Note: Descriptions are shown in the official language in which they were submitted.
CA 02226573 1998-O1-12
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DESCRIPTION
SEALING DEVICE AND CONTAINER
TECHNICAL FIELD
The present invention relates to sealing devices
comprising containers and synthetic resin caps having tamper-
evidence properties for sealing the mouth portions of these
containers, and relates to such containers.
BACKGROUND ART
In recent years, synthetic resin containers composed of
polyethylene terephthalate (PET bottles) have come into common
use as beverage containers. Synthetic resin containers have
the advantageous properties of being light and shatterproof in
comparison with conventional glass bottles.
Addii~ionally, as caps for this type of synthetic resin
container,, metallic caps of aluminum alloy or the like have
been conventionally used. Using synthetic resin caps in place
of these i=ypes of metallic caps has also been considered.
With regard to these types of synthetic resin caps, those
disclosed in Japanese Patent Application, First Publication No.
Sho 62-25:L352 and Japanese Patent Application, First
Publication No. Hei 2-296666 are known.
These conventional synthetic resin caps are screwed ;;nto
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containers having an external thread formed on the mouth
portions and annular expanded portions below the external
thread; the caps are composed of a synthetic resin cap
main body formed by a top plate portion and a tubular
portion which extends downward from the peripheral
portions thereof, and a thin liner provided on the inner
surface of the top plate portion of the cap main body, the
cap main body being such that the bottom portion thereof
is partitioned, by means of a horizontal score formed
around the circumference while leaving a plurality of thin
bridges, into a main portion above the horizontal score
and a tamper-evidence ring portion below the horizontal
score. A threaded portion for screwing onto the external
thread on the mouth portion of the container is formed on
the inner wall surface of the main portion of the cap main
body, and multiple wings or tabs are provided so as to be
erectable on the inner wall surface of the tamper-
evidence ring portion.
Additionally, as the containers, those having an
e~:ternal thread formed on the outer circumference of the
top end portion of the mouth portion and provided with an
annular expanded portion (locking ring) below the external
thread are used.
With these types of caps having tamper-evidence
properties, it is preferable that the relationship between
th.e seal release angle, hereinafter abbreviated to SRA,
and the bridge breaking angle, hereinafter abbreviated to
BBA, be held to be such that SRA - BBA = 0 degrees or
greater, more
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preferably +30 degrees or greater, wherein SRA is the
rotationa:L angle at the moment the seal of the container is
released due to the top end of the mouth portion of the
container being separated from the inner surface of the cap or
the liner when the cap attached to the mouth portion of the
container is rotated from the initial position in the
direction of opening, and BBA is the rotational angle at the
position where the bridges are broken when the cap attached to
the mouth portion of the container is rotated from the initial
position ._n the direction of opening. That is, it is
desirable, when opening the cap, that the bridges are broken
before the seal is released due to the top end of the mouth
portion of the container being separated from the liner or the
like.
However, with the above-mentioned synthetic resin caps,
there are cases wherein the bridges formed from synthetic
resin expand and the engaging projections (wings or tabs) are
so soft a:~ to bend when engaging with the annular expanded
portion, as a result of which the BBA can increase and SRA -
BBA can become less than 0 degrees; thus, there are points
requiring improvement from the point of view of tamper-
evidence properties.
Techniques for separating a cap main body and a tamper
evidence ring portion with a small rotational angle in order
5 to enhance tamper-evidence properties are disclosed, for
example, in Japanese Patent Application, Second Publication: iJ;:~.
Sho 32-1945.
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As sealing devices designed to increase the above-
described tamper-evidence properties using synthetic resin
caps, those described in Japanese Patent Application,
Second Publication No. Hei 3-56990 are known. These
sealing devices comprise engaging claws having engaging
side edges extending downward with a tilt in the cap-
opening direction underneath the external thread of the
container, and engaged claws which cooperate with the
above-mentioned container engaging claws formed on the
inner walls of the tamper-evidence ring portion of the
ca.p. With the sealing device of Japanese Patent
Application, Second Publication No. Hei 3-56990, when the
cap is turned in a cap-opening direction with the cap
attached to the mouth portion of the container, the
engaged claws formed on the tamper-evidence ring portion
are guided to the tilted engaging side edges of the
engaging claws so as to be forced downward, and the
tamper-evidence ring portion is forced to move downward to
accelerate tearing along the tear line formed on the cap
tubular portion.
However, in these conventional sealing devices, since
the engaged claws formed on the cap have a fixed structure
such as not to bend, the engaged claws on the cap must be
forced past the engaging claws on the container when the
cap is attached to the container, so that the plurality of
bridges which couple the main portion of the cap tubular
portion with the tamper-evidence ring portion must be
reinforced to some extent, as a result of which the
resistance to breakage of the bridges when the cap is
opened is large and the seal cannot be easily
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opened. Additionally, in order to prevent the bridges from
breaking when the cap is attached to the container (when
the container is sealed), the tamper-evidence ring portion
could be given an engaging structure for preventing
5 relative movement in the cap-closing direction, but this
presents a problem in that it would become difficult to
mold the cap and the costs would increase. Furthermore,
since these containers according to the conventional art
ar_e for engaging side edges of the engaged claws having
fixed structures such as not to bend, these containers
cannot be applied to caps provided with multiple wings or
tabs which are erectable on the inner wall surface of the
tamper-evidence ring portion as described in Japanese
Patent Application, First Publication No. Sho 62-251352
and Japanese Patent Application, First Publication No. Hei
2-296666. That is, with the structure of the container
described in Japanese Patent Application, Second
Publication No. Hei 3-56990, only engaging claws having
engaging side edges extending downward while tilting in
th.e cap-opening direction are formed underneath the
external thread, so that when the above-mentioned cap
having the wings or tabs is attached and the cap is turned
in a cap-opening direction, the wings or tabs contact the
tips of the engaging claws, the tips of the wings or tabs
are bent upward, allowing the engaging claws to pass
without engaging the engaging claws, as a result of which
the cap can be removed without breaking the bridges.
