GB2267484A

GB2267484A - Container closure assembly

Info

Publication number: GB2267484A
Application number: GB9209420A
Authority: GB
Inventors: Roger Milner King
Original assignee: Beeson and Sons Ltd
Current assignee: Beeson and Sons Ltd
Priority date: 1992-04-30
Filing date: 1992-04-30
Publication date: 1993-12-08
Anticipated expiration: 2012-04-30
Also published as: GB9209420D0; GB2267484B

Abstract

A screw-threaded container neck (10) and closure (12), having respective sealing surfaces also have projections (28) on the closure and projections (22) on the neck which ride resiliently over each other as the closure becomes fully closed. The projections (22, 28) may be ramp-shaped, with a gently sloping lead-in portion (26, 32) and a steeper portion (24, 30), so that when the apexes of the ramps are coincident the closure will snap into a sealed position. The ramps may have a projecting ridge (25), and there may be a range of sealing positions. The closure may have an easily graspable part to facilitate its removal, and may be combined with a tamper-evident or child-proof element. The sealing may be effected by a chamfered end of the neck fitting into a correspondingly-shaped socket in the closure. <IMAGE>

Description

CONTAINER CLOSURE ASSEMBLY FIELD OF THE INVENTION This invention relates to a container closure assembly in the form of a container neck and a closure therefor. In particular it relates to a screw threaded closure assembly which provides a seal between the closure and the container neck when the closure is screwed into its fully closed position.

BACKGROUND OF THE INVENTION In order to avoid a person overtightening a closure on the container neck, it has been proposed to provide a radial stop projection on the neck, and a corresponding radial stop projection on the closure, which projections "click" past each other as the closure reaches its fully closed position.

This indicates to a person that no further tightening is required. To unscrew the closure out of its closed position, a person has to apply a predetermined release torque to "click" the projections back past each other. The projections therefore also serve to prevent the closure from becoming loose accidentally, even though the closure is not screwed down especially tightly.

A closure assembly having these features is described in our UK patent applications nos. 9120264.8 and 9122097.0.

With such a design, the manufacturing tolerances for the closure and the container neck are quite critical. The projections have to be positioned and dimensioned such that they "click" past one another at precisely the position of the closure on the container neck at which the seal is formed.

An aim of the present invention is to improve on this design. More generally, however, the invention has been devised for offering an improvement for general use on other types of container closure assemblies.

SUMMARY OF THE INVENTION In a first aspect, the invention provides a container closure assembly comprising a container neck, a closure therefor, screw thread means on at least one of the closure and the container neck for retaining the closure on the container neck, sealing means for forming a seal between the closure and the container neck when the closure is at a sealing position on the container neck, and urging means cooperating between the closure and the container neck when the closure is near the sealing position for urging the closure into the sealing position independently of whether an external closing torque is being applied to the closure, and thereafter for maintaining the closure in the sealing position until a sufficient external release torque is applied to the closure.

Such an arrangement can positively retain the closure in its sealing position, without having to be manufactured to the same precision as the prior art.

Preferably, the urging means maintains a force on the sealing means when the closure is in its sealing position.

This can ensure that the respective sealing surfaces of the sealing means are firmly seated against each other, even though the closure may not be screwed down especially tightly when in the sealing position. The arrangement can thus increase the force experienced by the sealing means, leading to an improved seal, without requiring the closure to be screwed down very tightly on the container neck.

Preferably, the urging means comprises first means on the container neck for co-operating with the second means on the closure, at least one of the first and second means including a ramp surface against which the other of the first and second means bears when the closure is near the sealing position, the ramp surface extending in a direction to urge the closure in a direction towards its sealing position.

Preferably, the first and second means each comprise a respective ramp surface extending in a direction to urge the closure towards its sealing position.

Preferably, the first means comprises one or more outwardly facing projections on the container neck, and the second means comprises one or more inwardly facing projections on the closure.

Preferably, the or each second means projection is mounted on a resilient portion of the closure which portion is capable of deforming to enable that projection to ride over the first means projection when the closure is screwed into, or out of, the sealing position.

Preferably, the projections include respective lead-in ramp surfaces which bear against each other, in use, to ease the projections over each other when the closure is being screwed towards its sealing position, before the aforementioned ramp surfaces which apply an urging force begin to bear against each other.

Preferably, the urging means is arranged to apply a rotational urging force to the closure relative to the container neck.

