Note: Descriptions are shown in the official language in which they were submitted.
CA 02449926 2003-11-17
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CLOSURES AND CONTAINERS IN CO1~INATION THEREWITH
The present invention relates to the packaging of
fluids and, in particular, to closures for containers
in which the closure is capable of providing
resealable access to the contents of the container.
In the specification which follows the problems
of fluid packaging will be discussed with particular
reference to the problems associated with the
packaging of milk. However, it will be appreciated
that other potable fluids such as water and fruit
juices present similar packaging problems.
Conventionally, milk has been packaged in blow-
moulded plastics containers which are provided with
resealable caps. The resealable caps are typically
formed of injection moulded plastics material. There
is however, a fundamental problem in achieving a good
seal between a blow-moulded plastics container and an
injection moulded plastics cap. This is because the
tolerance of the neck of the container may be of the
order of ~ 0.3mm whereas the tolerance of an injection
moulded item, such as the cap, is typically ~ O.lmm.
This means that it is inevitable that a proportion of
the caps made to a particular specification will not
seal tightly when fitted to the necks of the
containers for which they are intended. This in turn
leads to production difficulties in applying the caps
to the container necks and leakage problems for both
retailers and distributors of the packaged product.
This problem is further exacerbated by the fact
that the blow-moulded plastics containers are
typically manufactured at a different location and by
a different producer from the injection moulded
plastics caps. 'This is because, although the
containers could be supplied to the bottling plant
ready made, this would inevitably result in the need
,r
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to transport large volumes. It is therefore more
usual for the blow-moulded containers to be produced
in a blow-moulding plant adjacent the dairy so that
they can be formed and filled on one continuous
production line.
However, the consequence of having two parts, the
container and the cap, which must co-operate if there
is to be an adequate seal, manufactured by different
parties and at different locations means that on those
occasions when the sealing characteristics of a batch
of containers is poor there is also a lack of
accountability as to which of the container or the cap
is responsible.
In order to address the problems of leakage,
there have in recent years been proposed a large
number of different designs of cap. For example, in
one design, the cap is provided with a top and a
downwardly extending skirt portion which depends from
the top. The skirt portion is provided on an inner
surface with one or more threads for engagement with
one or more complimentary threads provided on an outer
surface of the container neck. A downwardly depending
annular plug is provided on an underside of the top,
spaced radially inwardly of the skirt. The plug is
dimensioned to engage a rim of the container opening
defined by the neck so as to form a primary seal. A
secondary seal may be provided by means of an annular
bead or shoulder provided on the cap at or adjacent
the intersection of the top and the depending skirt
such that, upon application of the cap to the
container neck, the bead or shoulder engages an
external surface of the neck at a location above the
threads. However, although commercially successful,
this design of cap does not adequately address the
fundamental problem of providing a reliable seal
between a blow-moulded component and an injection
moulded component. Instead, leakage rates have been
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reduced by providing ever increasing numbers of
primary, secondary and sometimes even tertiary sealing
surfaces. However, on occasion, the provision of so
many seals can be counter productive and actually
cause leakage rates to rise as the interrelated
tolerances of the cap and neck result in clashes
between the sealing surfaces.
Another design of closure is described in
GB-A-2,374,068. In this document there is proposed a
container comprising a blow-moulded plastics body and
an injection moulded neck and cap assembly which can
be fused to the body after the body has been filled
with a fluid. In other words, the closure to the
container comprises two parts, a neck and a cap, both
of which may be injection moulded to the same
tolerances. This enables the cap and neck, by virtue
of their mutual cooperation, to provide a plurality of
reliable sealing surfaces. At the same time, the
injection moulded neck is permanently adhered to the
blow-moulded plastics body so as to prevent any
leakage between the two.
Initially, the injection moulded neck is formed
with a membrane with which to close off the opening in
the blow-moulded plastics body. However, this
membrane may be removed and discarded by pulling on a
pull-ring with which the membrane is provided. This
allows access to be gained to the contents of the
blow-moulded plastics body while the resealing
capability of the closure is provided by the
engagement of an annular plug provided on an underside
of the cap with the bore of the injection moulded
neck.
This two part closure design clearly has the
potential to provide improved sealing characteristics.
