JPH1120845A - Container lid made of synthetic resin having tamper-evident characteristics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove also an inner plug sufficiently surely from a neck part of a container incident to removal of a lid body from the neck part of the container by improving a container lid comprising the lid body and the inner plug. SOLUTION: On the inner peripheral face of a main part 14 on a skirt wall 10 of a lid body 4, an arcuate engaging protruded streak 32 which extends horizontally from a piece end approximate to the top end of a female helical streak 28 or connected thereto is formed. At a protrusion 54 of an extended peripheral edge area 46 on a top face wall 40 of an inner plug 6, an expanded protruded streak 56 which is expanded downward is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin container lid having a tamper-evident characteristic, comprising a synthetic resin lid main body and a synthetic resin inner plug incorporated in the lid main body.

[0002]

2. Description of the Related Art A container for a soft drink or the like has a substantially cylindrical mouth-and-neck portion, and an outer peripheral surface of the mouth-and-neck portion is provided with a male thread and a locked means located below the male thread. Containers in the form provided are widely used in practice. Such a container is formed of a suitable synthetic resin such as polyethylene terephthalate or glass. As a container lid for a container having a mouth and neck as described above, a tamper has recently been constituted by a synthetic resin lid main body and a synthetic resin inner plug incorporated in the lid main body. A synthetic resin container lid having an evidence characteristic has been proposed.
Prior art documents which disclose the synthetic resin container lid of such a form include JP-A-8-48350 and JP-A-8-48350.
169455, JP-A-8-217101, and JP-A-8-217104.

[0003] The lid body of the above-mentioned synthetic resin container lid has a top wall and a skirt wall hanging down from the periphery thereof. A break line extending in the circumferential direction is formed on the skirt wall, and the skirt wall is partitioned into a main portion above the break line and a tamper-evident hem below the break line. On the inner peripheral surface of the main part of the skirt wall, there is formed a female thread which is screwed into a male thread formed on the mouth and neck of the container. The tamper-evident skirt has a locking means that protrudes radially inward and is locked by a locked means formed on the mouth and neck of the container.

A typical example of the inner plug in the above-mentioned synthetic resin container lid is a circular top wall extending along the inner surface of the top wall of the lid body and a substantially cylindrical sealing wall hanging from the top wall. And The top wall has a central region and an overhanging peripheral region. A sealing wall closely contacting the inner peripheral surface of the mouth and neck of the container depends from the boundary between the central region and the overhanging peripheral region. The overhanging peripheral region of the top wall has a close contact with the top surface of the mouth and neck of the container and a protrusion projecting radially outward beyond the mouth and neck.

[0005] The container lid of the above-described embodiment is fitted to the mouth and neck of the container and rotated in the closing rotation direction, and the female screw of the lid body is screwed into the male screw of the mouth and neck to thereby close the mouth. It is worn on the neck. The lid body is lowered with the rotation in the closing direction, and the locking means disposed on the tamper-evident hem of the lid body is elastically deformed or displaced and passes through the locked means of the mouth and neck. Then, after that, it is restored to the original state and locked by the locked means. With the lowering of the lid body, the inner plug is also lowered, and the sealing wall of the inner plug enters the mouth and neck and is brought into close contact with the inner peripheral surface of the mouth and neck, and the overhanging peripheral region of the inner plug is brought into close contact. The part is brought into close contact with the top surface of the mouth and neck, thereby sealing the mouth and neck.

When opening the mouth and neck of the container, the lid body is rotated in the opening rotation direction. Thus, the main part of the skirt wall rotates with respect to the tamper-evident hem that is prevented from rising because the tamper-evident hem is locked by the locked means of the mouth and neck. As a result, the rupture line formed on the skirt wall is broken and the tamper-evident hem is separated from the main part of the skirt wall (the tamper-evident hem extends in the axial direction along the skirt wall). If a line is formed, the axial rupture line is broken, the tamper-evident hem is expanded from an endless annular shape to an end strip, and the rupture line extending circumferentially through the skirt wall is part of the rupture line. Is maintained without breaking, so that the tamper-evident skirt is not completely separated from the main part of the skirt wall). Thereafter, the main part of the skirt wall is further raised with rotation, so that the upper end of the female thread formed on the inner peripheral surface of the skirt wall contacts the lower surface of the protrusion of the inner plug, and The inner plug is raised in conjunction with the lifting, which releases the seal of the mouth and neck. When the lid body, more specifically its top wall and the main part of the skirt wall are further raised with rotation, the tamper-evident hem remains on the mouth and neck (the tamper-evident hem forms the main part of the skirt wall). If it is not completely separated from
The lid body and the inner plug (including the tamper-evident hem) are removed from the mouth and neck, thus opening the mouth and neck.