Preferably, the closure can be moved between its sealing position and a fully open position by relative rotation through 1800 or less, and more preferably through about 900 or less. The rotation may, for example, be about 45 500.

The invention is important in enabling the closure to be retained securely on the container neck during transportation, or if the container is accidentally dropped.

Additionally, the invention can serve to pull automatically the sealing surfaces of the closure and container neck against each other to achieve a reliable liquid-tight and/or air-tight seal.

The sealing surfaces may comprise a tapered rim on the container neck, and a matching tapered surface on the inside of the closure. In the preferred embodiment angle of taper is about 40 relative to the longitudinal axis of the container, but of course any taper angle might be used.

In the preferred embodiment, the resilience of the material of the closure is used to supply an urging force.

The closure deforms slightly from its circular shape to an oval shape when the first and second means projections engage, and the resilience of the closure tends to urge the closure to return to its circular shape.

In the preferred embodiment, the closure has a handle in the form of an upstanding diametric flange. This enables the closure to be gripped and turned easily, and is especially advantageous for disabled or elderly people.

The closure may include tamper evident means and/or child resistant means.

In one embodiment, the container neck and the closure may be manufactured to a certain tolerance such that the fully closed and sealing position of the closure on the container neck will be within a tolerance range of possible closed positions, as defined relative to the position of the urging means. The urging means is then preferably arranged such that the urging means will act on the closure at least whenever the closure is at a position within the tolerance range of possible closed positions, and more preferably when the closure is at a position which is near but outside the tolerance range of possible closed positions.

In a second aspect related particularly to this, the invention provides a container closure assembly comprising a container neck, a closure therefor, screw thread means on at least one of the closure and the container neck for retaining the closure on the container neck, sealing means for forming a seal between the closure and the container neck when the closure is at a sealing position on the container neck, which sealing position is within a predetermined tolerance range of possible sealing positions, and urging means cooperating between the closure and the container neck when the closure is at a position anywhere within the tolerance range of possible sealing positions, for urging the closure into its sealing position independently of whether an external closing torque is being applied to the closure, and thereafter for maintaining the closure in the sealing position until a sufficient external release torque is applied to the closure.

With this aspect of the invention, closure assemblies can be manufactured which achieve a reliable seal, and which avoid overtightening, without requiring each container neck and each closure to be manufactured to strict tolerances.

The container necks and the closures can therefore be made easily, and quite cheaply without prejudicing the reliability of each closure assembly. The invention can also compensate for any wear of the closure or of the container neck, if they are made of materials which will wear in use, e.g. soft plastics material.

DESCRIPTION OF THE DRAWINGS An embodiment of the invention is now described by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a side view of a closure and container neck with the closure being shown in section; Fig. 2 is a half underside view of the closure of Fig.

1; Fig. 3 is a half plan view of the container neck of Fig. 1; and Figs. 4-6 are diagrammatic illustrations of the urging means as the closure approaches its fully closed position.

DESCRIPTION OF A PREFERRED EMBODIMENT The drawings show a container closure assembly in the form of a container neck 10 and a container closure 12, both made of plastics material.

The neck 10 is of generally circular section, and includes a screw threaded portion 14 which has a four-start, square section thread. The closure 12 has a complementary threaded portion 16, such that the closure can be screwed into a fully closed sealing position on the neck by relative rotation through about 900 or less. The closure 12 has a handle in the form of an upstanding diametric flange 17.

The neck 10 and the closure 12 also include complementary sealing surfaces 18 and 20, respectively, for forming a liquid-tight and/or airtight seal between the closure and neck when the closure is in its fully closed, sealing position. The sealing surfaces 18 and 20 are tapered at an angle of about 40 relative to the longitudinal axis of the neck 10. In this embodiment, the engagement of the sealing surfaces 18 and 20 when the closure 12 is screwed on to the neck 10 defines the fully closed position of the closure.

The neck 10 also carries first means in the form of two radially opposite projections 22 which extend in the circumferential direction around portions of the neck 10.

Each projection 22 comprises a respective first radial ramp surface 24 forming one side of the projection 22 and a respective second radial ramp surface 26 forming the other side of the projection 22. The first ramp surface 24 has an inclination of about 300 relative to the radial direction of the neck (i.e. about 600 relative to the tangent of the neck surface), and the second ramp surface 26 has a much gentler inclination to serve as a lead-in ramp surface. Each projection 22 also includes a small ridge 25 between the ramp surfaces 24 and 26.