Additionally, as another example of conventional art,
those described in Japanese Patent Application, First
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Publication No. Hei 7-291317 have been proposed.
The sealing device described in this publication
comprises an external thread on the mouth portion of the
cc>ntainer, an annular chin portion positioned therebelow,
and ratchet claws positioned therebelow spaced along the
ci.rcumferential direction. An internal thread is formed on
the inner circumferential surface of the main portion of
the tubular portion of the synthetic resin cap, and
engaging flaps which extend upward at an incline in the
radial inward direction from the base end are formed on
tree inner circumferential surface of the tamper-evidence
ring portion spaced in the circumferential direction.
When this type of sealing device formed by combining
a container with a cap has the mouth-neck portions sealed
by attaching the cap to the mouth portion of the
container, the rotation of the cap in the cap-opening
direction, not the movement in the upward direction, is
inhibited due to the side edges in the circumferential
direction of the engaging flaps formed on the tamper-
evidence ring portion of the cap contacting the rear
surfaces of the ratchet claws which extend at a steep
incline.
That is, the conventional sealing device composed of
a synthetic resin cap and a container as mentioned above
has a formation wherein, when the cap attached to the
mouth portion of the container is turned in the cap-
opening direction, the engaging flaps formed on the inner
circumferential surface of the tamper-evidence ring
portion of the cap are engaged with
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the ratchet claws formed on the mouth portion of the
container to inhibit the rotation of the tamper-evidence
ring portion in the cap-opening direction, as a result of
which a force in the rotational direction is directly
applied to a plurality of bridges which couple the main
portion of the cap tubular portion with the tamper
evidence ring portion to break the bridges.
However, with regard to the above-mentioned
conventional sealing devices, since the bridges are
severed by pulling apart the plurality of bridges at once,
there is a risk that the rupture resistance of the bridges
could increase so that the bridges are not sufficiently
severed, or that the engaging flaps could be folded back
due to the strong rupture resistance so as to pass the
ratchet claws.
That is, in the weakened line of a cap tubular portion
formed from a horizontal score cut along the
ci.rcumferential direction of the tubular portion while
leaving a plurality of thin bridges, each bridge has a
thin pillar shape composed of synthetic resin. This type
of bridge is comparatively easily stretched when a tensile
force is applied in the longitudinal direction, and easily
and reliably severs after a certain degree of stretching.
However, when shear stress arising from the movement of
the main portion which is turned in the cap-opening
direction with respect to the fixed tamper-evidence ring
portion is instantaneously applied to this type of bridge,
the bridge has a high rupture resistance. In other words,
tamper-evidence ring portions coupled to main portions by
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means of multiple bridges in this way are not easily torn
even when a rotational force is applied in the cap-
opening direction.
Additionally, with formations wherein bridges are
severed according to conventional products as mentioned
above, a large cap-opening torque is required in order to
~~eparate the tamper-evidence ring portion from the main
~>ortion, and this makes it difficult for children to open
t:he cap. Additionally, even if one attempts to open the
c:ap by applying a large cap-opening torque, this large
force can be applied to the engaging flaps so as to cause
the engaging flaps to be folded back and pass the ratchet
claws, thereby making it impossible to separate the
tamper-evidence ring portion.
DISCLOSURE OF INVENTION
The present invention has the object of offering a
sealing device which prevents the cap-opening torque from
becoming high due to the rupture resistance of the
bridges when the cap attached to the mouth portion of the
container is turned in the cap-opening direction, and
which can yield good tamper-evidence properties by
reducing the BBA when the cap is being opened; and the
present invention has the object of offering such a
container.
According to an aspect of the present invention,
there is provided a sealing device comprising a container
and a synthetic resin cap attached to a mouth portion
thereof; said synthetic resin cap having a cap main body
having a top plate portion and a tubular portion
extending downward from the periphery thereof, said
tubular portion being partitioned by means of a tearable
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weakening line into an upper main portion and a lower
tamper-evidence ring portion, a threaded portion being
formed on an inner wall surface of said main portion, and
erectable engaging projections being provided on an inner
wall surface of said tamper-evidence ring portion, the
Engaging projections being oriented substantially
horizontally and having tips facing in a radially inward
direction and being foldable upward; and said container
has an external thread formed on an outer circumference
of an upper end of said mouth portion thereof, an annular
expanded portion formed underneath said external thread,
and at least one bridge-stretching means which is
provided continuously on said expanded portion, the
bridge-stretching means having a depressing portion which
engages said engaging projections on said cap and pushes
down said engaging projections when said synthetic resin
cap attached to said mouth portion of the container is
twisted in a cap opening direction, and an extended step
portion which engages the engaging projections when the
engaging projections are pushed down by the depressing
portion, so as to inhibit an upward movement of the
engaging projections.