However, the use of the described injection moulded
neck inevitably adds to the height of the packaged
product as well as to the radial dimensions of the cap
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with which it must interengage. As a result, the use
of such a closure necessitates the use of a dedicated
bottling line which is adapted to handle containers of
a non-standard height. Likewise, the use of a non-
standard cap requires the adaptation of existing
capping equipment. All this imposes a considerable
burden on those responsible for the bottling plant and
acts as a disincentive in moving from one design of
closure to another despite the anticipated improvement
in sealing characteristics that can be expected to
result.
Therefore, although it is known to overcome the
difficulties associated with providing a reliable
resealable closure by abandoning the previous attempt
to design an injection moulded cap capable of
sealingly engaging with a blow-moulded container and
replacing it with a two part assembly, both parts of
which may be injection moulded with one part
permanently adhered to the still blow-moulded
container and the other part providing resealable
engagement with the first part, nevertheless the
problem of providing such an assembly which is capable
of being applied using existing capping equipment
still remains.
In particular, it would be desirable to provide a
two part assembly which is capable of being used with
a container having a standard silhouette and being of
a conventional height. In this way there would be no
need for the various stations on a bottling line to be
specially adapted to accommodate a different shape or
height of bottle. Likewise, it would~also be
desirable to provide a two part assembly in which the
external dimensions of the cap, known as the cap
silhouette, were the same as an existing industry
standard. In this way, the two part assembly could be
used with existing "pick and place" equipment and with
existing capping machines, thereby removing the need
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for the bottling line to move over to new or different
equipment simply to process a batch of containers
having a different and otherwise highly desirable
closure system. The present invention seeks to
address these desires.
'According to a first aspect of the present
invention there is provided a closure for use with a
container neck, the closure comprising a cap and an
insert, the insert being adapted to be permanently
adhered to the container neck and having a sealing
surface and the cap comprising a complimentary sealing
surface for sealable engagement with the sealing
surface provided on the insert and engagement means
for releasable engagement with complimentary
engagement means provided on the container neck.
Advantageously the container neck may have a rim
surrounding an axial bore and the insert may be
adapted to be received within the bore, the insert
having a flange adapted to project outwardly from the
bore to overlie the surrounding rim such that the
insert protrudes axially from the bore no more than
the thickness of the flange. This provides the
advantage of restricting the height of the insert
above the container neck and so permits the use of a
conventionally dimensioned cap.
Advantageously the container neck may have an
external neck surface and the insert may be shaped
such that no part of the insert overlies the external
neck surface. This provides the advantage of
restricting the dimensions of the insert in a plane
perpendicular to the axis of the bore and so once
again permits the use of a conventionally dimensioned
cap.
According to a second aspect of the present
invention there is provided a closure for use with a
container neck, the container neck having a rim
surrounding an axial bore and the closure comprising a
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cap and an insert, the cap having a sealing surface
and the insert being adapted to be received within the
bore and permanently adhered to the container neck and
having a complimentary sealing surface for sealable
engagement with the sealing surface provided on the
cap and a flange, the flange being adapted to project
outwardly from the bore to overlie the surrounding rim
such that the insert protrudes axially from the bore
no more than the thickness of the flange. This again
provides the advantage of restricting the height of
the insert above the container neck and so permits the
use of a conventionally dimensioned cap.
Advantageously the cap may be provided with
engagement means for releasable engagement with
complimentary engagement means provided on the
container neck.
Advantageously the container neck may have an
external neck surface and the insert may be shaped
such that no part of the insert overlies the external
neck surface. This again provides the advantage of
restricting the dimensions of the insert in a plane
perpendicular to the axis of the bore and so once more
permits the use of a conventionally dimensioned cap.
According to a third aspect of the present
invention there is provided a closure for use with a
container neck having an external neck surface, the
closure comprising a cap and an insert, the cap having
a sealing surface and the insert having a
complimentary sealing surface for sealable engagement
with the sealing surface provided on the cap, the
insert being adapted to be permanently adhered to the
container neck and shaped such that no part of the
insert overlies the external neck surface. This again
provides the advantage of restricting the dimensions
of the insert in a plane perpendicular to the axis of
a bore defined by the container neck and so once more
permits the use of a conventionally dimensioned cap.
CA 02449926 2003-11-17
Advantageously the cap may be provided with
engagement means for releasable engagement with
complimentary engagement means provided on the
container neck.
Advantageously the container neck may have a rim
.surrounding an axial bore and the insert may be
adapted to be received within the bore, the insert
having a flange adapted to project outwardly from the
bore to overlie the surrounding rim such that the
insert protrudes axially from the bore no more than
the thickness of the flange. This again provides the
advantage of restricting the height of the insert
above the container neck and so once more permits the
use of a conventionally dimensioned cap.
