U.S. patent application number 14/934858 was filed with the patent office on 2016-03-03 for closure for a container.
The applicant listed for this patent is Threadless Closures Limited. Invention is credited to Anthony H. J. Fraser, John Hein.
Application Number | 20160059999 14/934858 |
Document ID | / |
Family ID | 44533411 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160059999 |
Kind Code |
A1 |
Fraser; Anthony H. J. ; et
al. |
March 3, 2016 |
Closure For A Container
Abstract
A closure for a container having a circular opening defining an
axis, the closure being securable to the container so as to close
said opening, the closure having an o-ring sealing member mounted
thereon so as to provide a seal with a sealing surface of the
container, when the closure is secured to the container, the
sealing surface extending around an upper surface or an internal
surface of the container. The closure may comprise a bore feature
which, in use, extends through the opening into the interior of the
container and the o-ring seal may be provided on the bore feature.
Various forms of closure are described, eg for closing a bottle
neck and a wide-mouth closure. The closure may comprise an inner
component and an outer component, eg a cap-on-collar closure, and
the container preferably has no thread features on the exterior
thereof so it is comfortable to drink from.
Inventors: |
Fraser; Anthony H. J.;
(Rutland, GB) ; Hein; John; (Leeds, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Threadless Closures Limited |
Rutland |
|
GB |
|
|
Family ID: |
44533411 |
Appl. No.: |
14/934858 |
Filed: |
November 6, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13701271 |
Nov 30, 2012 |
|
|
|
PCT/GB2011/000846 |
Jun 3, 2011 |
|
|
|
14934858 |
|
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Current U.S.
Class: |
220/304 |
Current CPC
Class: |
B65D 41/086 20130101;
B65D 41/62 20130101; B65D 2543/00972 20130101; B65D 2543/00564
20130101; B65D 41/08 20130101; B65D 53/02 20130101; B65D 41/00
20130101; B65D 41/0442 20130101 |
International
Class: |
B65D 41/04 20060101
B65D041/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 2010 |
GB |
1009429.0 |
Jul 14, 2010 |
GB |
1011800.8 |
Claims
1. A closure for closing a container, the container having a
sealing surface extending around an internal surface, a plurality
of circumferentially spaced apart thread features extending around
an external surface, and a substantially circular opening defining
an axis, the closure comprising: a cap having an upper portion; a
skirt portion depending from said upper portion, the skirt portion
comprising a plurality of circumferentially spaced apart thread
features for engagement with the thread features of the container,
the thread features selectively(?) spaced to enable fastening the
closure to the container with a rotation of less than 360 degrees;
a relatively rigid bore member comprising a groove formed in an
outer surface; and an o-ring sealing member comprising a toroid
formed of resilient elastomer material, the o-ring sealing member
received in the groove in the bore member and sized to enable
deformation and movement of the o-ring sealing member within said
groove, wherein when the bore of the closure is extended through
the opening of the container, the closure is securable to the
container by rotation about the axis, the rotation engaging the
thread features of the skirt with the thread features of the
container, drawing the bore member into the container so as to
press the sealing member against a side wall of the groove to seal
a gap between the side wall and the sealing surface so the o-ring
sealing member provides a seal between the bore member and the
sealing surface of the container within a rotation of less than 360
degrees.
2. A closure as claimed in claim 1 in which the groove comprises
two or three faces which, together with said sealing surface of the
container when the closure is secured to the container, define an
enclosure for constraining the cross-section of the torus.
3. A closure as claimed in claim 1 in which the o-ring sealing
member is able to move axially within said groove or gland in
response to an increase in pressure within the container whereby
the o-ring sealing member responds to the increase in pressure and
adopts a shape and/or position which is better able to withstand
the pressure.
4. A closure as claimed in claim 1 in which the closure comprises a
cap having an upper portion and a skirt portion depending from said
upper portion and in which the bore member is integrally formed
with the cap.
5. A closure as claimed in claim 1 in which an inner edge of the
container lip is chamfered so as to provide a lead-in surface for
the o-ring sealing member, said lead-in surface leading to said
sealing surface.
6. A closure as claimed in claim 1 in which said sealing surface is
spaced from an upper surface of the container.
7. A closure as claimed in claim 1 in which the upper portion and
skirt portion of the closure are formed as one-piece and the
closure is rotatably securable directly to the container by means
of a threaded engagement therebetween.
8. A closure as claimed in claim 1 in which the closure comprises
an inner component having a collar portion for locating about the
exterior of the container and an outer component for fitting over
and/or around the inner component and interacting therewith so as
to releasably secure the inner component to the container.
9. A closure as claimed in claim 1 when secured to a container
adapted to be closed by said closure.
10. A closure as claimed in claim 9 in which the compression ratio
of the o-ring (as herein defined) is in the range 5% to 35% and
preferably in the range 20% to 25%.
11. A closure as claimed in claim 9 in which the gland fill (as
herein defined) is in the range 50% to 90% and preferably in the
range 65% to 85%.
12. A closure as claimed in claim 9 in which the depth of a groove
in which the o-ring is located is at least 50% and preferably at
least 60% of the width of the o-ring cross-section in the
corresponding direction.
13. A closure as claimed in claim 1 made from metal having thread
features formed by a pressing operation.
14. A closure as claimed in claim 1 in which the thread form is an
eight-start thread form that requires a rotation of only about 45
degrees to fasten or release the closure.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/701,271 filed Nov. 30, 2012, which is a
national phase application of PCT/GB2011/000846 filed Jun. 3, 2011,
and also claims priority to GB 1009429.0 filed Jun. 4, 2010 and GB
1011800.8 filed Jul. 14, 2010, all of which are incorporated herein
by reference.
TECHNICAL FIELD
[0002] This invention relates to a closure for a container, in
particular a closure for a beverage or other foodstuff (although
the closure can be used on other types of container).
BACKGROUND ART
[0003] A variety of closures for beverage containers are known. For
example, cap-on-collar closures as described in WO2006/000774 and
WO2007/091068 and one-piece twist-off closures as described in
WO2007/057659. Such prior art describes a variety of seal members,
such as compression gaskets, for providing a seal between the
closure and the container.
