WO1990005681A1

WO1990005681A1 - Tamper evident closure

Info

Publication number: WO1990005681A1
Application number: PCT/GB1989/001371
Authority: WO
Inventors: Henryk Dudzik
Original assignee: Lawson Mardon (M.I.) Limited
Priority date: 1988-11-23
Filing date: 1989-11-17
Publication date: 1990-05-31
Also published as: CA2002940A1; KR900701617A; GB8827328D0; GB2225778A; ZA898948B; GB2241231A; AU4636189A; GB2241231B; GB9106466D0

Abstract

A screw cap (10) comprising an internally threaded skirt (14) including a frangible indicator (22) having a projection (30) adapted to be engaged by a projection (40) on the neck (20) of the jar (12) as the cap is rotated to remove it. Pressure applied by the projection (40) causes frangible supports (26) to snap and the indicator (22) to break, thus providing an indication (both visual and tactile) that the jar has previously been opened. The cap can be made and applied to a jar by currently used systems and is a little more expensive than a conventional cap.

Description

TAMPER EVIDENT CLOSURE

This invention relates to a tamper

closure and especially to a tamper evident screw cap for a container, a package including such a screw cap, and a container adapted for use with such a screw cap.

It is desirable to provide a clear indication to a purchaser that a package has not been tampered with especially where the package is a food package eg. a coffee or jam jar. It is a current practise to provide vessels, for example glass jars, with a closure cap removably attached to the jar by means of screw threads, the cap comprising a closure portion (generally planar) with a skirt depending from a periphery thereof, the skirt having internal screw threads adapted to cooperate with external threads on a neck portion defining an opening in the jar through which access may be gained to the interior of the jar. Such screw caps are commonly moulded of a suitable plastics material, for example polypropylene. Such jars when used for certain products, for example coffee, are commonly supplied with a. sheet material, for example a metal foil, covering the opening and sealed to the rim of the jar bounding the opening: intactness of the foil when the screw cap is first removed can provide some visual reassurance that the contents have not been tampered with, as well as the foil maintaining the contents of the jar in good condition. However, the foil may sometimes be damaged when first removing the closure so that this visual reassurance is not very reliable and in any event a hypodermic syringe may be used to inject noxious material through the foil in a position which is not readily noticeable at a casual inspection. Furthermore, jars are not sealed when used for other products, for example jam, with a separate foil seal of this type.

In GB-A-2203416 is described a tamper evident package

a seal member secured over the mouth of a receptacle and indicating means joined to the seal member projecting through an opening in a cover member ( in the form of a screw cap) which is ripped off when the cover member is moved from a closed condition towards an open condition. However, with a such_. a package there is a risk that the indicating means will merely be deformed should unauthorised removal of the cover member occur and, following replacement of the cover member over

mouth of the receptacle, returned tn its apparently "safe" condition, or that the indicating means may accidentally be detached (as it projects to some extent through the opening). Furthermore, the indicating means provides a substantially visual indication which is of little or no benefit to a blind or partially-sighted person. In addition, as the opening in the cover member is in register with the seal member there is a substantial risk that noxious substances may be introduced into the receptacle without disturbing the indicating means, through the opening itself, for example by a hypodermic needle introduced between the sealing member and the receptacle. Thus the package described in this specification has a number of disadvantages and does not provide a package which is reliably tamper evident nor convenient.

J t has also been proposed, for example, in GB-A- 2149765 and GB-A-2163413 to provide a tamper evident car- for a container comprising a closure portion with a skirt depending therefrom, inter-engaging means on the interior of the cap and on the exterior of a neck portion defining an opening in a container whereby to removably retain the cap on the neck portion to close the opening, the cap being removable form the container by an action including rotation of the cap relative to the neck portion, the ca further comprising at least one portion which is connected to the remainder of the cap by frangible means and means which is adapted to be engaged by a projection provided on the neck portion of a container to which the cap has been applied as the cap is rotated relative to the neck portion to remove it therefrom and to thereby fracture the frangible means but which is not fractured during initial application of the cap to the neck portion wherein said one portion of the cap comprises an indicator provided by a frangible portion of the skirt which when fractured becomes separated from the remainder of the skirt and leaves an opening in the skirt, thus to provide an indication that the cap has previously been removed from the neck portion.

