Patent Grant
9511905
This invention relates to a synthetic resin container closure having a locking means disposed on the inner peripheral surface of a tamper evident bottom section, and a combination of such a synthetic resin container closure and a container having a locking jaw portion formed on the outer peripheral surface of a mouth-and-neck portion.
As is well known, combinations of containers formed from glass, synthetic resins, or metal sheets, and container closures formed from synthetic resins, used for beverages, have found wide practical use. The container has a cylindrical mouth-and-neck portion, and an external thread and a locking jaw portion located below the external thread are formed on the outer peripheral surface of the mouth-and-neck portion. The container closure, on the other hand, has a circular top panel wall, and a cylindrical skirt wall extending downwardly from the peripheral edge of the top panel wall. The skirt wall has, formed therein, a circumferential breakable line extending in the circumferential direction, and the skirt wall is divided into a main section above the breakable line and a tamper evident bottom section below the breakable line. An internal thread to be screwed onto the external thread of the mouth-and-neck portion is formed on the inner peripheral surface of the main section of the skirt wall, and a locking means is disposed on the inner peripheral surface of the tamper evident bottom section of the skirt wall.
After a beverage is filled into the container, the mouth-and-neck portion of the container is fitted with the container closure, and the container closure is rotated in a closing direction to screw the internal thread of the container closure onto the external thread of the mouth-and-neck portion. In this manner, the container closure is mounted on the mouth-and-neck portion to seal the mouth-and-neck portion. The locking means disposed on the tamper evident bottom section of the skirt wall elastically climbs over the locking jaw portion of the mouth-and-neck portion, and settles below the locking jaw portion. In unsealing the mouth-and-neck portion in order to consume the beverage, the container closure is rotated in an opening direction. By so doing, the screwing between the external thread and the internal thread is released. In accordance with the release of the screwing, the container closure is allowed to ascend relative to the mouth-and-neck portion. Once the container closure is somewhat raised, the locking means disposed on the tamper evident bottom section of the skirt wall is stopped in engagement with the lower surface of the locking jaw portion of the mouth-and-neck portion. Thus, the tamper evident bottom section is inhibited from ascending. As the rotation of the container closure in the opening direction is continued, stress caused to the circumferential breakable line formed in the skirt wall breaks the circumferential breakable line. As a result, the tamper evident bottom section of the skirt wall is separated from the main section. (Alternatively, if an axial breakable line is formed in the tamper evident bottom section, the axial breakable line is broken to transform the tamper evident bottom section from an endless annular form into a strip form having an end, and the tamper evident bottom section continues to be connected to the main section partly in the circumferential direction without being completely separated from the main section.) When the rotation of the container closure in the opening rotational direction is continued, the container closure is removed from the mouth-and-neck portion, with the tamper evident bottom section remaining (alternatively, the entire container closure including the tamper evident bottom section is removed from the mouth-and-neck portion), whereby the mouth-and-neck portion is opened.
The locking means disposed on the inner peripheral surface of the tamper evident bottom section of the skirt wall can be composed of a plurality of protrusions projecting radially inwardly with spacing in the circumferential direction, or an annular ridge extending uninterruptedly in the circumferential direction and projecting in the radial direction. The amount of projection of the protrusions or the ridge is limited to a relatively small value in order to prevent so-called forced extraction for release from a molding die from becoming excessive. When the mouth-and-neck portion is to be unsealed, therefore, the engagement of the locking means with the locking jaw portion of the mouth-and-neck portion becomes insufficient, and thus tends to cause so-called slipping-out, which means that the locking means elastically climbs over the locking jaw portion without causing breakage of the breakable line. To prevent such slipping-out, Patent Document 1 to be described below involves setting the inner diameter of a site above the locking means in the inner peripheral surface of the tamper evident bottom section at a value somewhat smaller than the outer diameter of the locking jaw portion of the mouth-and-neck portion, and interference-fitting the inner peripheral surface of the tamper evident bottom section to the outer peripheral surface of the locking jaw portion at the site above the locking means, thereby suppressing the elastic deformation or displacement of the tamper evident bottom section. As disclosed in the Patent Document 1, however, the interference fit of the inner peripheral surface of the tamper evident bottom section of the skirt wall onto the locking jaw portion of the mouth-and-neck portion, with the container closure being mounted on the mouth-and-neck portion as required for sealing of the mouth-and-neck portion, poses the following problems: Initial torque required when rotating the container closure in the opening direction in order to unseal the mouth-and-neck portion becomes excessively high, and tends to make it considerably difficult for a child or a female to perform an unsealing operation.