[0004] There is a requirement to provide a seal which is able to
withstand high pressures within the container, eg when the
container holds a carbonated beverage and is subject to high
temperatures, yet which does not make it difficult for a user to
remove the closure from the container. A variety of problems can
arise with such seals, for example: high frictional engagement
between the seal and the container, (particularly for wide-mouth
containers), seals losing their resilience and/or becoming adhered
to the container after prolonged storage and imperfections in the
seal or the container (particularly if a glass container is used)
leading to weak points in the seal.
[0005] The present invention provides an alternative form of seal
for such closures which seeks to reduce or overcome one or more of
the problems experienced with the prior art.
SUMMARY OF THE INVENTION
[0006] According to a first aspect of the invention, there is
provided a closure for a container having a substantially circular
opening defining an axis, the closure being securable to the
container so as to close said opening, the closure having an o-ring
sealing member mounted or mountable thereon so as to provide a seal
with a sealing surface of the container, said sealing surface
extending around an upper surface or an internal surface of the
container.
[0007] It should be noted that the term o-ring seal as used herein
is to be understood to include a seal comprising a toroid or loop
of elastomer material having a circular cross-section, as well as
other cross-sections, including an oval cross-section, a
substantially square cross-section and a x-shaped cross-section
(sometimes referred to as an x-ring). It is also to be understood
to cover other forms of seal which simulate the function of an
o-ring (as described further below).
[0008] In addition to the elastomer toroid, an o-ring seal
comprises a groove (referred to as a gland) in which the toroid is
located. This groove typically has a substantially square
cross-section but other shapes can be used, including triangular
and semi-circular. The groove provides locating means for locating
the o-ring and at least one side wall. The side wall is located so
that when one side of the o-ring is subject to elevated pressure,
the o-ring is pressed against the side wall so as to seal a gap
between the side wall and the sealing surface of the container
body. For a container in which the internal pressure is reduced, eg
a vacuum pack, the side wall is on the inner side of the o-ring and
for a container in which the internal pressure is elevated, the
side wall is on the external side of the o-ring. If a side wall is
provide on both sides of the o-ring, it can provide a sealing
function in both circumstances.
[0009] The invention also relates to a closure as described above
in combination with a container adapted to be closed by said
closure.
[0010] The invention is particularly applicable to widemouth
closures (eg with a diameter of 50 to 80 mm) as the larger the
opening the more difficult it is to provide an effective and
reliable seal between the closure and the container whilst ensuring
the closure is still relatively easy to remove. However, the
invention is also applicable to narrower openings, eg of a bottle
such as those having a 28 mm diameter opening.
[0011] Directional terms, such as upper and lower, as used herein
are to be understood to refer to refer to directions relative to a
container standing on a horizontal surface with the axis passing
through its opening being substantially vertical (unless the
context clearly requires otherwise).
[0012] Preferred and optional features of the invention will be
apparent from the following description and from the subsidiary
claims of the specification.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The invention will now be further described, merely by way
of example, with reference to the accompany drawings, in which:
[0014] FIG. 1 is a part cross-sectional view of a first embodiment
of a closure according to the present invention when fitted to a
container body;
[0015] FIG. 2 is a part cross-sectional view of a second embodiment
of a closure according to the present invention when fitted to a
container body;
[0016] FIG. 3 is a part cross-sectional view of a third embodiment
of a closure according to the present invention when fitted to a
container body;
[0017] FIG. 4A is a perspective view of a fourth embodiment of a
closure according to the present invention and of a container body
to which it can be fitted;
[0018] FIG. 4B is a perspective view, part cut-away, of the fourth
embodiment when fitted to the container;
[0019] FIG. 5A is a perspective view, part-cut-away, of a fifth
embodiment of a closure according to the present invention when
fitted to a container body;
[0020] FIG. 5B is a perspective view, part-cut-away, of a modified
version of the fifth embodiment using a different form of
o-ring;
[0021] FIG. 6A is a perspective view, part-cut-away, of a sixth
embodiment of a closure according to the present invention when
fitted to a container body;
[0022] FIG. 6B is a perspective view, part-cut-away, of a modified
version of the sixth embodiment using a different form of
o-ring;
[0023] FIGS. 7A to 7C are schematic diagrams illustrating the
function and parameters of an o-ring seal.
[0024] FIGS. 8 and 9 are cross-sectional views of an embodiment of
a closure described in co-pending GB1011800.8 which, as described
therein, may be modified to include a bore feature and an o-ring in
accordance with a further embodiment of the present invention; FIG.
8 shows the parts thereof prior to securement to a bottle neck and
FIG. 9 shows the parts when the closure has been moved into secure
engagement with the bottle neck;
[0025] FIGS. 10A and 10B show a side view and a cross-sectional
view (taken on line E-E of FIG. 10A) of an inner component of the
closure shown in FIGS. 8 and 9;
[0026] FIGS. 11A and 11B show perspective views from above and
beneath of the inner component of FIG. 10;
[0027] FIGS. 12A and 12B show a side view and a view from beneath
of an outer component of the closure shown in FIGS. 8 and 9;
and
[0028] FIGS. 13A and 13B show perspective views from above and
beneath of the outer component of FIG. 12.
[0029] The embodiments shown in FIGS. 1 to 3 comprise cap-on-collar
closures. This type of closure is known from prior art, such as
WO2006/000774 and WO2007/091068 mentioned above, so will not be
described in detail.
[0030] FIG. 1 illustrates an embodiment that comprises a closure
for a container body 1 having a substantially circular opening with
an axis A and with an outwardly projecting lip 1A around the
opening. The closure comprises a cap 2 to close the opening and a
collar 3, the collar 3 being arranged to engage beneath the
outwardly projecting lip 1A and to fit between the container body 1
and the cap 2 so as to secure the cap 2 to the container body 1 in
the manner described in the prior art. The cap, collar and
container are typically formed of a plastics material eg
polyethylene terphthalate (PET) but may be formed of other
materials. The container may, for instance, be formed of glass and
the closure formed of metal.
[0031] The cap 2 has a circular upper portion which extends across
the container opening and a skirt portion 2B depending therefrom.
The cap also has a bore member 4 which, in use, extends through the
opening into the interior of the container 1 and has an o-ring
sealing member 5 on the outer surface of the bore member 4 for
providing a seal with an internal surface 1B of the container.