In the sealing device of the present invention, said
depressing portion may have a structure wherein an
inclined surface gradually expands downward in a cap-
opening direction.
In the sealing device of the present invention, said
depressing portion may have a structure wherein a side
which contacts the engaging projections when the cap is
opened is made into an inclined surface which gradually
expands downward in a cap-opening direction, and a
storage guide surface having a projection height which
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gradually decreases in a cap-opening direction is
provided on a side of the aforesaid extended step portion
which is the opposite side from said inclined surface.
It is preferable that the inclination angle of said
inclined surface of said depressing portion be 550
degrees.
The sealing device of the present invention may have
a. structure wherein an engaging claw portion for engaging
said engaging projections and inhibiting the rotation of
said tamper-evidence ring portion in the cap-opening
direction is formed at the end of said extended step
portion of the bridge- stretching means in a cap-opening
direction.
In the sealing device of the present invention, the
weakening line of said synthetic resin cap may be a
horizontal score formed by cutting said tubular portion
in a circumferential direction while leaving a plurality
of thin bridges.
In the sealing device of the present invention, the
engaging projections of said synthetic resin cap may be a
plurality of erectable tabs which are formed such as to
project plate-wise from an inner wall of said tamper-
evidence ring portion.
The sealing device of the present invention may have
a structure wherein a vertical weakening line which is
severed at almost the same time that the weakening line
is severed so as to break said tamper-evidence ring
portion into a band are formed on said tamper-evidence
ring portion of said synthetic resin cap.
The sealing device of the present invention should
preferably be such that the bridge breaking angle which
is the rotational angle of the position at which said
I I . i 1
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bridges are severed when said cap attached to said mouth
portion of the container is rotated in a cap-opening
direction is 90 degrees or less.
Another aspect of the present invention is a
<:ontainer which is to be attached with a synthetic resin
c:ap which has a cap main body having a top plate portion
and a tubular portion extending downward from the
periphery thereof, said tubular portion being partitioned
by means of a tearable weakening line into an upper main
portion and a lower tamper-evidence ring portion, a
threaded portion being formed on an inner wall surface of
said main portion, and erectable engaging projections
being provided on an inner wall surface of said tamper-
evidence ring portion; the engaging projections being
oriented substantially horizontally and having tips
facing in a radially inward direction and being foldable
upward;
said container comprising an external thread formed
on an outer circumference of an upper end of said mouth
portion thereof, an annular expanded portion formed
underneath said external thread, and at least one bridge-
stretching means which is provided continuously on said
expanded portion, the bridge-stretching means having a
depressing portion which engages said engaging
projections on said cap and pushes down said engaging
projections when said synthetic resin cap attached to
said mouth portion of the container is twisted in a cap-
opening direction, and an extended step portion which
engages the engaging projections when the engaging
projections are pushed down by the depressing portion, so
as to inhibit an upward movement of the engaging
projections.
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In the container of the present invention, said
depressing portion may have a structure wherein an
inclined surface gradually expands downward in a cap-
opening direction.
In the container of the present invention, said
depressing portion may have a structure wherein a side
which contacts the engaging projections when the cap is
opened is made into an inclined surface which gradually
expands downward in a cap-opening direction, and a
storage guide surface having a projection height which
gradually decreases in a cap-opening direction is formed
on a side of the aforesaid extended step portion which is
t:he opposite side from said inclined surface.
It is preferable that the inclination angle of said
inclined surface of said depressing portion be 550
degrees.
The container of the present invention may have a
structure wherein an engaging claw portion for engaging
said engaging projections and inhibiting the rotation of
said tamper-evidence ring portion in the cap-opening
direction is formed at the end of said extended step
portion of the bridge-stretching means in a cap-opening
direction.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a partially cut-away front view showing an
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example of a sealing device according to the present invention.
Fig. 2 is a front section view showing the same sealing
device in a sealed state.
Fig. 3 is an enlarged view of significant portions of Fig.
1.
Fig. 4 is a side view showing the same container.
Fig. 5 is an enlarged view of significant portions of Fig.
4.
Fig. 6 is a section view of significant portions showing
the same .sealing device in a sealed state.
Fig. 7 is a section view of significant portions showing
the same aealing device with the cap rotated in a cap-opening
direction.
Fig. 8 is a section view of significant portions of the
same directly after the bridges have been severed.
Fig. 9 is a front view of a container according to
another mode of the present invention.
Fig. 10 is an enlarged section view of significant
portions of the sealing device shown in Fig. 1.
BEST MODES FOR CARRYING OUT THE INVENTION
Figs. 1 to 3 show an example of the sealing device
according to the present invention. This sealing device
comprises a synthetic resin cap (hereinafter referred to as a
cap) 1 anc~ a synthetic resin contai:ver 21.
The cap 1 comprises a cap main body 4 composed of a
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synthetic resin such as polypropylene, comprising a top
plate portion 2 and a tubular portion 3 extending downward
from the periphery thereof, and a thin liner 5 composed of
a soft resin placed inside the cap main body 4.
The tubular portion 3 of the cap main body 4 is
partitioned into an upper main portion 8 and a lower
tamper-evidence ring portion 9 (hereinafter referred to as
the TE ring portion) by means of a horizontal score 7
formed by cutting the tubular portion 3 along the
circumferential direction while leaving a plurality of
thin bridges 6. A threaded portion 10 is formed on the
inner wall surface of the main portion 8, and multiple
p7_ate-shaped tabs 11 which form engaging projections are
erectably provided on the inner wall surface of the TE
ring portion 9. While not shown in the drawings, a
vertical weakening line which breaks the TE ring portion 9
up into a band by being severed almost simultaneously with
the severing of the horizontal score 6 is formed on the TE
ring portion 9.
