JPH0356988B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a container opening in which the materials and threads of the container and cap are modified, and a method for preventing leakage thereof.

<Conventional technology> Containers made of synthetic resin are now widely used as packaging containers for food products, etc. due to improvements in processing technology, but the problem always arises in sealing the contents. It is a matter of safety or leakage prevention. The mouth structure of a conventional synthetic resin container will be explained using FIG. 1. An opening is provided in the mouth 2 of the container body 1, and the contents are taken in and taken out through the opening 3. There is. A male thread 4 is formed on the outer surface of the mouth portion 2, and a female thread 6 is formed on the inner surface of the non-metallic cap 5 which is screwed into the mouth portion 2.
By screwing the male thread 4 and the female thread 6 together, the sealing of the container opening 2 is ensured. In this case, as shown in FIG. 1a, the cap 5 may be directly screwed onto the opening 2, but as shown in FIG. 1b, a discharge hole (not shown) is formed on the opening 3. At the same time, a thin metal plate 8 made of aluminum or the like is placed on the thin film 7, and the thin film 7 is placed on the thin film 7 by a contact ring 5' provided on the inner top surface of the cap 5.
and press the thin plate 8 against the opening 3, and in this state heat the thin metal plate 8 by high frequency induction heating,
In some cases, the thin film 7 is welded to the opening 3.

However, in any of the above cases,
As shown in FIG. 2, in the conventional cap 5 and mouth 2, a line A connecting the thread crests 4' ₁ and 4' ₂ of the male thread 4 forming the outer surface of the mouth 2 is connected. The inclination angle α with respect to Y, which is perpendicular to the axis X, and the inclination angle of the line B, which connects the thread crests 6' ₁ and 6' ₂ of the female thread 6 forming the inner surface of the cap 5, with respect to the line Y, which is perpendicular to the axis X of the screw. It is formed so that β is equal (α=β). Therefore, when the caps are fully screwed together, the contact between the threads of the container mouth 2 and the threads of the cap 5 is such that the top surface of the container mouth 2 hits the inner top surface of the cap 5. As a reaction, a force is generated in which the male thread ₄ of _the container opening 2 is directed upward and downward in the figure, and as a result, as shown in FIG _. , 10 ₂ and the valley bottoms 11 ₁ , 11 ₂ connecting the two flanks of the threaded rod had gaps. Therefore, the fact that the material constituting the container opening 2 is made of synthetic resin is also relevant, and when the above-mentioned reaction force weakens due to vibrations during the distribution process, the advancing side flank 9 ₁ ,
9 The contact of the screw threads at ₂ can no longer be ensured,
The screwing of the cap 5 and the container opening 2 becomes loose. Furthermore, when high-frequency induction heating is performed, the contact ring 5' melts and the contact with the top surface becomes loose, which in turn weakens the reaction force and loosens the contact between the screw threads. As a result of such loosening, in the case of a container opening formed by a high-frequency heating seal, if the seal is not completely sealed, the contents will leak out of the container body 1 through the opening and threaded portion. It had drawbacks.

<Problems to be Solved by the Invention> The present invention solves the problem of loosening of the threaded connection between the cap and the container mouth, resulting in incomplete sealing and the contents passing through the opening and the threaded part. To provide a container opening and a method for preventing leakage thereof, which prevents the disadvantage of leakage directly out of the container body, allows easy screwing of the cap and container opening, and prevents contents from leaking. It is something.

<Means for Solving the Problems> The gist of the present invention regarding a container mouth part that solves the above problems is as follows: 1) A male thread forming an outer surface of a synthetic resin container mouth part is screwed into the container mouth part. In the structure of the container opening formed by the female thread forming the inner surface of the non-metallic cap, the angle of inclination of the line connecting the thread crests of the male thread with respect to the line perpendicular to the axis of the thread is determined as described above. The angle of inclination of the line connecting the thread crests of the screw with respect to the line orthogonal to the axis is greater than the angle of inclination, for example, the outer diameter of the male thread forming the outer surface of the synthetic resin container opening and the diameter of the root of the male thread. The difference is gradually increased toward the opening of the container mouth, and the inner diameter of the female thread that forms the inner surface of the non-metallic cap that is screwed into the synthetic resin container mouth and the diameter of the valley of the female thread. The gist of the present invention regarding a method for preventing leakage at the mouth of a container is as follows: 2) The difference between A thin film made of almost the same material as the container is placed on the container, and a thin metal plate is placed on the thin film.In addition, when screwing a non-metallic cap onto the container opening, the outer surface of the container opening is The inclination angle of a line connecting the thread crests of the male threads to be formed with respect to a line perpendicular to the axis of the screw is determined from the inclination angle of a line connecting the thread crests of the female threads forming the inner surface of the cap with respect to a line perpendicular to the axis. High frequency induction heating is performed in the enlarged and screwed state to weld the thin film to the peripheral edge of the opening.

