WO2003062080A2

WO2003062080A2 - Container closure

Info

Publication number: WO2003062080A2
Application number: PCT/GB2003/000115
Authority: WO
Inventors: Nigel Thompson
Original assignee: Alcoa Closures Systems International Uk Limited
Priority date: 2002-01-17
Filing date: 2003-01-17
Publication date: 2003-07-31
Also published as: WO2003062080A3; GB0201055D0

Abstract

The present invention concerns a container closure comprising a crown and an annular skirt (14) depending from the crown, wherein the skirt has a circumferential line of weakness (15) defining a tamper-evident band (16) at the open end thereof. The tamper-evident band has one or more solid-form radially inwardly projecting protrusions (17) for inter-engagement with one or more corresponding protrusions provided to a container neck. The skirt (14) is provided with a lip (19) at or adjacent the line of weakness, the lip (19) depending from the skirt (14) and being positioned radially inwardly of the line of weakness (15), the lip (19) extending from the crown side of the line of weakness (15) away from the skirt (14) to an axial extent corresponding at least with an edge of the tamper-evident band (16), the lip (19) being configured not to project radially inwardly of the skirt (14).

Description

CONTAINER CLOSURE

The present invention relates to a container closure incorporating a tamper-evident band.

It is well known in the field to provide a container closure incorporating a tamper-evident band defined by a line of weakness in the skirt of the closure.

On removal of the closure from a container neck to which the closure has been applied, the line of weakness fractures such that the tamper-evident band becomes separated from the main body of the closure. End users can thus check that the tamper-evident band is intact with the main body before purchase to ensure that the container has not previously been opened.

In this connection, Figures 1 and 2 show a certain known type of closure 1 having a solid form of tamper-evident band construction. An external surface of a container neck 2 to which the closure is applied is provided with a circumferential projection 4 which engages and interlocks with a corresponding projection 3 on a tamper-evident band 5. The projection 3 is substantially solid or non-collapsible, as opposed to certain hinged flange arrangements which are known in the art. In use, this interlocking of the projections prevents the tamper-evident band from moving upwardly with the main body of the closure as it is unscrewed and removed by the end user. Hence the line of weakness fractures, leaving the tamper-evident band 5 located on the neck of the container. However, the action of screwing the closure onto the container neck during the capping process when the closure is first applied to the container can result in premature fracture of the line of weakness.

In this connection, as the closure 1 is screwed onto the container neck 2, a considerable turning moment acts on a top portion of the tamper-evident band 5 to urge the same radially inwardly of the main body as shown by the arrow.

Much work has been devoted to the design of the engaging surfaces of the projections of the tamper-evident band and the container neck. As will be seen such projections 3,4 are designed with particular inclined profiles to minimise the destructive forces applied to the line of weakness on capping.

However, the nature of the line of weakness means it affords a degree of flexibility, whereby under the action of such turning forces, all or part of the band can become tucked under the main body as the closure is applied downwardly, as shown in Figure 2, ultimately resulting in premature fracture. Further, if all or part of the tamper- evident band becomes tucked under the main body, the closure is rendered defective and, consequently, the container and its contents unsaleable.

The present invention seeks to provide an improved container closure which overcomes the aforementioned problems and is cost effective to produce and apply to a container.

According to an aspect of the present invention, there is provided a container closure comprising a crown and an annular skirt depending from the crown, wherein the skirt has a circumferential line of weakness defining a tamper-evident band at the open end thereof, the tamper-evident band having one or more solid-form radially inwardly projecting protrusions for inter-engagement with one or more corresponding protrusions provided to a container neck, wherein the skirt is provided with a lip at or adjacent the line of weakness, the lip depending from the skirt and being positioned radially inwardly of the line of weakness, the lip extending from the crown side of the line of weakness away from the skirt to an axial extent corresponding at least with an edge of the tamper-evident band, the lip being configured not to project radially inwardly of the skirt.

The lip acts to limit undesirable pivoting movement of the tamper-evident band and prevents all or part of the tamper evident band from being forced inside the main body of the closure during the capping process. The lip thereby provides a bar to curtail over flexure of the tamper evident band in the specific locality of the line of weakness for thereby preventing the tamper-evident band from becoming tucked under the main body and prematurely fracturing.

However, as the closure first moves down a container neck, this lip may catch on the top portion of the neck which will have the effect of pulling the skirt inwardly. Should this occur whilst the tamper-evident band is itself coming into contact with the container, lower down the container neck, then the closure can become distorted and damaged. In order to minimise this possibility, the lip is configured .not to project radially inwardly of the skirt.

During capping or subsequent closure application, the lip can further act as a guide to help centre the closure over the neck of the container. In this connection, the lip may have an inwardly facing guide surface provided on its end which is inclined relative to the axis of the closure, so as to taper inwardly closer to the crown of the closure. Such a lip guide surface may be provided with a curvature to optimise the guide effect. The lip guide surface can assist the closure over the outer diameter of a thread provided on the neck of the container to which the closure is applied.

A surface of an inner face of the skirt, adjoining the lip, may further also be inclined relative to the axis of the closure so as to taper inwardly closer to the crown. Such a skirt guide surface can also assist in guiding the closure relative to the container neck.