In both of these patents said one portion of- the cap is. provided by a band connected to the skirt of the cap by the frangible means. On rotation of the cap to remove it from a container the band is prevented from rotation by engagement, of the projection on the neck portion of the container with the means on the cap and the band is thus separated from the skirt portion. While this may provide an indication that a container has previously been opened in some circumstances, the band may remain around the neck portion and might only be seen to have been separated by very close examination. Even if the band becomes completely detached, for sighted people this may provide an indication of tampering (though only if an intact, cap is close by for comparison) but blind or partially sighted people would mee . ith difficulty in assessing the condition of the cap.

One of the various objects of the present invention is to provide an improved tamper-evident cap for use in closing an opening in a container.

Another of the objects of the invention is to provide an improved tamper-evident package.

In one aspect, the invention may be considered to provide a tamper evident* cap for a container, comprising a closure portion with a skirt depending therefrom, interengaging means on the interior of the cap and on the exterior of a neck portion defining an opening in a container whereby to removably retain the cap on the neck portion to close the opening, the cap being removable from the container by an action including rotation of the cap relative to the neck portion, the ca further comprising at least, one portion which is connected to the remainder of the cap by frangible means and means which is adapted to be engaged by a projection provided on the neck portion of a container to which the cap has been applied as the cap is rotated relative to the neck portion to remove it therefrom and to thereby fracture the frangible means which is not fractured during initial application of the cap to the neck portion wherein said one portion of the cap comprises an indicator provided by a frangible portion of the skirt which when fractured becomes separated from the remainder of the skirt and leaves an opening in the skirt, thus to provide an indication that the cap has previously been removed from the neck portion.

Preferably the iτiterengaging means of a cap in accordance with the invention has internal screw threads adapted to cooperate with external threads on the neck portion. Preferably the indicator comprises an inwardly projecting engagement portion comprising a first surface- adapted to be engaged by the external projection from the neck portion of a container to which the cap has been applied as the cap is rotated to remove it from the neck portion thereby to apply a force to the frangible portion causing it to fracture. Conveniently the engagement portion further comprising a second surface adapted to engage said external projection of a container as the cap is first applied thereto and to permit the indicator to pass the projection as the cap is first applied to the neck portion without fracture of the frangible portion.

The frangible portion is preferably attached to the remainder of the skirt, by frangible supports which extend between a body of the frangible portion and portions of the skirt at either side, axially, of the body. Suitably the supports have a relatively small circumferential u-idth (by comparison with the circumferential width of the bod ) .

In a preferred screw cap in accordance with the invention the body has a weakened portion at a eircumferentially central region of the body which extends generally axially across the body thus to divide jt into two parts. The weakened portion suitably has a circumferential width which is between about. 5% and 10% of the circumferential width of the frangible portion. Preferably the opening within which the frangible portion is supported extends between about 30° and 50° of arc around the skirt, suitably about. 40° . The preferred screw cap comprises two pairs of frangible supports each pair associated w th one of the two parts of the frangible portion. The supports of each pair are axially opposed at opposite, sides of the body and are conveniently situated at a central region of the associated part. Conveniently each of the frangible supports extends across between about 10 and 15% of the circum erential width of the associated part of the frangible portion, suitably about 12.5% and is disposed with its centre substantially at the centre of the associated part, considered circumferentially.

Preferably a screw* cap according to the invention comprises two inwardly projecting portions on the frangible portion, positioned at circumferentially opposite end portions thereof. The first, engagement portion is adapted to be engaged by a projection from the neck of the container as aforesaid, whilst the second projecting portion is adapted to engage the neck portion when the frangible portion is fractured to militate against the frangible portion becoming forced between the neck portion and the remainder of the skirt as the cap is rotated to remove it. Preferably, in addition, in the preferred screw cap, the second end portion is configured •JO that when the supports are fractured during removal of the cap, the second end portion is urged into engagement with part of the skirt bounding the frangible portion whereby to urge the frangible portion away from the skirt and, in some cases, to cause the weakened portion to fracture.

