IE54458B1 - Improvements relating to closures for bottles and other containers - Google Patents

Description

This invention relates to closures for containers and has a particularly useful but not exclusive application in closures for bottles intended to contain liquid carbonated or still beverages.

According to this invention there is provided a closure for application to the neck of a container, which closure has a top and a depending skirt, an internal annular resilient sealing fin extending inwardly from the region of the junction between the top and the skirt, and two support ridges projecting from the underside of the top towards spaced axial locations on the sealing fin, and passage means operating, when the support ridges are in contact with the sealing fin, to cause the annular space between the two support ridges and the annular space between the radially outer support ridge and the sealing fin to be subjected to the same pressure as obtains within a container to which the closure is to be applied.

The sealing fin is preferably inclined inwardly and away from the top of the closure.

Preferably also the radially inner support ridge projects further from the top than the outer support ridge.

According to a preferred feature of the invention the closure is a one-piece moulded closure, the skirt having an internal screw-thread and, above the screw-thread, a shoulder portion adapted to form a seal with an external cylindrical surface of the neck of a container to which the closure is to be applied, and the sealing fin has its root in the upper portions of the shoulder so that the shoulder and the fin together envelop said cylindrical surface and the top of the neck of the container. 4 4 5« The lower surface of the sealing fin is prefer,sb1y formed with concentric annular ribs for engaging the sealing surfaces of the container neck, and the radially inwardly facing surface cf the shoulder may also be formed with sealing ribs.

The sealing ribs preferably have a saw-tooth configuration when viewed in cross-section, and have the advantage of providing a series of line contacts between the fin and the co-operating sealing surfaces of the container. The ribs may also assist in centring the closure on the neck during application of the closure.

According to a preferred feature of the invention, the top of the closure thickens progressively towards its centre.

The skirt of the closure will normally be screwthreaded to engage a corresponding screw-thread provided on the external surface of the neck of a container.

Closures in accordance with the present invention are preferably moulded from a plastics material such as polyethylene or polypropylene by injection moulding.

The closure may also include a pilfer-proof sealing ring of a known type extending downwardly from the base of the skirt and adapted to engage with corresponding retaining means on the neck of the container.

One embodiment of the present invention will now be described by way of example with reference to the accompanying drawing showing in cross-section a closure according to the invention.

Referring to the drawing the closure is moulded from a plastics material and comprises a top 10 and 4 1 5 Β a peripheral depending skirt il. The top 10 increases in thickness progressively towards the lengthwise axis of the closure. The external surface of the skirt is provided with a plurality of longitudinal flutes 13 to provide improved grip for applying and removing the closure.

The skirt of the closure has an internal screwthread ridge 14 which in the illustrated construction extends through just over one complete turn of the closure, and above the ridge is formed with an inwardly projecting shoulder 15 extending to the top 10. From the shoulder, at a location near the top a resilient annular sealing fin 16 extends inwardlj' and downwardly and terminates in an edge 17. In the construction shown the fin is slightly curved in crosssection, the convex face 18 of the fin being nearer the top. The underneath face of t.he fin and the adjoining surfaces of the shoulder are formed with a series of sealing ribs 19 of saw-tooth form. Two stiff concentric support ridges 20, 21 project from the underside of the top tovi&rds the sealing fin, the inner ridge 20 projecting to a greater extent than the outer ridge 21. The two ridges have each four short interruptions 22 in their length, spaced apart at intervals of 90° about the central axis of the closure. When the closure is applied to a bottle, the sealing fin 16 flexes as it comes into engagement with the rim about the mouth of the bottle, and screwing the closure on to the bcttle bring the support ridges , 21 into contact with the upper surface of the sealing fin to press the ribs on the fin into good sealing engagement with the rim. At the same time the ribs 19 on the shoulder 15 come into sealing engagement 4 4 5 8 with an external cylindrical surface adjoining the riin of the bottle. Since the inner support ridge ?0 projects to a greater extent below the top than the outer support ridge 21 the two ridges tend to maintain the sealing fin in an inclined attitude. When the bottle contains a carbonated beverage, the gas pressure within the bcttle is transmitted through the interruptions 22 in the lengths of the support ridges to the upper surface of the fin so as to assist in pressing the fin on to the rim of the bottle. The ribs on the shoulder and sealing fin form a series'of line-contact sealing zones with the neck of the container and by reason of the support given tc the sealing fin by the support ridges the fin can be made more flexible, which also assists in achieving a satisfactory seal while enabling the amount of material in the closure to be reduced, and reducing the torque necessary to tighten ' the closure.

Claims (7)

1. A closure for application to the neck of a container, which closure has a top and a depending skirt, an internal annular resilient sealing fin extending inwardly from the region of the junction 5 between the top and the skirt, and two support ridges projecting from the underside of the top towards spaced axial locations on the sealing fin, and passage means operating, when the support ridges are in contact with the sealing fin, to cause the annular space between 10 the two support ridges and the annular space between the radially outer support ridge and the sealing fin to be subjected to the same pressure as obtains within a container to which the closure is to be applied.

2. A closure as claimed in claim 1, wherein the 15 sealing fin is inclined inwardly and away from the top of the closure.

3. A closure as claimed in claim 2, wherein the radially inner support ridge projects further from the top than the outer support ridge. 20

4. A closure as claimed in any one of claims 1 to 3, wherein the closure is a one-piece moulded closure, the skirt having an internal screw-thread and, above the screw-thread, a shoulder portion adapted to form a seal with an external cylindrical surface of the neck of a 25 container to which the closure is to be applied, and the sealing fin has its root in the upper portions of the shoulder so that the shoulder and the fin together envelop said cylindrical surface and the top of the neck of the container. 30 5. A closure as claimed in claim 4 wherein the lower surface of the sealing fin is formed with concentric annular sealing ribs. 6. A closure as claimed in claim 4 or claim 5 wherein the radially inwardly facing surface of the shoulder is formed with annular sealing ribs. 7. A closure as claimed in claim 5 or claim 6,

5. Wherein the sealing ribs have a saw-tooth configuration when viewed in cross-section.

6. 8. A closure according to claim 1, for application to the neck of a container, substantially as hereinbefore described with particular reference to and

7. 10 as illustrated in the accompanying drawing.