CA1166192A

CA1166192A - Container lid

Info

Publication number: CA1166192A
Application number: CA000387365A
Authority: CA
Inventors: Ole H. Willerup
Original assignee: Superfos AS
Current assignee: Berry Superfos Randers AS
Priority date: 1980-11-20
Filing date: 1981-10-06
Publication date: 1984-04-24
Also published as: NL8105173A; CH654807A5; ES269738Y; NL191258B; DK145194C; IT1142979B; GB2091706B; FI72937C; IE52644B1; DK145194B; SE450948B; SE8106169L; PT73853A; NO813924L; GB2091706A; IT8149584A0; BE891184A; ES269738U; SE450948C; AU541009B2

Abstract

A b s t r a c t A container lid is provided with a lid flange 2 downwardly merging into a releasing flange 13 which from a position in which an inwardly extending snap rib 8 on said flange 2 engages a sealing edge on a container flange 9 or a container mouth bead 12 is upwardly bendable to a position in which said snap rib 8 goes clear of said container flange or abuts it at slight pressure. Releasing flange 13 acts as a bistable snap catch and is retained in its extreme positions by means of its inherent annular tension.

Releasing flange 13 causes even a large container lid seated firmly prestressed on a container to be readily removed, no tools being necessary.

Fig. 3 to be published.

Description

1 ~ 66192 The present invention relates to a container lid of a resiliently deformable plastic material, having a down-wa;rdly extending lid flange provided with an inwardly extending annular snap rib engaging a peripheral bead or flange of a container to be sealed.

Lids of the type used as tight-sealing closures ~or con-tainers, e.g. paint buckets, are often difficult to remo~e because effective sealing implies powerful prestressing of th~ container lid material.

It is the object of the invention to facilitate removal of tight container lids from containers and this is achieved by the fact that the lid flange adjacent to the snap rib merges into a peripheral releasing flange constituting a bistable snap catch, said releasing flange being bendable from a down-wardly extending position in which in tensioned condition it may abut a bead or a flange on the container, to an up-wardly extending releasing position in which the snap rib goes clear of said container bead or flange or abuts the latter at reduced tension.

The lid flange and the releasing flange constitute the links of a bistable toggle joint, the portion between said flanges constituting a hinge connection, and the annular ten-sion of the releasing flange acting as a spring which in the one position of the flange assists in keeping said snap rib and said container bead or flange firmlv interengaged, and in the other position keeping the snap rib clear of or only in slight contact with said container flange or bead. By moving his fingers along the lower side of the releasing flange, a person handling the container may readily bring the releasing flange past a bent position, in which the annular tension is at maximum, thus enabling the releasing flange to snap up into its releasing position. The lid can now be easily removed, and when the container is in use the lid may be placed loosely thereon for temporary protection of its contents.

l l 661 92 One embodiment of the container lid according to the invention is characteristic by the provision of an annular recess on the inner wall of the lid flange, said recess widening conically downwards towards a thin bendable portion of said lid flange directly above the snap rib. The embodiment is particularly suitable in connection with axially tensioned lids, the lower surface of the lid tightly abutting the mouth edge of the container along a narrow sealing line, the lid flange lying at a radial distance outside of the container mouth and with a sharp bent merging into the lid surface proper without any possibility of transferring a bending momentum. A lid of the type just described is axially tensioned owing to the fact that the distance between the edge of the container mouth and the under side of the container flange or bead is greater than the vertical distance between the sealing line of the lid and the top side of the snap rib on said lid flange of the removed lid. Placing of the lid on the container generates a powerful axial tensile force in the lid flange, the tension being the higher, the higher the required pressure is per unit of area at the sealing line between the container mouth and the lid. Since the lid flange is only axially tensioned and thus only subjected to tensile force, the joint portion between the lid flange and the releasing flange may be relatively thin-walled, and thus bending the releasing flange from its one position to the other practically only requires the maximum peripheral tension of the releasing flange to be overcome.

If container lids are to be sealed by means of axial tension only, it is of minor importance whether the annular tension is greatest in the sealing position or in the releasing position of the releasing flange, and for this reason the releasing flange may extend substantially vertically downwards along the container wall so as to avoid problems when a number of containers are positioned next to each other. Other types of containers, e.g. marmalade containers and the like having outwardly bulging side walls below the mouthrim of the con-tainer, may be provided with a releasing flange having a dia-meter which in the sealing position of said flange is larger l l 661~2 than in the releasing position of same, the annular tension of said flange then being higher in the sealing position, and this is of particular importance in connection with lid t~pes where a sealing between a bead at the container mouth and the container lid is based on radial prestressing.

The invention will now be described im ore detail with re-ference being had to the drawing.

Fig. 1 is a radial sectional view of an e~bodiment of the lid according to the invention.
Fig. 2 is a top plan view of said lid, Fig. 3 is a sectional view of a preferred, embodiment of the container lid according to the inventions, and Fig. 4 is a corresponding sectional view of another embodiment of the container lid according to the invention.