There now follow detailed descriptions to be read with reference to the accompanying drawings of two screw caps embodying the invention. It will be realised that these screw caps have been selected for description to illustrate the invention by way of example and not of limitation of the invention.

Tn the accompanying drawings;

Figure 1 is a perspective view of a first cap embodying the invention;

Figure 2 is a perspective view showing part of a first container embodying the invention;

Figure 3 is a fragmentary perspective view showing part of the first illustrative cap; Figure 4 is a view in section of part of the first illustrative cap showing an indicator and showing in chain dot line a frangible portion of the indicator as it is fractured during the initial opening of the container;

Figure 5 is a view in section showing an indicator and screw threads of the first illustrative cap;

Figure 6 is a perspective view showing part of a second container embodying the invention;

Figure 7 is a view in section of part of a second illustrative cap showing an indicator;

Figure 8 is a plan view- of part of the second illustrative cap showing the indicator viewed from within the cap; and

Figure 9 is a view of the second illustrative cap generally corresponding to Figure 7 but showing the indicator as it is fractured during initial opening of the second illustrative container. n

The first illustrative screw cap 10 is intended for use with a container, namely a glass jar 11 which is especially suitable for use in storing granulated coffee or the like. The firs illustrative tamper evident screw cap 10 comprises a substantially flat closure portion 12 from which a skirt 14 depends. The skirt 14 has internal scret threads 16 (see figure 5) adapted to cooperate with external threads 18 on a neck portion 20 which defines an opening in the jar 11, whereby to retain the cap on the neck portion 20 to close the opening. The first illustrative cap 10 and jar 11 are provided with four- start threads; however, any convenient number of starts may be used, e.g. a six-start, thread which may simplify manu acture.

The skirt 14 comprises two indicators 22 (positioned at. opposite sides of the skirt. 14) which are frangible. Each indicator 22 comprises a frangible portion including a body 24 and frangible supports 26. The frangible supports 26 extend between the body 24 and portions of the skirt 14 at either side, axially, of the body 24 (that, is the portions nearer to the closure portion 12 and to the rim of the skirt 14 remote from the closure portion 12, respectively). The frangible supports 2n have a relatively small circumferential width by comparison with the circumferential width of the body 24, suitably being about 6% of the circumferential width of the whole of the body 24. The body 24 has a weakened portion 29 at a circumferentially central region of the body. The weakened portion is in the form of a groove 28 (positioned internally of the skirt 14) which extends generally axially across the body to divide it into two parts (see figure 4). The w^τidth of the groove 28 is about 7.5% of the circumferential width of the body 24. The body 24 further comprises two inwardly projecting portions 30, 32 positioned at circumferentially opposite end portions of the body 24 one on each of the two parts of the body. The first portion 30 comprises a first surface 34 and a second surface 36 the purpose of which will be described hereinafter. The end portion of the body 24 adjacent the second projecting portion 32 comprises a surface 38, the purpose of which will be described hereinafter.

The first illustrative cap 10 can readily be moulded from plastics material by the techniques commonly used in moulding caps and can be applied to the neck of an appropriate jar or other container including the necessary projections 40 by the techniques commonly used without there being any need to modify the operation of existing equipment. It is, of course, necessary to select an appropriate plastics material which will fracture when suitable pressure is applied in opening the container and to select the dimensions of the frangible supports 26, the weakened portion 29 and the width of the groove 28 so that the indicator 22 functions correctly. A suitable plastics material from which to manufacture the illustrative cap 10 is polypropylene. Although other sufficiently brittle polymers, for example, polystyrene or styrene acrylonitrile copolymer may be used.

