AU643008B2 - Container lid - Google Patents

Description

64309 COMMONWEALTH OF AUSTRA A PATENTS ACT 1952 COMPLETE SPECIFICATION (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name of Applicant: NCI PLASTICS (VIC.) PTY. LTD.

Address of Applicant: 19 Separation Street, Northcote Victoria, AUSTRALIA *s 20 Actual Inventor(s):

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Address for Service: DAVIES COLLISON, Patent Attorneys, see 1 Little Collins Street, Melbourne, 3000.

25 Complete Specification for the invention entitled: CONTAINER LID The following statement is a full description of this invention, including the best method of performing it known to us: -1- 91G429,dbwspc.029,cntai.cap,1 -2- CONTAINER LID The present invention relates to a container lid, and relates more particularly but not exclusively to a plastic container lid suitable for sealing a container in which hazardous substances are stored or proposed to be stored.

It is known to provide such a container lid for sealing container,-. However, where a container contains hazardous substances, such as chlorine, there are rigid standards which may need to be adhered to under national or international codes or regulations. One such recognised standard in Australia is that a container lid should be able to withstand force, stresses, and impacts that might occur during normal use. This standard may require tests involving two methods to be described below. A container lid may be required to successfully pass both tests to be approved for use.

The first test involves the ability to resist deformation of the lid to the extent that the seal between it and the associated container is not broken when positioned at the bottom of a stack of containers. Briefly, this test requires that the lid when attached to the container be able to withstand breaking of the seal between it and the associated container when subjected to a load exerted on it by the stacking of further sealed containers which are filled with a hazardous substance, or like substitute of equal or similar weight, on top of each other, and which might occur during transportation and/or storage. In particular, the required standard may require the lid to be able to withstand a load exerted on the lid by the stacking of at least seven other full containers on the top thereof.

The second test involves the ability of the lid to remain in sealing connection with the container when subjected to impacts with other objects. The most significant impact might occur when the container is dropped or otherwise falls downwardly whereby the edge or rim of the lid impacts with an underlying surface such as to break its seal with the container and separate therefrom, causing S 9308lI,p:\aopcibw,76162.91,2 -9-s -3the contents of the container to spill. Briefly, in this test a container filled with a hazardous substance, or like substitute, is sealed with the lid. The container is then inverted so that the edge of the lid points downwards and the container is then dropped over a predetermined distance onto an underlying surface, whereby to land on the edge or rim of the lid. The lid must be able to withstand the impact caused by the fall and as a result not separate from the container or be damaged in any way which may cause leakage of the contents of the container.

Presently used container lids have been known to fail these tests. A major reason for such failure is that the edge or rim formation of the known lids do not container satisfactory force, stress and impact distributing rib configurations. The rib configurations currently known extend separately, inwardly and radially from the periphery of, and usually on the underside, of the edge of the container lid and at least partially toward the centre of the lid.

It is therefore an object of the present invention to provide a container lid which at least attempts to overcome the current problems associated with known container lids.

20 The present invention provides a container lid comprising a rim including means for engaging and sealing, in use, an open end of a container, and pairs of diverging ribs which extend inwardly from said rim.

As a consequence of having such inwardly diverging ribs any forces, loads and/or impacts applied to a point on or near, the edge or rim of the lid are Idistributed and therefore shared by at least one pair of such diverging ribs to be transferred to separate parts of the body of the lid ather than concentrated at one point, as is the case with separate radially inwardly extending ribs.

Preferably the angular spacing between the ribs of said pairs is between 300 to 1 930811,p:opeeVbw,76162.91,3 -4- Preferably said spacing is between 400 to Preferably a rib of one of said pairs intersects a rib of at least one adjacent pair.

As a consequence of such intersections, any forces, stresses an/or impacts applied on, or adjacent, the rim of the lid will be distributed between a greater number of ribs, thus allowing the lid to absorb the forces, stresses and/or impacts more efficiently.

Preferably said ribs extend at least to an inner wall. Preferably said inner wall is curved towards the centre of said lid. Preferably said inner wall is disposed g* partially inwards from said rim.

15 Preferably the ribs of each pair meet at said rim. Preferably said ribs are disposed on the underside of said lid.

0 Preferably said lid includes an annular groove above said ribs for receiving 0 a bottom flange of another one of said container when the containers are stacked 20 on one another.

0g*0 Preferably said rim includes an outer skirt having holes disposed therein ;which enable a lower edge of said skirt to be cut to facilitate breaking of a seal between said sealing means and said open end.

Preferably said lid has a substantially circular shape and said pairs of ribs are circumferentially spaced around said rim.

Preferably said lid is formed of plastics material.

One preferred embodiment will now be described, by way of example only, 910429,dbwsp.029,containap,4 00 0 00 00 04 *0 0 00000 0S 09 *0 000 00 S 00.00 0 0 50000 000000 00 0

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00 0 OS*0 00 0 005 0 000000 0 0.00 00 00 ~t0*00 0 0 0000 *0 0**0 S 5000 0 0000 0000 00 00 0 00 0 1, 0 0 .0005 00 00 0 00 0 0 0 0 00 with reference to the accompanying drawings, in which: Figure 1 represents a side view of the container lid of the preferred embodiment; Figure 2 is a plan view of the top of the container lid of Figure 1; Figure 3 is a view of the underside of the container lid of Figure 1; Figure 4 is a cross-sectional view along line 4-4 of Figure 2; and Figure 5 represents a side elevational view, partly sectioned, of two stacked containers.

