Note: Descriptions are shown in the official language in which they were submitted.
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A CLOSURE DEVICE
This invention relates to a closure device for closing an
opened carbonated beverage can.
Carbonated beverages, otherwise known as fizzy drinks, are
sold in cans which conventionally have a ring-pull opening
mechan.ism. When a ring secured to the top of the can is
pulled, part of the top of the can itself is removed to
leave a hole through which the drink can be dispensed. A
problem with such cans is that the opening cannot be
resealed by the ring-pull mechanism. Thus if one wants to
drink only part of the can contents, then the remainder of
the contents cannot be kept fresh. Also, if the opened can
is to be carried about, or is to be carried in a moving
vehicle, then there is the risk of the contents being
spilt.
The shape of the opening which is revealed in the top of
the can when the ring is pulled varies from manufacturer to
manufacturer. In some cases the ring remains attached to
the can, and because of this variation it is not practical
to provide a resealable top which cooperates with the
aperture itself, although there are proposals in existence
which aim to work in this way (see for example EP-B-0 112
306 and GB-A-2 210 028).
According to the present invention, there is provided a
closure device for closing an opened carbonated beverage
can, the device comprising a seal adapted to seal against
a peripheral annular region of the can which surrounds the
opening of the can, and seal securing means which act
against the bottom of the can to secure the seal against
the annular region.
Many carbonated beverage cans have an outer rim and an
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inner rim, an annular gutter between the two rims and a top
surface inside the inner rim and in which the opening of
the can is located. In such a can, the seal may act
against the inner rim, the outer rim, in the gutter or
against an outer annular part of the top surface.
The seal may act against the inner base of the outer rim,
against the top of the outer rim (which will generally be
higher than the inner rim) or, as is preferred, against the
top of th0 inner rim where this connects with the top
surface.
The seal preferably has a diameter of between 50 and 60mm
so that it will provide a seal on the rim of a conventional
drinks can.
The seal may be formed by a flexible seal ring mounted in
a lid. The seal ring can be a push-fit in an annular
socket in the lid. Alternatively, the lid may have an
internal integral formation which forms the seal.
In a preferred form, the device is formed in two parts; a
cap which carries the seal, and a cup-like base. The base
locates under the bottom of a can or in a step near the
bottom of the can, and the cap and the base can be secured
together in such a way that a tension force is created in
the device between the bottom of the can and th~ cap to
pull the seal against the rim of the can. This force is
counteracted by a compression force arising in the walls of
the can.
Because the seal seals against a peripheral annular region
of the can which is concentric with the can itself, the cap
can be secured onto the base by screwing together threads
formed on the cap and the base. The axis of rotation on
which the screw threads are screwed together will
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correspond with the axis of the cylindrical can. The
complementary threads are part of the seal securing means
which produce the desired tension force in the device.
There may be a stop formed to prevent overtightening which
might lead to crushing of the can.
To allow quick release of the internal pressure, a valve
can be provided i.n the cap. This valve may operate
automatically to release pressure above a certain threshold
pressure, or may be user operated, for example so that the
pressure can be released before the cap is opened.
Instead of a base into which the can is inserted, the seal
may be provided with legs or other tension members which
engage under the bottom of the can and which can be placed
in tension to pull the seal onto the lip.
Where a base and a cap are used, they may be provided with
thermal insulation to keep the can and its contents cool.
The insulation may be an integral part of the material of
the base and/or the cap, or alternatively may be provided
by a filling between inner and outer skins which form the
base and the cap. If desired, drainage holes can be fitted
in the base of a thermally insulated device so that
condensation can drain away.
The external wall of the cap and the wall of the base may
be provided with ribbing or the equivalent to help in
screwing and unscrewing the cap from the base.
Alternatively either the base or the cap or both may have
apertures formed in their walls. This can help to prevent
condensation forming on the wall of the can as well as
providing a grip for the hands and exposing part of the can
itself so that the identity of the can inside the device
can be established.
