JPH0585422B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a synthetic resin container lid, more specifically,
The present invention relates to a synthetic resin container lid having pilfer-proof properties for a container having a neck portion in which a male thread and a locking jaw portion located below the male thread are formed on the outer peripheral surface.

<Prior Art> Recently, synthetic resin container lids have been proposed and put into practical use in place of metal container lids as container lids with pilfer-proof properties for containers such as food and beverage bottles. It's starting to feel like this. Such a synthetic resin container lid includes a top wall and a cylindrical skirt wall that hangs down from the periphery of the top wall.
A weakened line extending in the circumferential direction is formed in the skirt wall, and the skirt wall is divided into a main portion above the weakened line and a pilfer-proof hem portion below the weakened line. A female thread is formed on the inner surface of the main portion, and a plurality of locking protrusions are formed on the inner surface of the pilfer-proof hem.

The container lid as described above is applied to a container having a neck portion in which a male thread and a locking jaw portion located below the male thread are formed on the outer peripheral surface. When closing the mouth and neck of a container with a container lid, the container lid is fitted onto the mouth and neck and rotated in a predetermined direction, that is, the closing direction, and the female thread on the container lid is screwed into the male thread on the mouth and neck. . In this way, the container lid is lowered as it rotates, and the locking protrusion of the container lid is elastically displaced or deformed and passes through the locking jaw part of the mouth and neck, and then elastically restores itself to the locking jaw. It is locked to the bottom surface of the part. When opening the neck of the container, the container lid is rotated in the opposite direction, that is, in the opening direction.
In this way, the female thread on the container lid is moved along the male thread on the mouth and neck, and the container lid is therefore raised as it rotates. However, the pilfer-proof hem cannot rise because the locking protrusion formed on its inner surface is locked to the lower surface of the locking jaw on the neck and neck. Significant stress is created in the weakened line, which is completely ruptured and the pilfer-proof hem is separated from the main portion (alternatively, a weakened line extending axially into the pilfer-proof hem is is formed, at least a portion of the weakened line extending in the circumferential direction is maintained without being broken, and the weakened line extending in the axial direction formed at the hem of the pilfer-proof is The pilfer-proof hem is broken to change from an endless ring shape to an end band shape, thereby causing the locking projection to be disengaged from the locking jaw. After that, the container lid is
The pilf-proof hem remains (or the entire pilf-proof hem is included) and is removed from the mouth and neck, thus opening the mouth and neck.

<Problems to be Solved by the Invention> The conventional synthetic resin container lid as described above has the following problems to be solved regarding its molding.

First, container lids are generally formed by compression molding or injection molding, and when the molded container lid is removed from the mold, a plurality of holes are formed on the inner surface of the pilfer-proof hem. Although the locking protrusion inevitably causes so-called forced punching, such punching is not carried out sufficiently easily and smoothly, and it takes a relatively long time to remove the container lid from the mold.

Second, the locking protrusion formed on the inner surface of the hem of the pilfer-proof hem is defined by the recessed part carved at a predetermined location on the outer circumferential surface of the male die in the mold. The engraving of such recessed portions on the surface requires special machining such as electrical discharge machining, and therefore the production of the mold itself becomes quite expensive.

The present invention has been made in view of this fact, and the technical problem to be solved is to improve the shape of the locking protrusion formed on the inner surface of the pilfer-proof hem, and to attach the molded container lid to the mold. The object of the present invention is to allow the container lid to be easily and smoothly removed from the container lid, and to allow the mold itself for molding the container lid to be manufactured at a cost that is considerably lower than that of conventional molds.

<Means for Solving the Problems> As a result of intensive studies, the present inventors have determined that each of the plurality of locking protrusions formed on the inner surface of the pilfer-proof hem of a synthetic resin container lid,
In the axial cross-section, the shape rotates downward in the axial direction, gradually protrudes radially inward, and then gradually retreats radially outward from the inner surface of the pilfer-proof hem at a predetermined distance radially outward. It has been found that the above-mentioned technical problem can be achieved by creating a configuration that is rotated about an extending central axis.

