EP0056730B1

EP0056730B1 - Improved container assembly

Info

Publication number: EP0056730B1
Application number: EP82300267A
Authority: EP
Inventors: Derek Charles Roberts
Original assignee: Johnsen and Jorgensen Plastics Ltd
Current assignee: Johnsen and Jorgensen Plastics Ltd
Priority date: 1981-01-20
Filing date: 1982-01-19
Publication date: 1985-10-30
Also published as: DE3267073D1; EP0056730A1; ATE16266T1

Abstract

A container closure which has a cap part (5) with an internal screw thread (6) to engage with an external screw thread (2) on the container (1), a tear away band (7) connected to the skirt (9) of the cap part (5) to show whether the closure has been tampered with and a captive band (8) connected to the tear away band (7).

Description

This invention is concerned with the provision of an improved container and closure assembly. British Patent No. A1010762 discloses a bottle closure of the screw-type, in which a screw cap or screw stopper is moulded in one piece from a resilient plastic material with a skirt portion adapted to fit over the exterior of the bottle neck when the closure is fitted thereon and provided with an annular step, rib or equivalent projection or projections on the internal surface of the skirt portion at such a position that it engages beneath a ridge or shoulder provided on the exterior of the bottle neck when the closure is fully screwed home, said annular step or the like being urged by the resilience of the skirt to engage beneath the ridge or shoulder on the bottle neck whereby to prevent or resist unscrewing of the closure so long as the skirt remains intact and connected to the screw cap or stopper, and in which the skirt portion is provided with a line or lines of weakening along which the skirt may be torn to allow the closure to be unscrewed and also with a tab portion which is adapted to be gripped and pulled by the fingers to tear the skirt portion along said line or lines of weakening.
According to this invention a container and closure assembly is provided comprising a closure having a cap part with an internal screw thread, a tear-away tamper evident band connected to the cap part by a first line of weakness, a captive band connected to the tear-away band by a second line of weakness and an annular lower internal bead on the captive band and a container having an external screw thread on the cap part of the closure, an annular lower external bead below which the internal lower bead on the closure engages when in operative position and a ledge below the lower external bead on to which the captive band will adjust itself after the tear-away band has been removed characterised in that the screw threads on the container and on the closure are discontinuous threads and that the closure has an annular upper internal bead on the tear- away band for engagement below an annular upper external bead on the container.
The disclosure in British Patent No. A1010762 (Permuta Closures Ltd.) referred to above is probably the most relevant prior proposal. The Application that matured into Patent No. A1010762 was applied for in 1962 and since then it has become apparent that the Permuta closure, which is representative of the prior state of the art generally, can be improved. In the first place there is a need for a tamper-resistant screw closure of this kind that can be screwed on and screwed off by a partial turn of the closure rather than having to carry out one or more complete turns as in the Permuta closure. In fact many customers now seek a screw closure that can be pushed straight on in a vertical downward movement as in the present invention, a partial turn being required to remove the closure after the tear-band has been removed. In the second place experience has shown that closures having only one internal bead to engage with an external bead on the container, as in the case of the Permuta closure, are not sufficiently tamper-resistant to defeat dexterous and determined people who wish to tamper with the contents of a container. We decided that it was insufficient to rely only on a single internal bead on the closure for engagement with the container and our experiments have shown that the provision of an upper internal bead on the tear-band for engagement with the container to supplement the effect of a lower internal bead on the captive band which also engages with the container represents a considerably enhanced safety factor.
In this invention therefore the tear-away band assists the captive band in preventing unauthorised removal of the closure from the container. The discontinuous thread provided on the closure and on the container is similar to that described in our British Patents Nos. 1430302 and 1483404 in which there is described a container and closure assembly in which the closure comprises a retaining band combined with a screw cap characterised by the provision of a discontinuous screw thread on the cap with inclined lower surfaces when viewed in axial section for engagement with a discontinuous screw thread, around the mouth of the container, with inclined upper surfaces when viewed in axial section the contour of the screw-threads being such that if an attempt be made to unscrew the closure without first tearing away the retaining band, the inclined surfaces of the screw threads abut against one another, the resistance of the retaining'band being sufficient to cause the inclined surfaces on the cap to slip off the inclined surfaces on the container so that the closure goes round and round but does not come off the container.
In order that the invention may be more clearly understood reference is now directed to the accompanying drawings given by way of

example in which:

Figures 1 and 2 are elevation views of the container and closure assembly.
Figures 3 and 4 are top and bottom plan views.
Figure 5 is an enlarged section of A-A Figure 1.
Figure 6 is an enlarged fragmentary view of the container with the closure removed.
Figure 7 is a partly sectional view of a modified form of closure according to the invention.