[0007]

According to the experience of the present inventors, the conventional container lid of the above-described embodiment has the following problems to be solved. In particular, when the ambient temperature is relatively high, when the upper end of the female thread formed on the inner peripheral surface of the skirt wall of the lid body comes into contact with the projecting portion of the overhanging peripheral region on the top wall of the inner plug, the projecting portion is formed. Is elastically excessively deformed upward and retreats inward in the radial direction, the inner plug is not raised with the rise of the lid body, the inner plug is left at the mouth and neck, and only the lid body is opened. They may be removed from the neck. When the inner plug is left in the mouth and neck, a complicated operation for detaching the inner plug from the mouth and neck must be additionally performed.

The above problem in the conventional container lid can be solved by increasing the thickness of the top wall of the inner plug to increase the rigidity of the protrusion in the overhanging peripheral region. However, when the thickness of the top wall of the inner plug is increased, the amount of material required for forming the inner plug increases, and the manufacturing cost of the inner plug increases significantly. In addition, it is necessary to increase the height of the lid body, and thus the axial length of the skirt wall, in accordance with the increase in the thickness of the top wall of the inner plug,
As a result, the manufacturing cost of the lid body also increases significantly.

The above-mentioned problem in the conventional container lid is that an annular engaging ridge extending annularly above the female screw is formed on the inner peripheral surface of the skirt wall separately from the female screw. This can be solved to some extent by allowing the ridge to engage with the protrusion in the overhang peripheral region of the top wall of the inner plug. However, in the mouth and neck of many containers widely distributed in the market, in order to increase the screwing amount between the male thread of the mouth and neck and the female thread of the container lid as long as possible,
An external thread is formed near the upper end of the mouth and neck, so that the annular engaging ridge is formed at the upper end of the skirt wall without hindering the engagement between the external thread and the internal thread. Can not do it.

[0010] The present invention has been made in view of the above facts, and its main technical problem is that it does not cause a separate problem such as a large increase in manufacturing cost and can be applied even when the ambient temperature is relatively high. It is an object of the present invention to provide a new and improved synthetic resin container lid in which a stopper is left in the mouth and neck to sufficiently prevent only the lid body from being detached from the mouth and neck.

[0011]

In order to achieve the above-mentioned main technical problem, in one aspect of the present invention, the lower surface of the protruding portion in the overhanging peripheral region of the inner plug extends downward beyond the lower surface of the close contact portion. A bulging ridge is formed, which increases the rigidity of the bulge. Since the bulge is formed only on the lower surface of the overhanging peripheral region, the increase in the amount of material required to form the inner plug is small, and the manufacturing cost of the inner plug is not greatly increased. In addition, since the bulge is bulged downward from the lower surface of the protruding portion, the height of the lid body is not increased due to the formation of the bulge.

