GB2260746A - Collapsible containers - Google Patents

Abstract

A container of resilient flexible material, after it has performed its function, may be collapsed, to reduce its internal volume and retained collapsed, to make it easier to dispose of. The container is collapsed by displacing opposite side walls 14, 16 towards each other, said side walls being provided with inter-engageable retaining devices 26, 28. The inter-engageable retaining devices 26, 28 are preferably provided near the base on the blow mould part line and preferably comprise a recess 28 on one side wall and a cooperating projection 26 on the other side wall. Preferably the projection 26 fits in the recess 28 as a snap fit. The projection may be elongate and surrounded by a projecting rib (38, Fig 5A), more than one pair of cooperating projections 26 and recesses 28 may be provided (Figure 11), and the projection may be shorter than the recess to allow for misalignment (Fig 9). The container may have a crease or other weakening 24 on one or both sides near the base to ease the collapse process. The container may be used for cleaning or disinfecting liquids. <IMAGE>

Description

COLLAPSIBLE CONTAINERS This invention relates to collapsible containers, in other words containers which, during or after dispensing of their contents can be collapsed so as to reduce their internal volume.

It is becoming increasingly common for some products, such as household cleaning and disinfecting preparations, to be sold to the consumer in two different types of container. The primary container is relatively sturdy, and perhaps has special features, for example for dispensing the contents, but is correspondingly expensive to manufacture. The secondary container is relatively inexpensive, and is correspondingly less sturdy and more utilitarian in appearance than the primary container. The intention is that consumers will make their initial purchase of the product in the primary container, and, when that is empty, they will purchase further supplies of the product in the secondary container. They can then refill the primary container and discard the empty secondary container or return it for recycling.

This system has advantages for the consumer, in that it is not necessary to pay for a relatively expensive primary container every time the product is purchased. Also, it is possible for the secondary container to be made of material which is sufficiently flexible to enable the secondary container to be collapsed when it is empty, so as to occupy as little space as possible in the consumer's waste bin. A problem, however, is that the material from which such secondary containers are made (usually plastics material) is resilient, and so the containers, when collapsed, will tend to resume their initial shape unless measures are taken to prevent this. One way of doing this is to provide an airtight cap which can be refitted to the container after it has been collapsed, so preventing air from re-entering the container.

However, even a small leakage of air will enable the container to resume its original shape, and so this measure is not reliable.

According to the present invention there is provided a container of resilient flexible material, of which the internal volume can be reduced by displacing opposite side walls of the container towards each other, the opposite side walls being provided with inter-engagable retaining devices for holding the opposite side walls together.

Thus, a container in accordance with the present invention can be collapsed by bringing the opposite side walls together to engage the retaining devices with each other. The retaining devices then resist separation of the side walls under the resilience of the material of the container, so keeping the container in its collapsed condition.

In a preferred embodiment, the container is made from a plastics material, such as polyethylene. It may be manufactured by blow moulding.

The retaining devices are formed, during the manufacturing process of the container, by deforming regions of the side walls out of the general planes of those side walls. Thus, the retaining devices are in the form of protrusions or recesses formed in the material of the side walls. In a preferred embodiment, each pair of retaining devices comprises a recess on one side wall and a cooperating projection on the other side wall, which projection fits in the recess as a snap fit.

The projection and the recess may be elongate, in which case the snap fit may be provided by giving the projection and the recess a necked shape, as seen in a cross section taken transversely of their length. The projection and the recess may be disposed with their length vertical, when the container stands on a level surface, and the projection may be somewhat shorter than the recess in order to allow for vertical misalignment between the two.

Various configurations are possible for the retaining devices. In order to protect them from damage, the base of the recess and the head of the projection may both lie in the general plane of the side wall, and consequently may extend from regions which are displaced from the plane of the side wall.

The recess and the projection may alternatively be surrounded by a rib.

In one embodiment in accordance with the present invention, the retaining devices are provided on the side walls of the container nearer its base than its top. In some embodiments, more than one pair of retaining devices may be provided, and these may be at different vertical levels on the container, or side-byside at the same vertical level.

In order to assist in collapsing the container in a defined manner, the material of the container may be creased. In a preferred embodiment, at least one side wall has a horizontal crease or other line of weakening disposed near the base of the container. The other side wall may be uncreased, but preferably both side walls are creased.This measure may have advantages in collapsible containers even if no retaining devices are provided, and consequently another aspect in accordance with the present invention provides a container of resilient flexible material, of which the internal volume can be reduced by displacing opposite side walls of the container towards each other, at least one of the side walls having a line of weakening extending parallel to the base of the container, whereby displacement of that side wall towards the other side wall causes that side wall to buckle inwardly along the line of weakening.