The above-mentioned tabs 11 are oriented almost
horizontally with their tips facing in the radial inward
direction when not attached to the container, and when the
ca.p is attached to the mouth portion 21A of the container,
their top ends fold upward upon contact with the external
thread 22 or the annular expanded portion 23, so that they
can pass the external thread 22 or the annular expanded
portion 23 with almost no resistance.
The dimensions of the cap 1 and the mouth portion 21A
of
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the container are not especially restricted, but examples
for the range of preferable dimensions in a general-
purpose-size cap will be given in the following
embodiment.
5 The length of projection of the tabs 11 from the
inner wall surface of the TE ring portion 9 should be 1.5
4.0 mm, more preferable about 2.0 ~ 3.0 mm. If this
projection length is less than 1.5 mm, the contact of the
tabs with the outer surface of the container is reduced so
10 as to make it difficult for the bridges to be severed when
the cap is opened, while if the projection length is more
than 4.0 mm, it becomes difficult to mold and difficult to
cap. Additionally, the number of tabs 11 formed,
circumferential lengths of the tabs 11 and the spacing
15 between the tabs 11 is not especially restricted, but
taking the case wherein 12 tabs are formed on the inner
wall surface of a TE ring portion 9 having an inner
diameter of approximately 29 mm as an example, the
circumferential lengths of the tabs 11 should be about 4
8 mm and the spacing between the tabs should be about 0.2
0.8 mm. If the circumferential lengths of the tabs 11
are less than 4 mm, the engaging force of the tabs 11 on
the mouth portion of the container is weakened so as to
risk the occurrence of rupture defects in the bridges, and
if the circumferential lengths are greater than 8 mm, the
mechanical strength of the tabs 11 increases so as to make
melding difficult.
Additionally, the thickness of the tabs 11 can be
uniform, or the tip portion sides may be made thicker.
Normally, the
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thickness of the tabs is 0.2 ~ l.2mm, preferably about 0.6
1.0 mm. If the tab thickness is less that 0.2 mm, the tabs
can ea~;ily bend, so as to become incapable of guiding the TE
ring portion 9 downward when the cap is opened, thereby
risking the occurrence of rupture defects in the bridges; if
the tal> thickness is greater than 1.2 mm, molding becomes
difficult and the capping properties are made worse. As
shown i.n Fig. 10, when the thickness of the tabs 11 is made
greater on the tip portion side than on the base portion
(the inner wall side of the TE ring portion 9), for example
if the base portion length f is about 0.3 ~ 0.7 mm and the
tip portion length g is about 1.5 ~ 2.5 mm, the base portion
thickness h should preferably be about 0.4 ~ 0.6 mm and the
tip portion thickness i should be about 0.5 ~ 1.0 mm. As is
clears from the results of experimental examples which will
be given below, when the base portion thickness h and the
tip portion thickness i of the tabs 11 are less than the
above-given ranges, the strength (anti-bending strength) of
the tabs 11 is weakened, so that when the cap 1 is attached
to the mouth portion 21A of the container and turned in the
cap-opening direction, the tabs engaged with the depressing
portions 24 have their tips bent downward, so that there may
be cases wherein the cap 1 could come loose from the mouth
portion 21A of the container without the TE ring portion 9
becoming separated from the main portion 8. Additionally,
when the base portion thickness h and the tip portion
thickness i of the tabs 11 are greater than the above-given
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ranges, the strength of the tabs 11 (anti-bending
strength) is unnecessarily increased so that the
resistance when the tabs 11 pass the depressing portions
24 increases during attachment of the cap 1 to the mouth
portion 21A of the container, thereby risking a problem
wherein the cap 1 cannot be sufficiently closed to the
si~andard screw completion angle.
While the number of bridges 6 formed in not
especially restricted, the overall sum of the cross-
sE:ctional areas of all of the bridges 6 should be about
0.,3 ~ 9.0 mm2, and the overall sum of the rupture strengths
of the bridges 6 when pulled should be about 10 ~ 18 kg.
When the overall sum of the cross-sectional areas of the
bridges 6 is greater than 9.0 mm2 and the rupture strength
(when pulled) of the bridges is greater than 18 kg, the
cap can come loose without the bridges being severed when
tree cap is opened, or the relation BBA > SRA could arise
so as to make the tamper-evidence properties (cap-opening
display properties) worse. When the overall sum of the
cross-sectional areas of the bridges 6 is less than 0.3 mm2
and the rupture strength (when pulled) of the bridges is
less than 10 kg, the bridges can be severed during
capping.
The container 21 has an external thread 22 formed on
th.e outer circumference at the upper end portion of the
mouth portion, with an annular expanded portion 23
provided underneath the external thread 22, and a flange
portion 29 formed underneath the annular expanded portion
23.
