U.S. patent application number 12/741858 was filed with the patent office on 2011-02-03 for container closure with overcap.
This patent application is currently assigned to BEESON AND SONS LIMITED. Invention is credited to Roger Milner King.
Application Number | 20110024420 12/741858 |
Document ID | / |
Family ID | 38858460 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110024420 |
Kind Code |
A1 |
King; Roger Milner |
February 3, 2011 |
CONTAINER CLOSURE WITH OVERCAP
Abstract
A container closure comprising: a plastics inner cap (2) having
a base portion (4) and a skirt portion (5), a thread (10) on the
inside of the skirt portion, a first snap fitting element (11) on
the outside of the skirt portion, and a tamper evident ring (6)
formed integrally with the skirt portion and joined to an open end
of the skirt portion by severable connections (20,21); a plastics
overcap (3) having a base and a skirt portion (26) in mating
engagement with the skirt portion of the cap and extending beyond
the open end of the skirt portion of the cap to at least partially
cover the tamper-evident ring, and a second snap fitting element
(31) on the inside of the skirt that engages with the first snap
fitting element on the inner cap skirt to resist separation of the
overcap from the inner cap. Also provided is a closure assembly
comprising a threaded container neck (1) and a container closure
according to the invention.
Inventors: |
King; Roger Milner;
(Buckinghamshire, GB) |
Correspondence
Address: |
Stephen B. Salai, Esq.;Harter Secrest & Emery LLP
1600 Bausch & Lomb Place
Rochester
NY
14604-2711
US
|
Assignee: |
BEESON AND SONS LIMITED
STOKE POGES
GB
|
Family ID: |
38858460 |
Appl. No.: |
12/741858 |
Filed: |
November 7, 2008 |
PCT Filed: |
November 7, 2008 |
PCT NO: |
PCT/GB08/03756 |
371 Date: |
July 9, 2010 |
Current U.S.
Class: |
220/254.8 ;
220/266 |
Current CPC
Class: |
B65D 2251/0078 20130101;
B65D 2251/0015 20130101; B65D 51/18 20130101 |
Class at
Publication: |
220/254.8 ;
220/266 |
International
Class: |
B65D 51/18 20060101
B65D051/18; B65D 41/34 20060101 B65D041/34 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 9, 2007 |
GB |
0722052.8 |
Claims
1. A container closure comprising: a plastics inner cap having a
base portion and a skirt portion, a thread on the inside of the
skirt portion, a first snap fitting element on the outside of the
skirt portion, and a tamper evident ring formed integrally with the
skirt portion and joined to an open end of the skirt portion by
severable connections; a plastics overcap having a base and a skirt
portion in mating engagement with the skirt portion of the cap and
extending beyond the open end of the skirt portion of the cap to at
least partially cover the tamper-evident ring, and a second snap
fitting element on the inside of the skirt that engages with the
first snap fitting element on the inner cap skirt to resist
separation of the overcap from the inner cap.
2. A closure according to claim 1, wherein the overcap is
substantially blocked from axial movement relative to the inner cap
when the snap fitting elements are engaged.
3. A closure according to claim 2, wherein at least a region of an
interior surface of the overcap abuts against the base of the inner
cap when the overcap is secured on the inner cap by the snap
fittings.
4. A closure according to claim 4, wherein the overcap has a
bulbous base.
5. A closure according to claim 4, wherein the base of the overcap
is shaped to resemble the top of a champagne cork and the skirt of
the overcap is shaped to resemble the top of a champagne bottle,
whereby the overcap resembles the top of a champagne bottle and
cork assembly.
6. A closure according to claim 1, wherein the overcap is
substantially blocked from rotation relative to the inner cap when
the snap fitting elements are engaged.
7. A closure according to claim 6, wherein an outer surface of the
skirt of the inner cap is provided with one or more longitudinally
extending projections or recesses, and an inner surface of the
overcap is provided with one or more complementary recesses or
projections for engagement with the said projections or recesses on
the inner cap to transfer rotational force from the overcap to the
inner cap.
8. A closure according to claim 1, wherein the first snap fitting
element comprises a circumferential projection or recess on the
inner cap, and the second snap fitting element comprises a
circumferential recess or projection on the inside of the skirt of
the overcap.
9. A container and closure assembly comprising a plastics closure
according to claim 1 and a container having a neck, wherein the
neck comprises a neck thread on an outer surface thereof and a
flange located below the neck thread, and wherein the closure is
secured in sealing engagement on the neck by engagement of the
thread on the inner cap with the neck thread, and wherein the
tamper-evident ring is retained below the flange.
10. A container and closure assembly according to claim 9, wherein
the tamper-evident ring can drop down the neck by a distance of at
least about 1 mm following separation of the tamper-evident ring
from the closure assembly.
