AU742010B2 - A lid for a container - Google Patents

Description

P/00/0oII Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT a a. a a The following statement is a full description of this invention, including a a a.

a a. a a a a.

Invention Title: NATIONAL CAN COMPANY PTY LTD the best method of performing it known to me: CAkWNORD\IDELILAH\DCNODELE\DAVID\CANCAP.DOC -2- A LID FOR A CONTAINER This invention relates to a closure for an open-topped container wherein the container opening is relatively large and is defined by a rim structure having a radially inwardly positioned portion for engaging an edge structure on the closure.

In particular, the invention relates to edge structures of a closure for engagement with rim structures of a container. The invention also includes a closure assembled on a container. The invention will be described herein in relation to a closure in the form of a lid for a can for containing liquids, however it is to be understood that this is only one example application of the invention and that the closure may be used for other types of containers.

Paints and other industrial liquids are often sold by retailers in cans having a capacity of only a few litres, for example, 1, 2, 4, 10 and 20 litres are common sizes, and these containers have relatively large openings, for example the can opening may comprise substantially the whole of the top area of the can. The lids for such cans may include a depending annular flange, which is U-shaped in cross-section, for engagement in a complementary groove at the rim of the can.

Such a flange-groove interconnection for the lid of a paint can, for example, may provide a number of annular "friction seal" areas. A problem with such lid-type 20 closures, however, particularly for liquid containing cans, is that should the can topple over onto its side, the sudden force of the contents contacting the relatively Slarge inner surface area of the lid can cause the lid to come off and the contents to spill. This is a particular problem with retail size cans of liquid such as paint in that a sudden tipping over of the can causes a rush of the liquid onto the inner surface of the lid which can dislodge it from the can.

It is an object of the invention to provide a closure for an open-topped container which lessens the above described problem.

According to a first aspect of the invention there is provided a closure for an open-topped container wherein the container opening is relatively large and is defined by a rim structure, the closure including a circumferential edge structure for engaging the rim structure in a closed condition of the container, wherein the rim structure has a radially inwardly positioned portion for engaging the edge structure and the edge structure has a radially outwardly facing surface defining a seating region for seating engagement of said inwardly positioned portion with said -3edge structure when said closure closes said container for removably retaining the closure on the container, wherein the radially outwardly facing surface of the edge structure includes a plurality of radially outwardly directed formations around the closure, wherein an upper surface of the radially outwardly directed formations at least in part defines said seating region.

In this specification, the terminology "removably retaining" means that the closure is effectively prevented from inadvertent dislodgement from a container as can occur when the container tips over and the contents thereof suddenly contact the inner surface of the closure, whilst allowing legitimate removal of the closure from the container.

Preferably the closure is for use with an open topped container having an edge which is formed by a roll, curl or fold, wherein the seating region of the iradially outwardly facing surface of the edge structure receives the roll, curl or fold when said closure closes said container.

15 According to a second aspect of the invention there is provided a closure for an open-topped container wherein the container opening is relatively large and S. is defined by a rim structure having a U-shaped annular channel, the closure including a complementary depending structure for seating within the U-shaped °annular channel for closing the container, wherein a circumferential wall 20 constituting the radially inner leg of the U-shaped channel of the container is curled or rolled at its upper end and the closure includes a downwardly open Sannular channel for receiving said curled or rolled end, and wherein the downwardly open annular channel includes a plurality of radially outwardly *t *il directed formations around the circumference for co-operating with an undersurface of said curled or rolled end for removably retaining the closure in position on the container.

The invention also includes a closure in assembled relationship with a container.

DG W:\DELILAH\PRO\ALID doc -4- The central area or panel of the closure may be flat or stepped in known manner, preferably however it is concave as it has been found that this improves the retention of the closure on the container against inadvertent removal as may occur when a full container tips over.

Embodiments of the invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings.

In the drawings: Fig. 1 illustrates a cross-sectional portion of a prior art closure and portion of a container (the container being shown in dashed outline and portions only of the closure and container being shown).

Fig. 2 is a similar illustration to Fig. 1 showing a closure according to an embodiment of the second aspect of the invention.

Fig. 3 illustrates another embodiment for a closure and container according to the second aspect of the invention (portions only of the closure and container 15 being shown).