Therefore, according to one aspect of the present invention, a synthetic resin container lid for achieving the above-mentioned main technical object has a substantially cylindrical mouth and neck, and a male and female mouth is provided on the outer peripheral surface of the mouth and neck. A synthetic resin container lid having tamper-evident characteristics, which is applied to a container in which the thread and the locked means located below the male thread are disposed, and a synthetic resin lid main body, A lid made of a synthetic resin incorporated in the lid main body, the lid main body having a top wall and a substantially cylindrical skirt wall hanging down from the periphery of the top wall, A rupturable line extending in the circumferential direction is formed, and the skirt wall is divided into a main portion above the rupturable line and a tamper-evident hem portion below the rupturable line, and On the inner peripheral surface of the part, a female screw screwed into the male screw of the mouth and neck part Are formed, which locking means is caused to the locking is formed to said locking means of the mouth and neck projecting radially inwards in the tamper evident bottom portion,
The inner plug has a circular top wall extending along the inner surface of the top wall of the lid body, and a substantially cylindrical sealing wall depending from the top wall, the top wall being in tension with a central region. An outer peripheral region, wherein the sealing wall hangs down from a boundary between the central region of the top wall and the overhang peripheral region and is brought into close contact with an inner peripheral surface of the mouth and neck portion; The overhanging peripheral region has a close portion that is brought into close contact with the top surface of the mouth and neck portion and a protrusion that projects radially outward beyond the mouth and neck portion, and the lower surface of the protrusion has the close contact portion. A synthetic resin container lid provided with a bulging ridge bulging downward beyond the lower surface of the container.

[0013] In order to achieve the above main technical problems,
In another aspect of the present invention, the inner peripheral surface of the skirt wall of the lid main body is substantially horizontal in a direction away from the upper end of the female screw from one end close to or connected to the upper end of the female screw. Are formed so as to reliably engage with the projections in the overhang peripheral region of the inner plug. The engaging ridge is configured to extend close to or following the upper end of the female thread, rather than being located separately above the female thread, and also to be circumferentially continuous. Since it is not an annular shape extending so as to extend only in a desired angle range, the present invention is applied to a container in which a male screw thread is formed up to the vicinity of the upper end of the mouth and neck portion. Can be arranged without hindering the screwing with.

Therefore, according to another aspect of the present invention, there is provided a synthetic resin container lid for achieving the above-mentioned main technical object,
The present invention is applied to a container having a substantially cylindrical mouth-and-neck portion, on the outer peripheral surface of which a male screw and a locked means located below the male screw are arranged. A synthetic resin container lid having tamper-evident properties, a synthetic resin lid body, and a synthetic resin inner plug incorporated in the lid body,
The lid body has a top wall and a substantially cylindrical skirt wall hanging down from a periphery of the top wall, and a rupturable line extending in the circumferential direction is formed on the skirt wall, and the skirt wall is The main portion above the rupturable line and a tamper-evident hem portion below the rupturable line are partitioned, and the inner peripheral surface of the main portion includes the male thread of the mouth and neck portion. A female thread to be screwed is formed, and a locking means is formed on the tamper-evident hem to protrude inward in the radial direction to be locked to the locked means of the mouth and neck. The inner plug has a circular top wall extending along the inner surface of the top wall of the lid body, and a substantially cylindrical sealing wall depending from the top wall, wherein the top wall has a central region. And an overhang peripheral region, wherein the sealing wall is a boundary between the central region of the top wall and the overhang peripheral region. The hanging peripheral region of the top wall hangs down and is brought into close contact with the inner peripheral surface of the mouth and neck, and the overhanging peripheral region is radially outward beyond the mouth and neck with the closely contacted portion brought into close contact with the top surface of the mouth and neck. A protrusion protruding toward the inner surface of the skirt wall of the lid main body. An arcuate engaging ridge extending substantially horizontally away from the upper end of the ridge is formed, and the engaging ridge is engaged with the lower surface of the protrusion of the inner plug. A resin container lid is provided.

In a preferred embodiment of the present invention, a bulging ridge bulging downward beyond the lower surface of the close contact portion is formed on the lower surface of the protruding portion in the overhanging peripheral region of the inner plug, and the lid body is formed. The inner peripheral surface of the skirt wall is formed with an arc-shaped engaging ridge extending substantially horizontally from one end close to or connected to the upper end of the female screw in a direction away from the upper end of the female screw. It is preferable that the bulging ridge of the inner plug has an annular shape extending continuously in the circumferential direction. Further, it is preferable that a plurality of ribs extending in the radial direction at intervals in the circumferential direction are formed on the upper surface of the central region of the top wall of the inner plug.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a synthetic resin container lid constructed according to the present invention will be described below in more detail with reference to the accompanying drawings.