To solve the above-mentioned problems with the configuration disclosed in the Patent Document 1, Patent Document 2 to be described below makes the following disclosures: A loosely fitting upper portion with an inner diameter of d1 and a fitting lower portion with an inner diameter of d2, which is smaller than d1, are disposed above a locking means in the inner peripheral surface of a tamper evident bottom section. When a container closure is mounted, as required, on a mouth-and-neck portion of a container to seal the mouth-and-neck portion, the loosely fitting upper portion of the tamper evident bottom section is located opposite a locking jaw portion of the mouth-and-neck portion, and the tamper evident bottom section becomes loosely fitted to the locking jaw portion. When the container closure is somewhat rotated in an opening rotational direction and raised relative to the mouth-and-neck portion, the fitting lower portion of the tamper evident bottom section is located opposite the locking jaw portion and brought into an interference fit to the locking jaw portion. In such a disclosed configuration, an excessively high required initial torque is avoided. According to the experience of the present inventors, however, the following findings have been obtained: A step is present in a boundary region between the loosely fitting upper portion and the fitting lower portion of the tamper evident bottom section. Owing to the presence of this step, torque tends to increase sharply, when the container closure is raised relative to the mouth-and-neck portion and the fitting lower portion is fitted to the locking jaw portion. Moreover, the fitting lower portion engages the locking jaw portion over a relatively large area, and the locking means engages the lower surface of the locking jaw portion. Thus, the tamper evident bottom section is urged in a direction, in which it is inclined upwards and radially inwardly, whereby the pressing force of the fitting lower portion on the locking jaw portion is increased. Hence, so-called required secondary torque for breakage of a circumferential breakable line tends to become excessively high.
The present inventors' experience, moreover, has shown that in the conventional combinations, when the closure is mounted on the mouth-and-neck portion of the container to seal the mouth-and-neck portion, bridge portions in the circumferential breakable line tend to be broken.
The present invention has been accomplished in the light of the above-mentioned facts. Its principal technical challenge is to provide a novel and improved synthetic resin container closure which does not render required initial torque and required secondary torque for unsealing excessively high, and which can fully reliably prevent slipping-out, a phenomenon where the locking means elastically climbs over the locking jaw portion and ascends, without causing breakage of the circumferential breakable line, at the time of unsealing; and a combination of such a synthetic resin container closure and a container.
Another technical challenge of the present invention is to provide a novel and improved combination of a container and a synthetic resin closure which minimizes the possibility of the breakage of the bridge portions in the circumferential breakable line when the closure is mounted on the mouth-and-neck portion of the container, in addition to solving the above principal technical challenge.
The present inventors conducted in-depth studies and experiments, and have found that the above principal technical challenge can be solved by disposing an inverted truncated cone-shaped fitting surface, which extends upwards at a radially outward incline from the base edge of an upper surface of a locking means, in the inner peripheral surface of a tamper evident bottom section.
That is, according to a first aspect of the present invention, there is provided, as a synthetic resin container closure solving the above-mentioned principal technical challenge, a synthetic resin container closure which includes a circular top panel wall and a cylindrical skirt wall extending downwardly from a peripheral edge of the top panel wall, and in which a circumferential breakable line extending in a circumferential direction is formed in the skirt wall, the skirt wall is divided into a main section above the circumferential breakable line and a tamper evident bottom section below the circumferential breakable line, an internal thread is formed on an inner peripheral surface of the main section, and locking means is disposed on an inner peripheral surface of the tamper evident bottom section,
wherein an inverted truncated cone-shaped fitting surface, which extends upwards at a radially outward incline from a base edge of an upper surface of the locking means, is disposed in the inner peripheral surface of the tamper evident bottom section.
