AU2011347858A1

AU2011347858A1 - Closure for a container

Info

Publication number: AU2011347858A1
Application number: AU2011347858A
Authority: AU
Inventors: Lino Dreyer; Alexandre Rouquette
Original assignee: Obrist Closures Switzerland GmbH
Current assignee: Obrist Closures Switzerland GmbH
Priority date: 2010-12-23
Filing date: 2011-12-07
Publication date: 2013-06-06
Anticipated expiration: 2031-12-07
Also published as: NZ610137A; AR084560A1; WO2012084514A1; ES2535320T3; BR112013011387B1; AU2011347858B2; RU2013128775A; CA2820567A1; EP2468654B1; JP2014503434A; IL226008A; IL226008A0; BR112013011387A2; CN103261044B; EP2468654A1; CN103261044A; MA34825B1; MX2013005325A; US20130256306A1

Abstract

A closure for a container comprising a circular base (20, a skirt (30) extending from the periphery thereof, an outer seal (60) and a plug seal (50) in the form of an annulus and at least one rib (80) lying on the surface of the base (20) in a substantially radial direction and in contact with the radially inner surface of the plug seal (50) at one end for transferring any movement of the base (20), relative to the skirt (30), to the plug seal (50) such that the plug seal (50) is pulled radially inward to allow venting of excess pressure within the container, whereby the outer seal (60) of the closure comprises at least one deformation portion (65) which interrupts partially the sealing effect of the outer seal (60) in case overpressure occurs.

Description

WO 2012/084514 PCT/EP2011/072039 1 Closure for a container The present invention relates to a closure according to the pre amble of the independent claim. Screw closures for containers with pressurized fluids such as carbonated beverages are widely known. If the pressure build-up in the container exceeds a desired level sufficient to overcome the thread engagement, the closure may be suddenly ejected from the container neck, an effect also called "closure missiling" which may lead to possible injury of users. Closures for container have therefore been developed, whereby excessive gas pressure in the container is decreased by auto matic self-venting of the closure-container arrangement in the sense of a pressure control valve. EP 0 858 416 discloses a closure with a base and a downwardly depending skirt defining the outside of the closure. Within the closure, a bore seal downwardly depends from the base. Radially between this bore seal and the skirt, a stop also downwardly de pends from the base. This stop acts to prevent over-tightening of corresponding screw threads located within the shell and on an associated container, and acts against the rim of the con tainer. Between the stop and the bore seal the thickness of the base is thinned. A rib of uniform thickness lying on the inside of the base extends from the bore seal towards the axial centre of the base and the bore seal is bulged radially outwardly by its presence in case of overpressure, whereby the container is vented. The venting mechanism of EP 0 858 416 functions in that the thinned portion as described works as a hinge allowing the por- WO 2012/084514 PCT/EP2011/072039 2 tion of the base, including the part which has the bore seal de pending from it, to move upwards. Hence, the bore seal has to be lifted slightly from the inner side of the container neck to al low venting. WO 2006/051068 discloses a closure suitable for self-venting of excessive gas by a rib which is lying on the surface of its base and in direct contact with a bore seal and transfers any move ment of the centre of the base by excessive gas to that bore seal allowing venting. In accordance with self-venting mechanism of WO 2006/051068 the bore seal moves away from the inner side of the container be cause of its direct contact to the neck. The bore seal disclosed in these documents seals by pressing against the inner side of the neck of the container when the closure is applied. In this context, it is a known problem that damages or tortures at the rim or within the neck reduce the sealing effect. Therefore, in case of damages or tortures at the inner surface of the container neck, such arrangements for self-venting fur ther reduce the desired sealing effect of the bore seal or lead to premature venting intensifying the problem as mentioned. It is therefore the object of the present invention to overcome the drawback of the prior art and in particular to provide a closure which supports the functionality of such bore seal to improve the sealing properties and thereby not decreasing the workability of the self-venting function.