Fig. 4 illustrates a closure according to the second aspect of the invention o with a variation for the container (portions only of the closure and container being shown).

:o oi Figs. 5 to 7 are illustrations of example profiles for a closure according to 20 the second aspect of the invention, and Figs. 8 to 10 are illustrations of embodiments according to the first aspect of Sthe invention (portions only of the containers and closures being shown).

A container 1 (a portion of which is shown in dashed outline in Fig. 1) is S* typically a can made of a metal such as tin plate, and is for containing a liquid such as paint, although it is to be understood that the invention extends to containers formed of materials other than metal which may contain other OG3 W\DELILAH\PROV\LID.doc oPF\C substances. Can 1, which may typically have a capacity of 10 litres, has a relatively large opening that is defined by a rim structure 2 (also shown in dashed outline) having a U-shaped annular channel 3. The opening of the can is relatively large in the sense that it extends over substantially the whole of the cross-sectional area of the can. The rim structure 2 is known as a ring and is permanently attached to the top of can 1 by an interlocking seam arrangement 4.

A circumferential wall 5 constituting the radially inner leg of the U channel 3 is curled or rolled (hereinafter the term "curled" is to be understood as encompassing a rolled end or other like finish) at its upper end as shown by reference 6. The ring curl 6 shown in Fig. 1 is known as an "external" curl, however the can 1 could have an "internal" ring curl 6" as shown in Fig. 4.

A closure for the can 1 in the form of a lid 7 includes a depending annular structure 8 for engaging within the U-shaped channel 3 of the can and a downwardly open annular channel 9 for receiving the curled end 6. The outer oi 15 periphery 10 of the lid 7 is suitably finished with a roll, seam or the like, and typically a space is provided between seam 4 and finish 10 for insertion of a levering tool to assist in legitimately removing the lid 7 from can 1. Lid 7 is typically formed from metal, such as tin plate, using processing steps such as pressing, stamping, die forming or rolling. However the lid may be formed from materials other than metal such as, for example, a plastics material.

Depending structure 8 of lid 7 is dimensioned to seat within U channel 3 of can 1 to provide a friction or interference seal between the lid and the can. This seal is provided by resilient engagement between the walls constituting the legs of the channel 3 and the walls (legs) of structure 8. Generally, it is considered that a sealed area is provided at each of the walls (legs) that are in facing contact such that there are two annular seal areas. Channel 9 of lid 7 is also dimensioned to resiliently engage curl 9 such that a third annular area providing a friction seal may exist by virtue of engagement between the radially innermost wall 11 of the channel 9 and the curl 6.

According to an embodiment of the invention, and as shown in Fig. 2, the innermost wall 11 of channel 9 is provided with means in the form of a radially outwardly directed formation, which is preferably a bead 12 or like formation for DO C:\WlNWORDMDELILAHPROVLID.DOC co-operating with the curl 6 for removably retaining the lid 7 in position on the can 1. The terminology "removably retaining" means that the bead 12 prevents inadvertent dislodgment of the lid 7 as may occur if the can tips over whilst containing for example, a liquid such as paint, whilst allowing legitimate removal of the lid 7. The bead 12 extends for the full circumference of the lid and is interrupted, thus bead portions, also termed "beads" in the claims, are provided.

Bead 12 clips over and seats under the curl 6 to retain the lid 7 in position.

The curl 6 is inherently a strong part of the rim 2, that is, it is not easily permanently stretched and thus provides an appropriate structure for the additional lid retention feature of the invention. The rounded profile of the curl 6 also facilitates the clipping of the bead 12 thereover. A further advantage is that the bead 12 adds strength to the channel 9 formation on lid 7 and resists it being easily permanently compressed to a smaller diameter. With this inherent resistance to dimensional change in both parts and the correct amount of physical interference between the two diameters (see dimension x in Fig. the channel 9 and the curl 6 relatively resiliently move, or "spring" on assembly for the bead 12 to snap or clip into place under the curl 6.

A further advantage of the invention is that no alteration is required to be oooo° made to the ring 2, which is a standard structure.

