GB2275675A

GB2275675A - Ventable closure for pressurized containers

Info

Publication number: GB2275675A
Application number: GB9315709A
Authority: GB
Inventors: Stephen Graham Rutherford
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-06
Filing date: 1993-04-29
Publication date: 1994-09-07
Also published as: AU6147594A; WO1994020384A1; GB9315709D0

Abstract

A closure arrangement comprises a cap 1 with means for sealing the cap onto a container and an opening 9 in the wall of the cap normally sealed by a member 5 located within the cap and biased to seal the opening when the cap is fitted to a pressurized container, vent means eg. apertures 11 being associated with the member 5 to release pressure only when the member 5 is moved eg. by pressing boss 10 against the bias to unseal said opening 9. The member 5 is preferably pre-biased into the sealed condition and may comprise an oversized diaphragm of resilient material with its perimeter gripped by internal ribs 6. The opening may be shaped as a nearly circular slit (9A, Fig. 4) to provide hinged area (15, Fig. 5) which is depressed to release the pressure. Slit (9A, Fig. 4) may be formed from a line of weakness using a tear off tab (not shown). The arrangement is suitable for bottles containing carbonated drinks. The cap may be fitted by a screw thread to the container. A hinged cover (13, Fig. 1) may be provided to protect opening 9, or the opening 9 may be recessed (Fig. 7). The closure arrangement prevents the cap flying off the container by enabling pressure to be released before opening. <IMAGE>

Description

Improvements relating to Closure Arrangements This invention relates to closure arrangements and, more particularly, to closure arrangements incorporating locking caps for pressurised containers. The invention is applicable to containers, particularly bottles, intended to contain carbonated drinks.

It will be appreciated that such drinks generate a pressure which can be considerably higher than atmospheric pressure, which is thus exerted on the locking cap, thereby causing difficulty in initial opening of the cap.

To facilitate opening of screw-caps infirm people, children and others who do not have sufficient gripping strength, tend to use a gripping tool, such as a wrench, pliers, or the like. It has been found that use of such tools can result in distortion of the cap to such an extent that the mating screw threads of the cap and bottles are free from each other, whereby the pressure of the liquid causes the cap to fly-off the bottle. In some instances, users have sustained injury around the face, particularly the eyes, and this has become a cause for concern.

An object of the invention is to provide a closure arrangement which eliminates the possibility of the cap flying-off the bottle.

According to the invention, a closure arrangement for a container comprises a cap member having locking means arranged to engage cooperating locking means on the container, wherein the cap member defines an opening in its wall, a closure member is located within the cap member and adapted when the cap member is fitted to a container filled with fluid under pressure, to be biased into a normally closed condition to seal said opening, and vent means are associated with the closure member which are effective to release the fluid pressure only when the closure member is moved against its bias to unseal said opening.

Advantageously, the closure member may be fitted to the cap member in a manner such that it is normally pre-biased into its closed condition.

Preferably, said opening is defined in the end wall of the cap member and the closure member comprises a diaphragm of resilient material which is elastically deformed to seal across the opening of the cap member.

Conveniently, the vent means comprises one or more apertures in the wall of the closure member, providing a leakage path between the container and the opening only when the closure member is moved out of sealing engagement with said opening.

To avoid the possibility of unintentional opening, the cap member may conveniently be provided with a protective cover which can be fitted over the cap opening.

According to a feature of the invention, an area in the cap wall is defined by a shaped opening, the arrangement being such that sealing pressure is released via the shaped opening by applying pressure to said area.

In order that the invention may be readily understood, two embodiments and two modifications of screw-caps for bottles intended to contain carbonated drinks, will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the first embodiment, Figure 2 is a side view thereof, Figure 3 is a half-sectional view thereof, Figure 4 is a perspective view of the second embodiment, Figure 5 is a half-sectional view of Figure 4, and Figures 6 and 7 are half-sectional views of modified forms of the second embodiment.

Referring to Figures 1 to 3 of the drawings, in this embodiment, the screw-cap 1 is of circular form and comprises an end wall 2 and a skirt wall 3. The inner face of the skirt wall is formed with a screw-thread 4 intended to fit onto a mating thread (not shown) around the neck of the bottle. The inner face of the end wall 2 supports a closure member 5, in the form of a circular plastics disc, against which the free edge of the bottle is sealed in use when the mating threads are tightened.

The closure member 5 is made resilient and is oversized with respect to the inner diameter of the skirt so that when fitted within the skirt wall 3, as shown in Figure 3, its outer perimeter is gripped by internal ribs 6 provided on the inner face of the skirt wall and is thereby deformed to be convex. The member 5 thereby acts as a diaphragm with its central portion elastically biased into sealing engagement with an inwardly projecting circular lip 8 defining the mouth of a central opening 9 through the end wall 2. A boss 10 is provided on the central portion of the closure member 5 and projects into the opening 9.It will also be noted from Figure 3 that the closure member 5 is provided with at least an aperture or series of apertures 11 which, when the cap is fitted onto a bottle, provides a vent for the pressure of the liquid contained therein to a space 12 defined in the end wall between the lip 8 and the skirt wall 3.

A protective cover 13 is preferably hinged to the end wall of the cap to close over the boss 10 and hence prevent unintentional operation.

It will be appreciated that the screw cap, when fitted to a bottle containing a carbonated drink, the carbonated pressure will act on the closure member 5 to increase its sealing pressure. To open the bottle safely, the user must first press the boss 10 to release the seal between the lip 8 and the member 5, thereby releasing the pressure within the bottle via the vent aperture 11, space 12 and cap opening 9. This release of pressure reduces the frictional tension between the mating threads whereby the cap can be readily opened with a minimum gripping pressure and without any possibility of the cap flying-off the bottle neck.