11. A container and closure assembly according to claim 9, wherein
the axial (vertical) overlap between the skirt of the overcap and
the tamper-evident ring is less than the distance through which the
tamper-evident ring is free to drop following separation thereof
from the inner cap, whereby following said separation there is a
visible gap between the top of the tamper-evident ring and the
bottom of the overcap skirt.
12. A container and closure assembly according to claim 9, wherein
the threads on the neck and the inner cap are provided with
mutually engageable elements to block or restrict rotation of the
closure in an unscrewing direction beyond an intermediate position
when the closure is under an axial pressure in a direction emerging
from the container neck, the neck and closure being constructed and
arranged to provide a vent for venting gas from the container neck
at least when the closure is in the intermediate position.
13. A container and closure assembly according to claim 9, wherein
the overcap is gold- or silver-colored, and the assembly does not
comprise a foil over-wrap.
14. A closure according to claim 4, wherein the overcap is
substantially blocked from rotation relative to the inner cap when
the snap fitting elements are engaged.
15. A closure according to claim 4, wherein the first snap fitting
element comprises a circumferential projection or recess on the
inner cap, and the second snap fitting element comprises a
circumferential recess or projection on the inside of the skirt of
the overcap.
16. A container and closure assembly according to claim 10, wherein
the axial (vertical) overlap between the skirt of the overcap and
the tamper-evident ring is less than the distance through which the
tamper-evident ring is free to drop following separation thereof
from the inner cap, whereby following said separation there is a
visible gap between the top of the tamper-evident ring and the
bottom of the overcap skirt.
17. A container and closure assembly according to claim 11, wherein
the threads on the neck and the inner cap are provided with
mutually engageable elements to block or restrict rotation of the
closure in an unscrewing direction beyond an intermediate position
when the closure is under an axial pressure in a direction emerging
from the container neck, the neck and closure being constructed and
arranged to provide a vent for venting gas from the container neck
at least when the closure is in the intermediate position.
18. A container and closure assembly according to claim 12, wherein
the overcap is gold- or silver-colored, and the assembly does not
comprise a foil over-wrap.
Description
[0001] The present invention relates to a container closure with an
overcap, and to container assemblies sealed with such a
closure.
[0002] It is known to provide a plastics overcap for conventional,
metal, screw-top closures, wherein the overcap is shaped to
simulate a champagne cork. The overcap forms an interference fit
over the screw-top closure, and the assembly is then wrapped in
foil to provide a simulated champagne cork closure assembly. These
assemblies are popular for small (175 ml) champagne bottles,
especially for airline service. Overcaps of this type are available
under the Registered Trade Marks CHAMPLAST and TOPCAP 28. These
overcaps are quite crude. In particular, they completely cover the
tamper-evident ring of the screw-top closure, whereby there is no
visible indication of whether the tamper-evident ring is intact.
Furthermore, the overcaps must be fitted onto the bottles in a
separate step after the step of attaching the screw-top closure and
securing the tamper-evident ring.
[0003] In a first aspect, the present invention provides a
container closure comprising: a plastics inner cap having a base
portion and a skirt portion, a thread on the inside of the skirt
portion, a first snap fitting element on the outside of the skirt
portion, and a tamper evident ring formed integrally with the skirt
portion and joined to an open end of the skirt portion by severable
connections; a plastics overcap having a base and a skirt portion
in mating engagement with the skirt portion of the cap and
extending beyond the open end of the skirt portion of the cap to at
least partially cover the tamper-evident ring, and a second snap
fitting element on the inside of the skirt that engages with the
first snap fitting element on the inner cap skirt to resist
separation of the overcap from the inner cap.
[0004] In a second aspect, the present invention provides a
container and closure assembly comprising a plastics closure
according to the first aspect of the invention, and a container
having a neck, wherein the neck comprises a neck thread on an outer
surface thereof and a flange located below the neck thread, and
wherein the closure is secured in sealing engagement on the neck by
engagement of the thread on the inner cap with the neck thread, and
wherein the tamper-evident ring is retained below the flange.
[0005] The use of plastics to form both the overcap and the inner
cap enables the provision of snap-fitting elements to retain the
overcap on the inner cap, thereby removing the need for a foil
over-wrap in the final assembly. In addition, the closure can be
made with a clearance between the overcap and the tamper-evident
ring, whereby the tamper-evident ring is free to drop away from the
closure after opening to give a clear indication of tampering.
Finally, the closure can be assembled prior to capping of the
bottles, and the capping can be performed in one step by screwing
the closure including the overcap directly onto the bottle.
[0006] Suitably, both the inner cap and the overcap are formed from
a thermoplastic such as polyethylene or poly propylene, for example
by injection moulding. Suitably, both the inner cap and the outer
cap are molded in one piece. This simplicity of manufacture is a
further advantage of the assemblies according to the invention.