The container lid shown in Figs. 1 to 3 has a plane surface 1 and a substantially axial - and when in use - downwardly extending flange 2 which via a conical rim portion 3 merges into a radial flange portion 4 connected to the plane lid sur-face 1 through a substantially axial inner flange portion 5.
The lower surface of the radial flange portion 4 is pro-vided with an axial guide rib 6 and a sharp sealing rib 7 abutting the edge of a contianer mouth along a narrow sealing line. When the container is tightly sealed a snap rib 8 on the inner side of the lid flange 2 abuts a downwardly ex-tending locking edge at the extremity of a container flange 9 extendin~ from thecontainer wall 10. ~ig. 3 shows - in dotted lines - the position of the conical rim portion 3 when the lid is loosely seated on the container. In this position the vertical distance from the container mouth edge to the downward-ly extending locking edge of the container flange 9 is greater than the vertical distance from the sealing rib 7 to the top of the snap rib 8. When the lid is tightly seated on the con-tainer the conical rim portion 3 is pressed down - shown in full lines - by means of axial pressu~,the snap rib 8 thus engaging the locking edge of the container flange 9. The lid l 1 661 92 flange 2 is thus subjected to axial tensile force causing the sealing ribe 7 to be powerfully pressed against the cc,ntainer mouth.

Im~ediately above the snap rib 8 lid flange 2 is provided with an annular recess 11 and merges via a thin-walled portion 12 into a releasing flange 13 which in its sealin~
position extends downwardly as shown.

r~he~ a container u~er wishes to re~ove the lid, h~ mo~Ps his fin~ers along the lower surface of the sealing flange`13, exerting an outwardly ascending pressure thus increasing the annular tension to maximum so that the flange suddenly snaps upwards into its upper position shown in dotted lines, in which the snap rib 8 goes clear of the container flange 9.
The releasing flange 13 thus acts as a bistable toggle joint along the thinwalled portion 12 hingedly connected to lid flange 2 and retained in its extreme positions by means of the annular tension of the flange.When the releasing flange 13 is so shaped that in sealing position it extends further out from the container wall in radial direction, the increased an-nular tension will cause a still firmer interengagement of the snap rib ~ and the container flance 9, This is of special advantages when the sealing of the lid to the container mouth is achieved by means of radial tensile force of the lid as is the case according to the embodiment shown in Fig. 4. Here the plane surface 1 of the lid merges direct-ly into an axial lid flange 14 which is at its inner sur~ace provided with an annular sealing rib or bead 15 which in the sealing position of the lid engages a container mouth bead 16 at the top of the container wall 10. The diameter of the re-leasing flange 13 is - as shown - in the closed position of said flan~e larger than in the releasing position thereof, the sealing rib 14 in closed position thus being powerfully pressed around the bead 16, whereas rib 14, when the releasing flange is in its upper position (shown in dotted lines) goes substantially clear of bead 16. In releasing position the . 1166t92 sealing rib 14 and the container mouth bead 16 may remain :interengaged, but at slighter pression so as to enable the sealing rib tc readily pass bead 16 when the lid is being removed .

It is not absolutely necessary to let the sealing rib of the e~bodiment shown in Fig. 3 go completely clear of the con-tainer flan~e 9 durin~ removal of or replacing the lid on tne container. The container lid according to the invention with i~.s bist;lb'Q snar ca'-h rel2asing flange ma~ ~)e di~ferer.tli shaped from the embodiments shown on the drawing. In particular the periphery of the lid may be regularly polygonal with rounded corners, so as to be suited for corresponding poly~onal containers, like containers for the storase of food, lunch boxes, food buckets and the like.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

1. A container lid of a resilient deformable plastic material, having a downwardly extending lid flange provided with an inner annular snap rib engaging a peripheral flange on a container to be closed, said lid flange adjacent to said snap rib merging into an annular releasing flange which constitutes a bistable snap catch and is bendable from a down-wardly extending position in which in tensioned condition the snap rib may abut the peripheral flange, to an upwardly extending position in which the snap rib goes clear of the peripheral container flange or abuts the latter at a reduced tension, characterized in that;
a) said lid flange is located outside the container mouth at a radial distance therefrom, and b) is merging with a sharp bend into a conical rim portion of the lid, and that c) the vertical distance between the edge of the container mouth and the lower edge of container flange is greater than the vertical distance between the sealing line of the lid and the upper surface of the snap rib, when the releasing flange is in its downwardly directed position in the removed (unstressed) lid, and d) that an annular recess is provided in the inner wall of the lid flange, said recess widening conically downwards to a thin resilient portion of said lid flange directly above said snap rib.

2. A container lid according to claim 1, charac-terized in that the releasing flange is shaped so as to extend substantially axially when in its sealing position.