interchangeably. 5 An opening 11 is formed in one of the side walls 4 near the bottom of the side wall. This is to allow a bung or tap 34 fitted to a liner 32 to protrude from the liner through the side wall 4 and thereby allow easy access to liquid contained in the liner. 10 The base 5 of the container is formed of two flexible triangular sections 12 and 14 which are joined by a diagonally extending slide fastener 13. This may suitably comprise a zip fastener or other type of slide fastener of suitably robust manufacture. The slide fastener 13 allows ready fastening and releasing of the join between the two triangular sections 12 and 14 forming the base 5. This is to aid with collapsing of the 15 container 1 when it is to be folded. Another slide fastener 15 extends along the top edges 8 of three of the four side walls 3 and joins three of the edges of the lid 7 to the side walls. The remaining edge 16 of of the flap of the lid 7 is permanently affixed to the fourth side wall by stitching along 20 the top of the fourth side wall. Each of the vertical edges 17 is formed with a hinge 19. The hinge includes a dowel 18 housed in a vertically extending pocket 22 provided at each vertical edge 17. The dowel 18 may be wood or could be replaced with a suitable length of pipe or tubing. 25 The pocket 22 is formed as an extension of a flexible skin 21 formed on opposite sides of each of the side walls 3. The flexible skin may be formed of any flexible material normally used in the packaging art. Woven fabrics are particularly suitable and these may be laminated with a plastic film on one or both sides or may be uncoated. Woven 30 polypropylene or other plastics material, suitably reinforced as required, may be used to form the flexible skin 21. A particularly preferred material is an uncoated woven 9 polypropylene of 280g/m2 and having a weave count of 24 tapes/inch warp and 13 tapes/inch weft. The flexible skin 21 of each of the side walls 3 is formed by two layers of fabric which 5 forms a pocket 30 to receive a panel shaped stiffening board 25 made of a stiff planar material such as particle board or plywood. Openings 29 are formed at the bottom edge of each of the side walls 3 to allow entry of the stiffening panels 25 into the pockets 30 formed by the flexible skin 21. The 10 openings 29 incorporate fabric flaps (hidden in the Figures) which extend from the outer flexible skin on each side wall 3 to the inner flexible skin defining the side wall to close off the opening 29 after the stiffening board 25 has been inserted. Fastening means such as Velcro or the like may be used to affix the flaps in this fashion. Alternatively the flaps may be simply folded over the edge of their respective panel and 15 tucked into the pocket where it is held in place by friction. Each of the struts 9, comprise a flexible skin 26 also formed of the same material as the flexible skin 21 of the side walls. This flexible skin 26 on each strut 9 is joined by any means such as stitching, welding, etc to form a pocket 28. The pockets 28 are for 20 receiving corner stiffening boards 27. The stiffening boards 27 may conveniently be of the same board material as that used for boards 25 in the side walls. The flexible skin 26 of each of the struts 9 is joined to one of the two side walls which it contacts by stitching which forms a flexible join 23 leaving the opposite edge 24 of 25 the strut free to contact the adjacent side wall without being connected thereto. Thus a strut 9 may pivot about the join 23 so that, when the container is due to be collapsed, the strut may be laid flat against that side wall to which it is attached. The strut 9 can thus be rotated to form a structural support bearing against the adjacent side wall when the container 1 is erected. 30 Referring to Figures 5 and 6, it can be seen that the container in Figure 5 is shown prior to being collapsed, with the struts 9 folded over about their flexible joins 23 to sit 10 relatively flat against opposite side walls 3. The lid 7 has been unzipped from the three side walls to which it has been affixed by the slide fastener 15 and has been folded upon itself flat against the fourth side wall to which it is permanently affixed. 5 Prior to collapsing of the container, the slide fastener 13 in the base 5 is unzipped to release the two triangular sections 12 and 14 from each other. The container may then simply be flattened down to the form shown in Figure 6. It can be seen that the side walls hinge about the vertical edges 17, so that the walls 3 may be laid substantially flat upon each other. 10 The container can be easily re-erected by following the opposite routine. After erection, a flexible liner 32 may be placed in the container and filled so that the sides of the liner press outwards against the side walls 3 and push against the struts 9 to distribute load evenly over the furrows 20 at the vertical edges 17. The stiffening 15 panels 25 in the side walls 3 and the stiffening boards 27 in the struts 9 then serve to provide good crush resistance to the filled container when other containers are stacked thereon. It is to be understood that the word comprising as used throughout the specification is 20 to be interpreted in its inclusive form. This means that use of the word comprising does not exclude the addition of other elements. It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. These 25 modifications and/or additions are therefore considered to fall within the scope of the invention.