[0007] Suitably, the overcap is substantially blocked from axial
movement relative to the inner cap when the snap fitting elements
are engaged. This provides the advantage that the vertical (axial)
overlap between the overcap and the tamper evident ring is
substantially fixed once the snap fitting elements are engaged, and
prior to separation of the ring from the inner cap, whereby a
consistent visual indication of the tamper-evident ring is
achieved. The assemblies of the present invention are thus clearly
distinct from two-piece child-resistant closure assemblies such as
those described in GB-A-2298194. On the contrary, it is envisaged
that the closures of the present invention will be especially
suitable for use by children since they are readily gripped and
have an appearance that is attractive to children. This helps to
give an impression to the user that the two-part closure is
actually a single closure cap, for example resembling a champagne
cork.
[0008] For example, in certain embodiments a region of the interior
surface of the overcap abuts against the base of the inner cap when
the overcap is secured on the inner cap by the snap fittings. This
prevents the overcap from being forced too far onto the inner cap,
and in conjunction with the snap fittings or other abutment means
maintains the overcap in a fixed axial (vertical) position relative
to the inner cap.
[0009] The use of an overcap in addition to the inner cap permits
substantial design freedom in the shaping of the overcap. Suitably,
the overcap is a decorative overcap. In embodiments, the overcap
has a domed base, and in particular embodiments it has a bulbous
base for example resembling a champagne cork. A further advantage
of the domed or bulbous base is that it is particularly easy to
grasp and turn, especially by children. Surface profiling, such as
ribs or simulated champagne wires, can be provided on the overcap
to assist gripping and turning of the overcap.
[0010] The overcap, and also optionally the inner cap, may be
formed from gold- or silver-colored plastics and/or suitably
decorated. For example, the overcap may be shaped to resemble the
top of a champagne bottle and cork assembly. That is to say, the
base of the overcap is shaped to resemble the bulbous top of a
champagne cork and the skirt of the overcap is shaped to resemble
the top of a champagne bottle. In this way, the container sealed
with the closure assembly can resemble a champagne bottle,
especially if the overcap is formed from gold- or silver-colored
plastics and/or suitably decorated. The overcap may also have a
surface profile simulating the wire on a champagne bottle and cork
assembly. The container and closure assemblies of the invention may
further comprise a champagne-style foil over-wrap, but preferably
they do not. The use of suitably coloured plastic to form the
overcap and optionally also the inner cap enables the use of a foil
over-wrap to be dispensed with.
[0011] Suitably, the overcap is substantially blocked from rotation
relative to the inner cap when the snap fitting elements are
engaged. This enables rotational force to be transferred directly,
in either direction, from the overcap to the inner cap
substantially without play of the overcap on the inner cap. For
example, an outer surface of the skirt of the inner cap may be
provided with one or more longitudinally extending projections or
recesses, and an inner surface of the overcap may be provided with
one or more complementary recesses or projections for engagement
with the said projections or recesses on the inner cap to transfer
rotational force from the overcap to the inner cap for opening of
the assembly. Suitably, the projections on the inner cap comprise a
plurality of longitudinal ribs or recesses that engage with
complementary recesses or ribs on the inside of the overcap
skirt.
[0012] Suitably, the first snap fitting element comprises a
circumferential projection, such as a circumferential rib or flange
on the inner cap, and the second snap fitting element comprises a
circumferential recess on the inside of the skirt of the overcap.
The circumferential projection may, for example, be located
proximate to the bottom of the inner cap skirt, so that it looks
like a conventional cap skirt that having a flange at the bottom.
In alternative embodiments, one or more recesses may be provided on
the outside of the skirt of the inner cap for snap-fitting with
complementary projections on the inside of the overcap skirt.
[0013] The skirt of the overcap extends down to at least partially
cover the tamper-evident ring. This helps to give the closure
assembly a more natural champagne-bottle appearance. Suitably,
there is a clearance between the skirt of the overcap and the
tamper-evident ring so that the tamper-evident ring can drop clear
of the overcap following separation of the ring from the skirt of
the inner cap. Suitably, the container neck extends below the
tamper-evident ring for a sufficient distance with a sufficiently
small diameter for the tamper evident ring to drop down the neck by
a distance of at least about 1 mm, for example from about 2 mm to
about 10 mm, following separation of the tamper-evident ring from
the closure assembly. Suitably, the axial (vertical) overlap
between the skirt of the overcap and the tamper-evident ring is
less than the distance through which the tamper-evident ring is
free to drop following separation thereof from the inner cap,
whereby following said separation there is a visible gap between
the top of the tamper-evident ring and the bottom of the overcap
skirt. For example, this visible gap may be from about 0.1 mm to
about 5 mm, suitably from about 0.5 mm to about 5 mm. This clear
and visible separation of the tamper-evident ring is a further
advantage of the closures according to the present invention.
