COLLAPSIBLE DRINK CONTAINERS TECHNICAL FIELD This invention relates to collapsible containers and, more particularly, to collapsible containers suitable for use with liquid food stuffs or drinks for human consumption. However, the invention is not confined to drink containers, as the containers disclosed herein may be used for a variety of other purposes-for example, for storing photographic liquids which are oxygen-sensitive.

BACKGROUND TO THE INVENTION Collapsible bottles for drink and other flowable materials are known. Many of these have bellows-like side walls so that the bottle can be readily collapsed about its longitudinal axis of symmetry. Such containers have a number of recognised advantages: . The headspace above the contents can be kept to a minimum so that the storage-life of oxidation-sensitive materials, such as fruit juices, is extended.

. By the minimisation of the headspace and/or the minimisation of air ingress, the carbonation of carbonate beverages is preserved for longer.

. The space occupied by such a container in a crowded refrigerator is proportional to the volume of its contents, rather than being fixed by the volume of the bottle or other form of container as purchased.

. Such containers are readily compacted to a small volume when empty and, therefore, take much less room in waste or recycling bins.

However, collapsible bottles and containers of this type have two important disadvantages: . They are inherently weak in torsion so that screw-top closures are difficult to secure tightly, especially when partially empty, and . When partially full, they collapse laterally in an uncontrollable manner if gripped in the normal way, making them difficult to handle and prone to slip from the hand.

US patent 4,492,313 to Touzani discloses a collapsible bellow-

like drink bottle in which the bellows are formed so that they are self-latching as the bottle is compresse axially. While the latching is capable of resisting the uniform expansive pressure of a carbonated beverage, the bellows tend to unlatch if the bottle is gripped transversely in the normal manner. To prevent this, the base of the bottle is mounted in a rigid and deep cup by which the bottle can be gripped when pouring or when replacing the screw- cap. But the rigid base cup not oniy destroys most of the space-saving advantage of a collapsing bottle, it also adds considerably the cost of the bottle. To allow the cap to be tightened on the bottle, much of the upper portion of the bottle is formed without corrugations so that it can be gripped without collapsing. Not only does this further reduce the collapsibility of the bottle, but it significantly adds to the minimum headspace possible.

US patent 4,790,361 to Jones attempts to provide lateral stability to a partially empty collapsible bottle by providing radial as well as circumferential corrugations and by spacing axially extending facets at regular intervals around each corrugation. These facets also serve to provide portions of a cylindrical surface to which a label may be attached. The problem here is that, to the degree that lateral stability is provided by the facets and label, compressibility of the container is lost. As in the case of Touzani, the bottle is provided with an uncorrugated top by which it can be gripped by one hand while the cap is tightened by the other. Again, however, the top of the bottle cannot be collapsed.

US patent 5,573,129 to Nagata et al discloses a collapsible bottle having relatively few and large corrugations which decrease in diameter from the base to the neck so that they can nest one within the other when the bottle is collapsed. An elongate neck, having a hexagonal enlargement, is provided to allow a screw-cap to be tightened by gripping the neck.

OBJECTIVES OF THE INVENTION It is therefore an object of the present invention to provide an improved collapsible bottle or other container.

OUTLINE OF INVENTION The present invention is based upon the realisation that the

provision of valve means in the neck portion of a collapsible container can not only significantly reduce the need for torsional strength but can also greatly reduce the minimum headspace of the container when it is full or partially empty.

The containers of particular interest are those which are bottle- like, which are formable by blow-moulding, and which have bellows-like side walls that allow collapse of the bottle in the axial direction. The corrugations of the bellows may be formed in any suitable manner as disclosed in the prior art. For example, they may be of the latching type or of the nesting type, and, they may be of curved or angular section. However, in accordance with an optional feature of this invention, it is preferable for the corrugations to have upper and lower sides which are of different radial dimension, the upper face of each protruding corrugation being shorter then the lower face so that the corrugations nest pointing downwards on the inside of the container so liquid cannot pool therein when the container is collapsed.

The valve means may conveniently be a floating ball, flap or mushroom valve, but the use of spring-loading or gravity-loading is also envisaged. The valve means may include a stem or rod which may extend into or through the neck of the bottle so that it can be manually operated by the user. However, a floating valve which operates automatically as the container collapses on the liquid is preferred. The valve means may be formed within the container during manufacture, or it may be introduced through the neck of the bottle after the bottle has been formed.

It will be appreciated that, not only will the use of valve means in the neck or upper portion of the container allow the headspace of still liquids to be minimised, but it will also serve to maintain aerated liquids under pressure. Moreover, while a screw-cap may be used in addition to the valve means for safety and hygienic purposes at the time of manufacture, there is no need to retain it once the bottle has been opened (of, if it is retained, there is no need to screw it tightly on to the container. That is, the torsional strength óf a part-empty container is no longer of significance so that the corrugations can be made thin and flexible-that is, conducive to a self-sizing

container.