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Where the device is to be used with cans of a different
volume, the base may be designed to accommodate the largest
can size, and when a smaller can size is to be used, a
packing slug can be placed in the base before the can is
put in, to occupy the extra volume. The slug may be made
of or may contain a material which can be frozen before use
and which will be in contact with the can to assist in
keeping the can contents cool.
The invention will now be further described, by way of
example, with reference to the accompanying drawings, in
which:
Figure 1 is a side view of a conventional fizzy drinks
can;
Figure 2 is a perspective view of the top of the can
of Figure 1, with the can opened;
Figure 3 shows a cross section through a closure
device in accordance with the invention, with the can
of Figures 1 and 2 shown in position;
Figure 4 is a detail of part of the cap from Figure 3;
Figure 5 is an external view of the closure device of
Figures 3 and 4;
Figure 6 is a view corresponding to Figure 4 but
showing a second embodimenti
Figure 7 is a view corresponding to Figure 4 but
showing a third embodiment;
Figure 8 is a view corresponding to Figure 4 but
showing a fourth embodiment;
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Figure 9 is a view corresponding to Figure 4 but
showing a fifth embodiment;
Figure 10 shows a section through a sixth form of
closure device in accordance with the invention; .
Figure 11 is a view corresponding to Figure 10 but
showing a seventh embodiment of closure device in
accordance with the invention;
Figure 12 is a cross-section through an eighth
embodiment of closure device in accordance with the
invention;
Figure 13 is a cross-section through a ninth
embodiment of closure device in accordance with the
invention;
Figure 14 is a detail of a thread form for use with
lS the closure device of the invention; and
Figure 15 is a detail of part of the construction of
the ninth embodiment.
The can shown in Figure 1 has a top 1, a bottom 2 and side
walls 3. The top has an outer rim 4. At the top of the
can (see Figure 2) a top surface 5 is surrounded by a
gutter 6, with an inner rim 7 forming the outer edge of the
top surface. A ring-pull closure 8 can be pulled to open
a dispensing opening 9.
- The closure device shown in Figure 3 consists of a base 10
and a cap 12~ The base and the cap define a cavity between
them which is dimensioned so as to receive a standard sized
drinks can, for example a 330 ml fizzy drink can as shown
- ~ in Figures 1 and 2. The bottom of the can sits on the
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bottom 14 of the base 10. When the cap 12 is screwed onto
the base using the thread 16, an internal annular ridge 18
on the cap 12 will engage with the inner flank 20 of the
outer rim 4 on the can 22 to form a seal. The thread 16
can be a coarse thread with a number of starts.
The can 22 has had its ring pull closure removed so that
the top of the can has an opening 9. This opening now
communicates with a space 26 above the can, but this space
is bounded by the seal formed between the ridge 18 and the
flank 20. If the can is shaken around, some liquid from
the can may pass through the opening 24 into the space 26,
but it can go no further than this, and because of the
nature of the seal between the ridge and the flank,
pressure tightness of the can will be maintained. Where
the can has a ring-pull of the type which remains attached
to the can, as seen in Figure 2, then this ring-pull can be
accommodated in the space 26.
Figure 4 shows one type of sealing arrangement in more
detail. The can 22 has a top surface 5, an annular gutter
6 around the outside of the surface 5, an inner rim 7 and
an outer rim 4. Between the gutter 6 and the rim 4 is a
flank 34. The cans in which fizzy drinks are sold are
standard dimensions. For cans sold in the UK, the angle
which the flank 34 makes to the vertical t~ is
approximately 17. The diameter of the top of the outer rim
4 is about 57mm. Cans sold in other countries may have
different dimensions, but the skilled man will be able to
modify the profile and position of the rim 4 in this
emhodiment to provide the required seal. The external
diameter and the flank angle of the xidge 18 are chosen
such that the ridge will not bottom in the channel 30;
neither will the rim 4 come into contact with the top OI
the cap. Instead a seal is achieved over a wide area of
the flank 34.
