GB2186272A - Closure device - Google Patents

Abstract

A closure device of the pilfer- indicating type comprises-a cap (1) having a skirt (3) with a screw thread (4) for cooperation with the screw thread (11) on the neck (10) of a bottle, and a tubular anchoring member (20) within the skirt, below the screw thread (4), and connected to the skirt by a frangible connection (24). The tubular anchoring member (20) has a plurality of resilient tongues (22) extending away from the bottom of the skirt, the tongues (22) being of at least two different lengths (22b, 22c) and shaped such that in use the free end of at least one of the tongues (22) engages a radial shoulder (12) on the bottle. The cap (1) and member (20) may be formed separately and then connected by welding or snap-fitting, or they may be formed as a single moulding. In an alternative embodiment, the resilient tongues are formed on the bottle neck, and a cooperating annular shoulder is formed at the base of the cap skirt. <IMAGE>

Description

SPECIFICATION Closure devices This invention relates to closure devices for bottles, and particularly to closure devices of the tamper- or pilfer-indicating type.

Such closures are known comprising a cap having an internal screw thread, by means of which it is screwed onto a screw-threaded part of the neck of the bottle, the neck also being provided, below the thread, with an annular bead or shoulder. The closure also includes a tubular anchoring member axially spaced from the threaded portion of the cap, and connected to the cap by a frangible connection. The anchoring member comprises a number of resilient tongues which extend inwardly and away from the rim of the cap, and are so shaped that their inner edges lie in a circle the diameter of which is less than that of the annular shoulder on the bottle.

When a closure such as this is screwed onto a bottle, the resilient tongues deform in order to slide over the screw-threaded part of the bottle and also over the annular shoulder, and then "snap" back so that their inner edges contact the downwardly-facing portion of the annular shoulder on the bottle. Said shoulder prevents upward movement of the tongues, and hence the anchoring member.

Removal of the closure from the bottle by unscrewing can only then be effected by also causing breakage of the connection between the tubular anchoring member and the cap to which it is joined. Such breakage provides evidence that the bottle has been opened. An example of such a closure as the one described above is described and iliustrated in United Kingdom Patent Specification No: 1,459,980.

The known closures suffer from a significant drawback. Because of the dimensional variations inherent in any fabrication process, and usually catered for by specifying a tolerance range, there will be occasions when at one tolerance extreme the tongues snap tightly under the annular shoulder on the bottle. Any attempt at removal of the closure will then result in rupture of the frangible connection.

However, at the other extreme of tolerance, when the height of the annular shoulder from the sealing surface of the bottle is at a minimum, and the corresponding distance between the under side of the shoulder and the inner edges of the fingers is at a maximum, there will be some slack when the closure is fully applied. As a consequence there will be some relative axial movement of the closure, e.g.

some degree of unscrewing, before the tongues engage the shoulder on the bottle and start to strain the frangible connection. This degree of movement can be sufficient to allow seepage or leakage of product from the bottle, or ingress of some foreign material thereinto, particularly if the closed bottle is left in this state, e.g. on a supermarket shelf. The pack can thus in effect be tampered with although the evidence of this is absent.

It is the object of the invention to provide a closure which does not suffer from this drawback.

According to the invention a closure device for bottles of the type having a screw thread at or adjacent the end of the neck thereof and means forming a radial shoulder facing away from the mouth of the bottle, comprises a cap having a skirt with an internal screw thread for cooperation with the screw thread on the neck of the bottle, and a tubular anchoring member within the skirt of the cap, below the screw thread thereof, and connected to the skirt of the cap by a frangible connection, the tubular anchoring member having a plurality of resilient tongues extending away from the bottom of the skirt, said tongues being of at least two different lengths and being shaped such that in use the free end of at least one of the tongues engages the radial shoulder on the bottle.

Preferably the tongues are of at least three different lengths, and in a particularly preferred embodiment tongues of three different lengths are sequentially spaced around the circumference of the tubular anchoring member. In a typical construction, the tongues vary in length by between 0.4 and 0.8mm. In the preferred embodiment just mentioned, therefore, a resilient tongue may be flanked by a tongue 0.6mm. shorter and a tongue 0.6mm. longer.

The differences in length between the shortest and longest tongues are suitably chosen so as at least to compensate for the extremes of tolerance likely to occur between the cap and the bottle, so that at one extreme only the shortest tongues snap under the shoulder on the bottle whilst the longer tongues are simply splayed open by the shoulder. At the other tolerance extreme, the longest tongues just snap under the shoulder whilst the other, shorter tongues play no effective part in the initial function of the closure as it is removed.

They may, however, subsequently reinforce the longer tongues if for instance complete breakage of the frangible connection is not effected by the action of the longest tongues.