Referring to FIG. 1, a container lid generally designated by reference numeral 2 constructed in accordance with the present invention comprises a synthetic resin lid body 4 and a synthetic resin inner plug 6 incorporated in the lid body 4. It is composed of The lid body 4 is preferably formed of a relatively hard synthetic resin such as polypropylene, and the inner plug 6 is preferably formed of a relatively soft synthetic resin such as polyethylene.

The lid body 4 has a circular top wall 8 and a substantially cylindrical skirt wall 10 hanging from the periphery of the top wall 8. A rupturable line 12 extending in the circumferential direction is formed on the skirt wall 10. The skirt wall 10 has a main portion 14 above the rupturable line 12 and a tamper-evident hem 16 below the rupturable line 12. Is divided into An annular shoulder surface 18 facing downward is formed on the inner peripheral surface of the skirt wall 10, and a plurality of ridges 20 extending downward from the annular shoulder surface 18 are formed at appropriate intervals in the circumferential direction. ing. The breakable line 12 is formed by causing a cutting blade (not shown) to act on the outer peripheral surface of the skirt wall 10 at the axially intermediate portion of the ridge 20 to leave at least a part of the ridge 20, Wall 10
Formed by cutting Each part of the ridge 20 left without being cut constitutes a so-called bridging part 22, and the tamper-evident hem part 16 is the bridging part 2.
It is connected to the main part 14 of the skirt wall 10 via the second.

On the outer peripheral surface of the main portion 14 of the skirt wall 10,
A frustoconical portion 24 whose outer diameter gradually increases downward is formed near the lower end. The outer peripheral surface of the tamper-evident skirt 16 is also formed in a truncated cone shape whose outer diameter gradually increases downward. In an outer peripheral surface of the main portion 14, a concave-convex shape 26 for preventing a finger hung thereon from slipping is formed in a portion above the truncated conical portion 24. A female thread 28 is formed on the inner peripheral surface of the main portion 14. The female thread 28 has a notch 30 extending in the axial direction at an appropriate interval in the circumferential direction.
The notch 30 constitutes a so-called air passage when the mouth and neck of the container is opened.

Referring to FIG. 2 together with FIG. 1, an arcuate engaging ridge 32 is further formed on the inner peripheral surface of the main portion 14 of the skirt wall 10. Such an engagement ridge 32
2 extends substantially horizontally from one end located close to the upper end of the female thread 28, that is, the right end in FIG. 2, to the direction away from the upper end of the female thread 28, that is, to the left in FIG. The one end of the engaging ridge 32 is positioned slightly displaced upward with respect to the upper end of the female thread 28. The circumferential extension angle α of the engaging ridge 32 is 70 to 110 degrees, particularly 8
Preferably, it is about 0 to 100 degrees. As will be described further below, when the female thread 28 is screwed into the male thread 62 (see also FIG. 5) formed in the mouth and neck of the container, as shown by the two-dot chain line in FIG. The upper end of the male thread is inserted below the engaging ridge 32. In particular, if the upper end of the male thread formed on the mouth and neck of the container extends only to the upper end of the female thread 28 or to the front (below), the upper end of the female thread 28 may be provided if desired. The one end of the engaging ridge 32 can be directly connected. The cross-sectional shape of the engaging ridge 32 may be substantially the same as the cross-sectional shape of the female thread 28.

A locking means 34 is formed on the inner peripheral surface of the tamper-evident foot 16. The locking means 34 in the illustrated embodiment comprises an annular projecting piece 36 extending continuously in the circumferential direction. This annular projecting piece 36
Are inclined upward from the base edge connected to the inner peripheral surface of the tamper-evident hem portion 16 inward in the radial direction. The annular projecting piece 36 is formed with slits 38 extending from the tip to the vicinity of the base edge at intervals in the circumferential direction. If desired, instead of the annular protruding piece 36, for example, a flap piece, an arc-shaped ridge or a ratchet claw (in the case of a ratchet claw, the locking means at the mouth and neck of the container described later is not a circular jaw but a corresponding one. Protruding pieces in any other suitable form, such as
The locking means may be constituted by a ridge or a projection.