[0032] The bore member 4 may be an integral part of the cap 2 or,
as shown, may be a separate component carried by the cap 2 and is
arranged to be a close fit within the interior of the container 1
(but slightly spaced therefrom). A recess, eg in the form of a
groove 4A, is provided in the outer surface of the bore member
around the circumference thereof for receiving an o-ring 5 formed
of resilient elastomer material, such as rubber.
[0033] The cap 2 is rotatable relative to the collar 3, eg by means
of a screw thread therebetween. The collar 3 has radially moveable
parts 3B which engage beneath the lip 1A of the container body 1
and as the cap is rotated in the tightening direction it is
arranged to press the parts inward under the lip 1A and to hold
them securely in this position, eg by means of cam features at
spaced apart locations around the internal surface of the cap.
Alternatively, the moveable parts may be biased inwards by their
own resilience and the cap 2 rotated to a position in which it
holds the parts securely beneath the lip 1A by preventing them from
moving or flexing radially outwards.
[0034] Preferably, as the cap 2 is rotated in the tightening
direction relative to the collar 3, the cap 2 is drawn axially
downwards towards an upper surface 1C of the lip 1A. It may engage
this upper surface 1C when in the closed position or, as shown (in
an exaggerated form) in FIG. 1, may be spaced therefrom to reduce
the risk of becoming adhered thereto over time. If it is spaced
therefrom, the spacing is preferably relatively small, eg less than
0.5 mm so as to minimise the scope for vertical movement of the
closure relative to the container body when in the sealed
position.
[0035] In a further arrangement (not shown), the cap 2 may engage
the upper surface 1C of the lip directly or via a secondary sealing
member 6 therebetween to provide a secondary seal between the cap 2
and the container body 1.
[0036] As indicated above, when the closure is mounted on the
container body 1, the bore member 4 extends into the interior of
the container body 1 and the sealing member 5 is a close fit with
the internal surface 1B of the container body. As the cap 2 is
rotated relative to the collar 3 in the tightening direction, the
bore member 4 is drawn further into the container body 1 and the
o-ring provides a seal between the bore member 4 and the interior
of the container body 1.
[0037] The inner edge of the container lip is preferably chamfered
so as to provide a lead-in surface for the o-ring 5. The o-ring 5
then engages a portion 1B of the internal surface of the container
body which comprises a substantially parallel sided cylindrical
surface. The function of an o-ring 5 will be described further
below in relation to FIGS. 7A and 7B. The cylindrical surface 1B
extends axially for a distance (typically several millimetres),
sufficient to accommodate axial movement (up or down) of the bore
member 4, eg due to pressure differentials between the interior and
exterior of the container. As this surface 1B is parallel sided,
such movement can be accommodated without affecting the seal
between the closure and the container body.
[0038] It will be seen that the groove 4A within the bore member 4
is three-sided and, together with said internal surface 1B of the
container body, defines a four-sided enclosure for constraining the
cross-section of the o-ring 5. The side walls of the groove 4A are
preferably substantially perpendicular to the sealing surface 1B.
As will be described further below, the enclosure only needs to be
3-sided, ie two sided (eg L-shaped or V-shaped groove) together
with the sealing surface of the container.
[0039] A shoulder 1D is optionally provided beneath the cylindrical
surface 1B of the internal wall of the container leading to a
reduced diameter portion 1E of the container wall. Beneath this,
the container wall may have any desired shape. The reduced diameter
portion 1E is provided so that automatic handling tools, eg in a
filling line, can grip the interior of the container without
damaging the cylindrical sealing surface.
[0040] The shoulder 1D may also provide a stop feature for limiting
the movement of the bore feature into the container.
[0041] It will be appreciated that in arrangements in which the
thread form has an inclined portion rotation of the cap relative to
the collar is converted into axial movement of the o-ring within
the container and so provides a significant mechanical advantage in
effecting this movement. In addition, compression of the o-ring is
primarily in the horizontal direction so does not resist axial
movement of the ring. This greatly reduces the torque required to
tighten the closure.
[0042] As indicated above, the bore member 4 may be integrally
formed with the cap 2 or may be a separate component. In the latter
case, there are more options for forming the bore member 4 from a
material, eg a metal, different to that from which the cap 2 is
formed. A metal bore member is advantageous as it is generally
impermeable to gas. If a plastics bore member is used, it is
preferably formed of a plastic material which has been modified to
reduce its gas permeability. A metal bore member also has the
advantage that it expands as the temperature increases and thus
further compresses/deforms the o-ring seal to enhance the seal with
the container.
[0043] A separate bore member 4 may be mounted to the underside of
the cap 2 in a variety of ways, eg by being adhered or welded
thereto or by simply being clipped therein (as shown in FIG. 1).
The engaging portions of the cap and bore feature are preferably
provided at localised areas around the circumference to reduce the
frictional engagement therebetween (the benefit of which is
discussed below). The cross-section shown in FIG. 1 is through one
of these locations.
[0044] The bore member 4 may be arranged such that the cap 2 is
rotatable relative to the bore member 4 so, once the o-ring 5 has
frictionally engaged the sealing surface 1B, the bore member 4 no
longer rotates relative to the container body 1 as the cap 2 is
rotated further relative to the collar 3. Instead, if the
frictional engagement between the bore member 4 and the container
body 1 is greater than that between the bore member 4 and the cap
2, the bore member 4 merely moves axially within the container body
1. This means that the o-ring 5 also only has to move axially
within the container, rather than rotating relative thereto, as the
cap is tightened or loosened on the collar 3, and so greatly
reducing the torque required to tighten or loosen the closure. In
such an arrangement, rotation of the cap thus serves to drive the
bore member (and o-ring) axially further into the container. In
other cases, this need not be the case.
[0045] FIG. 2 shows a closure which is similar to that of FIG. 1
(with corresponding parts having reference numbers increased by 10)
except that the bore member 14 is integrally formed with the cap 12
and the upper portion 12A of the cap has an annular form (rather
than being circular and extending across the container opening). In
this case, it is just the bore member 14 that extends across and
closes the container opening.
[0046] This embodiment has the advantage of simplicity as it
comprises fewer components. The recess 12C in the closure can also
provide a location for a promotional item (not shown).
