GB2247231A

GB2247231A - Tamper-proof seals

Info

Publication number: GB2247231A
Application number: GB9118263A
Authority: GB
Inventors: Thomas Duncan Brownbill
Original assignee: Rankin Brothers & Sons
Current assignee: Rankin Brothers & Sons
Priority date: 1990-08-24
Filing date: 1991-08-23
Publication date: 1992-02-26
Also published as: GB9018697D0; GB9118263D0

Abstract

An injection moulded tamper proof seal for a container having a dispensing opening defined by a neck portion with a circumferential rim, the seal comprising a crown portion 11 adapted to overlay said opening, a skirt 12 depending from the crown adapted to cover said rim, tear means (21 with frangible ribs 23, Fig 2) provided about the skirt intermediate the crown and an extremity of the skirt to provide a detachable skirt portion 20 and rim engaging means 18 comprising a plurality of re-entrant barb elements extending upwardly and inwardly provided on the internal surface of said skirt portion adapted to engage the under surface of the rim. The seal may have arcuate openings 30 in the crown to aid the moulding of the re-entrant barb elements, the seal being moulded in polyethylene. The crown may have depending ribs 28 to aid centering of the seal on the neck opening of keg. <IMAGE>

Description

IMPROVEMENTS IN AND RELATING To TAMPER-PROOF SEALS DESCRIPTION This invention relates to tamper-proof seals and has particular reference to tamper-proof seals for sealing of metal beer kegs. Metal beer kegs are provided in an upper end with an upstanding neck providing the dispensing means for drawing off the contents of the keg; the neck is formed of metal and is provided with a spring loaded valve to seal the contents of the keg against the atmosphere. In order to prevent sampling of the keg by depressing the seal element against its spring loading, and either tipping the keg to empty some of the contents or inserting a tube to draw off the contents, seals are provided which are fitted over the neck to give an indication of whether or not the contents of the keg have been sampled.These seals are of the kind comprising a crown portion adapted to overlay the dispensing opening of the neck and a dispensing skirt. In one particular example of a seal currently employed, the skirt has a plurality of re-entrant fingers which extend from the inner surface of a lower part of the skirt. The fingers are angled inwardly and upwardly towards the crown, the arrangement being such that when the seal is applied over the keg rim the fingers engage the undersurface of the rim to restrain the seal against removal. In order to gain access to the contents of the keg, it is necessary to break or cut the seal, thus indicating opening or tampering.

In order to mold such a seal and particularly the re-entrant fingers, it is necessary to cut away the skirt between the lower skirt part and the crown in order that the molding elements of the tool forming the fingers may be withdrawn during release of the article from the mold. Accordingly, the skirt has a plurality of axially aligned openings extending from and into the crown juxtaposed each finger.

In practice it has been found that it is possible to insert a small tool behind a number of adjacent fingers and ease them outwardly enabling the seal to be carefully, but systematically "eased" over the rim thereby permitting removal of the seal without breaking any sealing rings or other frangible parts present thereon. This enables the contents of the keg to be sampled or tampered with and the seal can be reapplied simply by placing over the keg neck and applying pressure to urge the seal downwardly until the fingers again snap under the underside of the rim.

According to a first aspect of the present invention there is provided a tamper proof seal for a container having a dispensing opening defined by a neck portion with a circumferential rim, which seal comprises a crown portion adapted to overlay said opening to prevent access thereto, a skirt depending from said crown portion and adapted to cover said rim, tear means provided about said skirt intermediate said crown portion and an extremity of the skirt to provide a detachable skirt portion at least partially detachable from the remainder of the seal and rim engaging means provided on the internal surface of said detachable skirt portion adapted to engage a surface of the rim of the container remote from said dispensing opening, the arrangement being such that when applied to a container, the skirt shrouds the rim engaging means and removal of the seal is effected by tearing the tear means or otherwise destroying the seal to provide an indication of tampering.

By arranging for the skirt in accordance with the present invention completely to shroud the rim engaging means, thereby preventing interference with the rim engaging means through juxtaposed openings in the skirt.

According to a second aspect of the present invention there is provided a sealed container comprising an upstanding neck portion which defines a dispensing opening, and a tamper-proof seal according to the first aspect of the invention.

In one aspect of the invention, the skirt may comprise an upper skirt portion juxtaposed said crown, an intermediate skirt portion comprising said tear means and a lower skirt portion carrying said rim engaging means.

In a particular embodiment of the present invention the neck is a cylindrical neck and the crown portion is generally circular with a depending cylindrical skirt.

The rim engaging means comprises a plurality of re-entrant barb elements extending upwardly and inwardly from an inner surface of the portion of the skirt. In a particular embodiment of the present invention the barb elements are angled upwardly at an angle of between 25 and 350 to the skirt wall.

In one aspect of the invention the barb elements may be of a length such that upon engaging the rim of the container the crown is drawn positively into abutment with the annular end of the neck of the keg.