S: 20 It has been found that the performance of the invention is significantly reduced if the angle between the radially innermost wall 11 of channel 9 and the °°°eo Scentre panel of the lid 7 adjacent the wall 11 is less than 900. Thus the process of adding a bead 12 to a lid 7 should not reduce this angle to less than 900. This S* result can be ensured by making the angle between wall 11 and the centre panel, prior to the beading process, sufficiently greater than 900 (for example 1000) such that after the beading process the angle remains at 900 or greater. Preferably the final angle is a few degrees greater than 900 as it is thought that this improves the performance of the invention.

Fig. 3 illustrates the invention as applied to a known "locking-U" structure for a lid 7' and a container 1' wherein the U channel 3' of the container 1' is enlarged at its end (shown exaggerated in Fig. 3) and the complementary depending structure 8' of the lid 7' for resiliently engaging therein is ID doC -7correspondingly enlarged. Otherwise the features for this embodiment are the same as the Fig. 2 embodiment.

Fig. 4 illustrates a variation for the ring 2" of a container In this variation the upper end of the radially inner wall 5" of the U-shaped annular channel 3" has an internal curl 6" (rather than an external curl 6 as shown in Figs. 1-3).

Otherwise the features for this embodiment are the same as the Fig. 2 embodiment.

According to the invention the central area of a lid 7 can have any desired profile. Thus it may be flat, or comprise two shallow panels such as shown at 14 and 15 in Fig. 5. Alternatively and preferably it may be concave as shown at 16 in Fig. 6. In fact it has been found that a concave profile in combination with the bead 12 significantly improves the performance of the invention. A further example is shown in Fig. 7 wherein a series of stepped panels 17, 18, 19, 20 is provided to give a pseudo-concave profile. In each of these example profiles, the 15 angle between the radially innermost wall 11 of channel 9 and a centre panel 14 (in Fig. or 16 (in Fig. 6) or 20 (in Fig. 7) after a bead 12 has been inserted, is not less than 900 000. Fig. 8 illustrates portion of a container 30 such as a metal can having a ring type rim structure 32 having an inwardly positioned portion 33. Portion 33 of ring 32 has an edge which is formed by an internal roll or curl 34. A closure 36 for the container 30, such as a metal lid, includes a circumferential edge structure 38 for engaging ring 32 for sealingly closing the container. The circumferential edge structure 38 includes a radially outwardly facing surface 39 which defines a seating region for the radially inwardly positioned portion 33. At least one radially outwardly directed formation in the form of a continuous bead 40 extends from surface 39 for engaging the inwardly positioned portion 33 of the rim structure 32 of the container 30. Bead 40 resiliently seats under the roll or curl 34 and thus removably retains (as defined hereinabove) closure 36 on the container 30. This embodiment includes container rim structures wherein the edge is formed by a fold (not shown) instead of a roll or curl 34. Also a roll, curl or fold with this embodiment may be external instead of internal as for roll or curl 34. As an alternative to the continuous bead 40, the closure may include a plurality of DG C;AWINWORDIDELILAHIPROVUJD.DOC -8circumferentially radially outwardly directed formations. These may be provided by a number of bead lengths.

Ring 32 defines an upwardly open channel around the container 30 and the circumferential edge structure 38 of closure 36 includes a radially outwardly directed section 42 which is finished with a curl 44. When closure 36 is assembled on container 30, section 42 extends at least part way over the upwardly open channel defined by ring 32.

It will be appreciated from Fig. 8 that the radially outwardly directed formation or bead 40 provides an upper surface which at least in part defines a seating region of the radially outwardly facing surface 39 for receiving the roll or curl 34. In effect, outwardly facing surface 39 provides a shaped profile which defines the seating region for inwardly positioned portion 33 of rim structure 32.

Fig. 9 illustrates a can 50 which has a rim structure formed by a roll or curl 52, that is, can 50 does not include a ring, instead its edge is provided by the roll 15 or curl 52. The curl or roll 52 is generally elliptical in section. A closure 54 for the can 50 has a circumferential edge structure 56 that includes a radially outwardly directed formation in the form of a continuous bead 58 for resiliently seating under the roll or curl 52 for removably retaining the closure 54 on the can 50. The circumferential edge structure 56 of closure 54 comprises an upwardly directed 20 section 60 having a curved upper section 62 that provides a free end 64 which is directed radially inwardly. When closure 54 is assembled on can 50, the upwardly directed section 60 resiliently engages the rim structure of the can, thereby sealing the closure on the can. Roll or curl 52 may be internal rather than external as shown and may be of any cross-sectional shape, the requirement being that it provide a shoulder for the bead 58 to seat under.

