GB2280896A

GB2280896A - Container closure assembly

Info

Publication number: GB2280896A
Application number: GB9416243A
Authority: GB
Inventors: Roger Milner King
Original assignee: Beeson and Sons Ltd
Current assignee: Beeson and Sons Ltd
Priority date: 1993-08-13
Filing date: 1994-08-11
Publication date: 1995-02-15
Anticipated expiration: 2014-08-11
Also published as: GB9316938D0; GB9416243D0; GB2280896B

Abstract

A container and closure assembly comprises a container having a neck, and a closure to close said neck, a circumferential sealing rib 18 projecting from one of the neck or closure and forming a liquid and airtight seal with the other of the neck or closure when said neck is closed by said closure. Preferably, the sealing rib has a triangular cross-section, is non-deformable except at the tip, and projects to a height of 0.025 - 0.25 mm. Preferably first and second frustoconical sealing surfaces 16, 22 are provided on the neck and closure in addition to multi start screwthreads 11, 13 or snap-on fitments. The rib may be provided at the top of the sealing surface 16, providing a non-drip lip. The closure may also carry a plug portion 26 with a sealing rib 27. The container may contain a carbonated beverage and the closure may be heat shrunk onto the neck. <IMAGE>

Description

SEAL FOR CONTAINER CLOSURE ASSEMBLY This invention relates to a sealing arrangement for a container neck and closure assembly.

The invention provides a container and closure assembly, comprising: a container having a neck; a closure to close said neck; a first circumferential surface on said neck; a second circumferential surface on said closure, said second surface being located adjacent and opposite said first surface when said neck is closed by said closure; and a circumferential sealing rib projecting from said first or second surface and forming a seal with said second or first surface when said neck is closed by said closure.

Such an arrangement can provide a reliable pressuretight seal. The use of a sealing rib concentrates the sealing force between the first and second surfaces to achieve a high sealing pressure at the point where the tip of the sealing rib bears against the second surface.

The term "circumferential" implies that the sealing rib extends around substantially the whole circumference of the neck or closure, thereby forming a continuous seal when the closure is closed onto the neck.

Preferably the sealing rib has a generally triangular cross-section. This can provide good stability while providing a narrow tip to concentrate the sealing pressure.

Preferably, the sealing rib is substantially noncompressible so that it will not yield under high sealing pressure although it would adjust its profile at the outer tip of the triangle in order to form a more exact seal against or with the other surface. Preferably, the sealing rib is generally non-deformable except to the extent that at the tip of the sealing rib it will mould itself to the shape of the opposing face in order to create an air, gas and liquid-tight seal.

The sealing rib may in some cases project above the sealing surface by up to 1.00 mm. Preferably, the sealing rib has a projecting height of between about 0.025mm (about 1 thousandth of an inch) and 0.25mm (about 10 thousandths of an inch). More preferably, the height is between about 0.025mm and 0.127mm (about 5 thousandths of an inch). Most preferably, the height will be between about 0.07 (about 3 thousandths of an inch) and O.lmm (about 4 thousandths of an inch).

The first and second surfaces may comprise engageable sealing surfaces intended to form a secondary seal in combination with that produced by the sealing rib. In such a case, the sealing rib should be dimensioned such that it does not prevent the first and second sealing surfaces from contacting each other to form the secondary seal. For example, either the closure or the container neck (or both) may be made of plastics which is capable of deforming very slightly to accommodate direct contact between the first and second surfaces as well as the contact of the sealing rib against the second surface.

The closure and the neck of the invention may be made of any suitable material or materials. The closure may be made of a different material from the container neck. It is particulary envisaged that in one embodiment, one or both of the neck and closure are of plastics. It is also envisaged that in an alternative embodiment the neck is made of glass.

The sealing rib may be provided either on the neck or on the closure. For example, in the case of a glass container neck, it may be convenient to provide the sealing rib on the closure which, for example, is made of plastics.

In the case of the neck or closure being produced by moulding, the sealing rib can be defined by forming a very fine circumferential groove in the wall of the mould at a position corresponding to the desired location of the sealing rib.

Preferably, the first circumferential surface may be a top surface of the neck, with the sealing rib projecting from the top surface in a direction generally parallel to the longitudinal axis of the neck.

In other preferred embodiments, the first circumferential surface is an outside surface of the neck, and the sealing rib projects from the first surface in a direction substantially perpendicular to the longitudinal axis of the neck. More preferably, the sealing rib is located adjacent to the top of the neck, so that the sealing rib also functions as a drip-reducing lip for the neck when the closure has been removed and liquids are poured from the neck. Most preferably, the sealing rib has a substantially triangular cross-section such that one side of the triangular cross-section is substantially flush with a top surface of the neck and substantially perpendicular to the longitudinal axis of the neck.

Preferably the first and/or the second circumferential surfaces is or are frustoconical. This helps to ensure that sufficient radial force is applied between the surfaces when the closure is fitted to the bottle, thereby ensuring that a tight seal is formed between the sealing rib and the surface against which it is pressed. Preferably, the frustoconical surfaces are tapered at an angle of 20 to 100, more preferably 40 to 50, to the longitudinal axis of the container and closure assembly.