That is, according to the present invention, the container has pilfer-proof characteristics for a container having a neck portion in which a male thread and a locking jaw portion located below the male thread are formed on the outer peripheral surface. The container lid is made of synthetic resin and includes a top wall and a cylindrical skirt wall that hangs down from the periphery of the top wall, the skirt wall has a weakened line extending in the circumferential direction, and the skirt wall has a weakened line extending in the circumferential direction. It is divided into a main part above the weakened line and a pilfer-proof hem below the weakened line, and the inner surface of the main part has a female thread that is screwed into the male thread of the mouth and neck part. In a container lid in which a strip is formed and a plurality of locking protrusions are formed on the inner surface of the pilfer-proof hem portion to be engaged with the locking jaws of the mouth and neck; Each of the protrusions has a shape that gradually protrudes axially downward, radially inwardly, and then radially outwardly retreats at a predetermined interval from the inner surface of the pilfer-proof hem in the axial cross section. A container lid is provided, characterized in that the container lid is rotated about a central axis that extends in an axial direction at a distance.

In a preferred embodiment of the present invention, each of the locking projections has a smooth shape with no corners in the axial cross section, and in the axial cross section of each of the locking projections, the locking projections extend downwardly in the axial direction and radially inwardly. The gradually protruding portion forms an inclination angle α of 45 to 80 degrees, preferably 60 to 75 degrees, with respect to the inner surface of the pilfer-proof hem, and the portion gradually receding radially outward toward the axially downward direction It forms an inclination angle β of 15 to 60 degrees, preferably 30 to 50 degrees, with respect to the inner surface of the pilfer-proof hem.

<Function> The locking protrusion in the container lid of the present invention has a shape that gradually protrudes downward and radially inward in the axial cross section, and then gradually retreats radially outward, and Since the shape is rotated around a central axis that extends in the axial direction at a predetermined distance from the inner surface of the pilfer-proof hem in the radial direction, it gradually protrudes radially inward in the circumferential direction as well. It has a shape that gradually recedes outward in the direction, and therefore, when the molded container lid is removed from the mold, the locking protrusion can be forcibly removed without causing any particular problems. The container lid can be removed.

In addition, in order to form the recessed part that defines the locking protrusion on the outer peripheral surface of the male die, it is necessary that the cross-sectional shape of the blade provided on the outer peripheral edge be the same as the cross-sectional shape in the axial direction of the locking protrusion, and A rotary milling cutter whose radius of up to Corresponding to the maximum protrusion amount of the locking protrusion), it is only necessary to interfere with the required part of the outer peripheral surface of the male mold, and cut into the recessed part at the required part of the outer peripheral surface of the male mold. Regardless of the processing method, a required recessed portion can be carved extremely easily at a required location on the outer circumferential surface of the male mold.

<Example> Hereinafter, an example of a synthetic resin container lid improved according to the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIG. 1, the illustrated container closure includes a closure body, generally designated 2, which may be molded by compression or injection molding from any suitable synthetic resin material such as polyethylene or polypropylene. are doing. This lid body 2 has a circular top wall 4
and a cylindrical skirt wall 6 that hangs down from the periphery of the top wall 4.

An annular protrusion 8 is formed on the inner surface of the top wall 4, and a sealing liner 10 formed separately from the lid body 2 is disposed within the annular protrusion 8. Such a sealing liner 10 can be formed directly at a predetermined position on the inner surface of the top wall 4 by a well-known embossing process after molding the lid body 2, or can be formed at a predetermined position completely separate from the lid body 2. It can be formed into a shape and then inserted into the inner surface of the top wall 4 of the lid body 2. If desired, the sealing liner 10 can be formed integrally with the lid body 2.