[0014] The tamper-evident ring is retained under the flange on the
container neck when the closure is removed from the neck. Suitably,
the tamper-evident ring comprises a tubular body having a plurality
of partially cut-away sections and plurality of flexible tabs
formed integrally with the body in the cut-away sections, wherein
the tabs are inclined inwardly and upwardly from the tubular body,
whereby in use the ends of the tabs abut against the underside of
the flange on the container neck. Suitably, the container neck
further comprises one or more projections on the container neck
that engage with the tamper-evident ring to resist rotation of the
tamper-evident ring in an unscrewing direction and thereby assist
separation of the ring from the inner cap skirt when the closure is
removed from the container neck. Tamper-evident rings of this kind
are described for example in WO-A-9411267, the entire content of
which is incorporated herein by reference.
[0015] The containers in the assemblies of the present invention
suitably contain a carbonated beverage. Suitably, at least the neck
region of the containers is formed of thermoplastic, by injection
moulding. The body of the container may be formed by blow moulding
in conventional fashion. The threads on the container neck and the
closure are preferably of the pressure-safety type described in
WO-A-9505322, WO-A-9721602 and WO-A-9919228, the entire contents of
which are incorporated herein by reference. Briefly, the threads on
the neck and the closure are provided with mutually engageable
elements to block or restrict rotation of the closure in an
unscrewing direction beyond an intermediate position when the
closure is under an axial pressure in a direction emerging from the
container neck, the neck and closure being constructed and arranged
to provide a vent for venting gas from the container neck at least
when the closure is in the intermediate position. This pressure
safety feature prevents the closure from blowing off uncontrollably
once unscrewing of the closure from the container neck has started.
It thus allows the use of shorter, more steeply pitched or
multiple-start threads in the container and closure assembly,
thereby rendering the assembly much more elderly-and child-friendly
without sacrificing pressure safety.
[0016] Preferably, the mutually engageable elements comprise a step
or recess formed in the upper surface of one of the second screw
thread segments to provide a first abutment surface against which a
second abutment surface on one of the first screw thread segments
abuts to block or restrict rotation of the closure in an unscrewing
direction at the said intermediate position when the closure is
under axial pressure in a direction emerging from the container
neck.
[0017] In these embodiments, a first thread segment on the neck or
the inner cap skirt may comprise a first thread portion having a
first longitudinal cross section and a second thread portion having
a second longitudinal cross section narrower than the first cross
section, whereby the a second thread segment on the inner cap skirt
or the neck abuts against the first thread portion at the said
intermediate position when the closure is under axial pressure in a
direction emerging from the container neck. The relatively broad
first cross section is preferably adjacent to the circumferentially
overlapping region of the first thread segments, resulting in a
relatively narrow thread gap in that region.
[0018] Suitably, the closure can be moved from a fully disengaged
to a fully secured position on the container neck by a single,
smooth rotation through about 360.degree. or less, preferably about
180.degree. or less, for example about 90.degree.. Suitably, the
threads define a continuous helical thread path so that the cap
travels smoothly onto the neck, e.g. the threads are not
bayonet-type threads that follow a stepped thread path.
[0019] Suitably, the first and second threads on the container neck
and closure are variable pitch threads, for example as described in
WO97/21602, the entire contents of which are incorporated herein by
reference. The use of a variable pitch thread renders it easier to
combine fast-turn threads having a steep average pitch that are
elderly-and child-friendly with pressure safety. A problem that
could arise with fast-turn threads is that they are steeply
pitched, which results in a tendency to back off from the fully
secured position on the container neck when the container is
pressurized. This problem can be overcome by using bayonet-type
threads, but the use of bayonet-type threads results in a number of
different problems, as described above. In contrast, the variable
pitch threads solve the problem of backing off of the closure under
pressure, whilst retaining all of the advantages of continuous,
fast-turn threads.
[0020] Preferably, the container neck and the inner cap skirt
further comprise complementary locking elements that block or
resist unscrewing of the closure from the fully secured position on
the container neck until a predetermined minimum opening torque is
applied. In certain embodiments, the locking elements comprise a
longitudinal locking rib on one of the container neck or the inner
cap skirt, and a complementary locking ramp on the other of the
container neck and the inner cap skirt, said locking rib abutting
against the retaining edge of the locking ramp when the closure is
fully secured on the container neck. Preferably, the complementary
locking elements are provided on the same surfaces as the threads,
that is to say on the internal surface of the inner cap skirt and
the outside surface of the container neck.
[0021] The locking arrangement helps to prevent the closure from
backing off under pressure from inside the container. It also
provides a positive click that indicates to the user when the
closure has been screwed onto the neck sufficiently to achieve a
pressure-tight seal.
[0022] Accordingly, at least one, and preferably both of the
complementary locking projections on the neck and/or the closure is
substantially separate from the thread segments and can flex
substantially independently of the thread segments in order to
provide the snap-fitting and clearly audible click as the fully
secured position of the closure on the neck is reached. In general,
a radially innermost vertex of the locking element on the neck
rides over a radially outermost vertex of the locking element on
the inner cap skirt as the fully secured position is approached.
The neck locking element then rides back over the skirt locking
element when the closure is removed from the secured position, for
example when opening the assembly.