The neck portion 20 of the jar 12 as well as having screw threads 18 is provided with four projections 40 spaced equiangυlarly around the neck portion 20 but at the same position axially of the neck portion. There may, however, be provided more, or fewer, projections, e.g. six, likewise equiangularly disposed. Each of the projections comprises a stop face 42 which is substantially radial of the neck portion and meets a sloping cam face 44 at an apex, the cam face 44 smoothly merging at the end opposite the stop face 42 with the remainder of the neck portion 20. When the cap 10 is applied to the neck portion 20 the threads 16 on the cap engage with the threads 18 of the neck portion 20 and the cap 10 is rotated to tighten the closure portion 12 into sealing engagement with the rim of the neck portion 20. It will be understood that the mouth of the neck portion may, if desired, be also closed by a sealing member in known manner e.g. a foil which may be secured to the rim of the neck portion by- adhesive as is common practice. The sealing member may be applied carried within the cap and pressed Into adherent engagement with the rim by pressure applied by the cap as it is applied in known manner. After the closure portion 12 has been tightened against the rim, the indicators 22 are then positioned relative to the projections 40 in the relationship shown in figure 4 in full line, namely with the first surface 34 of the first projecting portion 30 of the body 24 adjacent the stop face 42. As the cap 10 is applied to the neck portion 20 it will be rotated in the direction indicated by the arrow A relative to the neck portion. As the indicator 22 approaches the position in which it is shown in full line in figure 4, the second surface 36 of the projecting portion 30 will engage the cam face 44 of the projection 40 from the jar and permit the frangible portion to pass the projection ^"40 as the cap is first applied to the neck portion 20, without fracture of the frangible portion, the surface 36 riding over the cam surface 44 and easing the projecting portion 30 past the projection 40. Likewise if the second projection 32 from the body 24 should engage the projection 40 during application, the projecting portion 32 is so shaped as to likewise engage the cam surface 44 and ride over the projection 40 without fracturing the frangible body 24 or the frangible supports 26.

When the first illustrative cap 10 is first to be removed from the neck portion 20, it is rotated in the direction indicated by the arrow B (figures 3. and 4). As can be seen viewing figure 4, the second surface 34 of the projecting portion 30 is moved firmly into engagement with the stop face 42. Continuing attempts to rotate the cap 10 to unscrew it from the neck portion 20 force the body 24 towards the position in which it is shown in line in figure 4 (and in which it is shown in figure 3). The body 24 pivots about the frangible supports 26 and the weakened portion 29 of the body at the bottom of the groove 28 acts as a hinge so that the body 24 begins to bend at the weakened portion 29. Continued rotation of the cap 10 breaks the frangible supports 26 and forces the surface 38 of the body 24 into engagement with a part 33 of the skirt defining the opening within which the frangible body 24 is positioned. When the surfaces 38, 39 come into engagement, the stop face 42 still continues to push against the firs surface 34 of the projection 30 and continues to cause the body to bend at the weakened portion 29 until the force exerted on the weakened portion 29 may be sufficient to cause it to fracture (as shown in chain dot. line in figure 4). The groove 28 is made as narrow as conveniently possible so that, when pressure is exerted as aforesaid during opening, the innermost edge portions contact each other as soon as possible. Continued pressure then causes these edge portions to act. as a pivot and thus applies increasing tension to the weakened portion 29, finally causing it to break. As can be seen from figure 4, the second projecting portion 32 from the body 24 engages the surface of the neck portion 20 when the body 24 is fractured and is configured to prevent the body 24 becoming forced between the neck portion 20 and the remainder of the skirt 14 as the cap is rotated to remove it.

The broken parts of the indicator 22 have thus become completely separated from the remainder of the skirt 14 and fall away leaving an opening in the skirt. A second illustrative cap and second illustrative container are described hereinafter.

The second illustrative cap and second illustrative container are generally similar to the first illustrative cap and container, except as hereinafter described and like numbers are used to indicate like parts in the drawings .