A weakened line 12 extending in the circumferential direction is formed in the skirt wall 6, and the skirt wall 6 is divided into a main portion 14 above the weakened line 12 and a pilfer-proof hem 16 below the weakened line 12. ing. The weakened line 12 itself includes a plurality of slits 18 extending circumferentially at intervals in the circumferential direction.
and a plurality of bridging parts 20 located between the slits 18, and the pilfer-proof hem part 16 is connected to the main part 14 by the plurality of bridging parts 20. If desired, the line of weakness 12 can also be constructed from a so-called score formed by reducing the residual thickness. The weakened line 12 itself can be formed when the lid body 2 is molded, or by cutting the slit 18 after molding the lid body 2.

Advantageously, the outer surface of the main portion 14 of the skirt wall 6 is provided with an uneven or knurled shape 22 to prevent fingers from slipping thereon. A female thread 24 is formed on the inner surface of the main portion 14 . The inner surface of the pilfer-proof hem 16, which is advantageously thinner than the main part 14, has a plurality of engagements spaced apart in the circumferential direction, and in the case shown, six engagements equally spaced in the circumferential direction. A stop projection 26 is formed.

In the container lid improved according to the present invention,
It is important that each of the locking projections 26 has a unique shape. Each of the locking projections 26 in the illustrated embodiment has a shape as shown in FIG. 2 in an axial section at its circumferential center. That is, in the axial cross section shown in FIG. 2, it has an upper part 28 that gradually protrudes downward in the axial direction and radially inward, and a lower part 30 that gradually retreats radially outward in the downward direction. The boundary area between the upper portion 28 and the lower portion 30 is rounded;
It is preferable that the shape is smooth as a whole and has no corners. The angle α of inclination of the upper part 28 with respect to the inner surface of the pilfer-proof hem 16 is preferably between 45 and 80 degrees, particularly between 60 and 75 degrees. Further, the angle β formed by the lower part 30 with respect to the inner surface of the pilfer-proof hem 16 is preferably 15 to 60 degrees, particularly 30 to 50 degrees. The overall shape of each of the locking protrusions 26 is such that the axial cross-sectional shape is preferably as shown in FIG. It is important that the shape is rotated about a central axis extending in the axial direction. Second
Referring to FIG. 3 together with the drawings, each of the locking protrusions 26 in the illustrated example has an axial cross-sectional shape as shown in FIG. The shape is defined by rotation about a central axis 32 that extends outward at a predetermined distance l and extends in the axial direction (that is, in the direction perpendicular to the plane of the paper in FIG. 3). Therefore, as can be easily understood by referring to FIGS. 2 and 3, each of the locking protrusions 26 protrudes radially inward from its center in the circumferential direction. The amount of radial inward protrusion gradually decreases upward and downward from the maximum protrusion in the boundary area between the upper part 28 and the lower part 30 in any cross section in the axial direction. are doing.

Therefore, in order to form the locking protrusion 26 on the inner surface of the pill-proof hem 16, the lid main body 2
Pilfer-proof hem 1 on the outer peripheral surface of the male mold in a mold used when compression or injection molding
It is necessary to carve recessed portions corresponding to the shape of the locking protrusions 26 at intervals in the circumferential direction at a portion defining the inner surface of the locking protrusion 26 . At this time, if the locking protrusion 26 has the shape described above, the required recessed portion can be carved very easily at the required location on the outer peripheral surface of the male die without using a special processing method such as electrical discharge machining. be able to. That is, a rotary milling cutter is used in which the cross-sectional shape of the blade provided on the outer periphery is as shown in FIG. produced,
The rotary milling cutter is rotated about its central axis, and the blade provided on its outer periphery is cut to a required cutting depth (this cutting depth is determined by the locking protrusion 26).
It is only necessary to make the recessed portion interfere with a desired portion of the male mold outer circumferential surface by a distance corresponding to the maximum protrusion amount of , and thus cut the recessed portion into the desired portion of the male mold outer circumferential surface.