<Function> The structure of the container opening according to the present invention is based on the following: ``The inclination angle of the line connecting the thread crests of the external threads forming the outer surface of the synthetic resin container opening with respect to the line perpendicular to the thread axis, By making the angle of inclination larger than the line connecting the thread crests of the female threads forming the inner surface of the non-metallic cap with respect to the line perpendicular to the axis, 1) The stronger the threading of the cap, the more the synthetic resin The resilient thread top of the external thread of the container collapses, and this collapse spreads over the entire thread groove, particularly above the container mouth, thereby further increasing the degree of adhesion between the container mouth and the cap.

2) The closer the container is to the mouth, the tighter the seal (see Figure 4a), the less the contents will leak inside the cap and stain the entire inside.

3) The container mouth and the outside of the cap can be completely sealed off, so even if there is a gap between the top inside of the cap and the container opening, the contents coming out of the opening will be completely sealed by the threaded part. It will not leak outside.

Furthermore, the method for preventing leakage at the mouth of a container according to the present invention is as follows: 4) By utilizing high-frequency induction heating in addition to the above structure, leakage prevention is further improved.

<Example> Hereinafter, a container opening and a method for preventing leakage thereof according to the present invention will be described in detail based on the example shown in the drawings.

The structural features of the present invention, as shown in FIG _.
The inclination angle α of the line A connecting 4' ₂ with respect to the line Y perpendicular to the axis X of the screw is the thread crest 6' ₁ of the female thread 6 forming the inner surface of the non-metallic cap 5 that is screwed into the opening 2. The inclination angle β of the line connecting 6′ ₂ with respect to the line Y perpendicular to the axis X of the screw is made larger (α
β) is at point. Because of these characteristics, when the cap 5 is screwed onto the mouth part 2 of the container body, the relationship between the thread crest 4 of the male thread of the mouth part 2 and the thread bottom 11 of the female thread of the cap 5 is as follows. Although not always clearly shown in Figure 3, the mouth 2 is generally
The closer it is to the top, the less likely a gap will occur. Therefore, unlike the conventional example shown in FIG.
The thread crest 4' ₁ of the male thread 4 is screwed into the root 11 ₁ of the female thread 6.
This means that the sealing of the container opening 2 is ensured not only by the leading side flank 9 ₁ but also by the root 11 ₁ of the female thread 6. Furthermore, the container opening 2 is made of synthetic resin and has elasticity;
As the screwing of the cap 5 is tightened, the thread crest 4' ₁ of the male screw 4 is crushed, and the amount of this crushing is the same as that of the cap 5.
It spreads over the entire thread groove of the female thread 6 formed on the inner surface of the cap, and due to the effect of this crushing margin, the degree of adhesion between the male thread 4 of the container opening 2 and the female thread 6 or the root 11 of the cap 5 is further increased. become. The degree of adhesion between the male thread 4 of the container mouth 2 and the female thread 6 or the root 11 of the cap 5 becomes stronger as it goes toward the container mouth 3 in the screwed state. It's getting weaker the further away it gets.
Therefore, at the starting position of the cap, screwing is easy, and when the cap is fully screwed, sufficient adhesion and sealing can be achieved at a position close to the container opening 3.
It is also less likely that the contents will leak.

FIG. 4 shows two modified examples of the leakage prevention structure according to the present invention. As mentioned above, the feature of the leak prevention structure according to the present invention is that the inclination angle α of the line A with respect to the line Y perpendicular to the axis X is made larger than the inclination angle β of the line B with respect to the line Y perpendicular to the line X. However, (α>β), this means that the difference between the outer diameter of the male thread 4 forming the outer surface of the container mouth 2 and the diameter of the trough can be calculated as shown in FIG. 4a. This can also be achieved by increasing the size gradually toward the opening 3.
Furthermore, as shown in FIG. 4b, the difference between the inner diameter of the female thread 6 forming the inner surface of the cap 5 and the diameter of the root is gradually increased toward the inner top surface 5'' of the cap 5. can also be realized.