Advantageously the cap may comprise a top and a
depending side wall, the engagement means being
provided on an interior surface of the depending side
wall. Advantageously the engagement means may
comprise a helical thread configuration.
Alternatively the engagement means may comprise a
first formation adapted to be snapped over and held in
position by a second retaining formation provided on
the container neck.
Advantageously the bore may be cylindrical and
the flange may be adapted to project radially
outwardly from the bore. Advantageously the external
dimension of the flange may be less than that of the
rim it is adapted to overlie. Advantageously the
flange may incorporate a pour lip. Advantageously the
flange may be adapted to be permanently adhered to the
container neck. Advantageously an undersurface of the
flange may incorporate a recess for the receipt of a
sealing medium with which to permanently adhere the
insert to the container neck.
Advantageously the insert may be adapted to be
wholly received within the external dimensions of the
cap. Advantageously the cap may have the same
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silhouette as that of a conventional cap thereby
enabling the closure to be applied using existing
capping equipment.
Advantageously the container neck may define a
bore and the insert may comprise a wall adapted to be
received within the bore, an interior surface of the
wall defining the sealing surface provided on the
insert and an exterior surface of a plug provided on
the cap defining the complimentary sealing surface
provided on the cap. Preferably the bore and wall are
cylindrical and the plug provided on the cap is
annular.
Advantageously the insert may be provided with a
removable membrane with which to close off the
container neck. Preferably the removable membrane may
be at least in part defined by a frangible line of
weakness and may be provided with a pull-ring with
which to separate the membrane from the remainder of
the insert. Advantageously at least a portion of the
removable membrane may be concave.
Advantageously both the cap and the insert may
comprise injection moulded plastics components.
According to a fourth aspect of the present
invention there is provided a closure in combination
with a container having a container neck, the closure
being as previously described. Advantageously the
container and container neck may be of a conventional
design thereby enabling the container to be
manipulated on a production line using existing
equipment.
According to a fifth aspect of the present
invention there is provided a closure in combination
with a container having a container neck defining a
bore, the closure comprising a cap and an insert, the
insert being permanently adhered to the container neck
and comprising a wall received within the bore and the
cap comprising a plug which sealingly engages with an
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interior surface of said wall at a location within the
container neck. This provides the advantage of
enabling the strength of the container neck to
contribute towards the adequacy of the seal.
Advantageously, at the location of sealing
engagement, the wall of the insert may be interposed
between the plug and a surface of the container neck
defining the bore. Advantageously the plug may be
formed so as to not only sealingly engage with an
interior surface of the wall but also to urge an
external surface of the wall into sealing engagement
with a surface of the container neck defining the
bore. Advantageously the insert may be formed of low
density polyethylene (LDPE) and the cap may be formed
of high density polyethylene (HDPE). Advantageously
the closure may have any of the additional features
previously described.
An embodiment of the present invention will now
be described by way of example with reference to the
accompany drawings in which:
Figure 1 is a perspective view of a container
neck and a closure;
Figure 2 is an exploded view of the container
neck of Figure 1 and showing the closure to comprise a
cap and an insert received within the container neck;
Figure 3 is an exploded view of the container
neck of Figure 1 and showing the closure to comprise a
cap, an insert and a sealing medium;
Figure 4 is a cross-sectional view of the
container neck of Figure 1 with the closure applied to
the container neck;
Figure 5 is an enlarged cross-sectional view of a
detail of Figure 4;
Figure 6 is a perspective view of an insert
forming part of the closure;
Figure 7 is a cross-sectional view of the insert
of Figure 6 taken along line VII - VII;
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Figure 8 is a cross-sectional view of the insert
of Figure 6 taken along line VIII - VIII; and
Figure 9 is a cross-sectional view of an
alternative design of container neck and showing an
alternative design of cap, the alternative designs of
neck and cap cooperating to provide the closure with a
tamper-evident capability.
Referring to the accompanying drawings and in
particular Figures 4 and 5 there is shown a neck 10 of
a container 12, an insert 14 received within the neck
10, and a cap 26 which engages with both the neck 10
and the insert 14. Together, the insert 14 and cap 16
define a closure 1$ for the container 12.
The container 12 may be of any conventional
design. In particular, the body shape of the
container 12 may take any suitable form and may, for
example, be of square, rectangular or circular cross-
section. Likewise, an integral handle may be formed
as part of the body shape.