[0047] FIG. 3 shows a third embodiment similar to that of FIG. 1
(with corresponding parts having reference numbers increased by 20)
but in this case, the o-ring sealing member is part of a resilient
member 25 fitted to the underside of the bore member. The resilient
member 25 is moulded to fit the underside of the bore member 24 and
has a portion 25A which simulates a toroidal o-ring. This portion
25A has an approximately circular cross-section, eg square with
rounded corners as shown in FIG. 3, and is located in a groove 24A
which extends around the circumference of the bore member 24. As
shown, this groove 24A comprises an upper face and a rear face and
these faces, together with the cylindrical face 21 B of the
container body, constrain the cross-section of said part 25A, at
least when subject to an elevated pressure within the container 21
(NB this embodiment would not be suitable to for use in
applications in which the pressure in the container is reduced, ie
in a vacuum pack, as the groove does not have a lower face to
constrain said part against movement into the container).
[0048] FIGS. 4 and 5 show embodiments in which the closure is
secured directly to the container, eg by means of a thread on the
exterior of the container, ie without the need for a collar. These
embodiments also employ an o-ring to provide a seal between the
closure and the container and many features correspond to those
described above (and are given similar reference numbers but
increased by 30 or 40).
[0049] FIGS. 4A and 4B show a fourth embodiment with a one piece
closure that is rotatably secured to the container by means of a
threaded engagement therebetween. The closure comprises a cap 32
with a circular portion 32A that closes the mouth of the container
31 and a skirt portion 32B. The skirt portion 32B has thread
features 32C at spaced apart positions around its circumference
which engage with thread features 31A spaced around the exterior of
the container lip 31B. As shown in FIG. 4B, the circular portion
32A is part of a bore member 34 that extends into the container 31
and an o-ring seal 35 is provided in a groove 34A in the exterior
of the bore member 34. The o-ring seal 35 engages a sealing surface
31C around the inner circumference of the container 31. Preferably,
this surface 31C is substantially cylindrical (as discussed above)
but, as shown in FIG. 4B, may also be part of a surface that
reduces in diameter towards the mouth of the container 31. With
this arrangement, an elevated pressure within the container 31
urges the cap 32 upwards so the o-ring 35 engages a sealing surface
31C of reduced diameter so the sealing engagement therewith is
increased.
[0050] The cap 32 shown in FIG. 4 may be made from metal and the
thread features 32C thereof formed by a pressing operation. As
shown, the thread form is preferably a multi-start thread form, in
this case an eight-start thread form that requires a rotation of
only about 45 degrees to fasten or release the closure.
[0051] FIG. 5A shows a fifth embodiment of a closure. This is
similar to the one-piece closure of FIG. 4 except that the o-ring
45 is mounted in a groove which is positioned on the bore feature
44 such that the sealing surface 41C that the o-ring engages is a
conical surface of the container 41. In the example shown, this
conical surface 41C lies at an angle of substantially 45 degrees
with the axis A and comprises the chamfer which extends from an
upper surface of the container lip into the interior of the
container 41. The conical surface 41C may lie at other angles to
the axis A depending upon the application, the nature and magnitude
of the internal pressures and the hardness of the o-ring material
45.
[0052] This embodiment has the advantage that the cap 42, and
particularly the groove used to housing the o-ring, is easier to
form by a pressing operation than the arrangement shown in FIG.
4.
[0053] Also, as the sealing surface 41C has a vertical component,
the o-ring moves down this surface as the cap 42 is tightened onto
the container 41. This reduces the force required to tighten the
closure (compared to an arrangement in which the sealing surface is
perpendicular to the axis A) as this force moves the o-ring
downwards as well as compressing the ring. As the sealing surface
is inwardly inclined, it also serves to compress the o-ring in the
horizontal direction.
[0054] FIG. 5B shows a modified form of the fifth embodiment in
which an o-ring seal 45' having a cruciform cross-section
(sometimes referred to as an x-ring) is used in place of an o-ring
with a circular cross-section. This form of o-ring has the
advantage that it seals at four points rather than two.
[0055] FIG. 6A shows a sixth embodiment of a closure. This is
similar to the one-piece closure of FIG. 4 except that the o-ring
35 is mounted in a groove which is positioned so that the sealing
surface that the o-ring engages is an upper surface of the
container lip. Preferably, as shown, the cap still has a bore
member that extends into the interior of the container. In the
arrangement shown, the sealing surface is a radially inner portion
of the upper surface which abuts the internal surface of the
container. If the interior of the container is subject to reduced
pressure, eg in a vacuum container, the o-ring is thus pressed into
the gap between the bore member and the inner rim of the container.
The seal thus formed may thus be regarded as being formed with the
interior surface of the container if the corner where this meets
the upper surface is included as part of the interior surface.
[0056] FIG. 6B shows a modified form of the sixth embodiment in
which an o-ring seal 55' having a cruciform cross-section
(sometimes referred to as an x-ring) is used in place of an o-ring
with a circular cross-section. As indicated above, this form of
o-ring has the advantage that it seals at four points rather than
two.
[0057] In a further modification (not shown) of the sixth
embodiment, the upper surface of the container lip may be shaped so
that the sealing surface that the o-ring engages is not the
uppermost surface of the lip. This sealing surface may be provided
on the inner side of the lip, in which case the bore feature and
the o-ring carried thereby extend through the opening of the
container into the interior of the container (in a similar manner
to that shown in FIG. 5).
[0058] Alternatively, the sealing surface may be around the
exterior of the upper surface of the container lip, eg in the form
of a recess or chamfer about the external diameter of the lip. As
indicated above, if the sealing surface is inclined (so as to have
a vertical component), the torque required to tighten the closure
is reduced as the forces applied to compress the o-ring are at an
angle to the axis A so are not directly opposed to the vertical
movement (along axis A) of the closure.
[0059] Thus, in these modifications, the sealing surface is an
upper surface of the container lip (or an internal surface of the
container) but not necessarily the uppermost surface of the
lip.
[0060] Preferably, as will be seen that in each of these
embodiments, the side walls of the groove housing the o-ring are
substantially perpendicular to the sealing surface of the
container.