Referring to FIGS. 3 and 4 together with FIG. 1, the inner plug 6 has a circular top wall 40 and a substantially cylindrical sealing wall 42 hanging from the lower surface of the top wall 40. The top wall 40 has a central region 44 and an overhang peripheral region 46, and the sealing wall 42 is suspended substantially vertically below the boundary between the central region 44 and the overhang peripheral region 46 of the top wall 40. .

A central region 44 in the top wall 40 of the inner plug 6
A circular concave portion 48 is formed at the center of the groove (the concave portion 48 constitutes a synthetic resin material entrance when the inner plug 6 is injection-molded). In the central region 44 of the top wall 40, four raised ribs 50 arranged around the concave portion 48 are further formed as shown in FIGS. The ribs 50 are arranged at equal angular intervals in the circumferential direction (ie, at 90 ° angular intervals), and extend in the radial direction. These ribs 50 increase the rigidity of the central region 44 of the top wall 40.

The overhanging peripheral region 46 in the top wall 40 of the inner plug 6 has a close portion 52 and a projecting portion 54. When the container lid 2 is attached to the mouth and neck of the container as required, as will be described later, the lower surface of the close portion 52 of the overhanging peripheral region 46 is brought into close contact with the top surface of the mouth and neck of the container, and Outer peripheral area 46
Projecting radially outward beyond the mouth and neck of the container. As is clearly shown in FIG.
On the lower surface of the protruding portion 54, there is formed a protruding ridge 56 which protrudes downward beyond the lower surface of the close contact portion 52. It is preferable that the bulging protrusion 56 is an annular shape extending continuously in the circumferential direction. If desired, a plurality of bulging ridges extending circumferentially at an interval in the circumferential direction may be formed. Conveniently, the lower surface of the bulging ridge 56 is a plane that extends substantially horizontally. The outer peripheral surface of the bulging protrusion 56 extends substantially vertically, while the inner peripheral surface is inclined downward and radially outward at an inclination angle β that may be about 40 degrees.

Continuing the description with reference to FIG. 3, an annular sealing ridge 58 bulging radially outward is formed on the outer peripheral surface of the sealing wall 42 of the inner plug 6. The bulging surface of the sealing ridge 58 is arcuate in cross section. Sealing wall 4
The outer diameter of 2 gradually increases from its lower end toward the most protruding portion of the sealing ridge 58, and then gradually decreases upward.

As shown in FIG. 1, the inner plug 6 is incorporated in the lid body 4, and the top wall 40 of the inner plug 6 extends along the inner surface of the top wall 8 of the lid body 4. Top wall 4 of inner stopper 6
0 is the main part 1 of the skirt wall 10 of the lid body 4.
4 is set larger than the diameter of the circle defined by the leading edge of the female thread 28 and the projecting edge of the engaging ridge 32 on the inner peripheral surface of the inner peripheral surface 4. In the state shown in FIG. 1, the peripheral portion of the top wall 40 of the inner plug 6 is somewhat elastically deformed. The inner diameter of the portion of the main portion 14 of the skirt wall 10 of the lid body 4 above the female thread 28 and the engagement ridge 32 is somewhat larger than the outer diameter of the top wall 40 of the inner plug 6, and Above the screw 28 and the engagement ridge 32, the inner plug 6 is
Can move freely in the axial direction with respect to.

The container lid 2 composed of the lid body 4 and the inner plug 6 incorporated therein is applied to a container made of a suitable synthetic resin such as polyethylene terephthalate or glass. Referring to FIG.
The container to which the container lid 2 is applied has a substantially cylindrical mouth-and-neck portion 60. An external thread 62 and an annular jaw 64 located below the external thread 62 are formed on the outer peripheral surface of the mouth and neck 60. The annular jaw 64 is provided with the locking means 34 on the lid body 4.
Constitute locked means to be locked.