The profile of the neck 10 is preferably also of
a conventional design and may, for example as shown in
Figure 9, comprise a pull-up neck finish formed as a
result of a blow pin being pulled up through an
annular shear steel to create a neck opening having a
relatively thin, but generally smooth, annular rim.
Alternatively, the neck 10 may comprise a ram-down
neck finish formed as a result of a technique in which
a blow pin and cutting ring are rammed down through an
annular shear steel to produce a neck opening which is
surrounded by a much more rigid perimeter and which
contains far more plastics material than its pull-up
counterpart. As will be readily appreciated by those
skilled in the art, the embodiment illustrated in
Figures 3 to 5 shows a container 12 having just such a
ram-down neck finish as evidenced by the
characteristic annular wall which projects upwardly
from a radially inner edge of the annular rim and
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which is known in the art as a chimney.
The profile of the neck 10 is shown in more
detail in Figures 3 to 5 to comprise a radially
extending rim 20 which merges, at a radially inner
end, with the chimney 22. The chimney 22 is in turn
defined by an upwardly extending, radially outer wall
24; an upper, generally horizontal surface 26; and a
downwardly extending, radially inner wall 28.
At a radially outer end, the rim 20 merges with a
downwardly extending neck stretch portion 30 which is
provided, on an exterior surface, with engagement
means 32 with which to engage complimentary engagement
means provided on the cap 16. In the example shown,
the engagement means 32 takes the form of a male
helical thread configuration comprising a single
start. It will be apparent however, that the
engagement means 32 may take a number of different
forms and, in particular, may not be limited to a
single thread or lead but may comprise two, three,
four or more threads as appropriate. For example, the
engagement means may comprise five, six, seven or
eight threads if so desired. Indeed, although not
illustrated, for certain packaging requirements a
plurality of threads may be preferable.
In the illustrated embodiment, the single thread
extends approximately 450° around the circumference of
the neck stretch portion 30. Once again however, it
will be understood that threads of a lesser or greater
extent may also be employed. For example, in a four
start thread configuration, each thread may extend
within a range from 90° to more than 360°.
Preferably the helical thread configuration has a
fine thread density to limit the vertical float of the
cap 16 on the neck 10. Thus, the thread density
preferably lies within the range of between 6 and 12
threads per linear inch. Most preferably of all, is a
thread density of approximately 8~ threads per linear
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inch.
Below the engagement means 32, the neck stretch
portion 30 merges with a generally horizontal,
radially extending wall 34. This generally
horizontal, radially extending wall 34 merges, at a
radially outer end, with an arcuate wall portion 36
before in turn merging with a downwardly and radially
outwardly extending wall 38. The precise direction
and extent of the downwardly and radially outwardly
extending wall 38 are determined by the shape of the
container 12 which, as stated previously, may be
entirely conventional, and forms no part of the
present invention.
Irrespective of the neck finish, the container 12
may be blow-moulded from high density polyethylene
(HDPE) so as to have a typical wall thickness of
between 0.1mm and l.Omm. A container having a wall
thickness of less than O.lmm is unlikely to have the
necessary structural integrity to hold its shape when
filled with fluid. For a milk container having a
capacity of up to six pints (3.41 litres) a wall
thickness of between 0.4mm to 0.6mm is preferred.
The cap 16 which forms part of the closure 18
preferably has a conventional silhouette. In other
words, its external dimensions, for example, its
height and diameter, are the same as those of existing
caps and may therefore be handled using existing
capping equipment.
As shown in Figures 4 and 5 the cap 16 comprises
a circular top 40 which merges at a radially outer
edge with a depending annular side wall 42. The
depending annular side wall 42 terminates at an end
remote from the circular top 40 in a generally
horizontal annular surface 44 while, on an exterior
surface, the depending annular side wall 42 is
provided with a plurality of circumferentially spaced,
vertically extending ribs 46 which serve as knurls to
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facilitate the gripping of the cap 16 by a user. In
contrast, on a radially inner surface, the depending
annular side wall 42 is provided with complimentary
engagement means 48 for repeated and releasable
engagement with the engagement means 32 provided on
the neck 10. As before, this engagement means 48 may
take many forms but, in the example shown, comprises a
male helical thread configuration having a single
start and a thread density of approximately 8'~ threads
per linear inch. Once again, however, it will be
appreciated that the complimentary engagement means 48
need not be limited to a single thread or lead but may
comprise two, three or four threads as appropriate.