Referring to Figures 4 and 5, in the second embodiment like parts have been given the same reference numerals. In this embodiment, it will be seen that the opening is in the form of a near circular slit 9A in the end wall 2 of the cap member 1, the portion 14 of the end wall between the ends of the slit being left to act as a hinge. In this embodiment, the plastics closure member 5 is dimensioned to fit snugly within the inner diameter of the skirt wall 3 and be retained in position against the inner face of the end wall behind a circular rib 6. Thus, the closure member 5 is not pre-biased into contact with the end wall; instead it relies upon the carbonation pressure, exerted upon it when fitted, to effect sealing of the opening 9A. In use, it will be appreciated that the bottle can be depressurised via the apertures 11 by applying pressure to the area 15 bounded by the slit opening 9A.

It will be appreciated that if the bottle is partly used and re-sealed by the cap member, a reduced carbonation pressure would be retained within the bottle which should be sufficient to re-seal the closure member 5 although the reduced pressure may be such that the problem this invention seeks to overcome is not present. However, to ensure that the closure member 5 will remain effective, even after repeated opening and re-sealing, the closure member 5 could be pre-biased, e.g. by oversizing said closure member as for the first embodiment described above.

Referring to Figure 6, in a modification of the second embodiment, the inner face of the end wall 2 of the screw-cap 5 may be curved as shown, and the closure member 5 dimensioned to provide a corresponding curve when seated behind the rib 6.

Referring to Figure 7, in a further modification, the outer face of the end wall 2, instead of being provided with a protective cap, may be formed as a concave surface 16 to reduce the possibility of accidental pressure being applied to the area 15.

It will be appreciated that, instead of presenting a preformed slit opening 9A, the end wall 2 of the cap can be formed with a tear-off tab defined by lines of weakness so that the tab must first be removed to produce the opening.

Claims

1. A closure arrangement for a container comprising a cap member having locking means arranged to engage cooperating locking means on the container, wherein the cap member defines an opening in its wall, a closure member is located within the cap member and adapted when the cap member is fitted to a container filled with fluid under pressure, to be biased into a normally closed condition to seal said opening, and vent means are associated with the closure member which are effective to release fluid pressure only when the closure member is moved against its bias to unseal said opening.

2. A closure arrangement according to Claim 1, wherein the closure member is fitted to the cap member in a manner such that it is normally pre-biased into its closed condition.

3. A closure arrangement according to Claim 2, wherein said opening is provided in the end wall of the cap and the closure member comprises a diaphragm of resilient material which is elastically deformed to seal across the opening of the cap member.

4. A closure arrangement according to any one of Claims 1 to 3, wherein the vent means comprises one or more apertures in the wall of the closure member, arranged to provide a leakage path between the container and the opening only when the closure member is moved out of sealing engagement with said opening.

5. A closure arrangement according to any one of Claims 1 to 4, wherein the cap member is provided with a protective cover fitted over the cap opening for preventing unintentional opening.

6. A closure arrangement according to any one of Claims 1 to 5, wherein an area in the cap wall is defined by a shaped opening, the arrangement being such that sealing pressure is released via the shaped opening by applying pressure to said area.

7. A closure arrangement according to any one of the preceeding Claims, wherein a tear-off tab is provided defined by lines of weakness, and wherein the tab must be first removed to produce said opening.

8. A closure arrangement constructed, arranged and adapted for use substantially as hereinbefore described with reference to, and as shown in Figures 1 to 3, or 4 and 5, or modified as shown in Figure 6, of the accompanying drawings.

Amendments to the claims have been filed as follows 1. A removable closure cap for a necked container of the kind comprising a cup-shaped cap member and a gasket adapted to seal between the neck opening and the end wall of said cap member, and in which the skirt wall of the cap member has an internal thread or thread parts for co-operating with a mating external thread or thread parts on the container neck, wherein said end wall defines a first opening, said gasket is adapted when the closure cap is fitted to a container filled with fluid under pressure to be urged into a normally closed condition to seal said first opening, said gasket defining a second opening which communicates with said first opening to release fluid pressure only when said gasket is moved from its closed condition, and release means are provided externally of said closure cap for applying pressure to said gasket for moving the latter away from its closed position to reduce the pressure in said container, whereby the closure cap can be safely removed from the container.

2. A closure cap according to Claim 1, wherein a lip encircles said first opening and projects inwardly from the end wall of said cap member to facilitate sealing engagement by said gasket.

3. A closure cap according to Claim 1, or 2, wherein said gasket is fitted to said cap member in a manner such that it is normally pre-biased into its closed condition.

4. A closure cap according to any one of Claims 1 to 3, wherein said gasket is of resilient material which is deformed into its closed condition to seal across said first opening of the cap member.

5. A closure cap according to any one of Claims 1 to 4, wherein said release means comprises an operating member in the end cap.

6. A closure cap according to Claim 5, wherein said operating member comprises a boss forming part of said gasket and projecting into said first opening.

7. A closure cap according to Claim 5-or 6, wherein said cap member is provided with a protective cover fitted over said operating member for preventing unintentional operation.

8. A closure cap according to Claim 5, 6, or 7, wherein said end wall is formed externally with a concave surface surrounding said first opening, to reduce the possibility of external pressure being applied to said release means.

9. A closure cap according to Claim 5, wherein said first opening is defined together with a tear-off tab by lines of weakness in said end cap, whereby the tab is torn off to produce said first opening.

10. A closure arrangement constructed, arranged and adapted for use substantially as hereinbefore described with reference to, and as shown in Figures 1 to 3, or 4 and 5, or modified as shown in Figure 6, of the accompanying drawings.