Liner capable of collapsing within its own cross-section and a container which includes the liner

Abstract

 A container for transporting liquids comprises a rigid outer case and a liner. The liner is tapered and it collapses inside the case by rotating the top so that the sides fold inwards.

Description

[0001] The invention relates to containers for transporting liquids.

[0002] A known kind of container, referred to hereinafter as a container of the kind specified, comprises an approximately cubical liner moulded from a flexible thermoplastics material, e.g. polyethylene, and a rigid outer case, e.g. made from cardboard, to support and protect the flexible liner. The liners are usually blow moulded to give six substantially planar panels joined to adjacent panels with rounded edges, one panel having an opening shaped during the blow-moulding operation to provide or receive closure means. Typically, the opening is located adjacent one edge and provided with an outwardly extending tubular portion carrying integral screw threads around its outer surface, to receive a screw cap as closure means.

[0003] In use, the container is usually filled with the panel having the opening, uppermost, and in order to identify the panels in a simple manner the panel containing the opening will be referred to hereinafter as the top panel, and that opposite as the bottom panel. The panels linking the top and bottom will be referred to as side panels. However, this nomenclature is used for reference only, and as will be realised, during use the top panel will not necessarily be uppermost at all times. For example, containers of the kind specified are used for transporting liquids such as sherry, and to dispense the sherry at spaced intervals, the closure cap may be replaced by tap and the container rested on one side, or even inverted, during the dispensing operation.

[0004] U.S.patent specification 3 354 924 describes a collapsible container, similar to the liner described above, in which each side panel has a rectangular configuration with a diagonal foldline. All the foldlines are disposed in similar positions. When the top panel is rotated relative to the bottom panel each side folds inwardly along its foldline and the container collapses to a substantially flat configuration.

[0005] Containers of the kind specified are used for transporting alcoholic beverges and other liquids which deteriorate in contact with air. It is convenient to dispense the liquids from the liner while, the liner remains in.its outer case and it would be advantageous for the liner to collapse within its case as the liquid is dispensed, rather than for the dispensed liquid to be replaced in the liner by air, as is now the case.

[0006] According to the invention, a liner for a container of the kind specified, comprises side panels which taper from the top panel to the bottom panel, each side panel having a foldline along one of its diagonals said foldlines being along corresponding diagonals of each side panel, the taper being such that the length of each diagonal of the bottom panel is equal to or less than the length of each side of the top panel, so that when the liner is held within a parallel-sided outer case, the bottom panel can twist and allow the container to expand or collapse while residing within the outer case. Preferably the top panel and the bottom panel are both square.

[0007] The foldlines are preferably formed during the moulding process, and need not be a crease or other form of severe fold, a simple smooth shallow dish oriented along the corresponding diagonal being generally sufficient to facilitate the collapse of the liner. A shallow preformed dish has no noticeable effect on the performance of the liner when filled with liquid as the sides of the liner, being flexible, are normally pressed outwards. An alternative is to form the side panels with a diagonal crease by blowing the preforms in a mould having a corresponding raised profile. _.

[0008] A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 shows a liner in its expanded configuration and;

Figure 2 shows the liner of Figure 1 in its collapsed configuration.

[0009] The liner shown in Figure 1 is approximately the shape of a truncated pyramid on a square base. It has rounded edges and it was made by blow-moulding from low density polyethylene. The walls are sufficiently thick for the liner to be self-supporting but the edges are sufficiently flexible to fold when the liner collapses.

[0010] The liner has a square top panel 10 with a filler tube 11; the filler tube has a thread 12 on its outer surface. The liner also has a square bottom panel 13. The diagonal of the bottom panel is approximately equal to the side of the top panel. The means that the area of the top panel 10 is about twice the area of the bottom panel 13.

[0011] The liner also has four tapered side panels 14, 15, 16 and 17. Each has a diagonal foldline; the foldlines on sides 14 and 15 being indicated by 18 and 19. All the foldlines slope along corresponding diagonals; i.e. from top to bottom is in the anticlockwise direction. From the expanded configuration shown in Figure 1 the liner collapses to the configuration shown in Figure 2. This is achieved by rotation of the top panel relative to the bottom panel which is accompanied by inward bending along the diagonal foldlines of the side panels as well as flexing at the edges and corners.

[0012] In use the liner is enclosed in an outer case of cardboard. The case has a uniform square cross-section substantially the same size as the top panel. The height of the case is substantially the same as the height of the liner when the liner is full. The case protects the liner, e.g. it reduces the chances of the liner being perforated.

[0013] There is a hole in the top of the case and the filler tube of the liner projects through this hole. The liner can be filled with a liquid, e.g. sherry, in this position. Since the bottom panel of the liner is able to rotate within the cross-section the liner expands within the case as it is filled. When the liner has been filled the filler is sealed and the package can be transported to the consumer.

[0014] The package is suitable for dispensing its contents, e.g. sherry, with minimal access of air. To do this the consumer fits a suitable tap to the filler tube and inverts the package. This allows the contents to be withdrawn via the tap as required. As the contents are removed the "bottom panel" (which is now at the top) rotates within the case allowing the liner to collapse without the admission of air. This helps to prolong the life of beverages, such as sherry, which are adversely affected by air..

Claims

1. A liner which comprises a top panel, a bottom panel and side panels which join the top panel to the bottom panel, wherein each side panel has a foldline along one of its diagonals said foldlines being along corresponding diagonals of each side panel, characterised in that each side paneltapers from the top panel to the bottom panel wherein the taper is such that the length of each diagonal of the bottom panel is equal to or less than the length of each side of the top panel, so that when the liner is held within a parallel-sided outer case, the bottom panel can twist and allow the container to expand or collapse while residing within the outer case.

2. A liner as claimed in Claim 1, characterised in that the top panel and the bottom panel are both square.

3. A container which comprises a liner according to either Claim 1 or Claim 2 inside an outer case wherein the outer case has a uniform area of cross-section which is substantially the same as the top panel.

Drawing