AU669165B2 - Sealing system - Google Patents

Description

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C 6 9 1 S F Ref: 239272

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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.t 1 r Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: ASSOCIATED PROVISIONAL [31] Application No(s) PL2264 Plaspak Pty Ltd 22 Yalgar Road Kirrawee New South Wales 2232

AUSTRALIA

Malcolm Eoin Kinmont and Liam Stephem Irwin Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Sealing System APPLICATION DETAILS [33] Country

AU

[32] Application Date 5 May 1992 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815/3 Eb -1- The present invention relates to a one-piece plastics closure for a container and, in particular, to a one-piece plastics closure for a container having an integrally moulded sealing member.

Many proposals have been made for one-piece plastics screwed closures for glass bottles or glass jars, however, these prior art closures have been prone to loss of seal over extended periods of time because of deterioration or relaxation of the plastics material from which they are made. The prior art closures include the use of a resilient flange in the form of an annular ring which engages and seals the upper portion of the bottle or jar neck.

Many of the prior art closure arrangements have been found to be unsatisfactory. The sealing ring which is a compressive element if placed under excessive deformation over a period of time, has a loosening effect on the closure system. Another problem with existing systems is that many of the systems use intricate flanges and the tooling to manufacture the closures often are damaged and therefore need to be repaired. This obviously adds to the cost of production.

It is an object of the present invention to provide a sealing system for incorporation in a screw cap which substantially overcomes or ameliorates the above mentioned disadvantages.

According to one aspect of the present invention there is disclosed a sealing system to be used in a closure for a container, said system comprising a flexible annular 'sealing ring extending from the interior of said closure to make compressive contact i with the lip of the mouth of said container upon fixing of the closure to said container, said flexible annular sealing ring being outwardly radially curved and having a 2 secondary element extending from said interior of said closure to an upper surface of 25 said sealing ring and a circumferential protrusion means located on a lower surface of said sealing ring, together to prevent collapse of the sealing ring when under compression.

One embodiment of the present invention will now be described with reference to the drawing in which: Fig. 1 is a partial schematic cross sectional view of the sealing system of the preferred embodiment. i The sealing system 1 is to be used in a closure 2 (partially illustrated) for a container (not illustrated) such as a bottle or jar where an uneven surface on the mouth of the container opening may occur. The sealing system 1 includes an annular ring 3 which extends inwardly from the interior surface of the lid of the closure 2 (or screw cap). The annular ring 3 makes contact with the lip of the mouth or upper portion of the bottle or jar to thereby seal it.

i- -2- The annular ring 3 includes a curved flange 4. The following dimensions are relative to the dimension 1.0 (unity) of the height of the annular ring 3 which also has the dimension of 1.37 in radial extent.

The annular ring 3 is shown as tapering in thickness with increasing radius towards its free end 8. The curved flange 4 is supported by a secondary element 5 which has a 0.9 radial extent adjacent the lid of the closure 2. The secondary element 5 provides strength to the annular ring 3 to prevent its collapse when under compression. The secondary element therefore allows an unsupported compressive tip 9 to protrude therefrom, the unsupported compressive tip 9 being the extremity of the flange 4 and having a height of 0.15. The extending portion of the protruding unsupported compressive tip 9 is 0.6 in radial dimension and 0.45 in the height dimension from the secondary element The annular ring 3 also includes an annular thickened portion or rib 6 which extends around the annular ring 3. The rib 6 protrudes from the lower prolongation 14 of the curved flange 4 and provides a substantially non-compressive portion 16. The rib 6 has the radial dimension 0.4 and is spaced from the free end 8 by the radial extent 0.6. When the ring 3 is in its rest position, the rib 6 extends towards the container less than the height dimension 1.0 by a length 0.12.

The preferred angle between the side portion 15 of the rib 6 and the vertical is 27 and the curved portions between the closure 2 and the secondary portion 5 and side portion 15 of the rib 6 preferably have a radius of R 0.25.

In use, the sealing system 1 is used by placing the closure 2 on a jar or bottle mouth. The lip of the mouth engages the unsupported compressive tip 9 and the non-compressive portion 16. The unsupported compressive tip 9 is compressed, as the closure 2 is screwed on, until the non-compressive portion of the rib 6 abuts firmly against the lip of 30 the mouth of the jar or bottle. The degree of flexibility available in the annular ring 3 can be varied in relation to lack of flatness of the top of the jar or bottle finish.

The flexibility can be varied by changing the radial location of the rib 6 to that of the preferred dimensions as described above.

Preferably, the rib 6 is positioned with the radial extent in the range from 10% to 85% of the radial extent of the flange 4. The size the secondary element 5 can also be varied which changes the relative magnitude of the radial extent and thickness of the curved flange 4.

HRF/0688c -3- The height of the annular ring 3 can also be varied from 2% to 12% of the nominal pitch of the thread of the closure 2.

The foregoing describes only one embodiment of the present Invention, and modifications obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.

For example, in the embodiment illustrated in the drawing, the annular ring 3 extends from the top of the closure 2. However,the annular ring 3 can extend from the side of the closure in which case the ring 3 joins the side wall of the closure but the secondary element still extends from the lid or upper surface of the closure.

HRF/0688c ft ft t

Claims (9)

1. A sealing system to be used in a closure for a container, said system comprising a flexible annular sealing ring extending from the interior of said closure to make compressive contact with the lip of the mouth of said container upon fixing of the closure to said container, said flexible annular sealing ring being outwardly radially curved and having a secondary element extending from said interior of said closure to an upper surface of said sealing ring and a circumferential protrusion means located on a lower surface of said sealing ring, together to prevent collapse of the sealing ring when under compression.

2. The sealing system as claimed in claim 1 wherein the circumferential protrusion means comprises an annular thickened portion of said annular sealing ring.

3. The sealing system as claimed in claim 1 or claim 2, wherein said sealing ring includes an unsupported compressive tip at its extremity, said compressive tip being able to be compressed towards said closure.

4. The sealing system as claimed in either one of claims 2 or 3, wherein said annular thickened portion is positioned in the range from 10% to 85 of the radial extent of the sealing ring.

5. The sealing system as claimed in claim 4, wherein the radial extent of said annular thickened portion is in the ratio 0.9:1.37 of the radial extent of said sealing al 20 ring.

6. The sealing system as claimed in any one of claims 3-5, wherein the radial extent of said secondary element is in the ratio of approximately 0.9:1.37 of the radial extent of said sealing ring.

7. The sealing system as claimed in any one of the preceding claims, wherein the height of the sealing ring is in the range from 2% to 12% of the nominal pitch of a thread of the closure.

8. The sealing system as claimed in any one of the preceding claims, wherein said sealing ring extends from the top interior surface of said closure.

9. A sealing system to be used in a closure for a container, said systei' 30 being substantially as described with reference to the accompanying drawing. DATED this Twentieth Day of March 1996 Plaspak Pty Ltd Patent Attorneys for the Applicant SPRUSON FERGUSON [N:\1ibk100385:BFD ABSTRACT A sealing system to be used in a closure for a container such as a bottle or jar, is disclosed. The sealing system is to be used where an uneven surface on the mouth of the container opening may occur. The sealing system includes a flexible annular sealing ring (3) extending from the interior of the closure to make contact with the lip of the mouth of the container. The sealing ring has an outwardly radially curved flange a secondary support element and base element The curved flange is prevented from collapsing when under compression by the base element Fig. 1. i HRW/ 125c ii