[0061] FIGS. 7A to 7C illustrate the function and parameters of an
o-ring seal. FIG. 7A shows a cross-section of an o-ring 75 with a
circular cross-section in an undeformed state. The cross-section
has a diameter or width CS. FIG. 7B shows the o-ring 75 located in
a groove or gland 74A having a depth D and compressed between the
rear sealing face 74B of the groove and an external sealing face
71B (such as the internal surface of the container body). In this
case, the o-ring 75 is subject to equal pressures on either side
thereof (left and right in FIG. 7B).
[0062] An o-ring has an inner and outer diameter and a
cross-sectional diameter CS (which is the difference between the
inner and outer diameters). The outer diameter is determined by the
diameter of the container opening (and is typically slightly
greater than the diameter of the container opening). The
cross-sectional diameter CS will depend upon the application but
for containers having a diameter in the range 50-80 mm will
preferably be in the range of 2.0-3.0 mm. For narrower mouth
containers, eg with a 28 mm diameter opening, CS will preferably be
in the range 1.0-2.0 mm. It should be noted that CS refers to the
cross-section of the uncompressed o-ring when mounted in the
groove. If the ring is stretched when located in the groove this
cross-section will be smaller than the cross-section in an
unstretched condition.
[0063] O-rings are typically formed of elastomers. Elastomers may
be synthetic or natural resilient materials with sufficient memory
to return to their original shape after a major or minor
distortion. The resilience is what enables an o-ring to provide a
seal and the parameters of the seal and the gland are selected to
make effective use of this.
[0064] The o-ring is positioned in an enclosed space which both
compresses and locates the o-ring. The containment ensures that the
sealing function is maintained and the o-ring retained in the
desired position. The enclosed space is formed by the walls of the
groove or gland and a sealing surface facing the open side of the
groove or gland. FIG. 7B illustrates an enclosed space having a
height H and a width W. The gland is formed in a relatively rigid
material (and thus from a different material from the o-ring). The
o-ring positioned in this space is compressed so its
cross-sectional width is reduced from CS (shown in FIG. 7A) to
H.
[0065] The term `compressed` is used herein to describe this change
of shape. However, it should be noted that elastomers are
substantially incompressible so the term `deformation` is
technically more accurate. The cross-sectional area of the o-ring
in the `compressed` state is thus substantially the same as it is
in the uncompressed state.
[0066] The opposing surfaces 71B and 74B of the gland are sealing
surface and their spacing H is less than the o-ring cross-section
CS so the o-ring is compressed as shown resulting in sealing forces
between the o-ring and each of the surfaces 71B and 74B.
[0067] The opposing surfaces 74A and 74C are containing surfaces
and the distance W between them is equal to or larger than the
diameter CS of the o-ring. The primary function of these surfaces
is to keep the o-ring in place.
[0068] Two of the most important parameters that affect the
performance of an o-ring seal are the compression squeeze and the
compression ratio. The compression squeeze is defined as;
Compression squeeze=CS-H
[0069] And the compression ratio expresses what percentage the
compression squeeze is of the uncompressed o-ring
cross-section:
Compression ratio=(compression squeeze/CS).times.100
[0070] The compression squeeze should have a minimum value of 0.1
mm and is preferably at least 0.15 mm.
[0071] The compression ratio should be in the range 5% to 35% and
preferably in the range 20% to 25%.
[0072] Another parameter of an o-ring seal is the extrusion gap G
which is the height of the spacing between the sealing surface 71B
and the outer surface of the bore member (or other component)
adjacent the opening of the groove formed therein. The gap G is the
difference between the dimensions H and D: so G=H-D.
[0073] The gap G should be significantly smaller than the
cross-section CS of the o-ring, eg no greater than 20% of CS and
preferably no greater than 10% of GS. In most cases, the gap G is
very small, eg 0.5 mm or less and preferably 0.25 mm or less.
However, in some cases, the gap may be slightly larger due to
manufacturing tolerances in the formation of the container and the
bore member of the closure, or due to specific designs, such as
food applications, whether it may be desirable for the o-ring to be
allowed to extrude partially into the gap.
[0074] If the gap G is very small, this means that the depth D of
the gland is thus preferably 65%-95% of the o-ring cross section CS
and preferably 75% to 80% of the cross-section CS.
[0075] In cases where the gap G is larger, the depth D of the gland
should still be at least 50% and preferably at least 60% of the
cross-section CS.
[0076] Another important parameter of an o-ring seal is gland fill.
This is the percentage of the gland that is occupied by the o-ring.
The cross-section area (CSA) of a circular o-ring is
pi.times.(CS/2).sup.2 and the gland cross-sectional area (CSA) is
H.times.W. Thus, the gland fill is given by:
(o-ring CSA/gland CSA).times.100
[0077] The gland fill should lie in the range 50% to 90% and
preferably in the range 65% to 85%.
[0078] FIG. 7C illustrates how the o-ring 75 moves within the
groove 74A and is deformed when subject to pressure P from one side
(the right side of FIG. 7C). The o-ring 75 moves within the groove
74A away from the higher pressure P and is pressed against the side
face 74C at the other side of the groove 74A. It is deformed so as
to seal the gap 76 between the component housing the groove 74A and
the face 71B. Given the nature of the o-ring (and the size of the
gap), deformation of the o-ring into this gap is usually minimal.
It will also be seen that a substantial proportion (greater than
50%) of the o-ring surface is engaged with a surface (71B, 74B,
74C) of the gland so as to provide a seal therewith.
[0079] The parameters described above have been described in
relation to a conventional o-ring with a circular cross-section.
However, similar parameters apply to other variants of a o-ring, eg
when the o-ring has other cross-sectional shapes and/or when the
gland has other forms (eg a 3-sided gland as shown in FIG. 3, or an
L-shaped or V-shaped gland formed by two inclined side walls) with
the appropriate dimensions used in place of those illustrated in
FIG. 7. It will be appreciated that when the o-ring is subject to a
pressure differential acting to move it in one direction, the gland
only need have one side wall, eg so the groove is L-shaped.
[0080] The function of o-ring seals, and their technical
parameters, are further described in the Dichtomatik O-Ring
Handbook published by Dichtomatik North America (and available in
2010 on their web site at
http://www.dichtomatik.us./Literature/O-ring-Handbook.aspx)
[0081] It will be appreciated that the sealing action of an o-ring
is very different to that of known beverage container seals such as
a sealing gasket which is trapped between two flat surfaces, a seal
with one or more flexible sealing fins or a wedge seal trapped in a
tapering gap between a plug member and a container bore. The
principal sealing surfaces of an o-ring are the opposing surfaces
71B and 74B between which the o-ring is compressed and the
engagement of the o-ring therewith.