As shown in Figs. 3 to 5, two first bridge-stretching
means 26A and two second bridge stretching means 26B are
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alternately provided along the circumferential direction
continuously on the annular expanded portion 23; in each of
the first bridge-stretching portions 26A being formed a
depressing portion 24 for engaging the tabs 11 of the cap 1
and pressing down the tabs 11 when the cap 1 attached to this
mouth portion 21A of the container is turned in the cap-
opening direction, a horizontal extended step portion 25 which
engages the tabs 11 when they are pushed down by the
depressing portion 24, so as to inhibit an upward movement of
the tabs 11, and at the end of the extended step portion 25 in
a cap-opening direction, an engaging claw portion 28 for
engaging the tabs 11 and inhibiting the rotation of the TE
ring portion 9 in the cap-opening direction; each of the
second bridge-stretching portions 26B having the depressing
portion 24 and the extended step portion 25.
The number of the first bridge-stretching means 26A and
the second bridge-stretching means 26B are not especially
restricted, and the number may be one or plural.
On each of these depressing portions 24, the side which
contacts the tabs 11 when opening the cap is made into an
inclined surface which gradually expands downward toward the
cap opening direction. In addition, a side of the engaging
claw portion 28 in the first bridge-stretching means 26A,
which is the opposite side from the inclined surface, and a
_, side of the extended step portion 25 in the second bridge-
stretching means 26B, which is the opposite side from the
inclined surface, are made into storage guide surfaces 27 of
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which the projection height gradually decreases in the cap-
opening direction.
The angle of inclination g of the depressing portions 24
as shown in Fig. 3 and the angle of inclination a as shown in
Fig. 5 should be 5 ~ 50 degrees. If the angle g or a is
greater than 50 degrees, the resistance of the tabs to being
pressed down when the cap 1 attached to the mouth portion 21A
of the container is turned in the cap-opening direction
becomes too strong, and cases may arise wherein the tabs are
not pressed down. Additionally, when the angle a or a is less
than 5 degrees, the BBA becomes too large, which is
undesirable.
Additionally, the difference (a - b) between the length a
from the upper end of the mouth portion 21A of the container
to the lower end of the extended step portion 25, and the
length b from the upper end of the mouth portion 21A of the
container to the upper end of the tabs 11 of the cap 1 when
attached as shown in Fig. 2 should be at least 0.5 mm. If
this difference (a - b) is less than 0.5 mm, there may be
cases wherein the bridges 6 are not severed due to stretching
of the bridges 6.
Additionally, the length c, from the annular expanded
~ortion 23 to the extended step portion 25 as shown in Fig. 3
ahould be 0.5 ~ 4.0 mm. If this length c is less than 0.5 mm,
?~ she tab depressing effect is not sufficiently activated during
:ap-opening so as to increase the BBA, and if the length c i~
greater than 4.0 mm, the excess thickness is increased so as
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to present a disadvantage in terms of cost.
Additionally, the length d of the extended step portion
should be 3 ~ 10 mm. If this length d is less than 3 mm,
the BBA increases, and if greater than 10 mm, the excess
5 thickness is increased so as to present a disadvantage in
terms of cost.
Additionally, the length a of the depressing portion 24
should be 1.5 ~ 8.0 mm. If this length a is less than 1.5 mm,
the tab depressing effect is not sufficiently activated during
10 cap-opening, and if the length a is greater than 8.0 mm, the
excess thickness is increased so as to present a disadvantage
in terms of cost.
The angle of inclination ~i of the storage guide surface
27 as shown in Fig. 5 should be 15 ~ 60 degrees.
15 Additionally, the length of the engaging claw portion 28
extending from the lower end of the extended step portion 25
is such that the engaging claw portion 28 reaches the upper
surface of the flange portion 29, and should normally be about
2.5 ~ 7.0 mm.
20 Furthermore, the outer diameters of the external thread
22, the annular expanded portion 23, and the first and second
bridge-stretching means 26A,26B can be made equal.
Additionally, the width of the annular expanded portion 23
should be 0.5 mm or greater, more preferably 1.0 ~ 5.0 mm.
25 Next, the operations of the sealing device according to
the present example will be explained.
After being filled with a desired content fluid, the
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21
container 21 is conveyed to a cap attachment apparatus omitted
from the drawings, and the cap 1 is screwed and fitted to seal
the cap 1 onto the mouth portion 21A while supporting the
bottom surface of the flange 29, preferably in a suspended
state.
When the cap 1 is attached to the mouth portion 21A of
the container, the tabs 11 of the cap 1 pass by the annular
expanded portion 23 with the tips folded upward, so that no
excessive forces are applied to the bridges 6.
Additionally, In the final stage of attaching the cap 1,
the tabs 11 which overlap the four bridge-stretching means
26A,26B in the attached state pass the annular expanded
portion 23, and achieve contact with the storage guide
surfaces 27 of the bridge-stretching means 26A,26B with tips
slightly opened toward the radially inward side so that the
tips contact the outer circumferential surface of the mouth
portion of the container underneath the annular expanded
portion 23. In the present example, tab storage guide
surfaces 27 having projection heights which gradually decrease
in the cap-opening direction are formed on the bridge-
stretching means 26A,26B, as a result of which these tabs 11
are folded with the tips upward along the inclines of the
storage guide surfaces 27 when the tabs 11 are moved in the
cap-closing direction while contacting the storage guide
surfaces 27, so that bridges 6 are not severed.
The cap 1 is attached in the state shown in Fig. 2 by
twisting the cap 1 onto the mouth portion 21A of the container
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with a predetermined cap-closing torque value. In this state
wherein the cap is attached, all of the tabs 11 of the
plurality of tabs 11 on the cap 1 aside from the four which
overlap the bridge-stretching means 26A,26B are in a slightly
open state in the radially inward direction so that the tips
contact the outer circumferential surface of the mouth portion
of the container underneath the annular expanded portion 23,
and the four tabs 11 overlapping the bridge-stretching means
26A,26B have their tips folded upward.