In the description of the above embodiment, the case where the cap 5 is directly screwed onto the container opening 2 has been taken as an example, but in the present invention, as shown in FIG. A thin film made of synthetic resin having a discharge port is placed, a thin metal plate made of aluminum or the like is placed on top of the thin film, the cap 5 is screwed onto the container mouth 2, and a thin film is provided on the inner top surface of the cap 5. Pressing the thin film and the thin plate against the opening by the contact ring 5', and in this state, generating heat in the metal thin plate using high-frequency induction heating to weld the thin film to the opening, works in conjunction with the leak prevention structure according to the present invention described above. In other words, it is an effective method for preventing leakage. In other words, even if the top surface contact becomes loose due to melting of the contact ring 5' on the inner top surface 5'' of the cap 5 during high frequency induction heating, the cap 5 of the container body 1
Since the tightness of the threads is maintained, even if the thin film is not completely welded to the opening, the contents will not leak from the container opening 2 through the threaded part.

<Effects> As described above in detail based on the embodiment shown in the drawings, the line connecting the thread crests of the external threads forming the outer surface of the container opening is perpendicular to the axis of the threads. By making the inclination angle with respect to the line perpendicular to the axis of the screw of the line connecting the tops of the threads of the female thread forming the inner surface of the cap screwed onto the container opening, 1) the angle of inclination of the container opening Sealing is ensured not only by the advancing side flank but also by the root of the female thread, and together with the fact that the mouth structure is made of synthetic resin and has elasticity, the contact between the two threads is ensured. This will further improve the leakage prevention effect.

2) Therefore, when this mouth structure is used for high-frequency induction heating, together with the seal at the container mouth, it becomes an even more leak-proof structure, and even if the high-frequency seal at the container mouth is incomplete, Unlike conventional containers, however, the contents do not leak out, so products with high sealing performance can be manufactured with confidence.

[Brief explanation of drawings]

1 and 2 are partially broken sectional views showing the structure of a conventional container mouth, and FIGS. 3 and 4 are sectional views showing the structure of the mouth according to the present invention. In the drawing, 1 is the container body, 2 is the mouth, 3 is the opening, 4 is the male thread, 4' ₁ and 4' ₂ are the tops of the threads,
5 is a cap, 5' is a contact ring, 5'' is an inner top surface, 6 is a female thread, 6' ₁ and 6' ₂ are thread tops, 7 is a thin film, 8 is a thin plate, 9 ₁ and 9 ₂ are leading side flanks , 10 ₁ and 10 ₂ are the chasing side flanks,
11 ₁ and 11 ₂ are the valley bottoms.

Claims (1)

[Scope of Claims] 1. A container mouth comprised of a male thread forming the outer surface of a synthetic resin container mouth and a female thread forming the inner surface of a non-metallic cap screwed into the container mouth. In the structure of the part, the angle of inclination of the line connecting the crests of the male threads with respect to the line perpendicular to the axis of the screw is greater than the angle of inclination of the line connecting the crests of the female threads with respect to the line perpendicular to the axis. A container mouth portion characterized by: 2. A patent characterized in that the difference between the outer diameter of a male thread forming the outer surface of a synthetic resin container mouth and the diameter of the valley of the male thread is gradually increased toward the opening of the container mouth. A container opening according to claim 1. 3. The difference between the inner diameter of the female thread forming the inner surface of the non-metallic cap screwed onto the synthetic resin container opening and the diameter of the valley of the female thread is gradually increased toward the inner top surface of the cap. The container opening according to claim 1, characterized in that: 4. A thin film made of substantially the same material as the container is placed on the opening of the synthetic resin container mouth, and a metal thin plate is placed on the thin film, while a non-metallic cap is screwed onto the container mouth. In doing so, the angle of inclination of the line connecting the crests of the male threads forming the outer surface of the container opening with respect to the line orthogonal to the axis of the screw is determined by the line connecting the crests of the female threads forming the inner surface of the cap. A method for preventing leakage of a container opening, characterized in that the thin film is welded to the periphery of the opening by high-frequency induction heating while screwed together at an angle greater than an inclination angle with respect to a line perpendicular to the axis of the opening.