The closure may be applied to close the container neck by a variety of means, including snap-fitting and heatshrinking. Preferably, the neck and the closure are provided with complementary screw threads for securing the closure on the neck by screwing the closure down onto the neck. More preferably, the screw threads are multi-start threads such as two-start or four-start threads. Also preferably, the closure is screwed down into its sealing position on the neck by rotating through 3600 or less, more preferably 1800 or less, and most preferably about 900 or less.

Preferably, the container further comprises a first frustoconical sealing surface in addition to the first circumferential sealing surface (which may or may not be frustoconical), and the closure further comprises a second frustoconical sealing surface in addition to the second circumferential surface. The first and second frustoconical sealing surfaces are complementary so that they mate to form an interference fit seal when the closure is in its closed position on the container neck. this interference seal is in addition to the seal provided by the sealing rib and provides additional security against leakage or contamination of the contents of the container.

Preferably, each of the frustoconical sealing surfaces is tapered at an angle of between 20 and 100, more preferably 40 to 50, to the longitudinal axis of assembly.

It has been found that this relatively low angle of taper provides especially good pressure-tight seals.

Preferably, the assembly according to the present invention may also be supplemented by a plug portion of the closure which is intended to fit within the container neck opening and to seal against an inner surface of the neck.

More preferably, a sealing rib as hereinbefore described extends circumferentially around an outer surface of the plug portion for forming a seal against said inner surface of the neck.

Although not illustrated specifically herein, this invention may include any of the features described in our published International patent applications Nos.

PCT/GB91/00850 (published as WO-A-91/18799 and PCT/GB92/01255 (published as WO-A-93/01098), and in our United Kingdom patent applications 9223779.1 and 9226320.1.

The contents of these applications are included herein by reference.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a sectional view through a portion of a first embodiment of closure assembly, showing the closure displaced from the neck; Fig. 2 is an enlarged sectional view illustrating a detail of Fig. 1; Fig. 3 is a sectional view through a portion of a second embodiment of closure assembly, showing the closure displaced from the neck; Fig. 4 is an enlarged sectional view illustrating a detail of Fig. 3; and Fig. 5 is a sectional view through a third embodiment of a closure.

Fig. 1 illustrates a container closure assembly comprising a container neck 10 and a closure 12. For clarity, only the uppermost portions of the neck 10 and the closure 12 are shown. In this exemplary embodiment, the neck carries a screw thread 11 and the closure 12 carries a screw thread 13. The closure 12 and neck 10 also include resilient locking elements (not shown) to hold the closure positively in a closed position. The closure is securable by rotation through about 900 or less, and the detail of the screw threads and of the locking elements is as described in our published patent applications referred to above.

Immediately below the open end 14 of the neck 10 is formed a first frustoconical sealing surface 16 which tapers inwardly towards the open end 14 at an angle of about 4 or 5 degrees to the longitudinal axis of the closure. A fine sealing rib 18 projects axially upwardly from the rim at the open end 14 of the neck. (For clarity, the size of the rib 18 is exaggerated in Fig. 1). As best seen in Fig. 2, the rib 18 is integral with the rim and has a generally triangular cross-section, its uppermost point defining a sealing edge 20. The rib 18 extends circumferentially through 3600 on the rim. The size of the rib can depend on the application for which the container is intended as well as the sizes of the neck and of the closure, and the specific material or materials from which the closure and the neck are made.In this exemplary embodiment, the neck 10 and the closure 12 are both made of plastics, and the rib 18 has a projecting height of between about 0.07mm (about 3 thousandths of an inch) and about 0.1mum (about 4 thousandths of an inch).

The closure 12 is provided on its inner surface with a second frustoconical sealing surface 22 which is tapered to complement the shape of the first frustoconical sealing surface 16. The generally planar surface 24 extends radially inwardly from the second sealing surface 22 to form the uppermost interior wall of the closure 12.

In use, when the closure 12 is secured to the neck, a dual sealing effect is achieved. The threads hold the closure 12 against the neck 10 such that the sealing edge 20 of the rib 18 bears firmly against the surface 24 of the closure 12 to form an interference fit seal. Additionally, the first and second tapered surfaces 16 and 22 seat against each other to form a further interference fit seal. The assembly is arranged such that the rib 18 experiences a greater, more concentrated sealing force than the tapered sealing surfaces 16 and 22. The small area of the sealing edge 20 ensures that a large sealing pressure is achieved at the point where the sealing edge 20 bears against the closure.

As a modification of this embodiment, the frustoconical sealing surfaces 16 and 22 may be supplemented or replaced by a sealing plug 26 on the closure (shown phantom in Fig.

1) which fits inside the neck 10 to seal against an inner surface 28 of the neck. The plug 26 may be tapered to provide increased sealing pressure the further the plug is entered into the neck 10. The plug 26 may also have a sealing rib 27 which performs a sealing function in the same way as the rib 22.