[0023] At least one, and preferably both of the complementary
locking projections on the neck and/or the closure has a length in
the longitudinal direction (i.e. along the rotational axis of the
closure assembly) of from about 1 mm to about 6 mm, for example
from about 2 mm to about 4 mm. At least one, and preferably both of
the complementary locking projections on the neck and/or the
closure has a height of from about 0.25 mm to about 2 mm, for
example from about 0.5 mm to about 1.5 mm. In any case the height
of the locking projections is normally less than the average height
of the respective thread segments. At least one, and preferably
both of the complementary locking projections on the neck and/or
the closure has a maximum width (i.e. around the circumference of
the neck or closure skirt) of from about 0.5 mm to about 3 mm, for
example from about 1 mm to about 2 mm. At least one, and preferably
both of the complementary locking projections on the neck and/or
the closure has a ratio of the maximum height to the maximum width
of at least about 0.5, more preferably at least 1, for example from
about 1 to about 5.
[0024] The assemblies according to the present invention may
comprise more than one pair of complementary locking projections on
the container neck and the closure. Preferably there are at least
two such complementary pairs radially spaced around the neck and
the inner cap skirt. There will normally be at least one pair for
each thread start, for example there may be four pairs radially
spaced around the neck and inner cap skirt.
[0025] Preferably, the locking projections on the neck and the
inner cap skirt are radially positioned such that they are in
abutment when the closure is at the fully closed and sealing
position on the container neck. That is to say, the projection on
the inner cap skirt has ridden over one side of, and is resting in
abutment with the opposite side of, the corresponding projection on
the container neck at said fully closed and sealing position. This
ensures that there is no play in the cap at said closed and sealing
position that could allow leakage from the seal. Preferably, when
the projections are in abutment at the closed and sealing position,
the inner cap skirt and/or the projections are still slightly
distorted such that a resilient force is exerted between the
projections in abutment. This resilient force is leveraged by the
abutment into a closing torque between the closure and the neck
that urges the closure into the fully closed and sealing position.
This can ensure that the respective sealing surfaces of the
container neck and the closure are automatically seated against
each other, even though the closure may not be screwed down
especially tightly. Furthermore, the locking projections allow for
considerably lower manufacturing tolerances in the moulding of the
assembly, since effective sealing is achieved over a broader range
of radial sealing positions due to the interaction between the
locking projections and the radial deformation of the closure
skirt.
[0026] The advantages of such locking projections that urge the
closure into the sealing position are discussed in detail in
WO93/01098, the entire content of which is incorporated herein by
reference.
[0027] The complementary locking elements according to the present
invention provide a number of other important advantages, besides
urging the closure into the fully secured and sealing position as
described above. Firstly, they prevent accidental backing off of
the closure from the fully engaged and sealing position on the
container neck due to pressure from inside the container. These
elements enable more steeply pitched threads and free running
(parallel) threads to be used without risk of the closure
unscrewing spontaneously. The use of more steeply pitched threads
in turn makes it easier to remove and resecure the closure. This
system can also ensure that exactly the right degree of compression
is applied between respective sealing surfaces on the container and
closure to achieve an effective airtight seal when the closure is
on the fully secured position on the neck.
[0028] The closure assembly according to the present invention may
further comprise a projecting stop surface on one of the container
neck and the closure for abutment against a second stop or a thread
segment on the other of the container neck or the closure to block
over-tightening of the closure beyond a predetermined angular
sealing position of the closure on the container neck. The stop
means acts in conjunction with the locking arrangement to ensure
that exactly the right degree of screwing of the closure is
achieved in order to provide a pressure-tight seal with the sealing
arrangement of the present invention. Preferably, the complementary
stop means are provided on the outer surface of the container neck
and the inside surface of the inner cap skirt.
[0029] Suitable locking and stop arrangements for use with
assemblies according to the present invention are described in
detail in WO 91/18799 and WO 95/05322, the entire contents of which
are expressly incorporated herein by reference.
[0030] The assemblies according to the invention preferably
comprise sealing elements on the container neck and/or on the
closure for sealing the container when the closure is secured on
the container neck. The sealing elements may comprise a sealing
liner, for example a liner of elastomeric material, inside the base
of the inner cap. The liner is pressed against the lip of the
container neck to form the seal. However, the sealing elements
preferably comprise one or more circumferential sealing projections
on the container neck and/or the inside of the inner cap.
Preferably, the sealing projections are provided only on the inner
cap, so that the surface of the neck remains smooth to enhance its
user-friendliness. The sealing projections may comprise a
circumferential sealing skirt and/or one or more circumferential
sealing ribs and/or sealing fins for sealing against the lip or the
inside or outside surface of the container neck.