[0082] FIGS. 8 to 13 illustrate a two-part closure as described in
co-pending GB1011800.8. The inner and/or outer component of this
two-part closure may, as described in GB1011800.8, comprise a bore
feature (not shown) which projects through the mouth of the
container into the interior thereof and the bore feature may be
provided with an o-ring seal which engages and seals with the
interior of the container (or an upper surface thereof). These
further embodiments of the two-part closure thus form further
embodiments of the present invention. The two-part closure will be
described with reference to FIGS. 8-13 followed by description of
the arrangements (not shown in these Figures) having a bore feature
and an o-ring seal.
[0083] The closure shown in FIGS. 8-13 comprises an inner component
having a collar portion for fitting about the exterior of a
container 82, in this case a bottle neck having a container opening
defining an axis A, and which has radially moveable parts 83 spaced
around its circumference for engaging beneath a lip 82A of the
container 82, and an outer component having a skirt part 84A for
locating about the radially moveable parts 83 of the inner
component.
[0084] The outer component 84 is designed to be located over the
inner component 81 by substantially axial movement therebetween and
comprises one or more cam surfaces 84B on its inner surface which
engage the upper ends of the radially moveable parts 83 as the
components are moved axially so as to progressively press the parts
83 inwards into tight frictional engagement with the exterior of
the container beneath the lip 82A of the container 82. The cam
surfaces are thus arranged to hold and/or press an
expandable/contractable portion of the inner component into secure
engagement with the container beneath said lip.
[0085] Once the outer component 84 has been moved axially over the
inner component 81 so as to press the radially moveable parts 83
inwards, it is twisted relative to the inner component 81 about the
axis A so as to engage securement means which releasably secure the
inner and outer components together in this position. In the
embodiment shown, the securement means comprises substantially
upwardly facing surfaces 85A of inward projections 85 at the lower
end of the skirt part 84A of the outer component and substantially
downwardly facing surfaces 83A of the radially moveable parts 83.
The surfaces 85A and 83A may provide a bayonet-form of engagement
between the inner and outer components and/or a thread-like
engagement therebetween. The surfaces may be shaped or inclined
such that said relative rotation between the inner and outer
components also causes axial movement therebetween.
[0086] In the closure shown in FIGS. 8 and 9, the inner component
81 also comprises a flexible sealing portion 86 which extends over
the opening in the bottle neck, over an upper surface of the
container lip and extends down the exterior of the bottle neck. The
flexible portion 86 is preferably integrally formed with the
radially moveable parts, e.g. by a two-shot moulding process. The
radially moveable parts are formed of a relatively rigid material,
e.g. polyethylene terephthalate (PET), and the flexible portion of
a relatively flexible material e.g. an elastomer. The function of
the flexible sealing portion 86 will be described further
below.
[0087] The outer component 84 comprises a top part from which the
skirt part depends and which extends across the upper surfaces of
the lip 82A and across the container opening.
[0088] The inner component 81 will be described in more detail with
reference to FIGS. 10A and 10B. As shown in these figures, the
inner component comprises two principal parts: a collar portion
which comprises a ring 83B with a plurality of radially moveable
parts 83 upstanding from the ring 83B and circumferentially spaced
around the ring 83B and a flexible sealing portion (described
further below). Each of the moveable parts 83 has a rounded upper
end 83C for engagement with the cam surfaces 84B described above
and for engaging the underside of the container lip 82A.
Preferably, the upper end 83A of the moveable parts 83 is shaped to
substantially match the concave profile of the container on the
underside of the lip 82A (as shown in FIG. 9).
[0089] The outer face 83D of each of the moveable parts is
substantially flat so as to be a snug fit within the skirt 84A of
the outer component 84 when the closure is in an unsecured position
(as shown in FIG. 8). Each moveable part 83 also has a lower,
substantially downwardly facing surface 83A as described above.
This acts to retain the inner component 81 within the outer
component 84 in the unsecured position (as shown in FIG. 8) so the
inner and outer components can be easily pre-assembled; the inner
component 81 being a snap fit within the outer component 84 as they
are brought together in the axial direction, the moveable parts 83
flexing as they pass over the inward projections 85 until they snap
outwards so the lower surface 83A of the moveable part engages the
upper surface 85A of the inward projections 85.
[0090] In the position shown in FIG. 8, the surfaces 83A and 85A
are substantially horizontal i.e. perpendicular to axis A. However
when the inner and outer components are moved axially relative to
each other to the position shown in FIG. 9, the moveable parts 83
are flexed inward. The lower surface 83A of the moveable part is
thus tilted inwards so as to be inclined to the horizontal.
Accordingly, the upper surfaces 85A are preferably shaped so that
when the outer component 84 is twisted to the secured position the
surface 85A is similarly inclined to the surface 83A.
[0091] In addition, in many cases, is desirable for the engagement
between the surfaces 83A and 85A, as the outer component 84 is
rotated or twisted about axis A to a second position, for the inner
and outer component to be drawn together axially whereby the outer
component 84 is drawn down towards the upper surface of the
container lip 82A and the moveable parts 83 drawn tightly upwards
beneath the lip 82A of the container. The surfaces 83A, 85A are
thus inclined in the circumferential direction in the manner of a
screw thread to effect a tight securement of the closure to the
container as the inner and outer components rotated relative to
each other in a tightening or closing direction about axis A. As
the outer component is rotated relative to the inner component, the
outer component is drawn down so as to compress the flexible
sealing portion of the inner component against the upper surface of
the container lip and the moveable members 83 are pressed upwardly
into secure engagement with the container beneath the container
lip.
[0092] In the embodiment shown, the ring 83B projects beneath the
skirt 84A of the outer component so is visible from the exterior
(as shown in FIGS. 8 and 9). However, in other embodiments, the
ring may be concealed by the skirt, at least when in a secured
position corresponding to that shown in FIG. 9.
[0093] An important feature of the collar portion of the inner
component is that the upper ends of the moveable components that
are free to flex radially inwards and outwards, this movement
taking place about a pivot at or towards the lower end of the
collar (in contrast to a collar which is located the other way up
i.e. with the moveable parts extending downwards from a ring
portion).