Indeed, the complimentary engagement means 48 may
comprise five, six, seven or eight threads if so
desired. Indeed, as with the engagement means 32, for
some packaging requirements it may be preferable for
the complimentary engagement means 48 to comprise a
plurality of threads.
In the illustrated embodiment the single thread
extends about 450° around the inner surface of the
depending annular side wall 42. Once again however,
it will be understood that threads of a lesser or
greater extent may also be employed. For example, in
a four start thread configuration, each thread may
extend within a range from 90° to more than 360°.
hikewise, although a thread density of
approximately 8'~ threads per linear inch is preferred,
so as to limit the vertical float of the cap 16 with
respect to the neck 10, nonetheless the thread density
may differ from this figure. Preferably however, the
thread density lies within a range of between 6 and 12
threads per linear inch.
As will be apparent to those skilled in the art,
if one of the engagement means 32 or 48 comprises a
male helical thread configuration, then the other of
the two engagement means may comprise a helical groove
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configuration.
The two thread configurations 32 and 48 may be
shaped so as to slip past one another and engage when
a direct, axial downward force is applied to the cap
16 urging the cap into engagement with the neck 10.
In other words, when the cap 16 is pushed onto the
neck I0, the thread 48 on the cap snaps over and
engages the thread 32 on the neck. This may be made
possible by appropriate shaping of the threads 32 and
48, for example, by forming the threads with an
asymmetric cross-section or by making them less
pronounced. Alternatively, if it is desired to rotate
the cap 16 onto the neck 10, the threads may be of
symmetrical, as opposed to asymmetrical cross-section
and may be more pronounced.
In addition to the complimentary engagement means
48, the interior of the cap 16 is also provided with
an annular plug 50 which depends from an undersurface
52 of the circular top 40 and is spaced radially
inwardly of the depending annular side wall 42. The
annular plug 50 is defined by respective radially
inner and outer walls 54 and 56, the radially outer
plug wall 56 merging at an end remote from the
circular top 52 with a generally downward and radially
inwardly directed surface 58. This downwardly and
radially inwardly directed surface 58 intersects the
radially inner plug wall 54 and, together, serves to
provide the annular plug 50 with a bevelled radially
outer surface and a tapering cross-section. This
tapering cross-section is further accentuated by the
fact that, whereas the radially outer plug wall 56
extends in a direction substantially perpendicular to
the plane of the undersurface 52, the radially inner
plug wall 54 extends from the undersurface 52 in a
direction which is both downwardly and radially
outwardly.
Elsewhere, as it common with a number of caps, a
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small downwardly directed dimple 60 is formed in the
centre of the circular top 40 so that any flash left
after the cap 16 has been moulded does not project
above a plane defined by the upper surface of the
circular top 40.
The insert 14 which is received within the neck
of the container 12 is defined, in part, by a
downwardly extending cylindrical wall 62. At an upper
end, the downwardly extending cylindrical wall 62
10 merges with a radially outwardly extending annular
flange 64 while at an opposite, lower, end the
downwardly extending cylindrical wall 62 merges with a
generally downwardly and radially inwardly directed
annular wall 66 of arcuate cross-section. This wall
66 of arcuate cross-section terminates in an upwardly
and radially inwardly directed annular surface 68
which would define a circular aperture but for the
provision of a membrane 70 which spans the opening
defined by the upwardly and radially inwardly directed
annular surface 68. The membrane 70 is joined to the
generally downwardly and radially inwardly directed
annular wall 66 by means of a narrow annular web 72
which interconnects an upper, radially inner corner of
the generally downwardly and radially inwardly
directed annular wall 66 with a lower, radially
outward corner of the membrane 70. As for the
membrane 70, it is defined by a substantially
horizontally extending outer annular portion 74 which
merges with a central, circular, concave portion 76.
A pull-ring 78, defined by an annular band 80,
merges with the membrane 70 via a connection 82. The
connection 82 merges with the membrane 70 at a
location radially inward of, and adjacent to, the
annular web 72 such that the pull-ring 78 is joined to
the substantially horizontally extending outer annular
portion of the membrane 74 as opposed to the central,
circular, concave portion 76. The annular band 80 is
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sized so as to be located within the insert 14 below
the level of the radially outwardly extending annular
flange 64 and is provided with radiused upper and
lower external surfaces 84 and 86 so as to provide a
comfortable surface, devoid of sharp edges, for a
user's finger to pull against. The concave nature of
the central circular portion of the membrane 76
facilitates the gripping of the pull-ring 78 by
creating an increased void below the annular band 80
while, at the same time, reducing the effects of
shrinkage on the membrane tear line defined by the
narrow annular web 72. As illustrated, the connection
82 between the annular band 80 and the membrane 70 may
be strengthened by the provision of a pair of
reinforcing gussets 88.