[0031] In certain embodiments, a cylindrical sealing plug extends
from the base portion of the inner cap inside the container neck
for sealing engagement against an inside surface of the neck
proximate to the lip and above the first thread segments. The
cylindrical sealing plug may comprise at least one circumferential
sealing rib on an outer surface of said sealing plug for engagement
with the inner surface of the container neck proximate to the lip
when the closure is secured on the container neck. The sealing
means may alternatively or additionally comprise at least one
flexible sealing fin extending from the base of the inner cap for
engagement with the lip of the container when the closure is
secured on the container neck. The sealing means may alternatively
or additionally comprise a circumferential sealing skirt extending
around the inner cap for engagement with the lip or the outside
surface of the container neck. In these embodiments, at least one
circumferential sealing rib may further be provided on the skirt
for engagement with the outer surface of the container neck when
the closure is secured on the container neck.
[0032] Where present, at least one of the sealing ribs suitably has
a substantially triangular cross-section, for example substantially
equilateral triangular. This enables the sealing force to be
concentrated in the tip of the sealing rib to maximise sealing
effectiveness. Suitably, at least one of the sealing ribs has a
height in the range of 10 to 500 micrometers, more preferably 50 to
250 micrometers. Such micro sealing ribs are especially effective
to concentrate the sealing force and achieve an effective seal with
a substantially smooth sealing surface on the container neck.
Furthermore, such micro ribs are especially easy to mould in
high-speed cap moulding equipment, and to bump off the mould
mandrel of the equipment after moulding. Preferably, two
circumferential sealing ribs are located in facing relationship at
substantially the same height above the base of the inner cap so
that, in use the closure applies the sealing ribs symmetrically on
either side of the container lip to apply a symmetrical sealing
pinch.
[0033] The sealing fins may have their base in the base of the
inner cap between the skirt and the sealing plug, or they may
extend inwardly or outwardly and downwardly from the base of the
skirt or the sealing plug. Preferably, at least one of the sealing
fins extends in a direction downwardly and outwardly from the base
of the inner cap between the sealing plug and the closure skirt.
Preferably, the closure comprises two or four sealing fins
extending around the inner cap in concentric fashion.
[0034] Preferably, the height of the sealing fins is greater than
their width at their base. Preferably, the cross-section of the
sealing fins is substantially in the shape of an isosceles
triangle. Preferably, at least one sealing fin has a height of from
1 to 4 mm.
[0035] Sealing arrangements of this type incorporating
symmetrically disposed sealing ribs and fins are described in more
detail in WO02/42171, the entire content of which is incorporated
herein by reference.
[0036] Preferably, the torque required to secure the closure in a
sealing position on the container neck is less than 1.2 Nm, more
preferably less than 1 Nm and most preferably from about 0.7 to
about 0.9 Nm. This is the torque required to engage the
complementary locking arrangement (where present) at the sealing
position, or otherwise the force required to substantially
eliminate gas leakage at normal carbonated beverage pressure
differentials.
[0037] The closure assemblies of the present invention are
especially suitable for carbonated beverage containers for
consumption by children on account of their attractive appearance,
low cost, and high safety. The venting of gas when the closure is
opened for the first time gives a noise somewhat similar to that
provided by opening a conventional champagne cork, but with little
or no risk of missiling of the cap under pressure. In addition, the
all-plastic construction eliminates the sharp metal edges produced
by prior art overcap systems based on metal inner caps.
[0038] An embodiment of the present invention will now be described
further by way of example with reference to the accompanying
drawings, in which:--
[0039] FIG. 1 shows a side elevation of a container neck and
closure assembly according to a first embodiment of the present
invention with the closure secured on the neck;
[0040] FIG. 2 shows a side elevation view partially cut away of the
container neck and closure assembly of FIG. 1 with the overcap,
inner cap and neck shown separately, prior to securing the closure
on the neck; and
[0041] FIG. 3 shows a longitudinal cross-sectional view of the
container neck and closure assembly according to FIG. 1 with the
closure secured on the neck.
[0042] FIG. 4 shows a side elevation of a container neck and
closure assembly according to a second embodiment of the present
invention with the closure secured on the neck;
[0043] FIG. 5 shows a side elevation view partially cut away of the
container neck and closure assembly of FIG. 4 with the overcap,
inner cap and neck shown separately, prior to securing the closure
on the neck; and
[0044] FIG. 6 shows a longitudinal cross-sectional view of the
container neck and closure assembly according to FIG. 4 with the
closure secured on the neck.
[0045] Referring to FIGS. 1 to 3, the assembly comprises a
container neck 1, an inner cap 2 of, and an overcap 3. The
container neck 1 is formed from polyethylene terephthalate (PET) by
injection molding. The neck is normally integrally formed with a
container body (not shown) shaped by blow molding. The inner cap 2
and overcap 3 are also molded in one piece by injection molding
from polyethylene or similar thermoplastics.
[0046] The inner cap 2 comprises a base 4, a skirt 5 and a
tamper-evident ring 6 joined to the skirt by integral, frangible
bridges 7. The outer surface of the skirt 5 is ribbed. At the
bottom of the skirt 5 there is a circumferential snap-fitting
projection 11.