WO 2012/084514 PCT/EP2011/072039 3 This problem is solved with a closure according to the charac terizing part of claim 1. The invention provides a closure for a container comprising a circular base, a skirt extending from the periphery thereof, a plug seal in the form of an annulus, typically also called dive seal, and at least one rib lying on the surface of the base in a substantially radial direction. The plug seal seals the closure against the inner side of the container. The rib is in contact with the radially inner surface of the plug seal at one end for transferring any movement of the base, relative to the skirt, to the plug seal such that the plug seal is pulled radially inward to allow venting of excess pres sure within the container. An outer seal is arranged concentrically to the skirt. Such outer seal seals against an outer surface of the container weal and further centers the closure against the container and gener ates a counterforce to the plug seal supporting its sealing properties against the container neck. The outer seal has at least one deformation portion which is weaker than a main fraction of the outer seal and which will in terrupt partially the sealing effect of the outer seal in case overpressure occurs. Such a deformation portion maintains the desired functionality of automatical self-venting, whereas, es pecially at normal gas and ambient temperature conditions in the container, the sealing effect at the position of such deforma tion portion is as effective as at the main fraction of the outer seal. The deformation portion may be formed by locally re ducing the size of the seal, e.g. its axial length and/or by its radial thickness. The deformation portion might also be formed WO 2012/084514 PCT/EP2011/072039 4 by influencing the material properties. The deformation portion may even break when extreme pressure conditions are built up in side the container. The closure preferably comprises 6 main fraction and deformation portions, respectively, if the circular base has a diameter of 28mm. The closure preferably comprises 8 or 9 main fractions and deformation portions, respectively, if the circular base has a diameter of 38mm. The closure provides further preferably a top bulge located at the under side of the upper wall between the plug seal and the outer seal. The top bulge features at least one gap whereby ex cessive gas can pass through. Thereby, in addition to the defor mation portions, a defined route for the gas to escape strength ens the effect of self-venting. Preferably, the top bulge is arranged concentrically to and be tween the plug seal and the outer seal There is some free radial space between the top bulge and the outer seal such that excessive gas can reach and pass the defor mation portion. However, preferably the gap of the top bulge is circumferentially aligned with the deformation portion to guar antee a defined and direct route for excessive gas, thereby in creasing the effect of the self-venting. The outer seal of the closure is preferably arranged vertically to the circular base or may be inclined slightly radially in wardly or outwardly. Such inclination of the outer seal will re duce the surface contact and thereby reduce friction, in order to keep removal torques low. The end of the rib in contact with the radially inner surface of the plug seal is preferably thinner, in a plane parallel to the WO 2012/084514 PCT/EP2011/072039 5 base, than in a region spaced from the end of the rib in contact with the radially inner surface, in particular thinner than the other end of the rib. A relatively thin contact to the plug seal brings several advantages such as a minimized reduction of the flexibility of the plug seal. Such an arrangement is described in WO 2006/051068. The deformation portion may be formed by reduction of the radial thickness of the outer seal. Preferably, the rib is aligned to a deformation portion in order to shorten the way of excessive gas when venting. The deformation portions are preferably located in a constant circumferential distance to each other. The radial angle included between the deformation portions is preferably between neighbourly internal sides of 340 to 50', more preferably between 340 to 450, most preferably 340 to 400. A constant distance between the deformation portion leads to a homogeneous force allocation and centering when the closure is applied to the container. Furthermore, self-venting is effected homogeneously over the whole circumference of the outer seal. Furthermore, the thickness of those deformations portions is preferably between 0.3 to 0.5 mm, more preferably between 0.3 to 0.4 mm, as compared to a thickness of 0.7mm of the outer seal. The circumferential length of the deformation portion is deter mined by a radial angle from the centre of the circular base in cluding preferably between 6' to 30', more preferably between 6' to 20' , most preferably between 60 to 15'.

WO 2012/084514 PCT/EP2011/072039 6 Embodiments of the inventions will now be described, by way of example, with reference to the following drawings. FIG.1 shows an external view on the closure shell FIG.2 shows a cross-sectional view of the closure when self venting FIG.3 shows a plan view of a part of the base of the closure FIG.1 shows an external view on a closure 10. A base 20 is com prised as a circular upper fundament and depending downwardly from its periphery is a skirt 30. FIG.2 shows approximately half of the closure shell 10 in cross section. The base 20 may be seen here and depending downwardly from its periphery is the skirt 30. Located at the inner surface of this skirt 30 are screw threads 40. These screw threads 40 cooperate with corresponding con tainer screw threads 45 located on a radially outer surface of a container. Moreover, an olive type plug seal 50 is depending downwardly from the base 20 extending in a complete annulus as shown in FIG.3 and which seals with a radially projecting rib 51 against an inner side of a neck of a container. A top bulge 70 acts as a limitation for the container progress ing towards the base 20. The top bulge 70 is interrupted with at least one gap 75 constituting a passage for excessive gas P and the gap of the top bulge 70 is aligned with the deformation por tion as also shown in FIG.3. Concentrically to and as a next inner annulus to the skirt 30 is an outer seal 60 depending vertically from the base 20. The WO 2012/084514 PCT/EP2011/072039 7 outer seal 60 may also be slightly inclined radially inwardly or outwardly. The outer seal 60 is provided with at least one de formation portion 65 which is relatively thinner than a main fraction 61 of the outer seal 60. A rib 80 extends radially between a position of the base 20 and the inner surface of the plug seal 50. FIG.3 shows a plan view of a part of the base of the closure. FIG. 3 shows a base 20 which is substantially circular. Depend ing downwardly from the base 20 and extending as a complete an nulus from the centre of the base 20 is the plug seal 50, thereby providing a seal with an inside of a neck of a container as can be seen in FIG.1. The outer seal 60 is arranged concentrically to the skirt 30. At least one deformation portion 65 is shown as part of the outer seal 60 which is relatively thinner than the main fraction 61 of the outer seal 60. In a preferred embodiment, the thickness of those deformation portions 65 is between 0.3 to 0.4 mm. The radial angle between lateral sides of the deformation por tions 65 is between 34' to 40 and includes a constant circum ferential length between the deformation portions 65. The circumferential length of the deformation portion 65 is de termined by a radial angle of the circular base 20 including 60 to 150. Such closures comprise 8 or 9 deformation portions 65 and main fractions 61, respectively and their circular base 20 has a di ameter of 38mm.