Referring to the drawings a container 1 has a multi-start discontinuous external screw thread indicated generally at 2, a tearaway band-seating 3 and a captive band-seating 4. A closure 5 has an internal multi-start (in this example four start) discontinuous screw thread 6, a tear away band 7 and a captive band 8. Weakened lines 10 and 11 in the skirt 9 of the closure facilitate tearing away of the band 7. The container 1 is shaped to provide an external annular bead 12 that is nose shaped in section with an inclined upper surface 13 and a substantially horizontal lower surface 14. The closure 5 is shaped by the provision of an upper bead 25 on the inside of the band 7 so that it can easily be pushed downwardly over the bead 12 but when in position on the container 1 as shown e.g. in Figure 5, it is almost impossible to remove the closure simply by an upward movement. The downward movement of the closure 5 relatively to the container 1 is preferably effected by pushing straight down into position but alternatively the closure 5 can be applied by a screwing down movement.
The line 10 of weakness substantially coincides with the outer end of the bead 12 so that when the band 7 is torn away the top or cap part of the closure can easily be removed by unscrewing a part turn and can be replaced as required. The band 7 sits comfortably on the seating 3 as shown and the container is shaped to provide a lower bead 15 with which the captive band 8 engages. The engagement of the band 8 with the bead 15 provides an extra tamper proof feature because this engagement makes it even more difficult to remove the closure without first tearing away the band 7. When the closure 5 is in operative position on the container 1 as shown for example in Figure 5 the captive band 8 will be substantially in the position shown in Figure 5 and will be effective in its tamper proof function. When the band 7 is torn away by tearing alon.g the lines 10 and 11 the band 7 will fall away and the captive band 8 will be left in position. The band 8 will then adjust itself to the outer contour of the seating 4 and will probably move downwardly to rest on a ledge 16 on the container 1.
When in this position the captive band 8 serves no function other than to partially fill the gap between the bead 12 and the ledge 16 in order to improve the aesthetic appearance of the assembly after initial opening. The screw thread illustrated in the drawings is the same as the thread described in our British Patent No. 1430302 and 1483403. When the closure is complete and is seated in operative position on the container there is a very considerable constraint imposed upon the closure preventing upward movement due to the presence of both the bands 7 and 8 which engage with the container. Any attempt to unscrew the closure with the band 7 in position simply causes the discontinuous threads on the closure 5 to repeatedly jump off the discontinuous threads on the container due to the positive downward pull of the bands 7 and 8. To unscrew the upper part of the closure successfully it is first necessary to remove the band 7 whereupon the restraint is also removed. However removal of the band 7 is very obvious and if the band 7 be removed by an unauthorised person it is at once clear that the assembly has been tampered with.
The body part of the container may be of any desired and convenient shape and the parts of the assembly are preferably moulded from plastics material. The invention includes the improved closure with a complete circular captive band and also an assembly of the closure and a container. An important feature of the invention is the provision of a suitable sealing means to protect the contents of the container from contamination. Sealing may be effected by engagement of the outer top surface of the container with the inner top surface of the closure. Reference e.g. to Fig. 6 will show that the container 1 may be shaped at 20 to produce a top annular outer portion 21 with a smooth unbroken surface which can be of reduced diameter but the shaping at 20 is purely optional and the portion of reduced diameter need not be provided. The portion 21 engages with an inner annular portion 22 of the closure see e.g. Fig. 5. The top edge of the container may also be arranged to engage with a resilient washer or similar pad disposed within the closure.
In the embodiment described by way of example in Figs. 1 to 6 the screw thread has four starts but it will be understood that a thread having more or less starts may be used depending upon the circumstances.
Refering now to Fig. 7 it will be noted that the multi-start thread 6 in this example has six starts for co-operation with a container (not shown) also having six starts. In Figure 7 the same references are used for the same parts as in Figures 1 to 6; it will be noted however that in Fig. 7 an annular sealing bead 22 is provided on the underside 23 of the top of the closure 5. This bead 22 is of importance because in operation when the closure 5 is in position on the container 1 the bead 22 forms a plug which enters the mouth or top bore of the container. In addition an annular sealing bead 24 is provided to seal against the outer surface of the container.
In the Fig. 7 embodiment therefore we have made provision for a sealing plug within the top bore of the container and a sealing bead outside the top rim of the container due to the manner in which we have developed the mould design. This was difficult to achieve in an economic manner with our earlier design shown in Fig. 5 and is a feature not previously employed in our Patents 1430302 and 1483403.

Claims

1. A container and closure assembly comprising a closure (5) having a cap part with an internal screw thread (6), a tear-away tamper evident band (7) connected to the cap part by a first line of weakness (10), a captive band (8) connected to the tear-away band (7) by a second line of weakness (11) and an annular lower internal bead on the captive band (8) and a container (1) having an external screw thread (6) on the cap part of the closure (5), an annular lower external bead (15) below which the internal lower bead on the closure (5) engages when in operative position and a ledge (16) below the lower external bead (15) on to which the captive band (8) will adjust itself after the tear-away band (7) has been removed characterised in that the screw threads on the container (1) and on the closure (5) are discontinuous threads (2 and 6) and that the closure (5) has an annular upper internal bead (25) on the band (7) for engagement below an annular upper external bead (12) on the container. 2. A closure according to claim 1 wherein the internal bead on the captive band (7) has an inclined lower surface and the upper external bead (12) on the container (1) has an inclined upper surface (13) so that the closure (5) can be pushed straight down into operative position and wherein an annular sealing bead on the underside of the top of the closure forms a sealing plug within the mouth of the container when the closure is in operative position.

3. An assembly according to claim 1 or 2 wherein the upper part of the assembly above the ledge (16) has a diameter equal of the maximum diameter of the ledge (16) and greater than the lower part of the assembly below the ledge (16) which tapers downwardly and inwardly below the part of maximum diameter, there being an annular recessed captive band seating (4) above the ledge on which the captive band seats when the tamper evident band (7) is in position and upon which the captive band (8) adjusts its position to match the outer contour of the seating (4) when the band (7) has been torn away.