10 Referring to the drawings there is shown a lid generally indicated as 1 and having a rim formed by an outer downwardly extending circumferential skirt 2, with an inner circumferential bead 3 which engages under a radially outwardly directed peripheral flange 4 on the upper edge of an associated container 10 (see Figure 5) together with an inner circumferential skirt 5 whereby the upper edge of 15 the associated container is received between the outer and inner skirts 2 and The lid further comprises an annular portion 6 extending inwardly from the inner skirt 5 and terminating at an upstanding ridge 7 from which a downwardly and inwardly curved portion or wall 8 extends to merge with a further annular portion 9 extending inwardly to terminate around a central substantially frusto-conical 20 portion 9a. With reference to Figure 3 there is fuirther shown windows 11 which are formed through the outei- skirt 2 immediately above its lower edge and the purpose of which is to enable a knife or other such cutting instrument to be inserted through the window so as to cut through the lower edge of the skirt 2.

This allows individual circumferential sections of the skirt between the windows to 25 be pulled outwardly and upwardly away from the flange of the container to break the seal between it and the circumferential bead on the lid, thereby to allow the lid to be separated from the container.

With particular reference to Figures 3 and 4 of the drawings, and in accordance with this preferred embodiment of the invention, the underside of the lid is provided with a multiplicity of pairs of inwardly diverging ribs 12 which 910429,dbwspc.029,contain.cap,S -6extends from the inner circumferential skirt 5 to a position partially towards the centre of the lid. The angular spacing between the ribs of a pair is between 30° to and preferably of the order of 40° to 45°. As shown in Figure 3, the pairs of ribs are of such a number, length and spacing that they intersect the ribs of three adjacent pairs of ribs, whereby all the ribs form a honeycomb pattern. The underside of the lid further has a pair of additional circular strengthening ribs 13 and 14 progressively spaced radially inwardly of the outer circumference of the lid and co-axial with each other. As shown in Figure 4, the ribs 12 bridge between the inner circumferential skirt 5, and the pairs of ribs 13 and 14 before tapering or curving upwardly to the annular portion 9 of the lid to form substantially triangular shaped rib extremities 12a. A second intersection point 24 of the ribs 12 is shown in Figure 4. The strengthening ribs 13 and 14 may be omitted and furthermore, the third intersection points 26, which are closest to the centre of the lid 1, may also be omitted. If the third intersection points 26 are not included the rib extremities 12a end at the annular portion 9 or the curved wall 8 at a greater radial distance from the centre 9a. The taper of the rib extremities 12a may be increased or alternatively the slope of the curved portion 8 may be increased so the annular portion 9 is disposed at a lower position with respect to the first annular portion 6.

For some lids 1, the second points of intersection 24 may also be ,mitted if the configuration of the lid enables the pairs of diverging ribs to be spaced apart a greater circumferential distance along the inner skirt 5 without affecting the lid's performance in the sealing tests described previously.

.*9 As a consequence of having such a multiplicity of inwardly diverging ribs, any forces, loads and/or impacts applied to a point on, or near, the edge or rim of the lid are distributed, and therefore distributed by at least one pair of such diverging ribs to be transferred to, or .s a result of the intersections between 9* adjacent pairs of ribs to be transferred to, separate parts of the body of the lid rather than concentrated at one point as is the case with the separate radially inwardly extending ribs of known lids.

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.V -7- As shown in Figure 5 of the drawings, the edge of the base of the container has a circuniferentially extending, downwardly directed, flange 15 which, when containers with lids are stacked on top of each other, will seat in the trough formed, on the upper side of the lid of an underlying container, by the inner skirt 5, the annular portion 6, and the ridge 7.

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Claims (14)

1. A container lid comprising a rim including means for engaging and sealing, in use, an open end of a container, and pairs of diverging ribs which extend inwardly from said rim.

2. A lid as claimed in claim 1, wherein the angular spacing between the ribs of said pairs is between 300 to i 10

3. A lid as claimed in claim 2, wherein said spacing is between 400 to 0a L f G ap e .a

4. A lid as claimed in any one of the preceding claims, wherein a rib of one of said pairs intersects a rib of at least one adjacent pair. 15

5. A lid as claimed in any one of the preceding claims, wherein said ribs extend at least to an inner wall. 4

6. A lid as claimed in claim 5, wherein said inner wall is curved towards the centre of said lid.

7. A lid as claimed in claim 5 or 6, wherein said inner wall is disposed •partially inwards from said rim.

8. A lid as claimed in any one of the preceding claims, wherein the ribs of 25 each pair meet at said rim.

9. A lid as claimed in any one of the preceding claims, wherein said ribs are disposed on the underside of said lid.

10. A lid as claimea in claim 9, including an annular groove above said ribs for receiving a bottom flange of another one of said container when the containers are 910429,dbwc9,oananUcap,8 -9- stacked on one another.

11. A lid as claimed in any one of the preceding claims, wherein said rim includes an outer skirt having holes disposed therein which enable a lower edge of said skirt to be cut to facilitate breaking of a seal between said sealing means and said open end.

12. A lid as claimed in any one of the preceding claims, wherein said lid has a substantially circular shape and said pairs of ribs are circumferentially spaced around said rim.

13. A lid as claimed in any one of the preceding claims, wherein said lid is formed of plastics material.

14. A lid substantially as hereinbefore described with reference to the accompanying drawings. DATED this 11th day of August, 1993 NCI PLASTICS (VIC.) PTY. LTD. By its Patent Attorneys DAVIES COLLISON CAVE 9 9*b* *i 41 j 930811,p:opc4bW,76162.91,9