According to one aspect of the present invention there is provided a collapsible liquid container comprising a body, a neck, an opening from the neck, a collapsible wall section, and a valve within the body which is adapted to seal off the opening when the body contains a liquid in an erect or partially collapsed condition.

The valve is a ball valve.

A collapsible wall section of the body can be provided by the formation ofbellows.

The bellows can be substantially vee-section bellows.

One limb of the vee-section of each of the bellows is larger than the other limb.

The larger or smaller limb of each of the bellows can be the closest to the neck of the container.

The neck can include a valve seat defined by a sealing ring.

The ball valve can be constrained within a cage.

The valve seat is provided by a removable neck portion.

DESCRIPTION OF EXAMPLES Having broadly portrayed the nature of the present invention, particular examples will now be described by way of illustration only. In the following description, reference will be made to the accompanying drawings in which: Figure 1 is a diagrammatic elevational view of a collapsible bottle which comprises the first example of the invention, the bottle being shown in its full state.

Figure 2 is a diagrammatic elevational view of the bottle of figure 1, shown in its collapsed state.

Figure 3 is a diagrammatic sectional elevation of portion of the neck of a bottle like that of figures 1 and 2 but having a modified valve arrangement.

Figure 4 is a diagrammatic sectional elevation of portion of the neck of a bottle like that of figures 1 and 2 but having an alternative valve

arrangement to that shown in figure 3.

Figure 5 is a diagrammatic elevational view of a collapsible bottle which comprises the second example of the invention.

Figure 6 is a diagrammatic elevational view of a collapsible bottle which comprises the third example of the invention.

Referring to figures 1 and 2, the first example comprises a bottle 10 which is blow-moulded from HDPE, PET, PVC or other suitable plastics material in the conventional manner, except that prior to sealing the bottom end of the bottle, a hollow blow-moulded ball 12 of similar plastics material is formed or introduced into the body of the bottle. Preferably, the ball 12 is formed of soft rubber-like material which will seal well against the neck portion 14 of the bottle. Neck portion 14 is of conventional design and shape having an external screw-thread 16 to take a conventional screw-cap (not shown).

Between neck portion 14 and a base 18, a plurality of corrugations 20 are formed, each of which can be regarded as a radial and circumferential protrusion between two radial and circumferential intrusions.

Each protrusion in this example is formed by an inwardly and upwardly sloping conical upper facet 22 and an inwardly and downwardly sloping lower conical facet 24. Preferably, as shown, the radial dimension of lower facets 24 is greater than the radial dimension of upper facet 22. This arrangement allows the corrugations to interleave in a downwardly pointing manner when the bottle is collapsed, as shown in figure 2. The inwardly and downwardly sloping arrangement of the overlapping corrugations ensure that liquid is not trapped in them.

Since the insertion of a hollow ball into the bottle as it is being blown requires a complex die mechanism, other methods of providing an indwelling ball valve are envisaged. Figure 3 illustrates (in section) portion of the top of a bottle 10a having a neck 14a and a floating ball 12a which serves as a valve. In this case however, the ball is introduced through the neck 14a after the bottle has been formed. An O-ring 30 is then introduced into the neck and engaged with a groove formed therein, the O-ring serving both to retain the ball in the bottle and to form the seat of the floating ball valve.

In an alternative method illustrated diagrammatically in the sectional drawing of figure 4, a sleeve 40 is inserted and glued into the neck 14b of bottle 10b to form a seat for a floating bat ! 12b that is introduced into bottle 10b after it has been formed.

The second example, illustrated diagrammatically in figure 5, comprises a collapsible bottle 50 having bellows-type corrugations 52 in its wall and a normal externally threaded neck portion 54. A separate ball valve assembly 56 having a cage 58 containing a ball 60 is screwed onto neck 54 and is itself provided with an externally threaded neck 60 adapted to take a conventional screw-cap (now shown).

The third example, shown in figure 6, illustrates a wide-mouthed container 70 having corrugated sides 72 and wide, externally-threaded neck 74. A floating ball 76 is dropped in the container through the wide neck 74, but is of a much smaller diameter than that of the neck. To contain the ball and form a valve seat therefore, a separate tapered neck extension 78 is screwed onto mouth 74, extension 78 itself being formed with a narrow externally threaded neck adapted to take an internally threaded cap 82.

While a plurality of examples have been described which fulfil the objectives of the invention, it will be appreciated by those skilled in the art that many alterations and additions can be made without departing from the scope of the invention as outlined above. As previously indicated, the invention is not confined to the use of ball valves but may employ flap, mushroom or other types of neck valves with collapsible containers.

Aspects of the present invention have been described by way of example onty and it will be appreciated that modifications and additions thereto may be made without departing from the scope thereof, as defined in the appended claims.