[0047] The neck 1 is provided with an integral circumferential
flange 8 for retaining the tamper-evident ring after opening of the
assembly. A second, larger flange 9 is provided below the flange 8
for clamping the container neck during filling and handling. The
vertical spacing between flanges 8 and 9 is at least about 1 mm
greater than the vertical height of the tamper-evident ring,
whereby the ring drops at least about 1 mm to rest on the second
flange 9 after opening of the assembly, thereby giving a clear
visual indication that the assembly has been opened.
[0048] The neck 1 and inner cap 2 are provided with integrally
molded, fast-turn, steeply-pitched threads incorporating a pressure
safety feature, as described in detail in our International patent
application WO-A-9721602, the entire content of which is expressly
incorporated herein by reference.
[0049] Briefly, on the inside of the inner cap skirt 5 there is
provided a four-start first screw thread made up of four first
thread segments 10 as shown in phantom on FIG. 3. The thread
segments extend a total of about 170 degrees around the skirt 5,
whereby adjacent thread segments overlap around the circumference
of the skirt 5. A substantially continuous, approximately helical
thread gap is defined between overlapping regions of the first
thread segments on the skirt 5.
[0050] The container neck 1 is provided on its outer surface with a
second screw thread formed from four short second thread segments
13, each of which is a substantially continuous helical thread
extending about 20 degrees around the container neck.
[0051] A feature of this assembly is the profiling of the upper
surface of the thread segments 10 on the inner cap skirt 5, which
is described in more detail in WO-A-9721602.
[0052] The thread segments 10 on the inner cap skirt 5 also include
a pressure safety feature similar to that described and claimed in
our International Patent Publication WO95/05322. Briefly, a step 14
is provided in the upper surface of the thread segment 10 to abut
against an end of the neck thread segments 13 and block unscrewing
of the inner cap 2 from the neck 1 when the neck thread segments 13
are in abutment with the upper surface of the skirt threads, i.e.
when there is a net force on the cap in an axial direction out of
the container neck. This abutment acts to block further unscrewing
of the closure until venting of gas pressure from inside the
container is substantially complete, so that the cap can drop down
to bring the thread 13 out of abutment with the step 14. A region
of the upper surface of the inner cap skirt thread segments 10
situated adjacent to the step 14 has a low pitch of about 6 degrees
to reduce the risk of the pressure safety feature being over-ridden
by high pressure inside the container.
[0053] Each of the thread segments 10 on the inner cap skirt
includes a longitudinally upwardly projecting portion 15 that
defines a longitudinal stop surface against which a second end of
one of the short thread segments 13 on the neck may abut when the
closure is fully secured on the neck to block over-tightening of
the closure on the neck.
[0054] The assembly is also provided with complementary locking
elements on the container neck 1 and the inner cap 2 to block
unscrewing of the cap from the fully engaged position on the
container neck unless a minimum unscrewing torque is applied.
Briefly, the locking elements comprise four equally radially spaced
first locking projections 16 on the container neck, and four
equally radially spaced second locking projections 17 on the inside
of the inner cap skirt. The projections 16 on the container neck
are located below the short neck thread segments 13, where they are
least noticeable to a person drinking directly from the container
neck. The locking projections 17 on the inner cap skirt are located
level with, and radially spaced by about 2 mm from, the bottom of
the thread segments 10 on the skirt. The locking projections 17 on
the inner cap skirt form a continuation of the helical thread path
defined by inner cap threads 10 whereby the short thread segments
13 on the neck can pass smoothly past the locking projections 17 on
the closure as the cap is secured on the neck. Locking projections
of this type are described and claimed in our International Patent
Publication WO2005/058720, the entire content of which is
incorporated herein by reference.
[0055] Each of the locking projections 16,17 is substantially in
the form of a triangular prism having its long axis aligned with
the axis of the assembly. The height of each locking projection is
about 1.5 mm, and the base width is about 1.5 mm. This ensures that
the projections have sufficient strength to snap over each other
without permanent deformation. The complementary locking elements
signal to the user by means of an audible "click" when the sealing
position has been reached. The complementary locking elements
resist "backing-off" of the closure, which is especially
advantageous for the steeply pitched threads when the contents of
the container are pressurized.
[0056] The tamper-evident ring 6 on the inner cap 2 comprises a
tubular body 19 having a plurality of cut-away regions 21, and a
plurality of integrally formed, flexible, radially inwardly
pointing retaining tabs 20 located in cut-away regions 21 of the
tamper-evident ring body. The tamper-evident ring construction is
described in more detail in WO94/11267. Briefly, the inside
diameter of the ring 6 is greater than the maximum diameter of the
neck flange 8, but the tabs 20 project inwardly of the maximum
diameter of the neck flange 8 whereby the tamper-evident ring can
be snap-fitted over the flange 8 without stretching the
tamper-evident ring 6, but merely be resilient flexing of the tabs
20. However, the abutment of the tops of the tabs 20 against the
underside of the flange 8 prevents removal of the tamper-evident
ring from the neck and thereby causes separation of the
tamper-evident ring when the inner cap 2 is unscrewed from the neck
for the first time.