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Figure 5 shows the exterior of the closure device. It will
be seen in this Figure that the base 10 has oval shaped
cut-outs or apertures 36 which allow the can to be seen in
the interior of the device, and also allow air to circulate
around the can to prevent condensation being formed on the
outside of the can. Figure 3 also shows a shoulder 38 on
the base lo which forms a stop for screwing up movement of
the cap 12 to prevent overtightening taking place.
Figure 6 illustrates on a larger scale, an alternative
embodiment where the sealing function is performed in a
slightly different manner. The cap 12a of the closure
device of Figure 6 has two internal ridges 18 and 18a. The
ridge 18 seals against the flank 34 in much the same manner
as shown in Figure 4, and the ridge 18a provides a back-up
seal against the outer edge of the outer rim 4. This
therefore provides a double seal.
Figure 7 shows the same cap 12a, but this time with a body
35 of closed cell polyethylene foam retained in the cap by
the ridge 18. This foam pad does not take part in the
hermetic sealing of the can but does prevent any
substantial volume of liquid entering the space 26 and thus
prevents mess when the device is opened.
In Figure 8, a different arrangement of internal ridges is
used. In this Figure, the ridges are indicated by
reference numerals 18b and 18c. Both ridges lie inside the
circle of the rim 4 and between them define an annular
socket 45 in which a seal ring 37 is fitted. In this case,
a first seal is established between the ridge 18b and the
flank 34 of the rim 4, and a second seal is established
between the internal rim 7 and the seal body 37.
In Figure 9, the cap 12 has two internal ridges 18d and 18e
which form an annular sockst receiving an annular seal ring
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37a. The ridge 18d is shorter than the ridge 18b of Figure
8 and does not itself form a seal. The sealing function in
this embodiment is performed entirely by the ring 37a.
However the bottom edge of the ring 37a is formed so that
it creates a primary seal against the inner rim 7 and a
secondary seal by the engagement of an outer lip 39 in the
gutter 6. A rib 41 is also compressed against the top
surface 5 of the can 22 to improve the 'feel' experienced
by the user when screwing down the cap 12.
Figure 10 shows yet another embodiment where a base 10 and
a cap 12 are screwed together on a square section thread
16a. A can 22 is shown in place inside the base and the
cap, and it will be seen that the top internal face of the
cap 12 has a disc-like seal 40 which is pressed against
the top edge of the outer rim 4 of the can. The seal acts
by being simply pressed down against the rim of the can as
the cap is tightened on the base, and this forms a boundary
to the space 26 formed above the can. In this embodiment
also, three O-rings 42 are shown in the cap in order partly
to act as a back up seal for the can contents, and secondly
to prevent the can rattling inside the cap.
Figure 11 illustrates another embodiment which is shown in
the condition before sealing has been accomplished. A seal
disc 44 is mounted and supported on an upper frame 46. The
upper frame 46 includes a handle portion 48 containing cut-
outs 50 for the fingers. Tension straps 52 connect the
frame 46 to feet 54 which engage under the base 56 of the
can. The straps 52 can be tensioned by any suitable
mechanism, for example an over-centre mechanism (not shown~
which would pull the support member 46 down onto the can 22
to press the sealing disc 44 against the rim 32 of the can.
In Figure 11, lateral sealing strips 58 ar~ also shown
which act in the same way as the O-rings shown in Figure 4.
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Although the closure devices shown in the preceding figures
have not attempted in any way to provide thermal insulation
for the can, such insulation can very easily be
incorporated in the device. Figure 12 shows a base loc and
a cap 12c both of which have inner and outer skins 60,- 62
with a layer 64 of thermal insulation between the skins.
The inner and outer skins 60l 62 are separate moulding (two
mouldings for the base and two mouldings for the cap). The
thermal insulation 64 if formed as a separate pre-formed
component of a size sufficient to fit comfortably in the
cavity between the inner and the outer skins. Forming the
insulation in this way rather than foaming in place
provides a quick and reliable assembly technique which does
not require a waiting stage while a foam is formed and
cures. After assembly of the three parts (inner skin,
insulation and outer skin) the inner and outer skins are
bonded permanently together by an ultra sonic weld around
the joint 66.
