IE47964B1 - Cap and cap/container combination - Google Patents

Abstract

In order to prevent "missiling" of the cap of a bottle or other screw-top container intended to contain a carbonaceous beverage, the screw-thread ridge 11 on the neck 13 of the container has one or more transverse notches 12 in its length so as to relieve the gas pressure as the cap is removed. The radial depth of the notches may conveniently be equal to the radial height of the screw-thread ridge in which it is formed. Notches in adjoining turns of the ridge may be circumferentially staggered. Additionally or alternatively the screw-thread ridge in the screw-cap for the container may be provided with similar notches in its length.

Description

This invention relates to caps for containers, more particularly bottles, having screw-threaded necks and to combinations of such caps and containers.

When a screw-capped bottle containing a carbon5 ated beverage is partly empty the liquid is more susceptible to shaking and disturbance, causing the carbon dioxide to come out of solution and create a substantial gas pressure in the bottle. It is wellknown that the pressure and quantity of trapped gas may be sufficient to blow the cap out of the hands as· the cap is unscrewed. The cap is thus potentially a missile capable of inflicting serious damage on property and person.

According to this invention there is provided a screw-cap moulded from a plastics material and.having a top and a depending skirt which is screw-threaded on its radially inner surface to form a helical screwthread ridge in which are formed a plurality of transverse venting notches spaced apart along the length of the ridge and said cap having above the screwthread an internal portion which is adapted to form a gas-tight seal with a container about the mouth of the container.

Thus excess pressure in the container can be relieved during removal of the cap, as gas escapes across the screw-thread by way of the notch or notches.

Where the ridge extends in more than one turn, notches in successive turns of the thread are preferably formed in axial alignment with each other so as to shorten the escape path.

The container with which the cap is associated in use may have its screw-thread ridge similarly formed 7 9 6 4 with a plurality of transverse venting notches spaced along its length, notches in successive turns of the thread on’ the container being substantially axially aligned with each other.

The notches may have a radial depth equal to or less than the radial height of the thread-forming ridge.

The distances measured along the ridge between adjacent notches may differ. For example the distances between adjacent notches may be greater at either end of the ridge than the other.

One embodiment of the invention is illustrated in tbe accompanying drawings and will now be described by way of example. In tbe drawings: Figures 1 and 2 are respectively a sectional elevation and underneath .plan of a cap according to the invention, and Figures 3 and 4 show in elevation and plan respectively the neck portion of a container which may be used in conjunction with the cap of Figures 1 and 2.

Figures 1 and 2 show a cap 15 according to the invention. The cap is moulded from a suitable plastics material and has an internal screw-thread ridge 16 which is formed with a series of transverse notches 17 spaced along its length. The radial depth of the notches is equal to the radial height of the ridge 16. An annular sealing fin 18 and rib 19 and an annular surface 20 are provided to form a pressure-tight seal with the uppermost portions of the screw-threaded neck portion of a container. Figures 3 and 4 show the neck portion 21 of such a container in the form of a bottle with an external helical ridge 22 constituting the screwthread. The portion 24 of the neck above the 7 9 6 4 thread has a closely controlled external diameter and forms a seal with the surface 20, fin 18 and rib 19 of the screw cap. During removal of the cap, the seal with portion 24 is broken whilst the screw5 threads on the cap and bottle are still well engaged, and any pressure in the bottle is then relieved by flow of gas past the sealing surfaces and thence through the notches 17 in the cap and round the profile of the complementary thread-cutting ridge of the bottle. The ridge 22 of the bottle is preferably formed with aligned transverse notches 23 as shown, to shorten the escape path of the gas, but may if desired be uninterrupted.

Claims (4)

1. A screw-cap moulded from a plastics material and having a top and a depending skirt which is screwthreaded on its radially inner surface to form a helical screw-thread ridge in which are formed a plurality of transverse venting notches spaced apart along the length of the ridge, and said cap having above the screw-thread an internal portion which is adapted to form a gas-tight seal with a container about the mouth of the container.

2. A screw-cap as claimed in claim 1 wherein each notch is constituted by an interruption in the ridge so that the notches have a radial depth substantially equal to the height of the ridge.

3. A screw-cap as claimed in claim 1, characterised in that the notches in successive turns of the ridge are aligned with each other.

4. In combination a container having an externally screw-threaded neck the screw-thread ridge of which is formed with a plurality of transverse venting notches spaced along its length, notches in successive turns of the thread being substantially axially aligned with each other, and a moulded plastics screw-cap engaged on the neck of the container, said screw-cap having a top and a depending skirt which is screw-threaded on its radially inner surface to form a helical screw-thread ridge in which are formed a plurality of transverse notches spaced apart along the length of the ridge, said cap having above the screw-thread an internal portion adapted no form a gas-tight seal with the container about the mouth of the container.