One intended use of a container in accordance with the present invention is as a secondary container for repeat purchases of a product previously purchased in a more substantial primary container. However, a container in accordance with the present invention may also be used as a primary container where a lightweight, easily disposable primary container is required.

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a collapsible bottle; Figure 2 is a view taken on the arrow II in Figure 1; Figure 3 is a top view of the bottle; Figure 4 shows the bottle of Figures 1 to 3 in a collapsed condition; Figures 5A, 5B and 5C show retaining devices of the.bottle of Figures 1 to 4; Figures 6A, 6B and 6C show an alternative configuration for the retaining devices; Figure 7 shows a third configuration for the retaining devices; Figures 8 shows a fourth configuration for the retaining devices; Figures 9A and 9B show a modification of the retaining devices of Figures 6a, 6b and 6c; Figure 10 shows another collapsible bottle;; Figure 11 shows the bottle of Figure 10 in a collapsed configuration; and Figure 12 shows a third collapsible bottle.

The bottle shown in Figures 1 to 4 is blow moulded from a suitable plastics material such as polyethylene.

It comprises a body 2 having a screwthreaded neck 4 and a base 6. The body 2 has a shoulder region 8 which supports the neck 4. This shoulder region 8 has arcuate surfaces 10 (Figure 2) which meet each other at upwardly sloping edges 12.

As shown in Figure 3, the body 2 comprises two side walls 14 and 16 which are connected to each other at creases 18. The side walls 14 and 16 each comprise a central panel 20 and oblique side panels 22.

A short distance above the base, the central panel 20 of each side panel 14 has a line of weakening in the form of a crease 24. Each crease 24 extends across the respective central panel 20 but not across the side panels 22. The creases 24 are situated a short distance above the base 6. In the embodiment shown in Figures 1 to 3, this distance is approximately half the shorter width of the base as shown in Figure 2.

However, the distance from the base 6 to the creases 24 can be varied. For example, it could be equal to, or even slightly greater than, the shorter width of the base 6, or it could be approximately one third of the shorter width of the base 6, or anywhere between these limits.

In the central panels 20 of the side walls 14 and 16 are provided respective cooperating retaining devices 26, 27 respectively. In the bottle of Figures 1 to 4, the retaining device 26 is a male retaining device, and the retaining device 28 is a female retaining device. The retaining devices 26, 28 may lie on the mould part line of the bottle, since this makes it easier to eject the bottle from the mould. These retaining devices are shown in more detail in Figures 5A to 5C. Figure 5A shows the female retaining device 28 (from the outside of the bottle) while Figures 5B and 5C show both retaining devices 26 and 28.

As viewed from within the container (i.e. between the side walls 14 and 16 in Figures 5B and 5C), the retaining device 26 comprises a projection 30 and the retaining device 28 comprises a recess 32. As shown in Figure 5C, the projection 30 and recess 32 have necked, or narrower, regions 34, 36, respectively, with the width of the necked region 36 of the recess 32 being smaller than the width of the head of the projection 30. Consequently, as the projection 30 is pressed into the recess 32, it has to be pushed past the necked region 36, so engaging within the recess 32 with a snap action.

The projection 30 and the recess 32 are formed by deforming the material of the side walls 14 and 16 out of the general plane in which they lie. This can be done by using an appropriately shaped mould for blow moulding the bottle. In order to avoid damage to these components, circular ribs 38 are formed, surrounding the projection 30 and the recess 32. The rib 38 on the side wall 14 is slightly thinner than the rib 38 on the side wall 16 so that, when the retaining devices 26 and 28 engage each other the two ribs 38 nest one within the other.

A cap 40 is fitted to the screwthreaded neck 4 and preferably makes airtight contact with the neck 4.

When the bottle is empty, and with the cap 40 removed, it can be collapsed by hand pressure applied to the side walls 14 and 16. This pressure will displace any air from the bottle, and one of the side walls 14 and 16 (it is the side wall 14 in Figure 4) can be buckled along one of the creases 24, as shown in Figure 4. Also, the-rounded shoulder region 8 of the side wall 14 can be pushed inwardly to assume a somewhat inside-out configuration, also as shown in Figure 4, so as to nest with the shoulder region 8 of the side wall 16.