The tear means is preferably constituted by a tear strip which extends about the skirt, said tear strip being constituted by a separate removable and tearable band extending about the periphery of the skirt, said band being connected to upper skirt part and the lower skirt portion by means of lines of weakness. The tear strip may be a circumferential strip having a depending tab extending into the lower skirt portion with a line of weakness to aid starting of the tear strip and removal of the seal at the point of use of the keg. The tear strip may comprise a plurality of circumferentially spaced frangible nibs extending between the tear strip and the juxtaposed portions of the skirt. The tear strip may extend substantially completely about the skirt of the tamper-proof seal of the invention or may extend over a significant portion thereof.In one aspect of the invention the tear strip may extend over a range of 750 to 2750 of an arc. In another aspect of the present invention it may extend over a range of 900 to 1800.

In a further aspect of the present invention, the crown of the closure is provided with a plurality of arcuate openings juxtaposed each barb element, the opening being of an extent sufficient to allow access by portions of a molding tool in forming of the barb elment. By providing openings in the crown for access in the molding tool to the barb elements, when applied to a container, the barb elements are shielded by the rim of the neck to which the seal is applied and access through the molding ports is not available.

The crown of the closure may be provided with a plurality of centering nibs which serve to centre a seal about the keg neck to which it is applied.

The seal in accordance with the present invention may be formed of a high density polyethylene and produced by injection molding techniques well known to the man skilled in the art.

In a preferred embodiment of the present invention, four barb elements are provided with four juxtaposed openings in the crown of the seal. Each arcuate barb element may extend substantially over a 500 arc.

The seal in accordance with the present invention is manufactured to tolerances sufficient that when produced the seal may be effected by simply driving the seal over the neck of the container to be sealed.

The barb elements engage under the rim of the neck and any attempt to remove the seal by manipulation will result in tearing of the tear strip or otherwise in destruction of the seal thereby giving a clear indication that the seal has been tampered with and an indication as to the possibility that the contents of the container may have been sampled.

Following is a description by way of example only and with reference to the accompanying informal drawings of methods of carrying the invention into effect.

Figure 1 is a cross-section of a seal in accordance with the present invention.

Figure 2 is a plan view from above of the seal of Figure 1.

Figure 3 is a detail of the tear strip of the closure of Figure 1.

The closure 10 comprises a substantially circular crown 11 having a depending cylindrical skirt 12. The skirt 12 has an upper skirt portion 15 juxtaposed crown 11, an intermediate portion 13 of reduced thickness provided by means of a shallow annular recess 14 in the external surface thereof defining a radially extending upper rim 15 and a lower reinforced portion 16.

The lower reinforced portion 16 is provided on its inner surface 17 with a plurality, in the case of the specific example illustrated four, arcuate, inwardly directed barb elements 18. Each barb element 18 is in the form of a generally arcuate portion of a frusto-cone of substantially uniform wall thickness and terminating at its upper edge 19 in an annular surface 19 dispersed in a plane subtantially parallel with the undersurface of crown 11.

The intermediate portion 13 of skirt 12 is provided, over an arc of 1900 with a tear strip 20 constituting a circumferentially disposed band which serves to join the upper portion 15 with the lower reinforced portion 16, the jointing being effected by means of a pair of axially spaced, circumferential lines of weakness 21. Each line of weakness 21 is defined by a spacing which is bridged by a plurality of circumferentially spaced frangible nibs 23. Band 20 is spacially separated at each end 24, 25 from the remainder of the skirt and at one end 25, the spacing 26 is juxtaposed of V-notch 27 in the lower reinforced portion 16 to provide for ready starting of the tear strip on removing seal prior to use.

The crown 11 of the seal and the adjacent upper skirt portion 15 is provided with four circumferentially spaced semi-circular rib elements 28 adapted to engage with the rim of the container and serve to centre the tamper proof seal 10 on the neck of the keg during application.

In use, the seal 10 described above is entered over the neck of the container by entering the lower portion 16 over the rim of the container neck. The seal 10 is then driven downwardly onto the container neck with the result that the frangible nibs 23 collapse and the arcuate barb elements 18 "fold back" against the skirt 13, 15 while the "collapsed" frangible nibs 23 allow sufficient expansion of the side walls of the skirt 13, 15 to accommodate the bulk of the elements 18 as they pass over the rim of the container without rupture of the ribs 23.On driving the seal home over the neck of the container until the underside of the crown 11 abuts the annular end edge of the neck of the keg, the end 19 of each barb element 18 springs outwardly to engage the underside of the neck rim at the same time "stretching" the frangible nibs 23 sufficiently to leave them slightly in tension as they draw the crown 11 into contact with the annular end of the keg neck.

Provided the seal 10 and the tear strip 20 remains unruptured and unbroken, this is a clear indication the contents of the container have not been sampled or pilfered since sealing. Any attempt to pilfer the contents of the container will necessitate the lifting of the crown 11 of seal 10. In doing this the barb elements 18 will engage the underside of the neck rim to prevent removal of the seal 10. The application of force will result in stretching of the frangible nibs 23 and ultimate breaking thereof providing a clear indication that the contents of the container have been sampled.