The cap and bottle of the invention may be of any suitable material, provided that the tongues of the tubular anchoring member have the necessary resilience to ride over the annular shoulder on the bottle and "snap" back beneath it. Thus, the cap may be made of metal or plastics material, a particularly suit able plastics material being high impact poly styrene. The bottle may be of a plastics material, metal or glass.

In a modification of the invention, the resili ent tongues are formed on the bottle neck, a cooperating annular shoulder being formed at the base of the cap skirt.

An embodiment of the invention is illustrated in the accompanying drawings, in which Figure 1 is a sectional elevation of part of a closure device of the invention, showing a cap seated on the neck of a bottle; Figure 2 is a part-sectional elevation of the tubular anchoring member of Fig. 1; and Figure 3 is a plan view of the tubular member of Fig. 2.

A cap 1 comprises a disc-like top 2 and a peripherally depending skirt 3. The skirt 3 is internally screw-threaded, at 4. The outside wall of the skirt 3 is knurled, as indicated at 5.

The cap 1 is shown applied to the neck 10 of a bottle. The neck 10 has a screwthreaded portion 11, and beneath the screwthreaded portion is an annular outwardly-extending bead 12 having a downwardly-facing shoulder 13. A sealing liner 14 is situated between the top 2 of the cap and the mouth of the bottle.

Frangibly attached to the lower end of the skirt 3 of the cap is a tubular anchoring member 20, comprising a circumferential skirt 21 and a series of circumferentially-spaced flexible or resilient tongues 22. The tubular member 20 is shown in greater detail in Figs. 2 and 3.

The tongues 22 together form a discontinuous wall of substantially frusto-conical form, which merges into a vertical wall 23 integrally attached to the circumferential skirt 21. Uniformly spaced on the top of circumferential skirt 21 are a series of integrally-moulded pips 24 merging into upstanding splines 25 on the vertical wall 23. The lower end of the skirt 3 of the cap is welded to the pips 24 in order that the tubular member 20 should be frangibly connected to the cap 1.

The tongues 22 are of different lengths, as best seen in Fig. 2. Tongue 22a is shorter than tongue 22b, which is in turn shorter than tongue 22c. As shown in Fig. 3, this sequence of tongues of different lengths is repeated around the member 20.

As an alternative to joining the cap 1 to the tubular member 20 by welding, the two components could equally well be press- or snapfitted together.

In operation, the cap 1 together with its associated tubular member 20 is screwed onto the neck 10 of the bottle. During its initial passage over the bottle neck, the tongues 22 are splayed outwardly by, and ride over, the screw threaded portion 11- on the container neck. They then ride over the annular bead 12, and at least some of them, and possibly all of them, snap back under the bead 12 and at least some of them come into contact with the shoulder 13 of the bead.

This is best seen in Fig. 1, where the tongue 22b is in contact with the shoulder 13, but the longer tongue 22c remains outwardly deformed by the bead 12.

Relative axial movement between the cap and the bottle in the unscrewing direction is thus prevented by the tongues 22b engaging the shoulder 13. The cap 1 can only be removed from the bottle if the connection between the cap and the tubular member 20 i.e.

at the weld pips 24, is broken. The broken connection between the cap 1 and the tubular member 20 provides evidence that tampering with the package has occurred.

In the above, the cap 1 and the tubular member 20 are formed separately, and connected by welding or snap-fitting. They could of course be formed as a single moulding, the frangible connection being formed during moulding or subsequently.

Claims (6)

1. A closure device for a bottle of the type having a screw thread at or adjacent the end of the neck thereof and means forming a radial shoulder facing away from the mouth of the bottle, comprising a cap having a skirt with an internal screw thread for cooperation with the screw thread on the neck of the bottle, and a tubular anchoring member within the skirt of the cap, below the screw thread thereof, and connected to the skirt of the cap by a frangible connection, the tubular anchoring member having a plurality of resilient tongues extending away from the bottom of the skirt, said tongues being of at least two different lengths and being shaped such that in use the free end of at least one of the tongues engages the radial shoulder on the bottle.

2. A closure device according to claim 1, comprising tongues of at least three different lengths.

3. A closure device according to claim 2 in which said tongues of three different lengths are sequentially spaced around the circumference of the tubular anchoring member.

4. A closure device according to any of claims 1 to 3 in which each tongue is between 0.4 and 0.8mm. longer or shorter than the tongues of different length.

5. A modification of the closure device according to any of claims 1 to 4, wherein the resilient tongues are formed on the bottle neck and a cooperating annular shoulder is formed at the base of the cap skirt.

6. A closure device, substantially as described with reference to the drawings.