GB2410494A

GB2410494A - Pressure venting container closure

Info

Publication number: GB2410494A
Application number: GB0401917A
Authority: GB
Inventors: Francis Showering
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-30
Filing date: 2004-01-30
Publication date: 2005-08-03
Also published as: GB0401917D0; WO2005075301A3; WO2005075301A2

Abstract

A closure (10) is described for a mouth (12) of a container (14) for pressurised contents, such as a pressurised beverage. The closure (10) may include engagement means (18) for securing the closure (10) to the mouth (12). Venting means (42a, 36a) may be provided for venting internal pressure before the closure (10) is opened. The venting means (42a, 36a) may be operated before the engagement means (18) is released or relaxed. The venting means may comprise a removable portion (42a) of a pressure block (42) for applying a sealing pressure to a sealing surface (36) of the closure. The removable portion (42a) may be carried on a bracing band (30) for bracing the engagement means (18). The removable portion (42a) may be carried on a stowable grip (50) of the bracing band (30). The closure (10) may be a pull-off type closure or a screw-type closure.

Description

CONTAINER CLOSURE

Field of the Invention

This invention may relate to the field of container closures. The invention may relate especially to the field of container closures for pressurised products, such as pressurised beverages

Background to the Invention

An inherent problem with many types of container closures for pressurised contents is allowing adequate venting of internal pressure to enable the closure to be removed safely without risk of blowing off violently. Normally, it is necessary to at least partly open the closure to vent the Internal pressure.

For example, for screw-type closures, it is normally necessary to partly untighten the closure, in order to allow the internal pressure to vent around the screw threads or along vent passages in the screw threads. The screw threads have to be engineered so that the closure will not unscrew itself, or risk being blown off violently, once the closure is partly loose.

For pull-off closures, venting is more difficult. It is normally necessary to release or relax an engagement device holding the closure on to the container mouth. Releasing the engagement device may allow the closure to lift partly away from the container mouth, to provide a vent path for internal pressure.

However, with the engagement device released, the closure may be vulnerable to blowing off the container mouth if the internal pressure Is high.

It would be desirable to enhance the venting of internal pressures for container closures for pressurised container contents.

Summarv of the Invention Broadly speaking, one aspect of the present invention may be to provide a closure with a vent means that can be opened prior to releasing or relaxing an engagement means for holding the closure on a container mouth.

The closure may include a sealing member or sealing surface that, in use, engages a seal seat of the container mouth, to provide a pressure-tight seal.

The vent means may comprise means for releasing or relaxing a sealing force on the seal member, to allow the seal member to lift from the seal seat, at least over a portion of the seal contact area, to provide a vent path.

The vent means may be operable without releasing or relaxing a primary engagement between the closure and the container mouth that holds the closure in position on the container mouth.

The vent means may be configured to be operable as part of an opening sequence for releasing the closure. For example, the vent means may be configured to be operable by lifting, bending or deploying a gripping portion by which the closure can then be released. The gripping portion may be a pull tab. The gripping portion may be attached to a bracing means for bracing an engagement means of the closure.

The closure may be of any type. For example, the closure may be braced or non-braced The closure may be a pull-off type closure or a screw-type closure.

Brief Description of the Drawinas

Non-limiting preferred embodiments are now described, by way of example only, with reference to the accompanying claims and drawings, in which: Fig. 1 is a schematic perspective view of a first embodiment of closure on a container mouth; Fig. 2 is a schematic perspective view similar to Fig. 1, but showing a pull tab in a deployed position; Fig. 3 is a schematic sectional view through the closure in a moulded position similar to Fig. 2; Fig 4 is a sectional view along the line IV-IV of Fig. 1, Fig 5 is a sectional view along the line V-V of Fig. 1; Fig 6 Is a sectional view similar to Fig. 5, but showing the pull tab in a partly deployed position; Fig. 7 shows a detail of Fig. 6 on an enlarged scale; Fig. 8 is a schematic sectional view through a second embodiment of closure on a container mouth; Fig. 9 is a schematic sectional view through a third embodiment of closure on a container mouth; and Fig. 10 is a schematic sectional view through a portion of a fourth embodiment of closure on a container mouth.

Detailed Description of Preferred Embodiments

Referring to Figs. 1 to 7, a container closure 10 may be illustrated for a mouth 12 of a container 14. The container 14 may, for example, be of plastics or glass The container 14 may contain pressurised contents, such as a pressurised beverage. The container mouth 12 may be relatively wide, for example, at least 5cm, or at least 6cm.