[0094] The other principal part of the inner component is the
flexible sealing portion 86. In the embodiment shown, this is in
the form of a cap with an upper end 86A extending across the upper
end of the container 82 and an upper surface of the lip and a skirt
portion extending down the outside of the bottle neck to the ring
83B of the collar.
[0095] The flexible portion 86 performs several functions. First,
it acts as a sealing component in that it is sandwiched between the
outer component 84 and the upper surface of the lip 82A of the
container so as to provide a gasket seal therebetween. In the
arrangement shown, it also extends across the mouth of the
container and so closes the container opening. In addition the
flexible portion lies between the substantially rigid moveable
parts 83 and the outer surfaces of the bottle neck and acts as a
high friction component between these surfaces.
[0096] As indicated, the collar portion and the sealing portion are
preferably integrally formed. This can be achieved, for example, by
a two-shot moulding technique in which the different materials are
consecutively injected so they are integrally bonded or connected
to each other. This also has the significant advantage that the
closure comprises just two parts: the inner component and the outer
component. In known cap-on-collar closures, it is usually necessary
for the sealing component to be provided separately or secured in
some manner to the underside of the outer component.
[0097] The outer component 84 will now be described in more detail
with reference to FIGS. 12A and B and FIGS. 13A and B.
[0098] In the embodiment shown, the outer component is in the form
of a cap with an upper portion 84C which extends over the upper
surface of the lip 82A and extends across the opening of the
container 82 and has a skirt portion 84A depending therefrom.
[0099] The skirt portion 84A is provided with inwardly extending
projections 85 at or toward the lower end thereof. As described
above, the upper surface 85A of each projection 85 is preferably
inclined circumferentially so it acts as a screw thread and tilts
radially inwards to an increasing extent along its circumferential
length so as to match the inclination of the lower surface 83A of
the moveable part 83 that it engages. This thread path may extend
over two or three adjacent parts 83.
[0100] The closure is designed so that only a relatively small
twist is required to move it from an unsecured (FIG. 8) position to
a secured (FIG. 9) position. In the embodiment shown, a twist of
only approximately 60 degrees is required. Accordingly, the inward
projection 85 comprises six sections around the inner circumference
of the skirt portion 84A as shown in FIGS. 12B and 12B.
[0101] As indicated above, the outer component engages downwardly
facing surfaces of the radially moveable parts so as to secure
and/or tighten the inner and outer components together in the axial
direction. This is an important feature as it enables both the
inner and outer components to be relatively short in the axial
direction so they can be formed to resemble a conventional cap-like
closure. This also means that the threaded engagement between the
inner and outer components comprises circumferentially spaced apart
features (the surfaces 83A of the respective parts 83). This
enables the threaded engagement therebetween to require only a
relatively small rotation or twist (rather than several complete
rotations as required by a continuous helical thread form).
Furthermore, this provides a very compact and robust construction.
The upwardly facing surfaces 85A of the outer component apply an
upward force which is directly transmitted via surfaces 83A through
parts 83 which have a rigid, strut-like form to the underside of
the lip 82A.
[0102] This high friction engagement can also be provided in other
ways. The collar component may be provided with a lining of high
friction material (irrespective of whether this is connected to a
sealing component that passes over the upper surface of the
container lip) or the inner surface of the collar component could
be provided with a roughened finish which is sufficient to increase
the frictional engagement with the container to the required level.
In another alternative, a high friction sleeve, eg of rubber, could
be fitted around the container neck.
[0103] In addition, the flexible sealing component extends over the
upper surface of the lip 82A and so provides a sealing member
between the closure and the container. The provision of a single
component that acts both as a collar for fitting around the
exterior of the container and as a sealing component between the
closure and the container, is a significant feature of this
closure.
[0104] As described, when the outer component is moved with respect
to the inner component so as to press the moveable parts 83
inwards, this movement is primarily axial. In other embodiments,
this axial movement may be provided by means of a small twisting
movement although it is the axial component that moves the cams
downwards so as to press the parts 83 inwards. The twisting
movement is preferably less than 360 degrees and more preferably
less than 90 degrees or less than 60 degrees. This is in contrast
to arrangements in which a small axial movement is a consequence of
several complete rotations of the outer component relative to the
inner component, eg as provided by a continuous helical
threadpath.
[0105] In further embodiments (not shown) of the closure shown in
FIGS. 8-13, in particular closures for widemouth containers, the
inner and/or outer component may comprise a bore feature which
projects through the mouth of the container into the interior
thereof. The bore feature preferably comprise a relatively rigid
component, eg formed of PET or metal, and may be integrally formed
with the outer component or secured thereto. In a particularly
advantageous arrangement, the outer component is able to rotate
about the axis A relative to the bore feature. The outer component
can thus be rotated, eg to fasten or release the closure whilst the
bore feature moves axially within the bore without rotating
therein.
[0106] The bore feature may also be provided with an o-ring seal
which engages and seals with the interior of the container (or an
upper surface of the container lip). The bore feature and o-ring
may be as described above. The o-ring may be in the form of a
toroid of an elastomer located in a groove or gland on the outer
surface of a bore feature. The o-ring may also be part of a
resilient member moulded to fit the underside of the bore feature.
The resilient sealing portion described above in relation to FIGS.
8-13 may include such a member. Thus, if the outer member shown in
FIG. 9 projects into the bore of the container (rather than being
flat) and the resilient sealing portion follows the underside of
this feature (again, rather than being flat) the resilient
component may be formed with a portion which simulates the function
of an o-ring to provide a seal with the interior of the
container.
[0107] In such embodiments employing an o-ring seal, the seal
provided by the sandwiching of the flexible part of the inner
component between the outer component and the upper surface of the
container lip may no longer be required. In this case, the outer
component need not engage and/or compress the flexible sealing
component against the upper surface of the lip.
[0108] These further embodiments thus provide a closure for a
container having a circular opening defining an axis and a lip
around said opening, the closure comprising: an inner component
having a collar portion for locating about the exterior of the
container beneath the lip of the container and a sealing portion
which, in use, extends from said collar portion over an upper
surface of said lip; and an outer component for fitting over the
inner component and interacting therewith for releasably securing
the collar portion thereof under said lip, the closure having an
o-ring seal for providing a seal between the closure and an upper
or interior surface of the container.