In contrast to the generally downwardly and
radially inwardly directed annular wall 66, the
radially outwardly extending annular flange 64
provided at an upper end of the downwardly extending
cylindrical wall 62 is defined by an upper surface
which slopes upwardly and radially outwardly before
terminating in an annular pour lip 92. At the same
time, a lower surface of the radially outwardly
extending annular flange is provided with an annular
recess 94 which extends from the radially outer
surface of the downwardly extending cylindrical wall
62 and is bound, at an end of the annular flange 64
remote from the cylindrical wall 62, by a downwardly
depending annular lip 96.
In order to assemble the closure 18 comprising
the insert 14 and cap 16 to the container 12 a sealing
medium 98 is applied to the lower surface of the
radially outwardly extending annular flange 64 of the
insert 14. The sealing medium 98 may be extruded,
sprayed, painted or otherwise applied. However, in
the preferred embodiment, the sealing medium 98 has
sufficient structural integrity to form an annular
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ring which can be received within the annular recess
94. For example, the sealing medium 98 may comprise an
electrically conductive substrate coated on opposed
surfaces with respective first and second layers of an
adhesive. The electrically conductive substrate may
be formed of any of the materials traditionally used
for providing a heat seal in existing plastics
containers and may, for example, comprise a metallic
foil such as an aluminium foil. Likewise, the layers
of adhesive may be of any commercially available type
which is capable of bonding with the surrounding
plastics material once activated by, for example, the
application of heat.
Thus, in this embodiment, the first step in
assembling the closure 18 is to assemble the insert 14
and the sealing medium 98. This may be achieved
either by inserting the downwardly extending
cylindrical wall 62 through the central aperture of
the annular ring or else by inverting the insert 14
and pressing the annular ring over the downwardly
extending cylindrical wall 62. In either case, the
assembly is facilitated by the arcuate cross-section
of the generally downwardly and radially inwardly
directed annular wall 66. Although in the described
embodiment the sealing medium 98 is received within
the annular recess 94, nonetheless it is preferably
retained in place by means of a friction fit with the
radially outer surface of the downwardly extending
cylindrical wall 62. Thus the provision of the
downwardly depending annular lip 96 is preferably for
cosmetic purposes only and serves to conceal the
presence of the sealing medium 98 rather than to
retain it in position. Indeed, in some embodiments,
the downwardly depending annular lip 96 may be
omitted.
Having assembled the insert 14 and sealing medium
98, the two are then assembled to the cap 16. The cap
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16 is offered up to the insert 14 and, in so doing,
the annular plug 50 is received within the blind bore
defined by the downwardly extending cylindrical wall
62. The receipt of the annular plug 50 in this way is
facilitated by the bevelled nature of the plug as a
result of the generally downward and radially inward
directed surface 58. Nonetheless, the annular plug 50
is so positioned as to be required to flex radially
inwardly in order to be received within the
aforementioned blind bore. In this way, once the
annular plug 50 has been fully received, the
resilience of the material forming the plug causes the
radially outer wall 54 to be urged into sealing
engagement with the inner surface of the downwardly
extending cylindrical wall 62.
It will be noted that the limit to which the
annular plug 50 can be received within the blind bore
defined by the downwardly extending cylindrical wall
62 is determined by the engagement of the upper
surface 90 of the radially outwardly extending annular
flange 64 with the undersurface 52 of the circular top
40. However, even in the fully received position, the
pull-ring 78 is positioned such that it remains spaced
from and does not abut the cap 16.
The closure 18, comprising the insert 14 and cap
16 as well as the sealing medium 98, is now fully
assembled. However, all of the components are
received within the cap 16 with the result that the
external dimensions of the closure 18 are the same as
those of the cap 16 which, as stated previously, may
be entirely conventional. As a result the assembled
closure 18 may be manipulated and applied using
conventional processing and capping equipment.