On the other hand, in order to form the locking protrusion 26 on the inner surface of the pilfer-proof hem 16, if a recessed portion is carved at a required location on the outer peripheral surface of the male mold, the molded lid main body 2 can be When separating from the male mold, a so-called forced punch is inevitably generated. However, as described above, each of the locking protrusions 26 has a form in which the amount of protrusion decreases smoothly from the maximum protrusion portion toward both sides in the circumferential direction, and the amount of protrusion decreases smoothly upward and downward in the axial direction. As can be easily understood, if there is, the above-mentioned forcible removal can be accomplished easily enough without causing any particular problems.

A container closure as described above is applied to a container provided with a neck 34, which is known per se, in the form as shown in FIG. A male thread 36 and a locking jaw portion 38 located below the male thread 36 are formed on the outer peripheral surface of the mouth and neck portion 34 .

When closing the mouth and neck part 34 by attaching the container lid to the mouth and neck part 34, the container lid is fitted onto the mouth and neck part 34 and rotated in the closing direction, that is, clockwise when viewed from above in FIG. The female thread 24 of the container lid and the male thread 36 of the neck part 34 are screwed together. In this way, the container lid is moved downward as it rotates,
At this time, the locking protrusion 26 of the container lid is elastically displaced or deformed to overcome the locking jaw 38 of the neck portion 34. When the female thread 24 is fully screwed into the male thread 36, the locking protrusion 26 is inserted into the locking jaw portion 36.
8 and elastically recovers to engage the underside of locking jaw 38 as shown in FIG. In the specific example shown, the lower part 30 (FIG. 2) of each of the locking protrusions 26 has a protruding amount that gradually decreases from the center to both sides in the circumferential direction, and also extends along the axis. The amount of protrusion decreases smoothly and gradually in the direction of the locking protrusion 26.
The angle β that each lower portion 30 (FIG. 2) makes with the inner surface of the pilfer-proof skirt 16 is relatively small. Therefore, the locking projection 26 can pass through the locking jaw 38 with sufficient ease, so that when the locking projection 26 passes through the locking jaw 38 the bridge 20 of the weakened line 12 Breaking of the bridge portion 20 due to excessive stress is reliably avoided. When the female thread 24 is fully screwed into the male thread 36, the sealing liner 10 of the container lid is pressed against the top surface of the neck 34, as shown in FIG. sealed.

When opening the neck part 36, the container lid is rotated in the opening direction, that is, in the counterclockwise direction when viewed from above in FIG. In this way, the female thread 2 on the container lid
4 is moved along the male thread 36 of the neck portion 34, the container lid is moved upward as it rotates. However, the pilfer-proof hem 16
cannot move upward because the locking protrusion 26 formed on its inner surface engages with the lower surface of the locking jaw 38 of the mouth and neck portion 34. Accordingly, considerable stress is generated in the bridge 20 of the weakened line 12, which causes the bridge 20 to rupture. In the illustrated embodiment, the angle α formed by the upper part 28 (FIG. 2) of each of the locking protrusions 26 with respect to the inner surface of the pilfer-proof hem 16 is relatively large. Each of the locking projections 26 engages the underside of the locking jaw 38 with sufficient certainty. Therefore, without the bridging portion 20 being broken, the locking protrusion 20 passes through the locking jaw portion 38 and moves upward due to the so-called slip-off, and the container lid is removed from the neck portion 34. It is reliably avoided that the pilfer-proof property is damaged due to detachment. After the bridging portion 20 is broken and the pilfer-proof hem 16 of the skirt wall 6 is separated from the main portion 14, the portion of the container lid other than the pilfer-proof hem 16 is moved upward as it rotates. Mouth and neck 34
The mouth and neck region 34 is thus opened. The pilfer-proof hem 16 is connected to the mouth and neck part 34.
is forced to remain in the

Although one embodiment of the container lid improved according to the present invention has been described above in detail with reference to the accompanying drawings, the present invention is not limited to such embodiment, and does not depart from the scope of the present invention. It goes without saying that various modifications and modifications can be made without any problems.