The second illustrative container namely a glass jar 11a_. (see ' Figure 6) is identical with the first illustrative container, shown in Figure 2, except, that it is provided with a cylindrical collar 50. The collar 50 extends around the neck portion 20 remote from its rim. The collar 50 is intended to be slidingly received, as a cap 10 is applied to the neck portion 20, in the skirt 14 so that the rim portion of the skirt 14 remote from the closure portion 12 cannot be squeezed inwardly. Thus distortion of the skirt in such a manner that the indicators 22 might be eased, without fracturing, passed the projections 40 when the cap 10 is rotated to remove it, is prevented. The second illustrative cap is generally similar to the first except in the region of the indicator 20, as described hereinafter with reference to and as shown in Figures 7 to 9 of the drawings. The body 24 of the indicator is connected to the skirt 14 not merely by axially extending frangible supports 26 but also by a circumferential frangible support 56 extending between an end portion of the indicator adjacent the projecting portion 30 and the skirt 14. At the circumferentially opposite end of the indicator there is no corresponding support. However, the skirt 14, adjacent, the second projecting portion 32, is formed with a guide passage 52 terminating, remote from the indicator, with a stop face part 39 of the skirt 14. A web 54 overlies the passage 52, spaced from the neck portion 20.

As the second illustrative cap 10a is rotated to remove it from the neck portion and the portion 30 engages the projection 40, the frangible support 56 first stretches and finally snaps: however the support 56 acts to assist in retaining the portion 30 firmly in contact with the projection 40 (preventing the indicator being lifted and eased passed the projection 40) and to prevent the body 24 twisting, thus facilitating effective operation of the indicator. Additionally, as the body 24 is forced by the projections towards the part 39 it is guided by the thin, relatively flimsy, web 54 into the passage 52 in which the body is slidingly received. When the surface 38 of the body engages the part 39 of the skirt, the second illustrative cap 10a functions in a similar manner to the first, the portion 32 preventing the body 24 becoming jammed between the skirt 14 and neck portion 20. However, the passage 52 guides the body 24 assisting in holding the portions 30, 32 in contact with the neck portion 20 and preventing the body 24 twisting, thus ensuring that the indicator operates as intended. The indicator of the second illustrative cap functions satisfactorily, the body 24 being reliably ejected from the opening in the skirt 14 as the cap 10a is removed.

The weakened portion of the second illustrative cap 10a, primarily acts as a hinge and does not. normally break when the cap is removed from a container.

Any rotation of the caps 10 of the illustrative packages, sufficient to permit access to the contents of the jar 12 causes the frangible supports 26, 56 to fracture the body 24 of the indicator to become separated from the remainder of the skirt. This provides a clear visual indication that the cap 10 has previously been removed from the jar 20 and the absence of the indicator is also readily detectable by touch so that it also provides a warning to a blind person.

Because the opening in the skirt 14 formed when the parts of the indicator 22 fall away (after fracturing the frangible supports) is disposed below the rim of the neck portion 20 there is little or no possibility of any contaminant being introduced into the jar through the opening in the skirt and the neck portion, especially where a separate sealing member e.g. a foil is secured over the mouth of the neck portion.

Claims

1. A tamper evident cap (10) for a container (11), comprising a closure portion (12) with a skirt (14) depending therefrom, interengaging means (16,18) on an interior of the cap (10) and on the exterior of a neck portion (20) defining an opening in a container (11) whereby to removably retain the cap (10) on the neck portion (20) to close the opening, the cap (10) being removable from the container (11) by an action including rotation of the cap (10) relative to the neck portion (20), the cap (10) further comprising at least one portion (22) which is connected to the remainder of the cap by frangible means (26) and means (30) which is adapted to be engaged by a projection (40) provided on the neck portion (20) of a container (13) to which the cap (10) has been applied as the cap (10) is rotated relative to the neck portion (20) to remove it therefrom and to thereby fracture the frangible means (26) but which does not fracture the frangible means (26) during initial application of the cap to the neck portion characterised in that said one portion of the cap comprises an indicator (22) provided by a frangible portion (22) of the skirt (14) which when fractured becomes separated from the remainder of the skirt (14) and leaves an opening in the skirt, thus to provide an indication that the cap (10) has previously been removed from the neck portion (20).