[0057] Referring to FIG. 3, the inner cap comprises a cylindrical
sealing plug 24. The closure further comprises a cylindrical
sealing skirt 22 that is substantially concentric with to the
sealing plug. The sealing plug 24 and the sealing skirt 22 are
concentric with the threaded inner cap skirt 5 and located inside
the threaded skirt 5 for sealing abutment against opposite sides of
the container neck 1 proximate to the container lip.
[0058] The overcap 3 comprises an overcap skirt 26 and hollow top
28. The top 28 is formed in the shape of a champagne cork top,
including integrally molded, simulated champagne cork wires 29. The
overcap skirt 26 fits tightly over the inner cap skirt 5. The
overcap skirt 26 has a ribbed internal surface, whereby the ribs on
the overcap internal surface engage with the ribs on the outer
surface of the inner cap skirt to transfer rotational force from
the overcap 3 to the inner cap 2. A circumferential recess 31 is
provided on the internal surface of the overcap skirt 26, which
receives the flange on the bottom of the inner cap skirt to retain
the overcap 3 on the inner cap 2 by snap-fitting. The inside
surface of the overcap tapers inwardly above the overcap skirt 26
to form a ledge 30 against which the base of the inner cap 2 abuts
to prevent the overcap 3 from being pushed too far down on the
inner cap 2. The bottom of the overcap skirt 26 partially covers
the tamper-evident ring but does not contact the tamper-evident
ring, whereby the tamper-evident ring is free to drop down after it
has been severed from the inner cap skirt. A further advantage of
this arrangement is that the outer cap skirt 26 blocks access to
the tabs 20 of the tamper-evident ring, thereby increasing the
security of the tamper-evident ring.
[0059] It is an advantage of the caps according to the present
invention that they can be assembled by pushing the overcap over
the inner cap prior to securing the caps on the container neck,
since the overcap does not interfere with the fitting of the
tamper-evident ring onto the container neck. In contrast, the prior
art overcaps for use with metal screw closures had to be fitted
after the step of securing the metal closure and tamper-evident
ring on the neck.
[0060] In use, the cap is secured on the container neck as shown in
FIG. 3. The cap assembly is screwed directly onto the container
neck. The flexible tabs on the tamper-evident ring flex radially
outwardly to pass over the retaining flange on the container neck
without substantially stressing the tamper-evident ring.
[0061] Both the sealing skirt 22 and the sealing plug 24 are
radially slightly flexible to engage the sealing lip. The
circumferential sealing skirt and the plug engage opposite sides of
the neck 1, and pinch the neck between them to form a highly
effective seal by concentrating pressure at the sealing ribs.
Further details of the sealing arrangement may be found in
WO2007/057706, the entire content of which is incorporated herein
by reference.
[0062] The assembly of FIG. 3 is opened by unscrewing. The ribs on
the inside of the overcap skirt engage with the ribs on the outside
of the inner cap skirt to transmit the unscrewing torque. The
snap-fitting between the inner cap and the overcap prevents
separation of the inner cap and overcap. The tops of the flexible
tabs on the tamper-evident ring abut against the underside of the
flange on the container neck, thereby causing the tamper-evident
ring to separate from the inner skirt and drop down the neck onto
the lower flange, giving a visible indication that the
tamper-evident ring has separated. This visual indication may be
accentuated by making the inner skirt and tamper-evident ring from
a plastic of different color from the overcap and neck.
[0063] Referring to FIGS. 4 to 6, the construction of the container
and closure assembly 40 according to this embodiment is generally
the same as for the embodiment described in FIGS. 1 to 3, and will
not be described again. The embodiment of FIGS. 4 to 6 comprises a
plastics overcap 41, a plastics container neck 42, and a plastics
inner cap 43 having a tamper-evident ring 44 formed integrally
therewith. A lower flange 45 on the container neck supports the
tamper-evident ring 44 after it has separated from the inner cap
following opening of the container. An important feature of this
embodiment is that the vertical distance between the bottom of the
tamper-evident ring in FIG. 3 is less than the vertical overlap
between the bottom of the overcap skirt 46 and the tamper-evident
ring 44, whereby, when the tamper-evident ring has separated from
the inner cap and dropped down onto the flange 45, there is a
visible gap between the top of the tamper evident ring 44 and the
bottom of the overcap skirt 46. This visible gap gives a clear
indication that the assembly has been opened, even after resecuring
of the closure on the neck.
[0064] The above embodiments have been described by way of example
only. Many other embodiments falling within the scope of the
accompanying claims will be apparent to the skilled reader.
* * * * *