Additionally, the upper end portion of the container 21
is pressed into contact with the liner 5 of the cap 1 so as to
cause a slight indentation, thereby sealing the container 21.
The operations for opening the cap of the sealing device
when the cap is attached will be explained with reference to
Figs. 6 through 8.
When the cap 1 attached to the mouth portion 21A of the
container as shown in Fig. 6 is turned in the cap-opening
direction, a slight rotational movement of the cap 1 causes
the upper ends (tips) of the tabs 11 on the cap-opening
2G direction side to contact the depressing portions 24 of the
bridge-stretching means 26A,26B formed on the mouth portion
21A of the container, so that the tabs 11 are gradually pushed
down along the inclines of the depressing portions 24 (Fig. ?i.
The tabs 11, which make a rotational movement along the
depressing portions 24 while they are pushed down along the
inclines of the depressing portions 24, proceed smoothly from
the depressing portions 24 to the horizontal extended step
CA 02226573 1998-O1-12
23
portions 25. When the tabs 11 reach the extended step
portions, the main portion 8 is lifted upward along the
external thread 22 while the TE ring portion 9 is pushed down;
therefore, immediately after the rotation in the cap-opening
direction is initiated, the main portion 8 and the TE ring
portion 9 come apart, and a plurality of thin bridges 6
coupling the main portion 8 with the TE ring portion 9 are
stretched and severed, or formed into thin threads which may
be easily severed. In addition, the TE ring portion 9 can
move rotationally in the cap-opening direction together with
the main portion 8 until an end surface of a tab 11 reaches
the engaging claw portion 28 of the first bridge-stretching
means 26A.
After the tabs 11 proceed from the depressing portions 24
to the extended step portions 25, there is no push-down of the
TE ring portion 9; however, the main portion 8 is still lifted
upward along the external thread 22, as a result of which the
bridges 6 are further stretched, and completely severed while
the tabs 11 are moving along the extended step portions 25.
In the case where the severance does not occur while the
tabs 11 are moving along the extended step portion 25, the
tabs 11 are engaged with the engaging claw portions 28 formed
on the first bridge-stretching means 26A, and the rotation of
the TE ring portion 9 is completely inhibited, as a result of
which the bridges 6 which have been stretched and weakened by
the rotation of the main portion 8 are instantly severed.
At almost the same time that the TE ring portion 9 is
CA 02226573 2005-06-07
24
separated from the main portion 8, the vertical weakening
line formed on the TE ring portion 9 is severed so as to
break the TE ring portion 9 into a band, thus clearly
indicating that the cap 1 has been opened.
Thereafter, the main portion 8 can be removed from
the mouth portion 21A of the container by rotating the
main portion 8 further in the cap-opening direction.
Since the sealing device of the present example has
a1. least one bridge-stretching means 26A,26B which is
provided continuously on the mouth portion 21A of the
container, each of the bridge-stretching means having a
depressing portion 24 which engage and depress the tabs 11
of the cap 1 when the cap 1 attached thereto is turned in
the cap-opening direction, and an extended step portion 25
which engages the tabs 11 when they are pushed down by the
depressing portion 24, so as to inhibit an upward movement
of the tabs 11, when the cap 1 attached to the mouth
portion 21A of the container 15 turned in the cap-opening
direction, the tabs 11 adjacent to depressing portions 24
of respective bridge-stretching means 26A,26B contact the
depressing portions 24 and are pushed down such that the
TE~ ring portion 9 is pushed down; accordingly, the main
portion 8 which is lifted upward along the external thread
22 and the TE ring portion 9 quickly come apart and the
plurality of thin bridges 6 coupling the main portion 8
with the TE ring portion 9 are stretched. In addition,
after the tabs 11 proceed to the extended step portions 25
of the bridge-stretching means 26A,26B, since the main
portion 8 is
CA 02226573 2005-06-07
still lifted upward along the external thread 22 while the
TE ring portion 9 is inhibited from moving upward, these
bridges 6 are severed to separate the TE ring portion 9
from the main portion 8, thereby clearly indicating that
5 the cap has been opened. Therefore, according to this
sealing device, the bridge breaking angle (BBA) which is
the rotational angle of the position at which the bridges
6 are severed by rotating the cap 1 attached to the mouth
portion 21A of the container in the cap-opening direction
10 can be made 90 degrees or less, preferably 45 degrees or
less; furthermore, the problem wherein the cap-opening
torque is increased due to the rupture resistance of the
bridges can be prevented in comparison with conventional
products having the formation wherein the bridges are
15 severed by inhibiting the rotation of the TE ring portion
9, thus allowing the cap to be opened by a suitable cap-
opening torque .
Additionally, by forming the engaging claw portion 28
at the end of the extended step portion 25 of at least one
20 bridge-stretching means 26A in a cap-opening direction,
for engaging tabs 11 so as to inhibit the rotation of the
TE ring portion 9 in the cap-opening direction, even in
the case when the tabs 11 pass the extended step portion
25 without the bridges 6 being severed, the tabs 11 engage
25 the engaging claw portion 28, and the rotation of the TE
ring portion 9 is inhibited; accordingly, the bridges 6,
which have already been stretched and weakened, can be
severed easily and securely.