2. A tamper evident cap according to claim 1 wherein the interengaging means of the cap comprises internal screw threads (16) adapted to cooperate with external threads (18) on the neck portion (20).

3. A cap according to either one of claims 1 and 2 wherein the indicator (22) comprises an inwardly projecting engagement portion (30) comprising a first surface (34) adapted to be engaged by -the external projection (40) from the neck portion (20) of a container (11) to which the cap (10) has been applied as the cap is rotated to remove it from the neck portion (20) thereby to apply a force to the frangible portion (22) causing it to fracture.

4. A cap according to claim 3 wherein the engagement portion (30) further comprises a second surface (36) adapted to engage said external projection (40) of a container (11) as the cap (10) is first applied thereto and to permit the indicator (22) to pass the projection (40) as the cap is first applied to the neck portion without fracture of the frangible portion (22).

5. A cap according to any one of the preceding claims wherein the frangible portion (22) comprises frangible supports (26) by which it is attached to the remainder of the skirt the supports (26) extending between a body (24) of the frangible portion (22) and portions of the skirt (14) at either side, axially, of the body (24) of the frangible portion (22).

6. A cap according to claim 5 wherein the supports (26) have a small circumferential width relative to the body

(24).

7. A cap according to claim 6 wherein the body (24) ha:-**, a weakened portion (29) at a circumferentially central region and extending generally axially across the body (24) thus to divide it into two parts.

8. A cap according to claim 7 comprising two pairs of frangible supports (26), each associated with one of the two parts the supports of each pair being axially opposed at opposite sides of the body (24).

9. A cap according to claim 8 wherein each pair of supports (26) is positioned at a central region of the associated part.

10. A cap according to any one of the preceding claims comprising two inwardly projecting portions (30,32) on the frangible portion (22) positioned at circumferentially opposite end portions thereof the first engagement portion (30) being adapted to be engaged by a projection (40) from a neck portion (20) of a container (11) as aforesaid, and the second projecting portion (32) being adapted to engage the neck portion (20) when the frangible portion (22) is fractured to militate against the frangible portion (22) becoming forced between the neck portion (22) and the remainder of the skirt (14) as the cap (10) is rotated to remove it.

11. A cap according to either one of claims 7 and 8 comprising an engagement portion (30) which projects inwardly from one end portion of the frangible portion (22) and wherein the circumferentially opposite end portion is configured so that when the supports (26) are fractured during removal of the cap (10) said opposite end portion is urged Into engagement with part (39) of the skirt (14) adjacent the frangible portion (22) whereby to urge the frangible portion (22) outwardly of the skirt ( 14) .

12. A cap according to any one of claims 5 to 9 comprising a frangible support (56) which extends between one circumferential end portion of the body (24) and a portion of the skirt (14) adjacent to but at one side, circumferentially, of said one end portion.

13. A cap according to any one of the preceding claims comprising a passage (52) formed in the skirt (14) adjacent a circumferential end portion of the indicator (22) which is remote from the projection (40) when the projection (40) engages said means (30) as the cap is rotated to remove it from the neck portion (20) of a container (11a), the passage (52) being adapted to slidingly receive said end portion of the indicator (22) during separation of the indicator (22) from the remainder of the skirt (14).

14. A package, comprising a container (11) having a neck portion (20) defining an opening through which access to the interior of the container (10) may be gained characterised in that it comprises a cap (10) according to any one of claims 1 to 13 secured to the neck portion, interengaging means (16,18) being provided on the interior of the cap and the exterior of the neck portion whereby to removably retain the cap on. the neck portion.

15. A container (11) having a neck portion (20) defining an opening through which access to the interior of the container (11) may be gained, characterised in that the neck portion (20) comprises at least. one external projection (40), adapted to cooperate with an indicator (22) of a cap (10) according to any one of claims 1 to 13.