WO 2012/084514 PCT/EP2011/072039 8 The closure with 8 deformation portions 65 and main fractions 61, respectively, comprises a thread 40 which is two-start. The closure with 9 deformation portions 65 and main fractions 61, respectively, comprises a thread 40 which is three-start. The top bulge 70 is located radially outwardly to the plug seal 50. The top bulge 70 is placed between the plug seal 50 and the outer seal 60. The top bulge 70 is thereby interrupted by at least one gap 75 defining a passage for excessive gas P during self-venting. The rib 80 extends radially between a position of the base 20 and the inner surface of the plug seal 50. It may been seen in FIG.2 that the end 81 of the rib 80 contacting the inner surface of the plug seal 50 is thinner compared with the opposite end 84. It may be seen that the rib 80 has a first part 83 and a second part, the second part terminating at an end 81 in contact with the plug seal 50 and the first part 83 extending radially inwards from the other end of the second part. In a preferred embodiment, the first part 81 of the rib 80 is substantially stiffer than the second part 82.

Claims

1. A closure for a container comprising a circular base (20), a skirt (30) extending from the periphery thereof, a plug seal (50) in the form of an annulus and at least one rib (80) ly ing on the surface of the base (20) in a substantially radial direction and in contact with the radially inner surface of the plug seal (50) at one end for transferring any movement of the base (20), relative to the skirt (30), to the plug seal (50) such that the plug seal (50) is pulled radially in ward to allow venting of excess pressure within the con tainer, characterized in that the closure is provided with an outer seal (60) having at least one deformation portion (65).

2. A closure according to claim 1 characterized in that a top bulge (70) is located at the underside of the base (20) con centrically to and between the plug seal (50) and the outer seal (60) and interrupted with at least one gap (75).

3. A closure according to one of the claim 1 to 3 characterized in that the gap (75) of the top bulge (70) is aligned with the deformation portion (65).

4. A closure according to one of the claims 1 to 3 characterized in that the outer seal (60) is inclined radially inwardly.

5. A closure according to one of the claims 1 to 4 characterized in that the outer seal (60) is inclined radially outwardly.

6. A closure according to one of the claims 1 to 5 characterized in that an end (81) of the rib (80) in contact with the ra dially inner surface of the plug seal (60) is thinner, in a WO 2012/084514 PCT/EP2011/072039 10 plane parallel to the base (20), than in an area of the rib (80) arranged spaced from the inner surface of the plug seal (50).

7. A closure according to one of the claims 1 to 6 characterized in that the rib (80) has a first part (83) and a second part (82), the second part (82) terminating at an end (81) in con tact with the plug seal (50) and the first part (83) extend ing radially inwards from the other end of the second part (82).

8. A closure according to claim 7, wherein the first part (81) of the rib (80) is substantially stiffer than the second part (82).

9. A closure according to one of the claims 1 to 8 characterized in that the rib (80) is aligned to a deformation portion (65).

10. A closure according to one of the claims 1 to 9 characterized in that the deformation portions (65) are distanced con stantly and the angle included between lateral sides of the deformations portions (65) is preferably between 340 to 50', more preferably between 340 to 450, most preferably 34' to 40 .

11. A closure according to one of the claims of the claims 1 to 10 characterized in that the thickness of the deformation portions (65) is preferably between 0.3 to 0.5 mm, more pref erably between 0.3 to 0.4 mm as compared to a thickness of 0.7 mm of the outer seal. WO 2012/084514 PCT/EP2011/072039 11

12. A closure according to one of the claims 1 to 11 character ized in that the circumferential length of the deformation portion (65) including preferably between 6' to 30 , more preferably between 60 to 20' , most preferably between 6' to 150 .