As the side wall 14 buckles along the crease 24, the region of the side wall 14 below the crease 24 will form, with the base 6 and the lower region of the side wall 16, a triangular cross-section, as shown in Figure 4. The retaining devices 26 and 28 can then be engaged with each other in order to secure the bottle in the collapsed configuration. If the cap 40 is refitted to the neck 4, so preventing air from re-entering the bottle, this will additionally prevent the bottle from resuming the configuration shown in Figures 1 to 3 as a result of its own resilience.

Consequently, the bottle can be collapsed into a configuration, as shown in Figure 4, which takes up relatively little space in a waste bin.

Figures 6A, 6B and 6C correspond to Figures 5A, 5B and 5C except that the surrounding rib 38 is omitted.

Figure 7 corresponds to Figure 6C, except that the configuration of the retaining device 28 is modified.

In the embodiment of Figure 7, the recess 32 is formed in a region 42 which is offset from the general plane of the side wall 16. Consequently, the base 44 of the recess 32 is in generally the same plane as the remainder of the side wall 16, and so does not project on the outside of the bottle. This protects it from damage.

In the embodiment of Figure 8, the projection 30 of the retaining device 26 is also formed in an offset region 46, so that the head 48 of the projection 30 lies in the same general plane as the rest of the side wall 14.

In the embodiment of Figures 9A and 9B, the projection 30 is somewhat shorter than the recess 32, in order to allow for misalignment, in the vertical direction, between the two side walls 14 and 16.

Figure 10 shows a modified form of the bottle in which the crease 24 is absent on both sides, and two vertically spaced pairs of retaining devices 26, 28 are provided. With this construction, the collapsed bottle shown in Figure 11 is generally symmetrical. It would, of course, be possible for a crease 24 to be provided on one or both sides of the bottle of Figure 10, in which case the base region of the collapsed bottle would assume a configuration similar to that shown in Figure 4.

Figure 12 shows a further modification of the bottle shown in Figures 1 to 4, in which two pairs of retaining devices 26, 28 are provided at the same vertical level above the base. This provides an additional retaining force between the side walls 14 and 16 when the bottle is collapsed.

Claims (18)

1. A container of resilient flexible material, of which the internal volume can be reduced by displacing opposite side walls of the container towards each other, the opposite side walls being provided with inter-engageable retaining devices for holding the opposite side walls together.

2. A container as claimed in claim 1, in which the retaining devices are in the form of projections or recesses formed in the material of the side walls.

3. A container as claimed in claim 1 or 2, in which the retaining devices are formed in pairs and comprise a recess on one side wall and a cooperating projection on the other side wall.

4. A container as claimed in claim 3, in which the projection fits into the recess as a snap fit.

5. A container as claimed in claim 4, in which the projection and the recess are elongate and have a necked shape, as seen in cross-section taken transversely of their length.

6. A container as claimed in claim 5, in which the projection is shorter than the recess.

7. A container as claimed in any one of claims 2 to 6, in which the base of the recess and/or the head of the projection lie in the general plane of the side wall of the container.

8. A container as claimed in any one of claims 2 to 7, in which the recess and/or the projection is at least partially surrounded by a protective rib.

9. A container as claimed in any one of the preceding claims, in which the retaining devices are provided on the side walls of the container nearer its base than its top.

10. A container as claimed in any one of the preceding claims, in which a plurality of cooperating pairs of retaining devices are provided.

11. A container as claimed in claim 10, in which respective pairs of retaining devices are disposed at different vertical levels on the container.

12. A container as claimed in any one of the preceding claims, in which the material of the container is creased to assist controlled collapse of the container.

13. A container as claimed in claim 12 in which at least one side wall of the container has a horizontal crease or other line of weakening disposed near the base of the container.

14. A container as claimed in any one of the preceding claims, in which the container is made of plastics material.

15. A container as claimed in claim 14, in which the container is formed by blow moulding.

16. A container as claimed in any one of the preceding claims in which, during the manufacturing process of the container, the retaining devices are formed by deforming regions of the side walls out of the general planes of those side walls.

17. A container of resilient flexible material, of which the internal volume can be reduced by displacing opposite side walls of the container towards each other, at least one of the side walls having a line of weakening extending parallel to the base of the container, whereby displacement of that side wall towards the other side wall causes that side wall to buckle inwardly along the line of weakening.

18. A container substantially as described herein, with reference to and as shown in Figures 1 to 5, or Figures 1 to 5 as modified by any one of Figures 6 to 9, or Figures 10 and 11, or Figure 12.