According to another aspect of the present invention, there is provided, as a combination of a container and a synthetic resin container closure, adapted to solve the above principal technical challenge, a combination of a container and a synthetic resin container closure, in which
the container has a cylindrical mouth-and-neck portion; and an external thread and a locking jaw portion located below the external thread are formed on an outer peripheral surface of the mouth-and-neck portion, and
the synthetic resin container closure is mounted on the mouth-and-neck portion of the container, and includes a circular top panel wall and a cylindrical skirt wall extending downwardly from a peripheral edge of the top panel wall; a circumferential breakable line extending in a circumferential direction is formed in the skirt wall; the skirt wall is divided into a main section above the circumferential breakable line and a tamper evident bottom section below the circumferential breakable line; an internal thread to cooperate with the external thread of the mouth-and-neck portion is formed on an inner peripheral surface of the main section; and locking means to cooperate with the locking jaw portion of the mouth-and-neck portion is disposed on an inner peripheral surface of the tamper evident bottom section,
wherein an inverted truncated cone-shaped fitting surface, which extends upwards at a radially outward incline from a base edge of an upper surface of the locking means, is disposed in the inner peripheral surface of the tamper evident bottom section of the synthetic resin container closure, and
with the internal thread of the synthetic resin container closure being screwed onto the external thread of the mouth-and-neck portion to mount the synthetic resin container closure on the mouth-and-neck portion, thereby sealing the mouth-and-neck portion, an upper end edge of the fitting surface formed in the inner peripheral surface of the tamper evident bottom section is located to oppose an outer peripheral surface of the locking jaw portion of the mouth-and-neck portion.
Preferably, the fitting surface has an inclination angle of 3 to 15 degrees with respect to the central axis line. It is preferred that with the internal thread of the synthetic resin container closure being screwed onto the external thread of the mouth-and-neck portion to mount the synthetic resin container closure on the mouth-and-neck portion, thereby sealing the mouth-and-neck portion, a clearance x, at a minimum, of 0.0 mm≦x≦0.2 mm be present between the outer peripheral surface of the locking jaw portion and the fitting surface.
In connection with the other technical challenge stated above, the present inventors have found, as a result of eager studies, that in the conventional combinations, when the locking ridge formed on the inner peripheral surface of the tamper evident bottom section of the closure climbs over the locking jaw portion formed on the outer peripheral surface of the mouth-and-neck portion of the container, a downward force is exerted on the circumferential breakable line through cooperation between the locking jaw portion and the locking ridge, and an upward force is also exerted on the circumferential breakable line through cooperation between the internal thread formed on the inner peripheral surface of the main section of the skirt wall and the external thread formed on the outer peripheral surface of the mouth-and-neck portion of the container, with the result that the bridge portions in the breakable line are broken. Based on these findings, the present inventors have found that the other technical challenge can be solved by setting the axial clearance C between the external thread and the internal thread, which has been set to be smaller than the axial effective width W of the locking jaw portion in the conventional combinations, at a value equal to or greater than the axial effective width W of the locking jaw portion (i.e., C≧W). It is preferred for the axial clearance C to be larger than the axial effective width W by 0.0 to 0.7 mm (C−W=0.0 to 0.7 mm).
In the present invention, as the synthetic resin container closure is raised relative to the mouth-and-neck portion of the container at the time of unsealing, the fitting surface of the inverted truncated conical shape is fitted to the locking jaw portion of the mouth-and-neck portion gradually, rather than sharply. Thus, the situation where not only the required initial torque but also the required secondary torque becomes excessively high is avoided or suppressed to the utmost, and the tendency toward a sharp increase in the required torque is avoided. When the locking means is locked to the locking jaw portion, moreover, the fitting surface remains sufficiently locked to the locking jaw portion, thus fully reliably preventing the slipping-out phenomenon in which the locking means ascends while elastically climbing over the locking jaw portion, without causing the breakage of the circumferential breakable line.
In the preferred embodiment in which the axial clearance C between the external thread and the internal thread is set to be equal to or greater than the axial effective width W of the locking jaw portion (i.e., C≧W), when the locking ridge formed on the inner peripheral surface of the tamper evident bottom section of the closure climbs over the locking jaw portion formed on the outer peripheral surface of the mouth-and-neck portion of the container, the internal thread engaged with the lower side of the external thread is displaced toward the upper side of the external thread located below the internal thread. Thus, application of force to the circumferential breakable line of the skirt wall is avoided, so that the breakage of the bridge portions in the circumferential breakable line is maximally prevented.
Preferred embodiments of a synthetic resin container closure constituted in accordance with the present invention, and a combination of such a container closure and a container will now be described in further detail by reference to the accompanying drawings.
With reference to
The skirt wall 6 has a relatively thick-walled thick-wall upper portion 12 and a relatively thin-walled thin-wall lower portion 14. A circumferential breakable line 16 extending in the circumferential direction is formed in an upper end part of the thin-wall lower portion 14. The skirt wall 6 is divided into a main section 18 above the circumferential breakable line 16, and a tamper evident bottom section 20 below the circumferential breakable line 16. The circumferential breakable line 16 in the illustrated embodiment is composed of a plurality of slits 22 extending in the circumferential direction at circumferentially spaced locations, and a plurality of bridge portions 24 located between the slits 22.
