ZA200804658B - Container - Google Patents

Description

SE

FIELD OF THE INVENTION

} THIS INVENTION relates to flexible containers.

BACKGROUND TO THE INVENTION

Conventional flexible containers, often simply referred to as bags, are manufactured from sheet synthetic plastics material. The stock material used for production purposes can be tubular, a pair of superposed webs or a longitudinally folded web.

In many situations it is necessary for the bag to be closed, after filling, in a manner that enables a subsequent user to see if the bag has been tampered with since it was filled. Final closing in these circumstances involves the provision of a weld which permanently secures the two walls of the bag to one another.

In some industrial situations, such as where explosive materials are being packaged or where heat sensitive materials are involved, the use of the heat sealing equipment which is required to produce the weld is not desirable and is to be avoided. In other situations, such as rural healthcare establishments, the electrical supply necessary to run a heat sealer is not available.

The object of the present invention is to provide a flexible container which can be delivered open for filling purposes and then closed in a tamper evident manner whilst avoiding the difficulties discussed above.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the present invention there is provided a flexible container which is in a condition for filling and subsequent closing, the container comprising walling of flexible sheet material and being open along one side

S and closed along the remaining sides, and interlockable closure formations along the container’'s open side which, once interlocked, cannot be separated without leaving visual evidence of re-opening.

Further interlockable closure formations can be provided along another side of the container, the further interlockable closure formations being such that the container can be opened and closed multiple times.

A tear-off strip can also be provided which, once removed, enables access to be had to the further closure formations. There can be a line of weakness, such as a row of perforations, forming the boundary between the tear-off strip and the remainder of the container.

The tear-off strip can be bounded by said line of weakness and by a fold line parallel to the line of weakness or by a weld parallel to said line of weakness.

Two parallel lines of weakness can be provided so that two strips can be detached from the remainder of the container.

In another form a burstable membrane is provided which spans between opposed walls of the container and closes-off the upper end of a compartment the lower end of which is closed by the first mentioned closure formations.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:-

Figure 1 is a side elevation of a flexible container in accordance with the present invention;

Figure 2 is a pictorial view of the flexible container sectioned along a top to bottom line and showing the container prior to being filled and closed;

Figure 3 is a view similar to Figure 2 and showing the container after filling . and closing;

Figure 4 is a view similar to that of Figure 2 and showing the container after having been opened to access the contents;

Figure 5, 6 and 7 illustrates three forms of interlocking closure;

Figure 8 illustrates a method of manufacturing the flexible container of Figures 1to 4.

DETAILED DESCRIPTION OF THE DRAWINGS

The flexible container shown in Figure 1 comprises two walls of sheet synthetic plastics material. The flexible container can be manufactured using flattened tubular material, a folded web or two superposed webs. All these methods of manufacture will be described.

In one method of manufacture a tube of synthetic plastics material is extruded and then expanded. The extrusion die is configured so that the interlocking closure formations, to be described hereinafter, are extruded integrally with the tube.

Where a web, or two webs, of sheet synthetic plastics material are used as the main component of the flexible container, it is possible for the closure formations to be integral with the web or webs. It is also possible for ribbons which incorporate the interlocking closure formations to be welded onto the web or webs or extruded from a die onto the moving web or webs.

A container manufactured using a folded web as the stock material will be described with reference to Figures 1 to 4 of the drawings.

The flexible container shown in Figures 1 and 2 is designated 10 and comprises two walls 12 and 14. A first closure 16 is shown at the bottom of the container and a second closure 18 is shown close to the upper end of the container.

A line of weakening 20, preferably in the form of a row of perforations, or two parallel rows of perforations, extends across the container between the closure 18 and the upper end of the container. The line of weakening 20 forms the boundary between the main part of the container and a tear-off strip 22.

The vertically extending edges of the container are constituted by welds 24 and there is a fold at 26. The fold 26 is along the free edge of the tear-off strip 22. The end of the container opposed to the fold 26 is open, the two formations of the closure 16 not being engaged.