The closure 10 may be of moulded plastics, for example, polypropylene The closure 10 may generally comprise an upper portion 16 from which depend engagement means 18. The engagement means 18 may comprise one or more snap fit projections 20 carried on a side wall 22 The side wall 22 (or a portion of the side wall) may be segmented as lugs. The snap fit projections may engage with an undercut 24 around the container mouth 12. Each projection 20 may have a lead-in ramp surface 26 and a more abrupt abutment surface 28. The closure may further comprise bracing means, for example a bracing band 30, for bracing the side wall lugs 22. The bracing band 30 may prevent the side wall lugs 22 from moving outwardly, and may thus secure the lugs in a "locked" condition.

The radially outer surface of each lug 22 may be moulded with an arrangement of generally parallel, axially extending ridges 32. The bracing lS band 30 may be Integrally formed with the closure 12, and may be hinged thereto by one or more integral hinge webs (not shown), which define a hinging movement of the bracing band 30 relative to the remainder of the closure 10. Prior to the first time that the closure 10 may be opened, the bracing band 30 may further be joined to the side wall lugs 22 by a plurality of frangible bridges (not shown). As described so far, the closure 10 may be similar to that described in WO-A-00/69741, to which the reader may be referred for more detailed constructional details.

As best seen in Fig. 4, a seal member 36 may be fitted within the closure 10 for providing a seal between the closure 10 and the container mouth 12. The seal member 36 may, for example, be a gas impermeable liner 34 (or at least a portion of the liner) for providing a barrier layer to prevent transpiration of gas through the plastics material of the closure 10 The liner 34 may be a separate member that is placed, secured or adhered within the closure 10.

Alternatively, the liner 34 may be a layer of material that is injected into the closure during manufacture of the closure or prior to fitting of the closure 10 on the container mouth 12. As a yet further alternative, the liner may be integrally moulded as a part of the closure 10, for example, as part of a multi- shot moulding process. The seal member 36 may comprise a peripheral portion of the liner 34. A seal may be formed in a region 38 around the container mouth 12. The seal may be a radial seal or side seal (although in the third embodiment described later, the seal may be an axial seal). The container mouth 12 may include a surface acting as a seal seat 40. In this embodiment, the seal seat 40 may be on an outer surface of the container mouth 12 (although in the second embodiment described later, the seal seat may be on an inner surface). The closure 10 may comprise a pressure applying portion 42 for pressing a portion of the seal member 36 against the seal seat 40 when the closure 10 is in its operative position on the container mouth 12 The pressure applying surface 42 may also be referred to as a pressure block 42. The pressure block 42 may have an inner radius that may be slightly smaller than the combination of the outer radius of the seal seat 40 and the normal thickness of the seal member 36. In use, the pressure block 42 may press and/or compress the seal member 36 against the seal seat 40 l5 to provide a gas tight seal between the closure 10 and the container mouth 12.

Referring to Figs. 1-7, vent means may be provided for allowing internal pressure within the container 14 to be vented before the engagement means 18 is relaxed and/or released. In this example, the internal pressure may be vented before the bracing band 30 may be moved out of its normal bracing position. The vent means may comprise a movable portion 42a, e.g., a removable portion, of the pressure block 42. When the movable portion 42a may be in its fitted (e.g. "blocking") position (as best seen in Fig. 5), the movable portion 42a may act as an integral part of the pressure block 42 to compress the sealing member 36 against the seal seat. The movable portion 42a may have a pressure applying surface that is generally flush with the remainder of the surface of the pressure block 42. When the movable portion 42a may be displaced out of its blocking position (e.g. removed, as best seen in Figs. 6 and 7), a portion 36a of the sealing member 36 may be unrestrained. The internal pressure may lift the unrestrained portion 36a of the sealing member 36 from the seal seat 40, allowing the internal pressure to vent from the container. For example, the internal pressure may escape between the segments of the closure side wall 22. As can be seen in figs. 4 7, the closure 10 and the sealing member 36 may be dimensioned such that a clearance 44 (e.g., an axial or vertical clearance) may exist between the sealing member 36 and the rim of the container mouth 12 in a region communicating with the seal. The clearance 44 may be relatively narrow, for example, 0 25 mm The clearance 44 may provide a path for enabling gas within the container 14 to reach the peripheral radial seal region, and thus enable the gas to vent when the removable blocking portion 42a is removed from its blocking position.