A lid 70 for a container 72 as shown in Fig. 10 is similar to the lid 54 of Fig.

9, except that its circumferential edge structure 74 defines a downwardly open Ushaped channel for resiliently receiving the curled or rolled free edge 76 of the rim structure of container 72. The curl or roll 76 of this embodiment is generally circular, rather than elliptical as in Fig. 9. A radially outwardly directed formation for seating under roll or curl 76 for removably retaining the lid 70 on can 72 is shown at 78. As with all the embodiments, this may be a continuous or DG CAW:\NWORDDELILAHMPROVLID.DOC -9discontinuous bead. Also the roll or curl 76 may be external rather than internal as shown and may have other than a circular cross section, so long as it provides a shoulder for the bead 78 to seat under.

A lid according to the invention should be fitted to a container progressively around the container to ensure optimum lid retention. That is, optimum lid retention may not be achieved if the lid is fitted to the container rim or ring in a single vertical movement.

The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the following claims.

5 agO o *o e o o•* DG C:\WINWORD\DELILAH\PROV\LIDDOC

Claims (9)

1. A closure for an open-topped container wherein the container opening is relatively large and is defined by a rim structure, the closure including a circumferential edge structure for engaging the rim structure in a closed condition of the container, wherein the rim structure has a radially inwardly positioned portion for engaging the edge structure and the edge structure has a radially outwardly facing surface defining a seating region for seating engagement of said inwardly positioned portion with said edge structure when said closure closes said container for removably retaining the closure on the container, wherein the radially outwardly facing surface of the edge structure includes a plurality of radially outwardly directed formations around the closure, wherein an upper surface of the radially outwardly directed formations at least in part defines said seating region.

2. A closure as claimed in claim 1 for an open topped container having a rim structure having an edge which is formed by a roll, curl or fold, wherein the seating region of the radially outwardly facing surface of the edge structure o S.receives the roll, curl or fold when said closure closes said container.

3. A closure as claimed in claim 2 wherein the radially outwardly directed formations seat under the roll, curl or fold when said closure closes said 20 container.

4. A closure as claimed in claim 3 wherein the radially outwardly directed formations are beads. An open topped container having a relatively large opening defined by a rim structure having a radially inwardly positioned portion, wherein the container is closed by a closure according to any one of claims 1 to 4.

6. A closure for an open-topped container wherein the container opening is relatively large and is defined by a rim structure having a U-shaped annular channel, the closure including a complementary depending structure for seating within the U-shaped annular channel for closing the container, wherein a circumferential wall constituting the radially inner leg of the U-shaped channel of the container is curled or rolled at its upper end and the closure includes a downwardly open annular channel for receiving said curled or rolled end, and Awherein the downwardly open annular channel includes a plurality of radially vardly directed formations around the circumference for co-operating with an .doc -11 undersurface of said curled or rolled end for removably retaining the closure in position on the container.

7. A closure as claimed in claim 6 wherein said plurality of radially outwardly directed formations are beads for seating under the curled or rolled end.

8. A closure as claimed in any one of the preceding claims wherein the central area of the closure is concave.

9. An open topped container having a relatively large opening defined by a rim structure having a U-shaped annular channel, wherein a circumferential wall constituting the radially inner leg of the U-shaped channel is curled or rolled at its upper end, wherein the container is closed by a closure according to any one of claims 6 to 9. A closure as claimed in claim 1 or claim 6 substantially as iil hereinbefore described with reference to any one of Figures 2 to

11. A closure as claimed in claim 1 or claim 6 in assembled relationship with a container substantially as hereinbefore described with reference to any one of Figures 2 to DATED: 31 October 2001 PHILLIPS ORMONDE FITZPATRICK 20 Attorneys for: NATIONAL CAN COMPANY PTY LTD S o /:\DELILAH\PROVLID doc