The interlockable closure formations (see particularly Figure 5) of the closure 16 comprise an elongate arrow headed male rib 28 and an elongate female receptacle 30 having an entrance slit 32. Once the head of the rib 28 has been pressed into the receptacle 30 through the slit 32, it cannot be withdrawn.

Consequently, once fastened, the closure 16 cannot be re-opened.

The interlockable closure formations of the closure 18 can comprise an elongate male rib 34 and an elongate female groove 36 as shown in Figure 6. The configuration of these components is such that they constitute a closure which can be fastened and released multiple times. The releasable closure of Figure 7 is similar to that of Figure 5, but due to its unsymmetrical configuration, the rib designated 34.1 can be twisted out of the receptacle designated 36.1

When delivered for filling (see Figure 2) the flexible container is closed on three sides by the welds 24 and the fold 26. It is open along the fourth side as the male rib 28 has not been forced into the female receptacle 30. The rib 34 is in the groove 36 (or the rib 34.1 in the receptacle 36.1). The bag is filled through the open fourth side and then closed by forcing the head of the rib 28 into the receptacle

30 via the slit 32. The lower end of the container is now permanently closed (see

Figure 3). Destruction of the closure 16 is necessary to gain access from the lower end. The welds 24 and the fold 26 prevent access from either side of the container or from the top. : s

To dispense the contents of the container (see Figure 4) the strip 22 is torn off along the line of weakening 20 and the flexible container opened by : disengaging the rib 34 from the groove 36 or the rib 34.1 from the receptacle 36.1.

The flexible container can be re-closed by pressing the rib 34 into the groove 36 or the rib 34.1 into the receptacle 36.1.

In Figure 8 a web, folded at 26 and of synthetic plastics material, is shown being advanced in the direction of the arrow A. The top ply of the web can carry the male ribs 28, 34 and 34.1 and the bottom ply of the web can carry the female receptacle 30 or 36.1 or the groove 36. The line of weakening 20 is formed as the web advances and the rib 34 is pressed into the groove 36. The perforating wheel is not shown. The rib 28 and receptacle 30 are not forced into engagement at this stage.

The transverse welds 24 are then formed and each container is simultaneously cut-off the folded web. The containers are now ready for delivery, filling and closing. :

If tubular material in flattened form is used in place of the folded web,

8 — 658 the tubular material must be split along the left hand edge as viewed in Figure 5.

If two superposed webs are used, then slitting is not necessary but a weld must be provided to take the place of the fold 26.

Claims (10)

co lim CLAIMS:

1. A flexible container which is in a condition for filling and subsequent closing, the container comprising: - walling of flexible sheet material , being open along one side and closed along the remaining sides; and - interlockable closure formations along the container’s open side, which once interlocked, cannot be separated without leaving visual evidence of re-opening.

2. The flexible container as claimed in claim 1, which includes: further interlockable closure formations provided along another side of the container, the further interlockable closure formations being such that the container can be opened and closed multiple times.

3. The flexible container as claimed in claim 1 or claim 2, which includes: a tear-off strip which, once removed, enables access to be had to the further closure formations.

4. The flexible container as claimed in claim 3, wherein: a line of weakness is provided to form a boundary between the tear-off strip and the remainder of the container.

5. The flexible container as claimed in claim 4, wherein the line of weakness is a row of perforations.

6. The flexible container as claimed in claim 4 or claim 5, wherein the tear-off strip is bounded by said line of weakness, and by a fold line parallel to the line of weakness.

7. The flexible container as claimed in claim 4 or claim 5, wherein the tear-off strip is bounded by said line of weakness, and by a weld parallel to said line of weakness.

8. The flexible container as claimed in any one of claims 3 to 5, wherein two parallel lines of weakness are provided so that two strips can be detached from the remainder of the container.

9. The flexible container as claimed in any one of the preceding claims, which includes: - a burstable membrane which spans between opposed walls of the container and closes-off an upper end of a compartment; - the lower end of the compartment being closed by said interlockable closure formation which, once interlocked, cannot be separated without leaving visual evidence of re-opening.

10. The container as claimed in any one of the preceding claims, substantially as herein described with reference to and as illustrated in any of the accompanying figures.

Dated this 28" day of May 2008 Core Brian Bacon & Associates Inc.

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