Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to closures of the kind used
to sealingly cover containers.
Closures for containers may be constructed to fit
solely within the confines of side walls of the containers
and various methods have been devised for closure removal.
This invention is associated with the solving of a removal
problem sometimes presented by closures having margînal rim
flanges which fit around upper side wall regions and lips of
containers. In one basic type of construction, the closures
are held onto their containers by coacting locking means
which are provided by mutually opposed abutment shoulders
on an inwardly directed circumferentially extending rib on
the closure and an outwardly directed rib or lip on the con-
tainer. To remove a closure under these circumstances, it
is necessary to flex the marginal rim flange radially out-
wards so as to disengage the abutment shoulders thus allowing
the flange and closure to be moved upwardly off the rim.
With small containers, for instance of one gallon capacity,
this closure removal action causes no undue difficulty and a
closure formed of flexible resilient plastic material is
removable without undue distortion and without being cu~ so
as to be reuseable for covering and sealing of the same or
another container. However, for containers of greater
capacity, closures need to be made of thicker and stronger
section to make them more rigid as they are of larger
diameter and also to withstand impact loads, in the event
that a filled container is dropped, without being forceably
removed under the weight of the contents. The problem
presented by these closures, therefore, is in providing a
design which will make them sufficiently strong and rigid,
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particularly around the marginal rim flange, so ~hat
inadvertent or accidental removal of the closures is a
virtual impossibility, but at the same time ensuring that
the closures can be removed by manual effort in a not too
difficult a fashion and without causing any undue strain to
be placed upon any person desiring to open the containers.
This problem which becomes particularly acute with
containers of up to five gallon capacity has been solved by
constructions described in U.S. Patent Nos. 3,519,163
(Bardell) and 3,770,156 (Yates). In U.S. Patent No. 3,519,163,
there is described the use of tear lines in the marginal rim
flange along which the flange separates to allow for removal
of the closure. Tearing of a marginal rim flange has also
been disclosed elsewhere, such as in U.S. Patent No.
3,403,812 (Weber). In U.S. Patent No. 3,770,156, there is
a disclosure of a rim flange having a plurality of spaced-
apart slots spaced from a free end of the flange. This is a
construction rendered sufficiently rigid to prevent closure
removal by the rigidifying effect of the free end of the
flange. To allow for closure removal, it is necessary to
cut downwards from the slots to the free end of the flange
so as to make the free end discontinuous and form pivotal
tabs of the flange between slots.
The above described constructions may be referred
to as ~tamperproof closures" in that a cut or torn closure
which has been removed and reitted to its container can
immediately be identified as one which has been already
removed. Such knowledge is useful to a person who may wish
to know whether the container contents may have been inter-
fered with. However, defacement of the closure for its
1:119556
removal makes it a virtual impossibility to provide a
hundred per cent efficient seal between closure and container
when it is refitted. In addition, there are uses to which
containers may be put in which the user is more interested
in having an efficient seal when the closure is refitted
than he is in being able to identify from a torn closure
that the container cont~nts have been tampered with. Such
a situation may be found mainly with the larger containers
in which the robust nature of the closure and its sealing
fit to a container is also of importance so as to prevent
forceable removal under impact loads as mentioned above.
The present invention provides a closure with a
rim flange which allows for its removal without defacement
such that it can be re~ealed upon its container but at the
same time allows for a rigid construction which will
successfully resist any tendency for accidental removal under
impact loads in the event of the dropping of the filled
container.
Accordingly, the present invention provides a
closure for a container comprising:-
a) a cover portion; and
b) a continuous rim flange extending around thecover portion;
c) the rim flange extending downwardly from a
base end to a free end and having:-
(i) a circumferentially discontinuous andradially inwardly projecting locking bead for locking
engagement with a container;
(ii) a plurality of circumferentially spaced-
apart access regions disposed between the base end of the
:1119556
flange and the locking bead and in circumferential positions
between adjacent discontinuous sections of the locking bead
to enable a closure removal tool to be inserted downwardly
through each access region and between adjacent discontinuous
sections of the bead; and
~ iii) a plurality of rim stiffening protrusions
which project from the outer surface of the flange in at least
said circumferential positions between the discontinuous
sections of the bead and which overlie the circumferential
line of the locking bead to resist bending of the flange
circumferentially in said circumferential positions upon
prising of the free end of the rim flange radially outwards
by the closure removal tool inserted downwardly through the
access regions and to assist bending outwards of the flange
circumferentially at each side of said access regions to
promote radial outward movement of the locking bead.