to The movable blocking portion 42a may be configured to be movable by being displaced or withdrawn in a direction that is different from the direction in which the seal may be made. The two directions may be generally perpendicular, or at least substantially different. For example, in the first embodiment, the seal may be a radial seal. The movable blocking portion 42a may be moved by being displaced or withdrawn in a generally axial direction. Such different directions may reduce any tendency for the internal pressure to eject or displace the movable blocking portion 42a. The internal pressure may act on the seal in a substantially radial direction, whereas the movable blocking portion 42a may only be withdrawn or displaced by a substantially axial force. In an alternative embodiment (e.g., the third embodiment described later) the seal may be a generally axial seal, and the movable blocking portion may be withdrawn in a generally radial direction.

The movable blocking portion 42a may be completely removable from a slot 46 in the upper portion 16 of the closure 10, leaving the slot 46 clear. The slot 46 may then provide an additional escape path for gas venting under the unrestrained portion 36a of the sealing member 36 Alternatively, the movable blocking portion 42a may not be completely removable, but just displaceable out of its "blocking" position.

The movable blocking portion 42a may be joined to the closure by a flexible, foldable or articulated link 48. The movable blocking portion 42a and/or the link 48 may be integrally formed with the closure 10 For example, the movable blocking portion 42a and/or the link 48 may be integrally moulded as an extension of the bracing band 30. In the first embodiment, the link 48 may form part of a pull tab, handle or grip 50 by which the user can manipulate the bracing band 30 to open the closure 10. The grip 50 may comprise the link 48 and an integral finger loop 52. The grip 50 may be movable between a S stowed position (shown in Figs. 1 and 5) and a deployed position (shown in Figs 2 and 3).

The grip 50 may initially be moulded in the deployed position. Prior to fitting the closure 10 to a container mouth 12, the grip may be folded into the stowed position such that the finger loop 52 lies against the upper portion 16 of the closure 10, and the movable blocking portion 42a projects through the slot 46 to its blocking position. The closure 10 may be pressed onto the container mouth 12 by a suitable machine with the grip 50 in the stowed position. When a person desires to open the closure 10 for the first time, the grip 50 may be lifted from its stowed position by moderate finger pressure. Lifting of the grip withdraws the movable blocking portion 42a from the slot 46, thereby venting internal pressure from the container 14. Once the internal pressure has vented, the grip 50 may be used to hinge the bracing band 30 upwardly to release the bracing effect on the side wall lugs 22. With the bracing effect 2() released, the closure 10 may be lifted off the container mouth 12, for example, using the loosened bracing band 30 as a handle.

It will be appreciated that this arrangement may allow substantially all of the internal pressure to be vented before the engagement means 18 of the closure 10 is released or relaxed. Therefore, when the engagement means 18 is released, there may be no danger of the closure 10 blowing off the container mouth 12 as a result of unexpected internal pressure.

The movable blocking portion 42a may be provided with a barb 54 or other 3() projection or enlargement. The barb 54 may be shaped to facilitate insertion of the movable blocking portion 42a into the slot 46, but to resist withdrawal of the movable blocking portion 42a from the slot 46. A person may have to apply a reasonable amount of finger pressure to the grip 50 in order to force the movable blocking portion 42a from the slot 46. As a result, the barb 54 may deform such that it no longer presents the same degree of resistance to withdrawal should the movable blocking portion 42a be re-inserted into the slot 46. This provides a tamper evident feature that is readily discernable before the closure 10 is opened. If the grip 50 is movable easily out of its stowed position, then this is an indication that the closure 10 has been vented at least once before. If the grip 50 is relatively stiff and requires reasonable finger pressure to be lifted from its stowed position, then this is an indication that the closure 10 has not been vented previously.

In addition to, or as a possible alternative to, the barb 54, the closure 10 may optionally have a stud 56 that forms a tight fit with a socket 58 on the link 48.

The stud 56 and/or the socket 58 may be shaped to allow the stud 56 to be received within the socket 58 when the grip 50 is initially folded into its stowed position, but to obstruct removal of the stud 56. In the same manner as that described for the barb 54, a person may have to apply a reasonable amount of finger pressure to disengage the stud 56 from the socket 58. The stud 56 and/or the socket 58 may deform to provide a tamper evident feature, in a similar manner to that described for the barb 54. The relative locations of the stud 56 and the socket 58 may be reversed, if desired.