Conveniently, the lip extends away from the skirt to an axial extent corresponding at least with an edge of the tamper-evident band. In this way, the restraining characteristic of the lip is provided over substantially the entire line of weakness.

Preferably, the lip is a continuous element. In preferred embodiments, the line of weakness comprises discrete frangible bridges. In this regard, the lip may comprise a plurality of discrete lip elements, positioned circumferentially between frangible bridges making up the line of weakness.

A closure of this type can be manufactured from a plastics material using conventional moulding methods, for example injection or compression moulding, such methods being known to a skilled person. The invention will now be described, by way of illustration only, with reference to the following example and the accompanying figures, wherein;

Figures 1 and 2 show part of a vertical cross-sectional view of a prior art closure prior to and after premature fracture;

_*

Figure 3 shows part of a vertical cross-sectional view of a closure of the invention fitted to the neck of a container; and

Figure 4 shows an enlarged view of the closure cross- section of Figure 3.

As shown in Figures 3 and 4, a container closure 10 is screw-threadedly fitted onto the neck 11 of a container 12. The container closure includes a crown 13 and an annular skirt 14 depending therefrom. The skirt has a circumferential line of weakness 15 which fractures when the closure is removed from the container. A tamper-evident band 16 is provided below the line of weakness 15. In this connection, the line of weakness can, for example, be a score line, or as shown in Figures 3 and 4 may comprise a number of discrete frangible bridges circumferentially positioned around the skirt .

When an end user unscrews the closure 10 to open the container, the frangible bridges making up the line of weakness 15 fracture, allowing the end user to remove the skirt 14 of the main body, while the tamper-evident band 16 remains located around the neck 11 of the container 12. This occurs because the inner surface of the tamper-evident band is provided with a protrusion 17 which engages and interlocks with a corresponding protrusion 18 on the outer surface of a neck of a container.

The annular skirt 14 of the closure 10 has an inner lip 19 depending downwardly therefrom. The lip is positioned radially inwardly of the line of weakness 15 and extends axially downwardly from the crown side of the line of weakness towards the open end of the closure. The lip extends away from the skirt so that it reaches an axial position at least corresponding to a top edge 20 of the tamper-evident band 16. In this way, a barrier is provided over substantially the entire depth of the line of weakness.

This lip thereby limits pivoting movement of the tamper- evident band 16 and prevents all or part of the band from being forced inside the main body of the closure during the capping process.

On initial capping, in order to avoid damage to the closure resulting from the lip catching on a surface of the container neck, the lip is configured not to project radially inwardly of the skirt.

During capping, the lip also acts as a guide to assist the closure over the neck of the container. In this regard the lip has an inwardly facing guide surface 22 provided on its end which is inclined relative to the axis of the closure. The lip guide surface projects radially inwardly and tapers to an increasing extent closer to the crown. The lip guide surface 22 is further provided with a curvature to assist the ease of movement of the closure over the outer diameter of the thread of the container neck. A surface of an inner face of the skirt, adjoining the lip, may further also be inclined relative to the axis of the closure so as to taper inwardly closer to the crown. Such a skirt guide surface 21 can also assist in guiding the closure relative to the container neck.

In the embodiment shown, the lip 19 is formed as a continuous circumferential element which is an extension of the lower part of the skirt 14. However the lip may be provided as a discontinuous member, for example as discrete lip elements. In this regard, the lip elements may be positioned at areas of particular weakness, where the tamper- evident band is more likely to flex undesirably. Hence, where the lip elements are provided in conjunction with a frangible bridge construction, the lip elements may be provided circumferentially between frangible bridges.

Closures of this type can be manufactured from a plastics material using conventional moulding methods, for example injection or compression moulding, such methods being known to a skilled person.

Claims

1. A container closure comprising a crown and an annular skirt depending from the crown, wherein the skirt has a circumferential line of weakness defining a tamper-evident band at the open end thereof, the tamper-evident band having one or more solid-form radially inwardly projecting protrusions for inter-engagement with one or more corresponding protrusions provided to a container neck, wherein the skirt is provided with a lip at or adjacent the line of weakness, the lip depending from the skirt and being positioned radially inwardly of the line of weakness, the lip extending from the crown side of the line of weakness away from the skirt to an axial extent corresponding at least with an edge of the tamper-evident band, the lip being configured not to project radially inwardly of the skirt.

2. A container closure according to claim 1, wherein the lip is a continuous circumferential element.

3. A container closure according to claim 1 or 2, wherein the line of weakness comprises discrete frangible bridges.

4. A container closure according to any preceding claim, wherein the lip has an inwardly facing guide surface which is inclined relative to the axis of the closure so as to taper inwardly towards the crown.

5. A container closure according to claim 4, wherein the guide surface is provided with a curvature.

6. A container closure according to any preceding claim, wherein a surface of an inner face of the skirt, adjoining the lip, is inclined relative to the axis of the closure so as to taper inwardly closer to the crown.

7. A container closure according to claim 1, wherein the lip comprises a plurality of discrete lip elements, positioned circumferentially between frangible bridges making

_* up the line of weakness.

8. A container closure substantially as herein described with reference to the accompanying drawings.