The positioning of the access regions in circum-
ferential positions between adjacent sections of the locking
bead, i.e. directly above gaps between the sections, allows
the removal tool to exert its prising force within a gap so
that this force is transmitted directly in a circumferential
direction by the stiffening protrusions to the sections of
locking bead. Enabling the tool to operate in this way
ensures the tool is as close as possible to the ends of the
sections and thus reduces the chances of flexing of the
flange compared with a case in which the tool applies its
prising load at a position above the locking bead. In the
latter case, flexing of the flange between the point of
application of the tool and the locking bead would increase
the difficulty in removal of the closure. Alternatively,
~li9SS6
in a construction according to the invention where the
locking bead is spaced from the free end of the flange, the
prising tool could be pushed through an access region
sufficiently far to cause its lower end to extend through
and beyond the gap between the discontinuous bead sections.
While this would increase the distance between the point of
application of the tool and the ends of the bead sections,
this disadwantage would be outweighed by the mechanical
advantage gained by the increase in leverage distance of the
tool from its fulcrum position at or adjacent the base end
of the flange.
The transmission of the prising force to the dis-
continuous bead sections is assisted by the fact that the
protrusions overlie the circumferential line of the locking
bead. Also, in preferred constructions assistance is gained
in this respect where each protrusion extends circumfer-
entially at least the distance between ends o~ adjacent
locking bead sections and in which the protrusions extend
from the circumferential line of the locking bead to or
towards the free end of the flange.
The invention also includes a container and closure
assembly comprising:-
A) a container having a side wall, a lip at anopening to the container, and a radially outwardly projecting
bead; and
B) a closure comprising:-
a) a cover portion extending across the
opening to the container; and
b) a continuous rim flange extending around0 the cover portion and down around the lip and bead of the
1:~19556
container, the rim flange extending downwardly from a base
end to a free end and having:-
(i) a circumferentially discontinuous andradially inwardly projecting locking bead in locking engage-
ment beneath thè ~ead of the container, the flange and thebead of the container defining a space between them in
circumferential positions between adjacent discontinuous
sections of the locking bead;
(ii) a plurality of circumferentially spaced-
apart access regions disposed between the base end of the
flange and the locking bead and in said circumferential
positions to enable a closure removal tool to be inserted
downwardly through each access region and through said space
between the side wall and the bead of the container; and
(iii) a plurality of rim stiffening protrusions
which project from the outer surface of the flange in at
least said circumferential positions between the discontinu-
ous sections of the bead and which overlie the circumferential
line of the locking bead to resist bending of the flange
circumferentially in said circumferential positions upon
prising of the free end of the rim flange radially outwards
by the closure removal tool inserted downwards through the
access regions and through said spaces, and to assist
bending outwards of the flange circumferentially at each
side of said access regions to promote radial outward
movement of the locking bead.
The access regions may each be a hole formed in the
flange or a web of flange material which is thinner t~an
surrounding areas of flange. This web obviously needs to be
sufficiently thin to allow the closure removal tool to be
lil9556
forced to pierce it without difficulty. One advantage in
using such webs is that upon replacement of the closure
upon a container, the broken web will establish that access
may have previously been made to the container contents.
Thus, a tamperproof closure is provided without the sealing
and locking parts of t~le closure suffering any detrimental
treatment.
Embodiments of the invention will now be described,
by way of example, with reference to the accompanying draw-
ings in which:-
FIGURE 1 is a side elevational view of a container
and closure according to a first embodi-
ment;
FIGURE 2 is an isometric view of part of the
closure of Figure l;
FIGURES 3, 4, 5 and 6 are, respectively, cross-
sectional views on an enlarged scale taken
along lines III-III, IV-IV, V-V and VI-VI
in Figure 2;
FIGURE 7 is a view similar to Figure 3 showing the
action of a closure removal tool upon the
closure;
FIGURE 8 is a view similar to Figure 7 of a
modification to the first embodiment; and
FIGURE 9 is a view similar to Figure 2 of a second
embodiment.
In a first embodiment as shown in Figure 1, a
container and closure assembly comprises a five-gallon con-
tainer 1 and closure 2. Both the container and closure are
injection moulded from a poly-alpha-olefin such as high
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1~19556
density polyethylene although impact polypropylene may be
used. Alternatlvely, other suitable materials may be used
instead such as polyvinyl halide, e.g. polyvinyl chloride
or a polyvinyl aromatic, e.g. polystyrene.
The container has a base 3 and frusto-conical
side walls 4 terminating at an open upper end in a lip 5.
The lip has a radially outwardly projecting bead 6 with a
lower abutment shoulder 7 for engagement with the closure
as will be described.
The closure comprises a closure portion 8 around
which extends a continuous and downwardly flared rim flange
9. The rim flange extends upwardly from a lower free end 10
to a base 11 which extends radially inwards and connects the
flange to the closure portion in a manner to be described.