As best seen in Figs. 6 and 7, even when the movable blocking portion 42a has been withdrawn from the slot 46, it may be impossible for a malicious person to introduce a contaminant into the container 14. The slot 46 may not communicate with the interior of the container 14, only with a region outside the unrestrained portion 36a of the sealing member. The unrestrained portion 36a of the sealing member may only lift from the seal seat 40 when the internal pressure exceeds the external pressure. Once the internal pressure has vented, the unrestrained portion 36a of the sealing member may re- contact the seal seat 40, and thus provide a barrier to contaminants entering 3() the container 14.

Figs. 8-10 may illustrate alternative embodiments of a container closure. The configuration of the alternative embodiments may be similar to the first embodiment, and the same reference numerals are used where appropriate.

Referring to the second embodiment shown in Fig. 8, one difference between the first and second embodiments may be that the second embodiment may be applied to a standard bottle neck 59. The configuration of the bottle neck 59 may the same as, or similar to, a conventional bottle neck for a conventional crimp-on bottle top. Therefore, the closure 10 may be fitted to a conventional container mouth 12. The lateral (e.g. radial) dimension of the closure 10 may be smaller than that of the first embodiment. The finger loop 52 of the grip 50 may be dimensioned to be generally or roughly the same size as the closure 10.

Another difference between the first and second embodiments may be that the second embodiment may use a bore-type seal 60. The blocking portion 42 may fit inside the bore of the container mouth 12 so as to form a radial seal against an inner seat seal 62 of the container mouth instead of the external seal seat 40 of the first embodiment.

The third embodiment shown in Fig. 9 may be similar to the second embodiment The main difference may be that the seal may be an axial seal 64 instead of a radial seal as in the earlier embodiments. The axial seal 64 may be formed between an upwardly facing rim surface (seal seat surface) 62 of the container mouth 12, and a generally planar seal member portion 36 of the liner 34. The pressure block 42 may be configured to apply axial downward pressure when the closure 10 is fitted to the container mouth 12.

The movable blocking portion 42a may be configured to be movable (e.g., removable) generally in a different direction from an axial direction. For example, the movable blocking portion may be movable substantially laterally (e g., radially). The movable blocking portion 42a may project from the link 48 of the grip 50, so as to be moved laterally when the grip 50 is manipulated in the same manner as described previously When the movable blocking portion 42a is moved away from engaging an adjacent portion of the seal 36, the unrestrained portion of the seal can lift from the seal seat surface 62 under any internal pressure, to vent the internal pressure.

The closure 10 of the fourth embodiment shown in Fig. 10 may be similar to the first embodiment, except that the movable blocking portion 42a may be configured to be movable generally downwardly instead of upwardly as in the S first embodiment. The movable blocking portion 42a may be received in a slot 46 in the sidewall 22 of the closure 10. The movable blocking portion 42a may be angled through the slot 46 to extend from the link 48 of the grip 50.

The movable blocking portion 42a may be moulded to have a naturally bent shape (as shown in Fig 10), or the movable blocking portion 42a may be at least partly bendable or flexible. When the grip 50 is manipulated as described previously, the movable blocking portion 42a may be retracted downwardly and out through the slot 46, allowing the unrestrained portion of the seal member 36 to lift from the seal seat surface and vent internal pressure The configuration shown in Fig. 10 may optionally be designed to make it difficult for somebody to re-insert the movable blocking portion 46 fully home into its bent position within the slot 46 while the closure 10 remains fitted.

This could optionally provide additional security against, and/or evidence of, tampering.

Although the invention has been illustrated in the form of a braced container closure as a preferred embodiment, it may be appreciated that the same principles may be applied to other types of closures, such as non-braced pull off closures and screw-type closures.

By way of example, a closure may deform under the influence of pressurized contents. The top wall of the closure may deform by bowing outwardly. The deformation may be particularly apparent in plastics closures, but is not limited to plastics closures. The deformation may also be particularly apparent for wide mouth closures, but is not limited to such closures. The deformation may make the closure extremely difficult to remove under normal circumstances. For example, a screw closure may be extremely difficult to unscrew when deformed under internal pressure The invention may enable the internal pressure to be vented, to relax the deformation and permit easier removal of the closure.

A significant feature of the invention may be the facility to vent internal pressure from the container before the main engagement of the closure is released or relaxed. A further and/or alternative significant feature of the invention may be the provision of a movable blocking portion (or other pressure applying portion) that may apply pressure to a seal, but that may be removed to relax at least a part of the seal.

