Note: Descriptions are shown in the official language in which they were submitted.
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.