The closure comprises a discontinuous locking bead
extending circumferentially around it and in the form of
discontinuous sections 13 projecting inwardly from the rim
flange and spaced from the free end of the flange to engage
beneath the bead 6 when the closure is in position on top
of the container so as to hold the closure in this position.
A compressible sealing ring 14 is mounted between the lip 5
and base 11 of the closure to effect a seal.
For the purpose of enabling the closure to be
removed from the container, a plurality of access regions
for a removal tool are provided in spaced-apart regions
around the rim flange. Each access region is a hole 16
provided for the insertion of a tool in a downward direction
through the flange, the holes 16 being located in cir-
cumferential positions between the bead sections 13 and
between the base 11 of the flange and the locking bead.
1119556
As shown in Figure 5, the inner wall 17 of the
rim flange is a plain unrelieved or shaped wall between the
end of each bead section 13 and the base 11 and is of sub-
stantial thickness in section. However, to enable a removal
tool to be inserted in a downward direction between the rim
flange and the bead 7, the wall 17 is formed with a vertical
recess 18 which is the width of hole 16, has a vertical base
wall 19 and extends down to the free end 10 of the flange.
Measures are taken to prevent reduction in thickness caused
by recess 18 ~rom resulting in splitting of the flange upon
insertion of a removal tool. To this end, ~he flange is
provided with rim stiffening protrusions 20 which are of
rectangular shape in side elevation and extend directly one
from beneath each hole 16, across the circumfer'ential line
of the locking bead, and merge into the flange near free
end 10 of the flange. Each protrusion extends on each
circumferential side of the hole 16 to provide the parts of
the flange between the ends of the bead sections 13 and
recess 18 with substantial thickness and rigidity. Each
protrusion extends, in fact, as far as the ends of the bead
sections 13 as shown in Figure 6.
The flange 9 is connected by its base 11 to the
closure po~tion 8 by means of discontinuous arcuate sections
21 of a U-shaped reinforcement 22 lying radially within the
flange 9. Each section 21 has an outer leg 23 and inner leg
24 joined by a base 25 (Figures 4 and 5), the outer leg
lying within the side wall 4 of the container and being spaced
from the side wall except at the top of the outer leg which
is of larger diameter and engages the inner surface of the
side wall towards its top. The outer leg 23 is thus flared
-- 10 - .
111955~;
towards its lower end. The inner leg 24 is interconnected
with the closure portion 8 by a circular raised region 26.
The sections 21 of the reinforcement 22 are equal
in number to the sections 13 of the locking bead and are
spaced-apart by gaps 27 (Figure 6). These gaps are defined
by opposing end walls 2~ of adjacent sections 21 and by
radial extensions 29 of the raised regions 26 which connect
the closure portion 8 in the area of the gaps with the upper
end of the leg 23 ~Figure 3). The purpose of the gaps will
become apparent during the discussion below. For ease and
convenience of manufact~re, the gaps are radially aligned,
one with Pach recess 18 and the width of each gap 27 is
substantially equal to the circumferential width of each
recess. This allows for simplification in the manufacture
of mold parts for forming the gaps 27 and the configuration
of the recesses 18 and holes 16.
In line with the radial centerline of each gap 27
is a rib 30 of short radial length which extends upwardly
from the associated extension 29 of regions 26 and radially
inwards from the upper end of the leg 23. The ribs ha~e a
thickness slightly less than the width of gaps 28 and serve
to locate closures in a neat fashion when stacked with the
protrusions 20 of the stacked containers directly below one
another by registration of the ribs within the gaps 28.
In use of the closure, it is fitted onto the con-
tainer with the bead sections 13 locked beneath bead 6 as
shown in Figures 3, 4 and 5. The flared nature of the flange
9 and leg 23 provides a wide opening between flange and leg
for acceptance of rim 5 and the rim is easily led into the
opening by machinery designed for assembling the components
- 11 -
~119556
together. The gaps 27 allow for escape of air from inside
of the container and prevent pressurization of the container
in the event that the upper end of leg 23 provides a sub-
stantial seal with the side wall 4 during fitting of the
closure and before the container is sealed by seal 14. Air
is vented during the closure operation through the gaps 27,
under the seal 14 and either through holes 16 or between the
flange 9 and the side wall 4. In th~ assembled condition,
spaces 31 (Figure 3) are formed between flange 9 and the
bead 6 in positions between bead sections 13, wi~h the
recesses 18 widening the spaces at their mid-circumferential
positions.