It may further be appreciated that the foregoing description is merely illustrative of preferred forms of the invention, and that many modifications may be made within the scope and/or principles of the invention.

While features believed to be of significance may be indicated in the appended claims, the Applicant claims protection for any novel feature and/or idea described herein and/or illustrated in the drawings whether or not emphasis has been placed thereon.

Claims

Claims 1. A closure for a container for pressurised contents, the closure

comprising engagement means for releasably securing the closure to a mouth of the container, and vent means for allowing venting of internal pressure independently of the engagement means.

2 A closure according to claim 1, wherein the vent means is operable without relaxing and/or releasing the engagement means.

3. A closure according to claim 1 or 2, wherein the venting means is manually operable.

4. A closure according to claim 1, 2 or 3, wherein the closure comprises a sealing surface for forming a seal against a seal seat of the container, the vent means comprising means for relaxing a sealing pressure applied to the sealing surface.

5. A closure according to claim 4, wherein the sealing surface is provided 2() by a gas impermeable liner of the closure.

6. A closure according to claim 4 or 5, wherein the vent means comprises a movable portion of a pressure applying surface that, in use, applies pressure to the sealing surface.

7. A closure according to claim 6, wherein the movable portion comprises a removable segment of the closure.

8. A closure according to claim 6 or 7, wherein the movable portion is 3() movable In a direction substantially different from the direction in which, in use, sealing pressure is applied to the sealing surface.

9. A closure according to claim 8, wherein the movable portion is movable in a direction that is generally perpendicular to the direction in which, in use, said sealing pressure is applied.

10. A closure according to claim 9, wherein the movable portion is movable in one of a first direction generally parallel to an axis of the closure and a second generally radial direction, and wherein said sealing pressure is applied in the other of the first and second directions.

11. A closure according to any preceding claim, wherein the vent means is operable as part of a sequence for releasing the closure.

12. A closure according to claim 11, wherein the vent means comprises movable means attached to an opening member for opening the closure.

13. A closure according to any preceding claim, wherein the closure is a screw-type closure.

14. A closure according to any of claims 1 to 12, wherein the closure is a pull-off type closure.

15. A closure according to claim 14, further comprising a movable bracing band for encircling or surrounding the engagement means for bracing the engagement means In an engaged condition.

16. A closure according to claim 15, wherein the vent means comprises movable means integral with, or attached to, the bracing band.

17. A closure according to claim 16, wherein the movable means is part of a grip for enabling a person to grip the bracing band.

18. A closure according to claim 17, wherein the grip is movable between a stowed position in which the movable means obstructs venting of internal pressure, and a deployed position in which the movable means allows venting of Internal pressure 19 A closure according to claim 18, wherein the grip lies closely adjacent to the closure when in the stowed position.

20. A closure according to claim 16 or any claim dependent thereon, wherein the movable means is hingedly movable relative to the bracing band.

21. A container closure assembly, comprising: a mouth of a container for pressurised contents; a closure; engagement means for releasably securing the closure to the container mouth; and venting means for selectively venting internal pressure independently of the engagement means.

22. A container closure assembly, according to claim 21, wherein the venting means is operable without releasing and/or relaxing the engagement means.

23. An assembly according to claim 21 or 22, wherein the venting means is incorporated in the closure.

24. An assembly according to claim 21, 22 or 23, wherein the venting means is manually operable An assembly according to claim 21, 22, 23 or 24, wherein the venting means is operable as part of an opening sequence for opening the closure.

26 An assembly according to any of claims 21 to 25, wherein the closure is a pull-off closure and comprises a bracing band for bracing the closure to secure the engagement means 27. An assembly according to claim 26, wherein the venting means is operable without removing the bracing effect of the bracing band.

28. An assembly according to claim 26 or 27, wherein the venting means comprises movable means secured to, or integral with, the bracing band.

29. An assembly according to claim 28, wherein the movable means is carried on a grip for enabling a person to grip the bracing band.

30. An assembly according to claim 29, wherein the grip is movable between a stowed position in which the movable means of the venting means is so located to obstruct venting of internal pressure, and a deployed position in which the movable means of the venting means is so located to allow venting of internal pressure.

31. A container closure substantially as hereinbefore described with reference to any of the accompanying drawings.

32. A container closure assembly comprising a container mouth and a closure therefore, the assembly being substantially as hereinbefore described with reference to any of the accompanying drawings.