When the container lid 2 is mounted on the mouth and neck portion 60 of the container to seal the mouth and neck portion 60, the container lid 2 is fitted over the mouth and neck portion 60, and the lid body 4 is closed in the closing rotation direction (see FIG. 5, the female thread 28 of the lid body 4 is screwed into the male thread of the mouth and neck 60. As a result, the lid body 4 is lowered with rotation, and the locking means 34 formed on the tamper-evident foot 16 of the lid body 4 is elastically deformed and passes through the annular jaw 64 of the mouth-neck part 60. And
Thereafter, it is elastically restored and locked on the lower surface of the annular jaw 64. When the lid body 4 is lowered, the inner plug 6 incorporated therein is also lowered. When the lid body 4 is lowered to the position shown in FIG. 5, the sealing wall 42 of the inner plug 6 that has been lowered along with this is inserted into the mouth and neck portion 60, and the outer peripheral surface of the sealing wall 42 is The sealing ridge 58 formed is brought into close contact with the inner peripheral surface of the mouth-neck portion 60, and the lower surface of the closely-fitted portion 52 of the overhanging peripheral region 46 on the top wall 40 of the inner plug 6 is formed on the top surface of the mouth-neck portion 60. It is brought into close contact with the surface, thereby sealing the mouth and neck 60. The projecting portion 54 of the overhanging peripheral region 46 in the top wall 40 of the inner plug 6 is located radially outside the outer peripheral surface of the mouth-neck portion 60, and the projecting portion 54 is brought into close contact with the top surface of the mouth-neck portion 60. There is no.

In order to open the mouth and neck 60 of the container, the lid body 4 is rotated in the opening rotation direction (counterclockwise as viewed from above in FIG. 5). In this way, the tamper-evident hem 16 is provided with the locking means 3 formed on the inner peripheral surface thereof.
4 is locked to the annular jaw 64 of the mouth and neck 60, the lifting is prevented, but the other parts of the lid body 4 are raised in accordance with the rotation, and as a result, the skirt wall 10 is raised. A considerable stress is generated in the rupturable line 12 formed in the bridging portion 22, more specifically, the bridging portion 22 thereof,
2, the tamper-evident hem 16 is separated from the main portion 14 of the skirt wall 10. Next, the lid body 4
The portion other than the tamper-evident hem portion 16 is freely raised with rotation and is separated from the mouth and neck portion 60.
Thus, when the portion other than the tamper-evident foot 16 of the lid body 4 is raised with rotation after the breakable line 12 is broken, as shown by a two-dot chain line in FIG. An engaging ridge 32 formed on the main portion 14 of the wall 10 is formed on the projecting portion 54 of the overhanging peripheral region 46 of the top wall 40 of the inner plug 6, more specifically, on the lower surface of the projecting portion 54. Then, the inner plug 6 is raised along with the lid main body 4 and detached from the neck and neck portion 60, thereby opening the mouth and neck portion 60. In the illustrated container lid 2 improved in accordance with the present invention, (1) a bulging ridge 56 is formed at the protrusion 54 of the overhanging peripheral region 46 on the top wall 40 of the inner plug 6, and the protrusion 54 is formed. Of the top wall 40 is thus sufficiently reliably prevented from elastically bending the overhanging peripheral area 46 of the top wall 40 and separating from the engaging ridge 32 of the lid body 4. (2) An arcuate engaging means 32 extending substantially horizontally over an angle range α preferably in the range of 70 to 110 degrees, particularly preferably 80 to 100 degrees, is formed on the lid body 4. Since the projections 54 of the overhanging peripheral region 46 of the top wall 40 of the inner plug 4 are brought into contact with the protrusions 54 of the overhanging peripheral region 46 of the top wall 40 over the above angle range. Contact is sufficiently stable. Therefore, the lid body 4 is
When the inner plug 6 is detached from the mouth and neck 6, the inner plug 6 is also detached from the mouth and neck 60 sufficiently and reliably, and the inner plug 6 is left in the mouth and neck 60 so that only the lid body 4 is detached from the mouth and neck 60. That is largely avoided.

