Note: Descriptions are shown in the official language in which they were submitted.
CA 02212291 1997-08-OS
WO 96/26121 PCT/GB96/00346
- 1 -
SELF-CENTERING CONTAINER CLOSURE
The present invention relates to a self-centering container
closure particularly of the type adapted for utilisation with
a gaseous liquid.
Container closures moulded in one piece from a plastics
material are well known in the art. One such is disclosed in
our earlier European Patent No. 0136088 which relates to a
container closure moulded in one piece from a plastics
material and comprising a top (or crown), a dependent skirt
the radially inner surface of which is formed with screw
thread, a surface which is flared in a direction away from the
top being formed on the internal surface of the skirt where
it joins the top, and an annular resilient flexible fin
extending downwardly and outwardly from the underside of the
top at a position spaced regularly inwardly in said flared
surface and having a length such as to permit at least its
portion adjoining its free edge to lie against said flared
surface when the fin is deformed outwardly by the rim of the
neck of a container to which the closure is to be applied.
Whereas closures of -this type work satisfactorily but there
remains the problem of centralising the cap on the container
in a really reliable way and of preventing "cocking" which is
occasioned during capping. During capping it is difficult to
ensure that the plane of the crown becomes perpendicular~to
the axis of the container neck prior to rotation. This is not
always possible during high speed capping and accordingly a
problem arises when the caps are screwed rapidly onto the
container necks. Whereas a certain tolerance in the screw-
thread portions can allow a degree of "cocking" to be
corrected during capping, it is relatively easy to destroy the
closures during the capping procedure due to this defect.
CA 02212291 2004-04-07
Container closures including downwardly depending internal
bore seals are also known in the art. The purpose c~f these
arrangements is to enable a cap to be rapidly screwed onto a
container neck such that the rim of a container neck seals
against the underside of the crown, whereas the internal bore
of the container neck is in sealing contact with the bore seal
annulus..
Zn a full bottle of a carbonated beverage as the temperature
rises, gas tends to come out of SOlutipn and to increase the
gas pressure in the container. This tends to force the
underside of the crown of the co~ztainer closure upwardly
thereby overcoming the lateral pressure exerted on the inner
face of the prior art bore seals and thereby allows a fluid
1S path to open up between the outer face of the bore seal and
the inner face of. the container neck towards the rim.
Simultaneously a doming effect impairs the seal between the
underside of the crown and the rim of the container neck.
Accordingly. gaseous escape paths are generated and spas'
escapes from the container. xhe consumer can therefore be
left with "flat" contEnts. This effect is accentuated if
scratches are present on the rim of the container neck because
these also tend to allow gas to escape. This is an~especial
problem with recycled containers.
2S
GB-A-240720 provides a container closure molded in one piece
from a plastics material and comprising a crown, a dependent
skirt, the radially inner surface of which is formed with a
screw thread, an annulus resilient fin extending downwardly
from an articulation position on the underside of the crown
at a position spaced radially inward of the skirt and having
a length such as to permit at least a portion adjoining the
free edge to lie in use aga.irist the rim whereby the fin is
deformable by the rim of the container neck to which the
closure is to be applied.
Embodiments of the present invention provide for the
alleviation of the above problems by providing closures of the
foregoing general type provided with means for self-centring
CA 02212291 2004-04-07
--2A-
during capping and means fox alleviating the problem of
cocking_
.According to a first aspect of the inv~nt3.on, there is
pro~rided an assembly of a container comprising a screw
threaded neck in cooperation with a container closure moulded
in one piece from a plastics material and comprising a crown,
.a dependent skirt, a radially inner surface of which skirt is
formed with a screw thread, an annular resilient fin extending
downwardly from an articulation position on an underside of
the crown at a position spaced radially inward of said skirt
and having a length such as to permit at least a portion
adjoining its free edge to lie, in use, against a~rim of the
container neck, wherein the fin is deformable by the rims said
closure comprising a locator annulus depending downwardly from
an undersurface of the crown and disposed radially inwardly
of the fin, the locator annulus extending downwardly by a
distance greater than the fin and having an outer diameter
smaller than that of an inner diameter of the container neck
such that, as the c7.osure is screwed onto the container neck,
engagement between an outer surface of the locator annulus and
an inner surface of the conta~.~xer neck will assist in centring
the closuxe on the container neck.
According to a second aspect of the invention, there is
provided a container closure moulded in one piece from a
plastics material and comprising a crown, a dependent skirt,
a radially inner surface of which skirt is formed ~rith a screw
thread, an annular resirient fin extending downwardly from an
articulation position on an underside of the crown at a
position spaced radially inwardly of said skixt and having a
length such as to permit at least a portion adjoining its free
edge to lie, in use, against a rim of a container neck to
which the closure is to be applied, wherein the fin is
deformable by the rim, the container closure comprising a
locator annulus depending dpwnwardly from the underside of the
crown and disposed radially inwardly of the fin, the locator
annulus extending downwardly by a distance greater than the
fin and having an outex diameter smaller than that of an ~.nner
diameter of the neck of the container with which it is to be
used such that, as the closure is screwed onto the container
neck, engagement between an outer surface of the locator
CA 02212291 2004-04-07
annulus and an inner surface of the container neck will assist
in centring the Closure on the Container neck.