Fig. 9 shows another mode of the present invention. A
CA 02226573 1998-O1-12
26
sealing device according to this mode is characterized by
having a container 21 which has a bridge-stretching means 26C
formed by projecting an engaging claw portion 28B downward
from an extended step portion 25 with such a short length that
the tip of the engaging claw portion 28B does not reach the
upper surface of a flange portion 29. The engaging claw
portion 28B is formed to have a length k, measured from the
lower surface of annular expanded portion 23, of about 2.5
4.0 mm. If the length k is less than 2.5 mm, the engagement
of the tabs 11 of the cap 1 with the engaging claw portion 28B
becomes difficult. A length k greater than 4.0 mm would
present a disadvantage in that when opening the cap, the cap
cannot be smoothly removed since the tabs 11 contact the
engaging claw portion 28B many times during the removal of the
cap after the bridges are severed.
In this mode, since the container 21 is provided which
has the bridge-stretching means 26C formed by projecting the
engaging claw portion 28B downward from the extended step
portion 25 with such a short length that the tip of the
engaging claw portion 28B does not reach the upper surface of
the flange portion 29, the tabs do not contact the engaging
claw portion, or the contact fcrce is weakened, so that smooth
removal of the cap is possible.
The present invention is not limited to the above-
mentioned examples, and various changes or modifications are
possible.
For example, when providing a plurality of bridge-
CA 02226573 1998-O1-12
G7
stretching means 26A,26B, the positional spacing in the
circumferential direction may be uniform, or a number of
bridge-stretching means 26A,26B may be shifted by a few
degrees in the circumferential direction.
Additionally, besides attaching the cap 1 having a TE
ring portion 9 as with the previous example, the container of
the present invention can be applied to a synthetic resin cap
of the type wherein multiple wings are formed on the inner
wall surface of the TE ring portion 9.
Additionally, the annular expanded portion 23 may be
replaced by a broken annular type expanded portion wherein
island-type expanded portions are arranged in the
circumferential direction by providing at least one notched
portion in the circumferential direction of the annular
expanded portion.
[Embodiments]
Caps 1 and containers 21 having the same structures as
shown in Fig. 1 were made, and the performance of sealing
devices composed of these caps 1 and containers 21 was studied.
Cap:
Caps 1 were made by making the cap main bodies 4
constructed as shown in Fig. 1 with polypropylene as the
material, and forming liners 5 composed of a polypropylene-
type resin inside the cap main bodies 4 by means of an in-
shell molding method. The specifics of the resulting caps 1
CA 02226573 2005-06-07
28
are as follows:
Outer Diameter of Cap 30 mm
Height of Cap 24.7 mm
Height of TE Ring Portion 9.6 mm
Circumferential Length of Tabs 6.0 mm
(12 formed on the inner surface
of the TE ring portion)
Tab Projection Length 2.5 mm
Tab Thickness 0.60 mm
Sum of Cross-sectional Areas of
Bridges 5.7 mm2
Container:
Containers (pet bottles) with a capacity of 1.5
liters having a mouth portion 21A as shown in Fig. 1 were
made with polyethylene terephthalate as the material. The
specifics of the containers 21 are as follows:
Outer Diameter of Mouth Portion
(minimum outer diameter) 24.94 mm
Outer Diameter of External Thread and
Annular Expanded Portion 27.56 mm
Angles A and a of Depressing Portions 25 degrees
Length of in Fig. 2 15.4 mm
a
Length of in Fig. 2 13.6 mm
b
Length of in Fig. 3 1.8 mm
c
Length of in Fig. 3 6.6 mm
d
Length of in Fig. 3 3.9 mm
a
CA 02226573 2005-06-07
29
Inclination Angle f3 of Storage Guide
Surfaces 30 degrees
(Experiment 1)
The rupture strength of the bridges in the tensile
direction of the caps were determined. The TE ring portion
of_ each cap was affixed to the stand side of a push-pull
gauge (stand: IMADA SEISAKUJO Model 5020; push-pull gauge:
NTTONIC Type PDE-50R), the main portion was affixed to the
terminal portion of the gauge, then a tensile force was
applied across the main portion and the TE ring portion
and the tensile strength at the time the bridges broke was
measured. As a result, the produced caps had a rupture
strength of the bridges in the tensile direction of 14 kg
(average value, n = 100).
(Experiment 2)
Using the above-mentioned caps and containers, (1) the
bridge rupture occurrence rate when the caps were
attached, (2) the cap-opening torque value for opening the
caps, (3) the BBA, (4) the SRA, and (5) the bridge rupture
defect occurrence rate for opening the caps were
evaluated.
The above-mentioned containers were filled with a
standard amount of hot water of 85° C, and the caps were
attached to the mouth portions by using a capping machine
(ALCOA Magnatorque) . The capping conditions were set to
15 kg~cm of static torque and 15 kg of top-load.
CA 02226573 1998-O1-12
(1) Bridge rupture occurrence rate when caps were attached:
After the containers were capped, the caps were outwardly
checked for the presence of bridge ruptures, as a result of
5 which the bridge rupture occurrence rate was found to be 0
(n = 100) .
Next, the capped containers were opened to evaluate (2)
the cap-opening torque value for opening the caps, (3) the BBA,
(4) the SRA, and (5) the bridge rupture defect occurrence rate.