For example, in the illustrated embodiment, the mouth and neck region 34
Upon opening, all the bridging parts 20 are broken and the pilfer-proof hem 16 is completely separated from the main part 14 of the skirt wall 6, so that the pilfer-proof hem 16 is separated from the neck part 34. be allowed to remain there without being destroyed, but if desired,
For example, one or more of the bridging portions 20 may be made stronger than the others, and at least one weakening line extending in the axial direction in the pilfer-proof hem 16 (such a weakening line is a so-called score or a perforation), and when the neck part 34 is opened, the weakened line formed in the pilf-proof hem 16 is broken, and the pilf-proof hem 16 becomes endless. The ring shape is changed to an end band shape, whereby the locking projection 26 is separated from the locking jaw portion 38.
Also, one or more of the bridging portions 20 that are made rigid are maintained without being broken, thus allowing the entire container lid, including the pilfer-proof hem, to be separated from the neck portion 34. You can also do it.

<Effects of the Invention> According to the synthetic resin container lid having pilfer-proof properties of the present invention, it is possible to prevent so-called forced removal due to the plurality of locking protrusions when removing the molded container lid from the mold. It can be accomplished easily and smoothly. Furthermore, the required recessed portions on the outer peripheral surface of the male mold in the mold for defining the plurality of locking protrusions can be sufficiently easily carved without requiring special machining such as electrical discharge machining. ,
Therefore, the required mold can be manufactured at a sufficiently low cost.

[Brief explanation of the drawing]

FIG. 1 is a side view, partially in section, of an embodiment of a container lid improved according to the present invention. 2 is a partial cross-sectional view (cross-sectional view taken along the line - in FIG. 3) showing the shape of the locking protrusion in the container lid of FIG. 1; FIG. 3 is a partial bottom view showing the shape of the locking protrusion on the container lid of FIG. 1. FIG. 4 is a side view, partially in cross section, of the container lid shown in FIG. 1 attached to the mouth and neck of the container. 4... Top wall, 6... Skirt wall, 12... Weakening line, 14... Main part of skirt wall, 16... Pilfer proof hem, 24... Female thread, 26... Locking protrusion,
34... Container neck and neck, 36... Male thread, 38... Locking jaw.

Claims (1)

[Scope of Claims] 1. A composition having pilfer-proof properties for a container having a neck portion in which a male thread and a locking jaw portion located below the male thread are formed on the outer peripheral surface. The container lid is made of resin and includes a top wall and a cylindrical skirt wall that hangs down from the periphery of the top wall, the skirt wall has a weakened line extending in the circumferential direction, and the skirt wall has a It is divided into a main part above the weakened line and a pilfer-proof hem below the weakened line, and the inner surface of the main part has a female thread that is screwed into the male thread of the mouth and neck. in the container lid, wherein a plurality of locking protrusions are formed on the inner surface of the pilfer-proof hem to be locked to the locking jaws of the mouth and neck; Each of the pilfer-proof hem portions has a shape that gradually protrudes downward in the axial direction, radially inwardly, and then gradually recedes radially outwardly at a predetermined distance from the inner surface of the pilfer-proof hem portion radially outwardly. A container lid characterized in that it is rotated about a central axis extending in an axial direction. 2. The container lid according to claim 1, wherein each of the locking projections has a smooth shape with no corners in an axial cross section. 3 In the axial cross section of each of the locking protrusions,
The portion that gradually projects downward in the axial direction and inward in the radial direction is relative to the inner surface of the hem of the pilfer-proof.
forming an inclination angle α of 45 to 80 degrees, and the portion gradually retracting radially outward in the axially downward direction forming an inclination angle β of 15 to 60 degrees with respect to the inner surface of the pilfer-proof hem; A container lid according to claim 1 or 2. 4. The container lid according to claim 3, wherein the inclination angle α is 60 to 75 degrees. 5. The container lid according to claim 3 or 4, wherein the inclination angle β is 30 to 50 degrees.