Embodiments of either aspect of the invention may also provide
means fox reducing the incidence of doming. 'The arrangement
of the invention Can also reduce the possibility of successful
tampering because the closure is retained substantially
coaxial on the container neck,
In preferred embodiments of either aspect of the invention,
the locator annulus is continuous or discontinuous, depends
downwardly from the under surface of the crown and is disposed
radially inwardly of the fin, the locator annulus extending
downwardly by a distance greater than that of the fin and
1~ having an outer diameter just smaller than the inner d~.ameter
of the container neck with which it is to be used. The
distance may be up ,to 100 percent lpnger than the
corresponding distance from the underside of the crown to the
fin.
A thread surface may be formed on the inte.rr~al surface of the
skirt where it joins the crowns so as to be flared in a
direction away from the crovm, and wherein the fin e~stends
outwardly and downwardly from the articulation position so as
to contact the flared surface in use.
The fin may be bulbous at its remote end and may be provided
with a neck contact surface inclined inwardly and upwardly
towards the crown for contact in use with the outer rirn of the
container neck. Preferably, the central point of ar_
articulation portion of the fin is located along a line
parallel to the axis of the closure and within the outer on,e
half of the inner and outer diameters of the container neck
with which the closure is to be used, xn a preferred
em3aadimsnt, the central articulation positzan is within the
outer one third or even one quarter of the said diameters of
the container neck. -.~.~. ,
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CA 02212291 1997-08-OS
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- 3 -
The base of the bulbous fin may have a radial thickness
greater than one quarter of the radial thickness of the
bulbous portion of the bulbous fin. This means that when the
closure has been centred on the neck by operation of the
locator annulus, the inclined surface of the bulbous fin
contacts the outer rim of the container neck and, since the
closure is rotating and since the bulbous fin is a relatively
strong annulus, the inclined surface thereof tends to further
ensure centering of the closure prior to and during
deformation'. By this means, "cocking" is alleviated since
contact under rotation tends to locate the closure in its
correct orientation perpendicular to the axis of the closure.
The angle of the inclined plane of the bulbous fin is
preferably between about 35 ° and 55 ° and most preferably about
45° relative to the axis of the container closure.
The remote end of the locator annulus may be chamfered or the
radially outer remote end thereof may be inwardly and
downwardly inclined so as to present an outwardly and upwardly
inclined surface to the inner rim of the container neck.
Preferably the upper end of the inclined plane of the locator
annulus terminates at or adjacent a notional plane
perpendicular to the axis of the closure which is also
generally coincident with the lower end of the inclined
contact surface of the bulbous fin. Thus, the two mutually
opposed inclined planes respectively of the bulbous fin and
the locator annulus operate sequentially with respect to
opposed sides of a container rim. The angle of the inclined
~ plane of the locator annulus is preferably 25 ° to 35 °
relative
to the axis of the container closure.
It will also be appreciated that the positioning of the
locator annulus radially inwardly of the fin has the effect
of strengthening the crown against "doming". Thus a
combination of the fin (preferably bulbous) and the locator
annulus is particularly effective in resisting doming and its
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CA 02212291 1997-08-OS
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effects on the seal achievable by the fin outboard thereof.
The closures of this type are most preferably made by
injection moulding.
The invention will now be described, by way of illustration
only with reference to the accompanying drawings which show
in Figures 1 and 2 fragmentary elevations illustrating the
closures in accordance with the present invention prior to,
and on application.
The closure l0 is moulded in one piece from a resilient
plastics material and has a top (crown) 11 and a dependent
skirt 12 formed with an internal screw thread 13 and external
knurling 14. A corner region 15 at the upper end of the skirt
is thickened and has a conically flared internal surface 16
extending at an angle of about 30° from the axis of the
closure 10. Spaced radially inwardly of the surface 16 is a
resilient bulbous fin 18 which extends from an articulation
A~IENQED SHEET
CA 02212291 2004-04-07
-5-
paint 26 on the under side of the top 11. The bulbous fin 18
thus depends downwardly from the articulation point 26. The
~adially inner surface 2? extends generally parallel to the
plane of the skirt 12 whereas the radially outer portion 2$
of the bulbous fin is curved generally radially outwardly and
downwardly to define at its remote tip 19 an outer sealing
pardon. The outer sealing pardon is conjoined to the ~.z~r~er
radi.ally inner surface 27 by means of an inclined plane 25
having an angle of about 45°_
1,0
Closures of this type may be produced, preferably by inj ection
moulding, with or without a tamper evident band. Preferably
the skirt terminates in a plurality of frangible bridges 34
supportinr~ a tamper e~rident band 35 for cooperation with a
~5 plain security band 36 on the outer neck portion of a
container neck 20 in the usual way.