10 As a result, (2) the torque values for opening the caps were
13 kg~cm (one-dimensional) and 5-7 kg~cm (two-dimensional) (n
- 100). The (3) BBA was approximately 40 degrees (average
value, n = 100). The (4) SRA was approximately 120 degrees
(average value, n = 100). The (5) bridge rupture defect
15 occurrence rate was 0 ° ( n = 100).
(Experiment 3)
Caps were made wherein the shapes of the tabs 11 on the
caps 1 described above were such that the thickness of the tip
20 portion was greater than the base portion (near the TE ring
portion 9) as shown in Fig. 10, attached to the mouth portions
21A of the above-described containers 21, and the
relationships between the cap-opening display performance and
capping suitability were evaluated.
25 The tabs 11 were made so that the total projection length
( f + g) was 2 . 5 mm, the base portior~~ ~ el:gth ( f ) was 0 . 5 mm and
the tip portion length (g) was 2.0 nm, and caps of samples 1-7
CA 02226573 2006-O1-24
31
and comparative products having base portion thicknesses (h)
and tip portion thicknesses (i) as listed in Table 1 were
made.
The above-mentioned containers 21 were filled with a
standard amount of hot water of 85°C, and the caps were
attached to the mouth portions 21A by using a capping machine
(ALCOA Magnatorque). The capping conditions were set to 15
kg~cm of static torque and 15 kg of top-load. The following
categories a ~ d were studied for each sample, and the results
are recorded in Table 1.
a. Strength of Bridges of Cap
The rupture torque values of the bridges for opening the
caps was measured (units in kg'cm).
b. Strength of Tabs of Cap (Anti-bending Strength)
For each cap listed in Table 1, a sample was prepared
wherein the horizontal score 7 for separating the TE ring
portion 9 were not formed, each sample cap was attached to a
mouth portion 21A of a container and opened, and the torque
value at the moment the tabs 11 inverted so that the cap 1
came loose from the mouth portion 21A of the container was
measured (units in kg'cm).
c. Evaluation of Cap-opening Display Ability
The occurrence of cap-opening display defective products
wherein the tabs 11 inverted without the bridges 6 breaking
when the cap was opened so that the cap 1 came free from the
mouth portion 21A of the container with the TE ring portion 9
still connected to the main portion 8 was evaluated (n = 10).
The evaluations are indicated by a symbol "O" for sample caps
CA 02226573 1998-O1-12
32
without cap-opening display defective products, and by a
symbol "X" for sample caps wherein cap-opening display
defects occurred at least once.
d. Evaluation of Capping Suitability
The tightness of the caps when the sample caps were
respectively attached to the mouth portions 21A of the
container were evaluated as an average value of 10 trials (n =
10) per sample by measuring the relative rotational angles
between the beginnings of the threads on the containers (upper
side of the mouth portions) and the beginnings of the threads
on the caps (bottom side of the caps). The evaluations are
indicated by a symbol "~" for sample caps wherein the
relative rotational angle (average value) was 580° ~ 30°, and
by a symbol "X" for sample caps which lay outside the above-
mentioned angles.
CA 02226573 2005-06-07
33
TABLE 1
SAMPLE TAB STRENGTHSTRENGTHCAP- CAPPING
THICKNESS OF OF TABS OPENING SUIT-
BRIDGES DISPLAY ABILITY
ABILITY
(kgcm) kgcm)
ase
Tip
Portion
Portion
Comp.Ex. 0.3 0.3 13.2 10.8 X 0
mm mm
1 0.3 0.4 13.2 13.4
mm mm
2 0.4 0.5 13.2 20.9 ~ 0
mm mm
3 0.5 0.7 13.2 22.6
mm mm
4 0.5 0.9 13.2 23.6 ~ 0
mm mm
0.6 1.0 13.2 27.4 0
mm mm
6 0.7 1.2 13.2 30.3
mm mm
7 0.8 1.4 13.2 32.4 0
mm mm
As is clear from the above experimental results, the
5 sE:aling device according to the present invention was
e~:cellent in that problems of increases in the cap-opening
torque due to the rupture resistance of the bridges were
prevented, and in that the BBA when opening the cap was
small.
INDUSTRIAL APPLICABILITY
As explained above, with the sealing device according
to the present invention, the bridge breaking angle (BBA)
which is the rotational angle of the position at which the
bridges break, can be made 90 degrees or less, preferably
45 degrees
CA 02226573 1998-O1-12
34
or less; furthermore, problems wherein the cap-opening torque
increases due to the rupture resistance of the bridges can be
prevented in comparison with conventional products of the type
wherein the bridges are severed by inhibiting the rotation of
the TE ring portions, so as to allow the cap to be opened with
an appropriate cap-opening torque.
Additionally, by forming the engaging claw portion at the
end of the extended step portion of at least one bridge-
stretching means in a cap-opening direction, for engaging the
engaging projections so as to inhibit the rotation of the TE
ring portion in the cap-opening direction, even in the case
when the engaging projections pass the extended step portion
without the bridges being severed, the tabs engage the
engaging claw portion, and the rotation of the TE ring portion
9 is inhibited; accordingly, the bridges, which have already
been stretched and weakened, can be severed easily and
securely.
Accordingly, in accordance with the present invention, a
sealing device can be provided which prevents the cap-opening
torque from becoming high due to the rupture resistance of the
bridges when the cap attached to the mouth portion of the
container is turned in the cap-opening direction, and which
can yield good tamper-evidence properties by reducing ti-a BBA
when the cap is being opened; and such a container can G-~5o be
provided.