When it is required to remove the closure, a thin
rod-type rigid removal tool 31, such as a screw-driver blade,
is inserted downwardly through a hole 16 (Figure 7), and the
tool passes along the recess 18 so as to be disposed.with
its lower end lying either between adjacent bead sections 13
or lower and possibly even beyond the free end 10 of the
flange as shown in Figure 7. The top end of the tool is
then urged towards the center of the closure, shown by the
top arrow in Figure 7, so that the base of the flange acts
as a fulcrum point, and a lower end or part of the tool
exerts a prising force upon the flange at a point of applica-
tion between the circumferential line of the locking bead
and the free end of the flange to urge the flange outwards
(lower arrow in Figure 7). The protrusion at that position
is rigid so that local circumferential bending of the rim
flange in the vicinity of the access region does not result
or is negligible. Instead, because of the circumferential
stiffness of the protrusion, the outward force applied by
- 12 -
1'1 1955~;
the tool is transmitted to the parts of the flange disposed
circumferentially at the sides of the protrusion and from
there to the adjacent parts of t~e flanking bead sections 13.
The result is that the adjacent parts of the bead sections
are flexed and moved away from beneath the bead 6 of the
container to unlock that particular part of the closure.
This situation is shown by Figure 7. This procedure is then
followed at a next adjacent access region which will result
in complete unlatching of one of the bead sections 13 which
1~ was partially unlatched by operation upon the access region
just described, and also in partial unlatching of the next
adjacent bead section. The procedure is then followed pro-
gressively around the closure at other access regions until
sufficient bead sections have been unlatched to enable ~he
closure to be completely removed.
During flexing of bead sections 13, closure
removal is also assisted by the discontinuous nature of the
reinforcement 22. The gaps 28 allow for individual flexing
of adjacent sections 21 of the reinforcement by opening of
the gaps thus permitting the base 11 to be flexed in the
opening direction after slight opening movement of the
closure has occurred. At this point, a section 21 may
already have been dislodged slightly from within the con-
tainer and flexing of this section by operation of the
removal tool within a hole 16 moves the lower end of the
leg 23 towards the container side wall and lessens resistance
of the closure to unlatching of the bead sections 13.
As can be seen from the above described embodiment,
no splitting of the rim flange can result such as would be
the case if the removal tool were inserted through a hole
- 13 -
~19556
and operated in prising manner where the flange section was
weakened between bead sections 13 and not provided with any
additional reinforcement. Apart from preventing splitting,
each protrusion has a stiffening effect which resists bending
circumferentially and thus transmits the prising force to the
nearby bead sections 13 to cause their unlatching from the
bead 6. Thus, it can be seen that with this large size
closure, no damage results during its removal so that it may
be replaced while having as an efficient seal and the same
locking effect with its container which it had when initially
fitted. Also because of the position of holes 16 and the
locking bead together with the spacing apart of the bead
sections 13 beneath the holes 16, the point of application
of the tool may be chosen to be lower than the locking bead
whereby mechanical advantage upon levering is obtainable
because of maximizing the distance between the fulcrum
position of point of application for the prising force of
the tool. Further, with the point of application being
located thus, the bead sections are moved outwards without
placing undue strain at the top of the flange so that there
is little or no chance of distorting the flange base 11
beyond its elastic limit. Hence, the flange will return
resiliently to its former position after closure removal
thereby allowing for the closure to be refitted to the same
or another container with the locking bead still acting
effectively.
In a modification of the first embodiment shown in
Figure 8, each access region comprises a membrane or web 32
extending across a hole 33. To remove the closure, it is
necessary to break the web with the tool. While the closure
- 14 -
~19SS6
may then be refitted with its sealing and locking action
unimpaired, the closure is "tamperproof" in the sense that
broken webs at the access regions indicate to a second user
that access has previously been gained to the container
contents.
In a second embodiment shown in Figure 9, a closure
3~ is of construction basically similar to that of the first
embodiment and parts of similar construction bear the same
reference numerals. In this embodiment, the difference from
the first embodiment is the shape of protrusions 35 at each
access region. As can be seen, each protrusion 35 tapers
from top to bottom as in the first embodiment but also
extends circumferentially around the rim flange from its
access region and tapers at each side towards the free end
10 of the flange. Each side 36 of each protrusion overlaps
circumferentially, end portions of an adjacent bead section
13 so as to increase the stiffness of the flange in the
access region and in immediately adjacent regions and also
to assist in transmitting the prising force into the bead
sections 13.
In the second embodiment, a modification (not
shown) may be employed such as is described in the first
embodiment, i.e. in which webs of plastic extend across
holes in the access regions which it is necessary to break
before the closure may be removed. These closures are then
rendered "tamperproof" in the sense referred to in the
first embodiment.