In practice it is not possible to remove the seal without rupture of a substantial part of at least one of the lines of weekness of the tear strip 20 or in the alternative to otherwise destroy or mutilate the seal 10 thereby providing a clear indication of tampering.

In order to remove the seal, the end 24 of tear strip 20 is lifted which results in rupture of the frangible nibs 23. Continued tearing of the strip 20 from the upper and lower side portions continues peripherally to end 25 which results in rupture of weakened portion defined by V-notch 27 in lower reinforced portion 16 thus releasing lower reinforced portion 16 and the arcuate barb elements 18 to permit removal of the seal from the keg neck by sliding it sideways from the keg neck.

In order to facilitate molding, four arcuate slots 30 are provided in the crown 11 of the seal, each slot 30 corresponding in extent to the arcuate barb element thereby permitting access behind the barb element by the tool during molding thereof. With the seal applied to a keg neck, the continuity of the skirt shrouds and prevents access to the inside of the barb elements 18 for manipulation thereof and the opening 30 is obturated by the presence of the neck of the keg, thereby providing complete protection of the barb elements 18 against interference.

The material used in molding of the seal described above is high density polyethylene.

Claims

1. A tamper proof seal for a container having a dispensing opening defined by a neck portion with a circumferential rim, which seal comprises: a crown portion adapted to overlay said opening to prevent access thereto, a skirt depending from said crown portion, the skirt being adapted to cover said rim, tear means provided about said skirt intermediate said crown portion and an extremity of the skirt thereby to provide a detachable skirt portion at least partially detachable from the remainder of the seal, and rim engaging means provided on an internal surface of said detachable skirt portion and adapted to engage a surface of the rim of the container remote from said dispensing opening, the arrangement being such that when applied to a container the skirt shrouds the rim engaging means and removal of the seal is effected by tearing the tear means or otherwise destroying the seal to provide an indication of tampering.

2. A tamper proof seal as claimed in claim 1 characterised in that said skirt comprises an upper skirt portion juxtaposed said crown, an intermediate skirt portion comprising tear means and a lower skirt portion carrying said rim engaging means.

3. A tamper proof seal as claimed in claim 1 or claim 2 characterised in that the crown portion is generally circular with a depending, cylindrical skirt.

4. A tamper proof seal as claimed in any preceding claim characterised in that said rim engaging means comprises a plurality of re-entrant barb elements extending upwardly and inwardly from the inner surface of the skirt.

5. A tamper proof seal as claimed in claim 4 characterised in that said barb elements are of a length such that upon engaging the rim of the container, the crown is drawn positively into abutment with an end of the neck of the keg.

6. A tamper proof seal as claimed in any preceding claim characterised in that said tear means is constituted by a tear strip which extends about the skirt, said tear strip being constituted by a separate, removable and tearable band extending about the periphery of said skirt, said band being connected to the upper and lower skirt portions by means of lines of weakness.

7. A tamper proof seal as claimed in claim 6 wherein the tear strip is a circumferential strip having a depending tab which extends into the lower skirt portion with a line of weakness to aid starting of the tear strip and removal of the seal at the point of use of the keg.

8. A tamper proof seal as claimed in claim 6 or claim 7 wherein said tear strip comprises a plurality of circumferentially spaced frangible nibs extending between juxtaposed portions of the skirt.

9. A tamper proof seal as claimed in any of claims 6 to 8 wherein the tear strip extends substantially completely about the skirt of the tamper proof seal.

10. A tamper proof seal as claimed in any of claims 6 to 9 characterised in that the tear strip extends over a range of 750 to 2750 of an arc.

11. A tamper proof seal as claimed in any preceding claim wherein the crown of the closure is provided with an arcuate opening juxtaposed each barb element, the arrangement being such that each opening is of an extent sufficient to allow access by portions of a molding tool in forming of the barb element.

12. A tamper proof seal as claimed in claim 11 characterised in that said skirt is arranged completely to shroud the rim engaging means thereby preventing interference with the rim engaging means through said juxtaposed openings in the skirt.

13. A tamper proof seal as claimed in any preceding claim wherein the crown is provided with a plurality of centering nibs which serve to centre the seal about the neck of the keg to which it is to be applied.

14. A tamper proof seal as claimed in any preceding claim wherein said seal is formed of a high density polyethylene and produced by injection molding techniques.

15. A tamper proof seal as claimed in any preceding claim wherein the seal comprises four barb elements and four openings in the crown, each opening being juxtaposed a barb element.

16. A tamper proof seal as claimed in any preceding claim wherein each barb element extends substantially over a 500 arc.

17. A tamper proof seal constructed and arranged substantially as described herein with reference to and as shown in Figures 1, 2 and 3 of the accompanying drawings.

18. A sealed container comprising an upstanding neck portion which defines a dispensing opening, and a tamper proof seal as claimed in any of claims 1 to 16.