In the illustrated embodiment, when opening the mouth and neck portion 60 of the container, all the bridging portions 22 in the breakable line 12 formed on the skirt wall 10 of the lid body 4 are broken, The tamper-evident hem 16 is separated from the main portion 14 of the skirt wall 10, and the tamper-evident hem 16 is not detached from the cervical portion 60.
It remains at zero. Breakable line 1 if desired
At least one of the bridging portions 22 at 0 is a strong bridging portion that is maintained without being broken, and a rupturable line (not shown) extending in the axial direction is provided on the tamper-evident foot 16. When the mouth and neck portion 60 is opened, the axial break line is broken, and the tamper-evident hem portion 16 is expanded from an endless annular shape to an end belt shape, and is maintained without being broken. The tamper-evident hem 16, which continues to be connected to the main portion 14 of the skirt wall 10 via the entanglement, can also be detached from the mouth and neck 60.

[0031]

Next, examples of the container lid of the present invention will be described together with comparative examples.

Example 1 Fifty container lids having the forms shown in FIGS. 1 to 4 were manufactured. The lid body was compression molded from polypropylene, and the inner plug was injection molded from polyethylene. The main part dimensions of the lid body and the inner plug were as follows. Total height H of the lid body 20.30 mm Diameter D1 .. 25.70 mm defined by the thread leading edge of the internal thread Diameter D2 defined by protruding edge 25.70 mm Extension angle α of engaging ridge 90 degrees Outer diameter D3 of top wall of inner plug ... 27.25mm Outer diameter D4 of the close part in the overhang peripheral area of the top wall ... 25.20mm Thickness of the close part in the overhang peripheral area of the top wall T1... 0.93 mm Thickness of the protruding portion in the overhanging peripheral region of the top wall T2. ······· 40 ° Rise thickness of rib on top wall T3 ··· 0.20 mm Length of rib on top wall L ··· ··· 2.80mm Width W of rib on top wall ······· 1.20mm In an atmosphere of 40 degrees The container lid was attached to the mouth and neck of the container in the form of a bird shown in FIG. The container was made of polyethylene terephthalate. Then, in an atmosphere of 40 degrees, the lid main body was rotated in the opening rotation direction to be detached from the mouth and neck, and it was inspected whether the inner plug was left in the mouth and neck. The results were as shown in Table 1 below.

Example 2 The same container lid as in Example 1 was used except that there was no engaging ridge on the inner peripheral surface of the main part of the skirt wall of the lid body.
Then, the same inspection as in Example 1 was performed. The results were as shown in Table 1 below.

Example 3 The same as Example 1 except that the same container lid as in Example 1 was used except that there was no bulging ridge at the projecting portion of the overhanging peripheral area on the top wall of the inner plug. The inspection was performed. The results were as shown in Table 1 below.

[0035] It the engagement protrusion does not exist on the inner circumferential surface of the main portion of the skirt wall of the comparative example the lid body, and that the bulging protrusions does not exist in the projecting portion of the projecting edge region of the top wall of the inner plug Except for the above, the same container lid as in Example 1 was used for 50 containers, and the same inspection as in Example 1 was performed. The results were as shown in Table 1 below.

[0036]

[Table 1]

[0037]

According to the container lid of the present invention, the inner plug remains in the mouth and neck even when the ambient temperature is relatively high, without causing a separate problem such as a significant increase in manufacturing cost. It is sufficiently avoided that only the main body is detached from the mouth and neck.

[Brief description of the drawings]

FIG. 1 is a side view, partially in section, of a preferred embodiment of a container lid constructed in accordance with the present invention.

FIG. 2 is an exploded view showing a female thread and an engagement ridge formed on a main portion of a skirt wall in a lid body of the container lid shown in FIG. 1;

FIG. 3 is a sectional view showing an inner plug of the container lid shown in FIG. 1;

FIG. 4 is a plan view showing an inner plug of the container lid shown in FIG. 1;

FIG. 5 is a side view, partially in section, showing a state in which the container lid shown in FIG. 1 is attached to the mouth and neck of the container.