In use, the container closure 10 is applied to a neck 20 of
a container so that the rim 21 of the container neck moves
2Q upwardly as in Figure 1 to adopt the pos~.tiQn shown in Figure
2. As it does so, the inclined plane 2.5 of the bulbous fin
18 comes into contact with the outer rim portion 22 of the
container neck 20 while the clasure 10 is being rotated durixlg
the capping operation. This has the subsequent effect of
25 assisting in a centring action such that the axis of the
container closure and the container neck become coaxial with
more certainty. further rotation of the Container closure 10
relative to the container neck 20 causes the container neck
to move upwardly relative to the cvntainex closure to adopt
~0 the position shown, iz~ Figure 2. It will be noted that the
articulation of point 26 is disposed appxo~tianately one third
of the xadial distance between the inner and outer surface of
the container neck such that the bulbous fin 18 is deformed
radially outwardly to seal between the inclined surface 25 and
35 comically flared i.z~texnal suxface 16. At the same time,
because of this radial displacement, there is a pivotal force
applied to the internal surface of the crown closure which
tends to resist doming in conjunction with the locator annulus
30 referred to below.
Arrangements of the foregoing type are used with the main
feature of the invention shown in Figures 1 and 2, i_e_ the
CA 02212291 2004-04-07
locator annulus 30. Disposed radially inwardly of the bulbous
fin 18, the locator annulus 3D has a radially outer face 32
having an external diameter which is just smaller than the
inner diameter of the internal surface of the container neck
29. The locator annulus 30 is provided thereforw with a
radially inner face 31, a radially outer face 32, sand
radially outer face 32 culminating towards its remote end in
an annular inclined plane 33 which extends upwardly and
outwardly towards the inner face of the container neck 29_
In use during the capping procedure, the inner rim portion 23
which is radiused comes into contact with the inclined plane
of the locator annulus 30 which has the effect of Centring the
container closure on the container neck. As the cap is
1S rotated, there is relative movement between the container neck
and the closure 10 such that it adopts the position shown
in Figure 2. Because the locator annulus is not intended as
a seal but essentially and primarily as a locator means, the
sealing effect is to be found between the outer rim portion
2~ 22 and the bulbous fin 18. The effect of this i, that because
the closure 10 is correctly orientated relative to the
container necJ~ 20 the problems of 'cocking" and centring are
correctly addressed.
Further and pxobably as importantly, because the locator
annulus is disposed in-board of the bulbous fin, it tends to
strengthen the central portions of the crown 11. This resists
doming.
The locator annulus 30 has the further effect of retaining the
Closure coaxially upon the Container neck thus resisting
tampering,
It will thus be seen that during application of the closure
10 to the container neck 20, the rim 21 of the container
first Comes into contact with the inclined surface 33 of the
locator annulus 30 pr~.or to any contact of the bulbous fin 18.
This tends to centre and directly orientate the closure
relative to the container neck. Subsequently the outer rim
portion 22 of the container neck 20 comes into contact with
the inclined plane 25 which has a further centring and
anti-cocking action as a primary factor with the secondary
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CA 02212291 2004-04-07
a
effect of causing the bulbous fin 18 to articulate at the
point 26 as such that the surface 28 comes into contact with
the sonically flared internal surface 16 thereby causing
effective sealing.
It will also be apprec~.ated that by virtue of the relati~cre
thickness of the bulbous fin 18 taken with the effects of the
locator annulus, a more effective seal is provided than
previously. The locator annulus also tends to absorb all
~J lateral forces of application generated by the combination of
the application of force and the helical angle of the
containerlclosure threads . '~h~.s ensuxes that none of these
forces impinge upon the bulbous fin 18 such that the same is
inconsistently engaged with the container.
The locator annulus and the stiffness of .the closure crown
together have the effect that any doming of the crown under
pressure wil3. only take place within the circumference of the
locator annulus 30. This has twa~effects. 2n the first place
it redudes the effects of doming upon the bulbous fin 18 thus
ensuring that the fin~does not get pulled aut of sealing
engagement with the container during cases of extreme doming.
Further the locator ring acts as a stiffening rib which
resists and reduces the degree of doming exerted by the
iriternaZ force. This tends to reduce storage problems when
the containers are stacked.
34
This invention is particularly desirable when applying a
CA 02212291 1997-08-OS
WD 96/26121 PCT/GS96/00346
_ g
possible damage to the outside corner/surface of the container
which might provide a leakage path past the bulbous fin seal
in high temperature storage conditions where doming can be
expected.
The inventive closures are preferably made by injection ''
moulding of high density polyethylene plastics materials. The
locator annulus is intended to have no sealing properties and
hence needs to be used in conjunction with a primary seal for
example as hereinbefore set forth.
The invention provides therefore a closure as hereinbefore set
forth and an assembly thereof with container closure.