Non-slip knurls 26 composed of concavities and convexities alternately present, as viewed in the circumferential direction, are formed on the outer peripheral surface of the main section 18 of the skirt wall 6. Three internal threads 28 are formed on the inner peripheral surface of the main section 18 of the skirt wall 6. The three internal threads 28 are arranged at an angular distance of 120 degrees, and each of the three internal threads 28 extends over an angular range of nearly 160 degrees. A locking means 30 is disposed on the inner peripheral surface of the tamper evident bottom section 20. In the illustrated embodiment, the locking means 30 is formed from five protrusions 32 arranged with spacing in the circumferential direction and extending in the circumferential direction. A main part of each of the protrusions 32 (the part excluding both end parts of the protrusion) has a longitudinal sectional shape, which is a nearly right-angled triangular shape, and has an upper surface 32a extending radially inwardly at a slightly downward incline, an inner surface 32b of a nearly arcuate shape, and a lower surface 32c extending downward at a radially outward incline.
With further reference to
In the illustrated embodiment, it is important that the width of the internal thread 28 formed on the inner peripheral surface of the main section 18 in the skirt wall 6 of the closure 2 be set to be relatively small, and that the axial clearance C (see
In sealing the mouth-and-neck portion 40 by mounting the closure 2 on the mouth-and-neck portion 40 after filling the contents into the container, the closure 2 is fitted over the mouth-and-neck portion 40, and the closure 2 is rotated in a closing rotational direction, clockwise as viewed from above in
In the conventional combinations, the axial clearance between the external thread and the internal thread is smaller than the axial effective width of the locking jaw portion. Thus, at the very moment when the locking means climbs over the locking jaw portion, a downward force is exerted on the skirt wall to displace the internal thread downward, whereupon the internal thread is brought into intimate contact with the upper side of the external thread. Thus, a downward force is generated in the skirt wall through the cooperation of the locking jaw portion and the locking means crossing it. Moreover, an upward force is applied to the skirt wall through cooperation between the external thread and the internal thread in intimate contact with its upper side. Consequently, excessive stress is caused to the bridge portions in the circumferential breakable line, developing a tendency toward breakage of the bridge portions.
With further reference to
In unsealing the mouth-and-neck portion 40 in order to consume the contents, the container closure 2 is rotated in an opening direction, namely, counterclockwise as viewed from above in
In the illustrated embodiment, at the time of unsealing of the mouth-and-neck portion 40, the circumferential breakable line 16 is broken in the entire circumferential direction, and the tamper evident bottom section 20 is completely separated from the main section 18 of the skirt wall 6. If desired, however, there can be realized a configuration in which an additional break line extending in the axial direction is formed in the tamper evident bottom section 20; in unsealing the mouth-and-neck portion 40, the bridge portions 24 in the circumferential breakable line 16 are not locally broken, but are allowed to remain, and the tamper evident bottom section 20 continues to be connected to the main section 18 of the skirt wall 6; and the additional break line of the tamper evident bottom section 20 is broken to spread the tamper evident bottom section 20 in the form of a strip having ends, releasing the locking of the locking means 30 to the locking jaw portion 44, whereby the entire container closure 2 including the tamper evident bottom section 20 is removed from the mouth-and-neck portion 40.
Example: Three container closures substantially identical with the container closure illustrated in
The container closure as described above was mounted on the mouth-and-neck portion, as shown in
Comparative Example: For comparison, three container closures were formed which were the same as those in the Example, except that the shape of a site above the locking means in the inner peripheral surface of the tamper evident bottom section was as shown in
2: Container closure
4: Top panel wall
6: Skirt wall
16: Circumferential breakable line
18: Main section of skirt wall
20: Tamper evident bottom section
28: Internal thread
30: Locking means
34: Fitting surface
40: Mouth-and-neck portion of container
42: External thread
44: Locking jaw portion
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-276312 | Dec 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2012/074181 | 9/21/2012 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/088809 | 6/20/2013 | WO | A |
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| 2107055 | Sep 1993 | CA |
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| Entry |
|---|
| Search report from E.P.O., mail date is Jul. 6, 2015. |
| International Search Report issued Nov. 13, 2012 in PCT/JP2012/074181 and English language translation thereof. |
| Number | Date | Country | |
|---|---|---|---|
| 20140319093 A1 | Oct 2014 | US |
