GB2041892A

GB2041892A - Containers & Closures

Info

Publication number: GB2041892A
Application number: GB7904636A
Authority: GB
Original assignee: United Glass Ltd
Current assignee: OI Glass Ltd
Priority date: 1979-02-09
Filing date: 1979-02-09
Publication date: 1980-09-17

Abstract

A bottle having an upstanding neck 2 provided with a first sloping cam surface 6 has a snap-fitting cap 10 having an internal cylindrical skirt 14 provided with a second sloping cam surface 18 matching the first sloping cam surface 6, whereby relative rotation between the cap 10 and the bottle causes the second cam surface 18 to ride up the first cam surface 6 a distance sufficient to cause the cap to snap free of the bottle, the bottle being provided, beneath the first sloping cam surface 6, with an annular inwardly-directed groove 8 and the internal surface of the external skirt of the cap having at least one inwardly-directed protuberance 20 engaged in the annular groove. <IMAGE>

Description

SPECIFICATION Containers and Closures This invention relates to containers and closures, and especially to a bottle-closure cap combination whereby the cap may readily and efficiently be applied to and removed from the bottle.

In any bottle/cap packaging combination it is necessary that the contents of the package should be securely retained in the bottle when the cap is applied thereto, but at the same time it is desirable that the application to the bottle and the removal therefrom of the cap should be a simple matter, and one which does not require the use of excessive force. Two ways of closing bottles with caps have become conventional, the first involving the use of a screw-threaded cap which screws onto and off a bottle provided with a cooperating screw-thread. The second involves the use of a closure which snaps onto the bottle, normally by way of an inwardly directed bead provided on the cap snapping over and thereafter seating beneath an outwardly directed bead provided on the bottle. Both of these types of closure can give rise to difficulties in the removal thereof from the bottle.Thus, the screw-threaded type often requires considerable pressure to achieve the initial untightening movement, especially if it has been screwed down very tightly. The snap-fitting type of cap often requires an awkward upwards pushing opetittt s ap it free from the bottle.

There have recently been proposed bottle/cap combinations wherein the cap is applied to the bottle by a simple snap-fitting arrangement, but can only be removed therefrom by twisting the cap. Such arrangements normally include complementary cam surfaces on the cap and the bottle, such that when the cap is twisted the cam surface on the cap rides up that on the bottle and the snap engagement is released. One such combination is disclosed in our U.K. Patent Specification 1,260,128, wherein the snap-fitting features comprise an annular bead on an internal cylindrical skirt of the cap which co-acts with an outwardly-directed annular bead formed on the neck of the bottle at the top thereof, i.e. above the cam surface on the bottle.

The combination described in our Specification 1,260,128 is very effective, but difficulties can arise both in manufacture and also in use. For example, the co-acting beads may interfere with each other to the detriment of both sealing and cap retention. Again, the placement of the locking feature on the bottle, i.e. at the top of the bottle neck, created difficulties in the forming mould.

It is an object of the invention to provide a bottle/cap combination of the "push-on-twist-off" type, which does not suffer from these difficulties.

According to the invention there is provided a bottle and a closure cap snap-fitted thereon, the bottle having an upstanding neck provided with a first sloping cam surface and the cap having an internal cylindrical skirt provided with a second sloping cam surface matching said first sloping cam surface, whereby relative rotation between the cap and the bottle causes the second cam surface to ride up the first cam surface a distance sufficient to cause the cap to snap free of the bottle, the snap-fit of the cap on the bottle comprising an annular groove on the neck of the bottle below said first sloping cam surface and a co-operating internal projection of the inside of the external skirt of the cap.

Preferably there are two such projections, situated on opposite sides of the skirt of the cap, and preferably also each extends between 5 and 1 5% of the internal periphery of the cap skirt.

If desired, the cap may be provided'with a further cylindrical skirt which is adapted, when the cap is applied to the bottle, to enter the neck of the bottle and act as an internal stopper.

There must be a certain amount of flexibility between the bottle and the cap, or at least the snap-fitting parts thereof, in order for them to be able to snap free from one another. This may be accomplished by making either the bottle or cap, or indeed both, in a flexible material, such as a plastics material, e.g. polyethylene. Indeed, since it is possible, with the design according to the present invention better to control the dimensions of the bore of the bottle, it is possible to use high density polyethylene and polypropylene for both the bottle and the cap. The use of these technologically better materials enables the production of better bottles and caps.

The bottle/cap combination of the invention will be assembled by placing the cap on the bottle such that the two cam surfaces are aligned with each other, and pressing the cap onto the bottle.

The bead or beads on the inside surface of the outer skirt of the cap will snap into the annular groove on the bottle neck to retain the cap in position on the bottle. If the cap is then rotated, the cam surface on the cap will ride up the cam surface on the bottle and after a certain amount of rotation the skirt portion of the cap will have moved an axial amount sufficient to snap the bead or beads thereon free from the groove on the bottle neck. Preferably the cam surfaces are designed such that this snapping free occurs after 900 of rotation.

The invention will now be described with reference to the accompanying drawing, which is a part section view of a closure cap seated on the neck portion of a bottie.

Referring to the drawing, a bottle, e.g. a glass or plastics bottle, has an upstanding neck portion 2. This comprises a cylindrical mouth portion 4 at the base of which is an annular cam surface 6 which is shaped such that it has two high points 6a and two low points 6b. Beneath the cam surface 6 is an annular inwardly-directed groove 8.

Seated in closuring position on the neck 2 is a closure cap 10 of flexible material such as polyethylene or polypropylene. The closure cap is substantially oval in plan, and has an outer skirt 12, a cylindrical inner skirt 14 and an internal spigot or stopper portion 16. The base 18 of the inner skirt 14 is shaped so as to match the cam surface 6 on the neck 2.

Formed on the internal surface of outer skirt 12 are two opposed beads or projections 20. These, when cap 10 is pushed onto neck 2, "snap" into the annular groove or channel 8 so as to hold the cap 10 firmly on the bottle. The alignment of the two surfaces 6 and 1 8 is facilitated by making both the bottle, or at least its upper portion, and the cap 10 oval in shape.

When the cap 10 is required to be removed from the bottle it may be accomplished by rotating the cap through 900. The cam surface 1 8 will ride up the cam surface 6 and this relative axial movement between the cap and the bottle will snap the beads 20 clear of the groove 8.

Claims

1. In combination, a bottle and a closure cap snap-fitted thereon, the bottle having an upstanding neck provided with a first sloping cam surface and the cap having an internal cylindrical skirt provided with a second sloping cam surface matching said first sloping cam surface, whereby relative rotation between the cap and the bottle causes the second cam surface to ride up the first cam surface a distance sufficient to cause the cap to snap free of the bottie, the bottle being provided, beneath said first sloping cam surface, with an annular inwardly-directed groove and the internal surface of the external skirt of the cap having at least one inwardly-directed protuberance engaged in said annular groove.

2. A combination as claimed in claim 1 wherein the cam surfaces are annular surfaces.

3. A combination as claimed in claim 1 or 2, wherein the cap is provided with a second cylindrical skirt which fits inside the neck in the manner of an internal stopper.

4. The combination of a bottle and a closure cap, substantially as hereinbefore described with reference to the accompanying drawing.