The outer skin 62 o~ the base lOc also has drain holes 68.
The inner skins 60 of the base and of the cap carry the
threads which connect the two parts and also the seal
which, in use, will provide a seal at the top end of a
drinks can. In Figure 12, the ridges 18d and 18e (see
Figure g) are shown, but with the sealing ring 37a of that
Figure omitted. Figure 12 also shows axial ribs 70 which
help to centre the cap when it is screwed onto the base
with a can in place.
The threads 16 which connect the cap and the base are
preferably coarse, multi-start threads (for example there
may be three starts), and the thread profile as shown in
Figure 14 has been found to be suitable. There is axial
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play between the flanks of the thread until the cap is
screwed up tight onto a can, at which time the play is
taken up.
Figure 13 shows an insulated closure device with many of
tha features already described with reference to Figure 12.
In Figure 13, the sealing ring 37a is shown in place. The
base lOc does not differ from that shown in Figure 12, but
the cap 12d has a pressure release passage 72 which is
normally closed by a screw-on cap 74.
When an opened drinks can is inside the closure device,
pressure can build up to quite a high level. When the
pressure is high, the flanks of the thread 16 are forced
firmly into contact with one another and it may be
difficult to unscrew the cap from the base. In order to
overcome this problem, the passage 72 can be opened by
removing the screw-on l d 74. This will release the
pressure and the cap 12d can then be unscrewed.
The passage 71 may also constitute a drinking spout.
The screw-on lid 74 may have a non-round shape so that it
is easy to grip and turn.
The passage 72 can easily be incorporated in the
manufacturing process by making the walls of the passage 72
integral with the inner skin 60; making a suitable cut-out
in the insulation foam 64 and in the outer skin 62, and
then assembling the outer skin over the spout-like-end of
the passage 72 in the manner indicated in figur~ 15 where
the outer skin 62 snaps beneath an external bead 78.
Figure 13 also shows the use of a packing slug 76 which can
be placed in the bottom of the base lOc when the de~ice is
to be used with a smaller can. With the slug 76 in place,
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the bottom of the can will sit on the top of the slug so
that the top of the can is in the correct relationship with
the cap 12d. The use of such a slug, or a range of slugs
of different sizes, can allow one device to be used with
cans of a corresponding range of sizes.
The slug 76 may contain a material which can easily be
frozen and which acts as a cooling device in the base,
beneath the bottom of the can and in heat-transmitting
contact with the base of the can.
The closure device shown in the various embodiments of the
drawings is simple and effective to operate and serves the
primary function of sealing the opened can without allowing
any escape of gas which might allow the drink to go flat.
It is helpful if the can is a tight fit in the base 10 so
that once the cap has been unscrewed, the can can be held
by holding the base.
The components of the closure device can be easily moulded
from plastics materials. Food grade polypropylene, for
example the material sold by Repsol of France under the
Trade Mark Isplen and the designations PP/080 and PP/095
has been found to be suitable. In the embodiment shown in
Figures 1 to 3, the sealing ring inside the cap can be
integral with the cap material. Alternatively a separate
sealing disc of the appropriate rubber hardness could be
used. A suitable rubber is the thermoplastic rubber sold
by the Monsanto company under the Trade Mark Santoprene,
Grade 177.
It is an important part of the invention that the force
which is needed to make and maintain a seal around the open
3~ part of the can is generated by fitting an abutment beneath
the bottom of the can and then putting into tension linking
means which connect the seal to the abutments. The
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abutments do not need to completely enclose the bottom of
the can; they may only engage under part of the can bottom
as shown in Figure 11, or where the can has a stepped
bottom formation as at 43 in Figure 1, the abutment may
engage under the step at the bottom rather than fully under
the bottom.