Fig. 3 illustrates a second embodiment which is similar to the first. The same reference numerals are used where appropriate. The main difference in the second embodiment is that the circumferential sealing rib 18 projects from the first tapered surface 16 on the neck 10 rather than from the rim of the neck. As seen in Fig. 4, the rib 18 has a similar cross-sectional shape to the first embodiment, but it now projects outwardly substantially perpendicularly from the tapered surface 16. The sealing rib 18 is adjacent to the top of the container neck, and one side of the sealing rib is flush with the top surface of the container neck, thereby providing a drip-reducing lip around the top of the container.

In use, when the closure 12 is screwed on to the neck 10, the first and second surfaces 16 and 22 approach each other as in the first embodiment. However, before the second surface 22 engages directly against the first surface 16, the second surface 22 bears on the sealing edge 20 of the rib 18. In this exemplary embodiment, the neck and the closure 12 are made of plastics and are capable of deforming very slightly under strain. As the closure 12 is tightened further, the sealing edge 20 will begin to bite or bear very firmly against the second surface 22 to form a high sealing force. The neck 10 and closure 12 will be able to deform sufficiently to accommodate the very fine rib 18 and still be able to achieve direct contact with each other at least at the upper and lower end regions of the two tapered sealing surfaces 16 and 22 to form a secondary seal.

It will be appreciated that in other embodiments, it may not be necessary to achieve direct contact between the tapered sealing surfaces.

Figure 5 illustrates a further embodiment of a closure 12 which might be suitable for sealing the neck of, for example, a glass bottle (not shown). In this embodiment, the circumferential sealing rib 18 is provided on the underside of a top wall 30 of the closure 12. The rib 18 is located such that it will bear against the rim of the neck when the closure 12 is secured to the neck. The closure is preferably made of plastics to provide a natural resilience in order to achieve a tight but not damaging fit on the glass neck.

It will be appreciated that this invention can achieve a high contact pressure seal by concentrating the sealing force of a closure assembly through a fine-edge tip of a sealing rib which bears against another surface. The seal can be air-tight and liquid-tight, and sufficiently strong to withstand considerable pressures within a container (for example in the case of pressured drinks).

The sealing rib of this invention may generally be employed in any container closure assembly which includes two suitable surfaces which contact or almost contact each other when the closure is secured to the neck. Such surfaces may be curved or planar. The sealing ribs may vary in length and thickness to provide different deformation characteristics, and may be used in differing combinations.

It will be appreciated that the foregoing description is merely illustrative of embodiments of this invention, and that modification of detail may be made without departing from the scope and principles of the invention.

Claims

1. A container and closure assembly, comprising: a container having a neck; a closure to close said neck; a first circumferential surface on said neck; a second circumferential surface on said closure, said second surface being located adjacent and opposite said first surface when said neck is closed by said closure; and a circumferential sealing rib projecting from said first or second surface and forming a seal with said second or first surface when said neck is closed by said closure.

2. An assembly according to claim 1, wherein the sealing rib has a substantially triangular cross-section.

3. An assembly according to claim 1 or 2, wherein the sealing rib projects above said first or second surface to a height of between 0.025 mm to 0.25 mm.

4. An assembly according to claim 3, wherein said sealing rib projects above said first or second surface to a height of between 0.025 mm to 0.127 mm.

5. An assembly according to any preceding claim, wherein said first surface is a top surface of said neck, and said sealing rib projects from said top surface in a direction generally parallel to the longitudinal axis of the neck.

6. An assembly according to any of claims 1 to 4, wherein said first surface is an outside surface of said neck and said sealing rib projects from said surface in a direction substantially perpendicular to the longitudinal axis of the neck.

7. An assembly according to claim 6, wherein said sealing rib is located adjacent to the top of said neck, whereby said sealing rib also functions as a drip-reducing lip for said neck.

8. An assembly according to claim 7, wherein said sealing rib has a substantially triangular cross-section such that one side of the triangular cross-section is substantially flush with a top surface of the neck and substantially perpendicular to the longitudinal axis of the neck.

9. An assembly according to any preceding claim, wherein said first and/or second surfaces are frustoconical.

10. An assembly according to claim 9, wherein said frustoconical surface is tapered at an angle between 2 and 100 from the longitudinal axis of the neck.

11. An assembly according to any preceding claim, wherein said neck and said closure comprise complementary screw threads for securing said closure on said neck.

12. An assembly according to claim 11, wherein said complementary screw threads are multi-start threads.

13. An assembly according to any preceding claim, wherein said container further comprises a first frustoconical sealing surface in addition to said first circumferential surface, and said closure further comprises a second frustoconical sealing surface in addition to said second circumferential surface, whereby said first frustoconical sealing surface forms an interference fit seal against said second frustoconical sealing surface when said closure is in a closed position on said neck.

14. An assembly according to claim 13, wherein said frustoconical sealing surfaces are each tapered at an angle of from 20 to 100 to the longitudinal axes of said neck and closure.

15. An assembly according to any preceding claim, wherein the closure further comprises a plug portion dimensioned to fit within the container neck opening and to form a seal against an inner surface of the neck.

16. An assembly according to claim 15, wherein a sealing rib extends circumferentially around an outer surface of said plug portion for forming a seal against said inner surface of the neck.