To assemble the closure 18 to the container 12
the container is first filled with the desired
contents. Because the container 12 may be of a
conventional design, this filling step may be
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performed using existing equipment, as may its
subsequent processing elsewhere along the production
line. Once the container 12 has been filled, the
assembled closure 18 is offered up to the neck 10 in
such a way that the generally downwardly and radially
inwardly directed annular wall 66 of the insert 14 is
received within the bore defined by the downwardly
extending, radially inner wall 28 of the chimney 22.
Continued downward pressure of the closure 18 onto the
neck 10 causes the downwardly extending, radially
inner wall 28 of the chimney 22 to slide along the
radially outer surface of the downwardly extending
cylindrical wall 62 until such time as the upper,
generally horizontal surface of the chimney 26 engages
the sealing medium 98 received within the annular
recess 94. In so doing, as the downwardly extending,
radially inner wall 28 nears the end of its travel, so
the annular plug 50 is once again caused to flex
radially inwardly to accommodate both the annular plug
50 and the downwardly extending cylindrical 62 within
the bore defined by the chimney 22. As before, the
radial inward flexing of the annular plug 50 is
facilitated by the generally downward and radially
inward directed surface 58 while the resilience of the
material forming the annular plug 50 ensures that,
afterwards, the annular plug is not only urged into
sealing engagement with the inner surface of the
downwardly extending cylindrical wall 62 but also that
the outer surface of the downwardly extending
cylindrical wall 62 is urged into sealing engagement
with the downwardly extending, radially inner wall 28
of the chimney 22.
At the same time as the insert 14 is received
within the bore defined by the chimney 22, so the
depending annular side wall 42 of the cap 16 passes
over the downwardly extending neck stretch portion 30.
This brings the engagement means 32 into engagement
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with the complimentary engagement means 48. As stated
previously, these two engagement means 32 and 48 may
be shaped so as to slip past one another when a
direct, axially downward force is applied to the cap
16 urging the cap into engagement with the neck 10.
In other words, as the closure 18 is pushed onto the
container 12, so the threads on the cap 16 snap over
and engage the threads on the neck 10.
In an alternative embodiment the threads on the
cap 16 and the threads on the neck 10 may be shaped so
as to require the closure 18 to be rotated onto the
container 12. Nonetheless, the downwardly extending
cylindrical wall 62 of the insert 14 is still fully
received within the bore defined by the downwardly
extending, radially inner wall 28 of the chimney 22.
Once the closure 18 has been fully applied to the
container 12, the assembled closure and container are
exposed to a time varying magnetic field which gives
rise to eddy currents within the electrically
conductive substrate of the sealing medium 98 with the
resultant generation of heat. This heat in turn
activates the layers of adhesive and bonds the
radially outwardly extending annular flange 64 to the
upper, generally horizontal surface 26 of the chimney
22. If necessary, some pressure may be applied to
hold the closure 18 firmly against the container 12
during the bonding process.
Although the sealing medium 98 has been described
as comprising two layers of a heat-activated adhesive,
one on each side of the central electrically
conductive substrate, it will be apparent~that the
insert 14 and neck 10 may nevertheless be permanently
bonded together using only a single layer of heat-
activated adhesive provided that sufficient adhesive
is present within the annular space defined between
the cooperating parts of the fitment and neck and
provided that the adhesive is capable of flowing into
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contact with the surfaces defining that space. To
that end, the electrically conductive substrate rnay be
provided with one or more apertures to permit the flow
of adhesive from one side of the substrate to the
other.
In another embodiment the sealing medium 98 may
comprise a sealing compound, and in particular may
comprise a pressure adhesion compound such that, upon
application of a closing pressure to either the
closure 18 or the container 12, the insert 14 is
permanently bonded to the neck 10. Alternatively, the
sealing medium 98 may be a compound which is activated
when exposed to microwave radiation. In yet another
currently preferred embodiment, the sealing medium 98
is a composition that permanently bonds the insert 14
to the neck 10 when the sealing compound is softened
or melted by inductive and/or capacitive heating. To
this end, once the closure 18 has been applied to the
container 12, the assembled closure and container are
exposed to a time varying magnetic field in the case
of inductive heating or a time varying electric field
in the case of capacitive heating. In either case,
heat is generated within an inductive and/or
capacitive material contained within the composition.
This heat is then transferred to the rest of the
composition and the composition then either softens or
melts so that it flows into more intimate contact with
the surfaces of the annular space defined between the
cooperating parts of the insert and neck structures.
Upon cooling, the composition hardens to provide a
permanent weld or seal that bonds the insert 14 to the
neck 10.