The closure 12 carries second means in the form of four equally angularly spaced projections 28. Each projection 28 comprises a respective first radial ramp surface 30 on one side of the projection, and a respective second radial ramp surface 32 on the opposite side of the projections. The first radial ramp surface 30 has an inclination of about 300 relative to the radial direction of the closure (i.e. about 600 relative to the tangent of the closure surface), and second ramp surface 32 has a gentler lead-in inclination of about 550 relative to the radial direction of the closure (i.e. about 350 relative to the tangent of the closure surface).

Referring especially to Figs. 4 to 6, the projections 22 and 28 are arranged to form urging means which co-operate as the closure 12 nears its fully closed, sealing position to urge the closure 12 into its sealing position independently of whether any external closing torque is being applied to the closure.

As the closure 12 initially approaches its sealing position, two of the four projections 28 of the closure 12 will approach the two opposite projections 22 of the neck 10. As the closure 12 is further moved rotationally the lead-in second ramp surface 32 of the closure 12 will bear against the lead-in second ramp surface 26 of the neck (see Fig. 4). Further rotation of the closure 12 causes the wall of the closure 12 to deform slightly into an oval shape to enable the projections 22 and 28 to ride over each other.

When the closure 12 reaches the position depicted in Fig. 5, the resilience of the wall of the closure 12 urges the projection 28 of the closure radially inwardly (as depicted by the arrow 34) so that the first ramp surface 30 of the closure 12 now bears against the first ramp surface 24 of the neck 10, thereby urging the closure 12 in a rotational direction (as depicted by the arrow 36).

The ridge 25 is provided to positively define the point at which the urging effect of the projections 22 and 28 takes over. The ridge 25 also causes a "click" effect which a person can feel through the closure when screwing the closure closed. The "click" effect indicates that the closure is now being urged into its sealing position, and need not be further tightened.

The projections 22 and 28 are arranged such that the fully closed, sealing position of the closure 12 (as defined by the sealing surfaces 18 and 20) will occur while the first ramp surfaces 30, 24 respectively, of the closure 12 and the neck 10 are in contact (as depicted in Fig. 6).

This ensures that the closure 12 is urged fully into its sealing position, even if little or no external closing force is applied to the closure at that instant.

When in the fully closed, sealing position, the first ramp surfaces 24 and 30 of the projections 22 and 28, respectively, co-operate to maintain the closure firmly in its sealing position to prevent the closure from becoming loose, even though the closure is not screwed down especially tightly. The closure 12 is retained in this position until a sufficient external opening or release torque is applied to the closure 12 to cause the projections 22 and 28 to ride back over each other, whereafter the closure 12 can be unscrewed from the neck 10.

It will be appreciated that in the fully closed, sealing position, the urging force applied by the projections 22 and 28 urges the sealing surfaces 18 and 20 against each other. Therefore, the arrangement ensures that the sealing surfaces are seated against each other sufficiently firmly to form a reliable seal, even though the closure is not screwed down especially tightly on the neck.

The above effects are especially advantageous in the present embodiment, where the closure is movable between a fully disengaged position and a fully sealing position by relative rotation through 90 or less. The embodiment provides a container which is easily openable and closable even for elderly people, but yet which achieves a firm and reliable seal when closed.

It will also be appreciated that the exact rotational position of the closure 12 when in the fully closed, sealing position is not critical, owing to the configuration of the first ramp surfaces 24 and 30 of the projections 22 and 28, respectively. Therefore, the closure 12 and the container neck 10 can be manufactured to a much less critical tolerance than if the projections had had radially flat surfaces instead of ramp surfaces.

The manufacturing tolerances of the closure 12 and the container neck 10 are such that the sealing position of the closure will lie within a predetermined tolerance range of possible sealing positions. The projections 22 and 28 are arranged such that they will co-operate to urge the closure 12 towards its sealing position whenever the closure is at a position anywhere within the predetermined tolerance range of possible sealing positions. In this exemplary embodiment, the projections 22 and 28 are arranged to cooperate to apply the urging force when the closure is at a position near, but just outside, the predetermined tolerance range of possible sealing positions.

Two second means projections 22 on the container neck 10 are adequate to retain the closure 12 in its sealing position. Four first means projections 28 are provided on the closure 12 since the closure 12 can be placed on the neck 10 in any one of the four start positions defined by the four-start thread. The second means projections 22 are chamfered axially to prevent the first means projections 28 from coming into contact with them until the closure nears its sealing, fully closed position.