[0109] The o-ring may be provided on a bore feature which, in use,
projects through the opening into the interior of the container,
the bore feature being part of the inner and/or the outer
component.
[0110] In a preferred arrangement, the collar portion may be
relatively rigid and the sealing portion relatively flexible and
the collar portion and the sealing portion may be integrally formed
with each other, eg by a two-stage moulding process.
[0111] Preferably, the outer component has a skirt part for
locating about the collar portion of the inner component, the
collar portion comprising a plurality of spaced apart radially
moveable parts around its circumference pivotally joined at their
lower ends by a structure extending around the entire circumference
of the collar portion.
[0112] The provision of an o-ring seal between the bore member and
the internal surface of the container body has a number of
advantages: [0113] It has relatively stable geometry when subject
to pressure-induced lifting of the closure (compared to that of a
seal provided on the upper surface of the container lip) [0114] The
degree of o-ring compression that is required is reduced (compared
to a seal on the upper surface of the container lip) and the
direction of the compression does not increase the frictional
engagement of the thread so the torque required to compress the
seal is reduced [0115] Increased pressure within the container
presses the o-ring seal more tightly into the gap between the
closure and the cap so improving seal quality at higher pressures
[0116] Positive internal pressure also assists in releasing the
seal by applying an upward force against the underside of the
closure so helping overcome the frictional engagement between the
o-ring and the container wall. [0117] The sealing surface are
spaced from the container lip and thus less susceptible to damage,
eg during handling of the container. [0118] The bore member allows
the head space within the container to be significantly reduced.
[0119] The o-ring (in an appropriately shaped gland) is able to
provide a seal irrespective of whether the internal pressure is
higher or lower than the external pressure so can be used both for
carbonated beverages and for vacuum packs. Other forms of seal tend
to be designed cater for one or the other application.
[0120] Using a bore feature which is formed separately from the cap
also provides the additional advantages: [0121] Further reducing
the torque required as the bore feature (and hence the seal carried
thereby) does not have to rotate with the cap [0122] Allows the
bore feature to be formed of a different material, eg a metal to
reduce its gas permeability to almost zero [0123] Makes it easier
to separate the different components of the closure for ease of
recycling
[0124] As described, the o-ring is preferably a separate component,
typically having a circular cross-section (although other
cross-sectional shapes are possible) located within a recess
extending around the circumference of a bore member. However, in
other embodiments, the seal member may have other forms which
simulate the sealing action of an o-ring and may be integrally
formed with a bore member, for example by using an over-moulded
elastomer to form a virtual o-ring element.
[0125] An o-ring typically needs to be compressed by 10-30% to
provide an effective seal, whereas a compression gasket can require
a much higher degree of compression.
[0126] If the o-ring is located within a groove 4A as shown in FIG.
8, it is preferably able to move axially within this groove in
response to increases or decreases in pressure within the container
body. This enables the o-ring to respond to the increase in
pressure and adopt a shape/position which is better able to
withstand the pressure.
[0127] In each of the embodiments described, an o-ring is used to
provide a seal between a closure and a container. The o-ring
preferably seals against an internal surface of the container but,
in some embodiments, may seal against an upper surface thereof
(particular at the point where this meets the internal surface).
The sealing surface extends around either the internal or the upper
surface of the container.
[0128] The o-ring is located in a groove which has at least one
side wall, the arrangement being such that, when the closure is
installed on the container, when subject to a pressure
differential, the o-ring is moved and/or deformed so as to seal a
gap between side wall and the container, the width of said gap
being smaller than the cross-sectional width of the o-ring.
[0129] The closure may take a wide variety of forms including a
cap-on-collar and other two-part arrangements such as those
described as well as a one piece closure. Preferably, the closure
is arranged to be installed and/or released from the container by
rotation around the axis passing though the container opening.
[0130] An additional advantage of having a bore member which
extends into the interior of the container is that this occupies
space at the upper end of the container that in a beverage
container would usually otherwise be occupied by a gas or provide a
`headspace`, above the beverage. Reduction of the volume of this
headspace, if it is occupied by air, reduces the amount of oxygen
trapped within the container so increasing the shelf-life of the
beverage or, if it is filled with an inert gas, reduces the
quantity of inert gas required.
[0131] In some cases, the cap or outer component may comprise an
annular component that has an upper portion that overlies the upper
surface of the container lip so that it can provide a downward
force on the lip, or on a seal member located between the lip and
the cap, and a skirt portion which interacts with a collar or inner
component (as described above) whereby the cap is secured to the
container body.
[0132] The thread form used between the cap and the collar or inner
and outer components (for a two-part closure) or between the cap
and the container (for a one-piece closure) is preferably a
multi-start thread form such that less than 360 degrees of rotation
is required to install or remove the closure. With an eight-start
threadform, the closure needs to be rotated by only about 45
degrees to install or release the closure.
[0133] Intermittent threadforms and bayonet style threadforms such
as those described in WO2006/000774 and WO2007/091068 may be used.
In the case of a bayonet theadform, the cap or outer component need
not be moved axially as the outer component is rotatably secured to
the inner component. Similar threadforms may also be used with a
one-piece closure (with the thread form provided on the container
neck rather than on a collar).
[0134] For the avoidance of doubt, the verb "comprise" as used
herein has its normal dictionary meaning, ie to denote
non-exclusive inclusion. The use of the word "comprise" (or any of
its derivatives) does not therefore exclude the possibility of
further features being included.
[0135] All of the features disclosed in this specification
(including the accompanying claims, and drawings) may be combined
in any combination (other than combinations where at least some of
the features are mutually exclusive).
[0136] Each feature disclosed in this specification (including the
accompanying claims and drawings) may be replaced by alternative
features serving the same, equivalent or similar purpose, unless
expressly stated otherwise. Thus, unless expressly stated
otherwise, each feature disclosed is just an example of a generic
series of equivalent or similar features.
[0137] The invention is also not restricted to the details of the
embodiments described herein or to the specific combinations of
features of the embodiments described. In particular, the invention
includes arrangements as described in the claims with the addition
of any one or more features described or claimed herein including
generalisations of which those feature(s) are illustrative.
* * * * *
References