Once the insert 14 has been adhered to the neck
10, the container 12 may be opened by unscrewing and
removing the cap 16. This exposes the pull-ring 78
which may be gripped by a finger of the user and
pulled. The force imparted to the annular band 80 is
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transferred, via connection 82, to the membrane 70
which tears away from the generally downwardly and
radially inwardly directed annular wall 66 along the
line of weakness defined by the narrow annular web 72.
Once the pull-ring 78 and the membrane 70 to which it
is attached has been discarded, the contents of the
container 12 may be dispensed in the usual way.
To re-close the container 12, the cap 16 is
simply presented to the neck 10 in such a way that the
helical thread configuration 48 on the cap engages the
helical thread configuration 32 on the neck. As the
cap 16 is screwed home so the generally downward and
radially inward directed surface 58 of the annular
plug 50 engages the radially inner surface of the
downwardly extending cylindrical wall 62. This causes
the annular plug 50 to flex radially inwardly. Once
the cap 16 has been fully applied to the neck 10, the
resilience of the material forming the annular plug 50
ensures that the radially outer wall of the plug 56 is
urged into sealing engagement with a radially inner
surface of the downwardly extending cylindrical wall
62 and that a radially outer surface of the downwardly
extending cylindrical wall 62 is urged into sealing
engagement with the downwardly extending, radially
inner wall 28 of the chimney 22.
Because both the insert 14 and cap 16 may be
injection moulded and therefore made to the same
tolerances, it is anticipated that a reliable reseal
may be obtained every time and that, strictly
speaking, no secondary seal is required. Nonetheless,
a secondary seal may be provided radially outwardly of
the chimney 22 at the point of engagement between the
upper surface 90 of the radially outwardly extending
annular flange 64 and the undersurface 52 of the
circular top 40.
The cap 16 may be screwed on and off the neck 10
as many times as is required.
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It will be noted that because the sealing medium
98 is located within a space which does not
communicate with the interior of the container 12
there is little risk of the sealing medium tainting or
otherwise affecting the contents of the container.
Likewise, because the insert 14 is provided with a
downwardly extending cylindrical wall 62 which
sealingly engages against the downwardly extending,
radially inner wall 28 of the chimney 22, there is
little likelihood of the contents of the container
leaking out past the sealing medium 98 between the
insert 14 and the neck 10.
It will also be noted that because both the
effective size of the container opening (defined by
the diameter of the upwardly and radially inwardly
directed annular surface 68) and the annular pour lip
92 are both defined by the same injection moulded
component, the relationship between the two can be
optimised so as provide the optimum pouring angle
whilst retaining a practical bore.
Whilst the application of the closure 18 has been
described with reference to a ram-down neck finish, it
will be understood that the present invention may also
be applied to a pull-up neck finish. Indeed, the only
difference between the two resides in the fact that,
in the absence of the chimney 22, the sealing medium
98 serves to bond the underside of the radially
outwardly extending annular flange 64 to the radially
extending rim 20 rather than to the upper, generally
horizontal surface 26. Nonetheless, the downwardly
extending cylindrical wall 62 can still be received
within the bore defined by the radially extending rim
20 where, as before, it will be in sealing engagement
with both the radially extending rim 20 and the
annular plug 50. Thus, in all material respects the
closure 18 may be applied, opened and resealed to a
ram-down neck finish as described above. In
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particular, it will be noted that, notwithstanding the
absence of the chimney 22, the sealing medium 98 is
still contained within an annular space which does not
communicate with the interior of the container 12.
With containers having either a pull-up or ram-
down neck finish the provision of the downwardly
depending annular lip 96 serves to conceal the
presence of a sealing medium 98.
Although in the embodiment described the closure
18 has not been provided with any tamper evidence
capability, it will be understood that this could also
be provided. Indeed, since one of the advantages of
the present invention is that it may find use with
conventional containers 12 and makes use of caps 16
having a conventional silhouette, if those
conventional containers and caps incorporate tamper
evidence means, then so to may the present invention.
One such example is illustrated in Figure 9.
Although the engagement means 32 provided on the
neck 10 and the complimentary engagement means 48
provided on the cap 16 have been described in terms of
a helical thread or groove configuration, nonetheless
the two sets of engagement means 32 and 48 may simply
comprise a snap-band and cooperating retaining bead.
Alternatively, the engagement means 32, 48 may rely
upon nothing more than a friction or interference fit.
Under such circumstances the resulting cap may be
presented as a push-on cap rather than of the screw-on
variety.