It will be appreciated that the closure described above could also be supplemented by child-resistant means to make the closure child-proof, and/or by tamper-evident means to indicate whether the container has been opened since the closure was fitted during manufacture. Suitable childresistant and tamper evident mechanisms are, for example, described in our U.K. patent applications nos. 9120264.8, 9122097.0, 9124872.4, 9125397.1 and 9126242.8.

It will be appreciated that the invention has been described above purely by way of example, and that modifications of detail may be made without departing from the spirit and scope of the invention.

Claims

1. A container closure assembly comprising: a container neck; a closure for said container neck; screw thread means on at least one of said closure and said container neck for retaining said closure on said container neck; sealing means for forming a seal between said closure and said container neck when said closure is at a sealing position on said container neck; and urging means co-operating between said closure and said container neck when said closure is near said sealing position for urging said closure into said sealing position independently of whether an external closing torque is being applied to said closure, and thereafter for maintaining said closure in said sealing position until a sufficient external release force is applied to said closure.

2. The container closure assembly of Claim 1, wherein said urging means maintains a force on said sealing means when said closure is in said sealing position on said container neck.

3. The container closure assembly of Claim 1, wherein said urging means comprises first means on said container neck for co-operating with second means on said closure, at least one of said first and second means comprising a ramp surface against which the other of said first and second means bears when said closure is near said sealing position, said ramp surface extending in a direction to urge said closure in a direction towards said sealing position.

4. The container closure assembly of Claim 3, wherein said first means comprises a respective urging ramp surface, and said second means comprises a respective urging ramp surface, said ramp surfaces extending in a direction to urge said closure towards its sealing position.

5. The container closure assembly of Claim 3, wherein said first means comprises one or more outwardly facing projections on said container neck, and said second means comprises one or more inwardly facing projections on said closure.

6. The container closure assembly of Claim 5, wherein the or each said second means projection is mounted on a resilient portion of said closure, which resilient portion is capable of deforming to enable said second means projection to ride over said first means projection when said closure is screwed into, or out of, said sealing position.

7. The container closure assembly of Claim 4, wherein said first and second means each further comprise respective lead-in ramp surfaces which bear against each other, in use, to ease said projections over each other when the closure is being screwed towards said sealing position, before said urging ramp surfaces of said first and second means begin to bear against each other.

8. The container closure assembly of Claim 7, wherein at least one of said first and second means further comprises a projecting ridge formation between said respective leadin ramp surface and urging ramp surface.

9. The container closure assembly of Claim 1, wherein said urging means is arranged to apply a rotational urging force to said closure relative to said container neck.

10. The container closure assembly of Claim 1, wherein said closure can be moved between its sealing position and a fully open position by relative rotation through 1800 or less.

11. The container closure assembly of Claim 1, wherein said sealing position corresponds to a closed position of said closure on said container neck.

12. A container closure assembly comprising: a container neck; a closure for said container neck; screw thread means on at least one of said closure and said container neck for retaining said closure on said container neck; means for forming a seal between said closure and said container neck when said closure is at a sealing position on said container neck which sealing position is within a predetermined tolerance range of possible sealing positions;; urging means co-operating between said closure and said container neck when said closure is positioned anywhere within said tolerance range of possible sealing positions, for urging said closure into said sealing position independently of whether on external closing torque is being applied to said closure, and thereafter for maintaining said closure in said sealing position until a sufficient external release torque is applied to said closure.

13. The container closure assembly of Claim 12, wherein said urging means applies a closing force to said closure when said closure is at a position near but just outside said tolerance range of possible sealing positions.

14. The container closure assembly of Claim 12, wherein said sealing position corresponds to a closed position of said closure on said container neck.

15. A container closure assembly comprising: a container neck; a closure for said container neck; screw thread means on at least one of said closure and said container neck for retaining said closure on said container neck; first projection means on said neck for co-operating with second projection means on said closure as said closure approaches a closed or a sealing position on said container neck; and at least one of said projection means comprising a first ramp surface against which the other projection means bears to urge said closure towards said closed or sealing position.

16. A container closure assembly according to Claim 15, wherein said at least one of the projection means includes a relatively gentle lead-in ramp surface forming the opposite side of said projection means to said first ramp surface.

17. A container closure assembly according to Claim 16, wherein said at least one of the projection means includes a projecting ridge formation between said ramp surfaces.