[Explanation of symbols]

 2: Container lid 4: Lid body 6: Inner plug 8: Top wall 10: Skirt wall 12: Breakable line 14: Main part of skirt wall 16: Tamper evidence hem 28: Female thread 32: Engagement ridge 34: locking means 40: top wall 42: sealing wall 44: central area of the top wall 46: overhang peripheral area of the top wall 50: rib 52: close contact of overhang peripheral area 54: protrusion of overhang peripheral area 56: bulging ridge 60: mouth and neck of container 62: male thread 64: annular jaw (measured means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinji Goto 2-12 Nagatoro, Hiratsuka-shi, Kanagawa Prefecture Japan Hikarizuka Plant

Claims (5)

[Claims] 1. A container having a substantially cylindrical mouth-and-neck portion, wherein a male thread and a locked means located below the male thread are disposed on the outer peripheral surface of the mouth-and-neck portion. A synthetic resin container lid having a tamper-evident characteristic, comprising: a synthetic resin lid main body; and a synthetic resin inner plug incorporated in the lid main body. And a substantially cylindrical skirt wall hanging from the periphery of the top wall, wherein a rupturable line extending in the circumferential direction is formed on the skirt wall, and the skirt wall is higher than the rupturable line. And a tamper-evident hem portion below the breakable line, and an inner peripheral surface of the main portion is internally threaded to be screwed into the male thread of the mouth and neck portion. The tamper-evident skirt has a radially inwardly protruding portion at the tamper-evident hem and the engaging portion of the mouth and neck portion. A locking means is formed to be locked to the means, wherein the inner plug has a circular top wall extending along the inner surface of the top wall of the lid body, and a substantially cylindrical shape hanging from the top wall. A sealing wall, the top wall having a central region and an overhanging peripheral region, the sealing wall depending from a boundary of the top wall with the central region and the overhanging peripheral region, The overhanging peripheral region of the top wall is closely contacted with the top surface of the mouth and neck portion and the protrusion projecting radially outward beyond the mouth and neck portion. And a swelling ridge swelled downward beyond the lower surface of the close contact portion on the lower surface of the projecting portion. 2. The synthetic resin container lid according to claim 1, wherein the bulging ridge of the inner plug has an annular shape extending continuously in a circumferential direction. 3. An inner peripheral surface of the main portion of the skirt wall of the lid main body, in a direction away from an upper end of the female thread from one end close to or connected to an upper end of the female thread. 3. The synthetic resin container lid according to claim 1, wherein an arc-shaped engaging ridge extending substantially horizontally is formed on the inner plug, and the engaging ridge is engaged with the bulging ridge of the inner plug. . 4. A container having a substantially cylindrical mouth-and-neck portion, wherein a male thread and a locked means located below the male thread are disposed on an outer peripheral surface of the mouth-and-neck portion. A synthetic resin container lid having a tamper-evident characteristic, comprising: a synthetic resin lid main body; and a synthetic resin inner plug incorporated in the lid main body. And a substantially cylindrical skirt wall hanging from the periphery of the top wall, wherein a rupturable line extending in the circumferential direction is formed on the skirt wall, and the skirt wall is higher than the rupturable line. And a tamper-evident hem portion below the breakable line, and an inner peripheral surface of the main portion is internally threaded to be screwed into the male thread of the mouth and neck portion. The tamper-evident skirt has a radially inwardly protruding portion at the tamper-evident hem and the engaging portion of the mouth and neck portion. A locking means is formed to be locked to the means, wherein the inner plug has a circular top wall extending along the inner surface of the top wall of the lid body, and a substantially cylindrical shape hanging from the top wall. A sealing wall, the top wall having a central region and an overhanging peripheral region, the sealing wall depending from a boundary of the top wall with the central region and the overhanging peripheral region, The overhanging peripheral region of the top wall is closely contacted with the top surface of the mouth and neck portion and the protrusion projecting radially outward beyond the mouth and neck portion. Having an inner peripheral surface of the main portion of the skirt wall of the lid body,
An arc-shaped engaging ridge extending substantially horizontally in a direction away from the upper end of the female screw is formed from one end close to or connected to the upper end of the female screw, and the engaging ridge is formed. A synthetic resin container lid, which is engaged with a lower surface of the protrusion of the inner plug. 5. The inner plug according to claim 1, wherein a plurality of radially extending ribs are formed on a top surface of the central region of the top wall of the inner plug at intervals in a circumferential direction. A container lid made of a synthetic resin described in Crab