JPH0379269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic container lid with a gas vent hole, and more particularly to a plastic container lid used for sealing a container filled with a content having an autogenous pressure, such as a carbonated beverage.

Container lids used to seal contents with autogenous pressure, such as carbonated drinks, may cause the contents to blow out when the cap is opened, or the container cap itself may be damaged if the internal pressure is not released at the beginning of opening. This creates the problem of flight. Such problems are particularly noticeable in the case of threaded caps. In other words, in the case of a crown, the length of the side wall (skirt) of the lid is short, and when opening the lid, a part of the lid must be held down with a corkscrew, and it may peel off from one end edge of the sealed part. Since the opening operation is done gradually, the internal pressure is released gradually from the beginning of opening, and there are almost no problems with the contents blowing out or the lid flying off. However, in the case of a screw cap, The skirt of the lid is relatively long,
Moreover, since the internal pressure can only be released through the gap between the tip of the cap and the container, it is difficult to release the internal pressure gradually at the initial stage of opening the cap. This tendency is found to be particularly pronounced in plastic caps. In other words, in the combination of a metal cap and a glass bottle, both screws that engage are rigid, and therefore, even at the initial stage of opening, a gas vent passage is likely to be formed through the gap between the screws to release the internal pressure. In the case of plastic caps, the screw itself has a certain degree of compressibility and deformability, and even after the cap has been opened to a certain extent by turning, the internal pressure itself will cause the cap to open. There is a problem in that the screw and the screw of the container are airtightly engaged, making it difficult to form a gas vent passage.

Conventionally, in a threaded cap, in order to release the internal pressure at the initial stage of opening, a gas vent hole was already formed in the side wall between the sealing part and the screw, as described in Japanese Patent Publication No. 1983-
This is proposed in Publication No. 30266.

Although it is relatively easy to form such gas vent holes in the case of metal caps, which have excellent workability and cuttability, in the case of plastic caps,
It is difficult to make gas vent holes in the cap after molding, and on the other hand, if holes are to be formed at the same time as molding, there is a problem in that mold cutting becomes difficult.

The biggest problem with caps with gas vent holes is that foreign matter such as dirt can enter the cap through the gas vent holes and adhere to the container mouth, impairing the hygienic properties. From the standpoint of quickly releasing the internal pressure at the initial stage of the closure, there are two conflicting requirements: the gas vent hole should be located as close to the container mouth as possible. .

According to the present invention, a plastic cap with gas vent holes is provided that simultaneously satisfies the above two requirements.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic cap with a gas vent hole in which the opening of the container is protected from intrusion and adhesion of foreign matter through the gas vent hole.

Another object of the present invention is to provide a plastic cap with gas vent holes that allows the internal pressure to be released quickly and reliably at the initial stage of opening.

Still another object of the present invention is to provide a plastic cap with a gas vent hole that is constructed so that the gas vent hole can be easily formed during molding of the cap.

According to the present invention, the top plate portion and the circumferential side wall portion are integrally molded of plastic, and the inner surface of the side wall portion is provided with a screw for engaging the container opening and the sealing portion, and the inner surface of the top plate portion is provided with a screw for engaging the container mouth portion and the sealing portion. A container lid that has a gas vent hole between the sealing part and the threaded part to release the internal pressure when the cap is opened, and an annular projection defining the outer edge of the sealing part on the inner surface of the top plate. and an annular space between the protrusion and the side wall, and the side wall adjacent to the top plate has a notch extending perpendicularly from the edge of the top plate and having an inner circumferential surface aligned with the inner circumferential surface of the side wall. A plastic container characterized in that a plurality of notches are formed at small intervals so as to be substantially flush with each other, and a portion where the notches and the inner circumferential surface of the side wall portion coincide with each other serves as a gas vent hole connected to the annular space. A lid is provided.

The present invention will be explained in detail below based on specific examples shown in the accompanying drawings.

In FIG. 1, which shows a partially sectional side view of the plastic container lid of the present invention, the container lid is made up of a top plate portion 1 and a circumferential side wall portion 2, which are integrally formed by plastic injection molding or the like. . A knurled groove 3 is formed on the outer surface of the circumferential side wall 2 to facilitate finger gripping and turning, while a threaded portion 4 is formed on the inner surface of the circumferential side wall 2.
is provided. A sealing portion or liner portion 5 to be engaged with the container mouth is provided on the inner surface of the top plate portion 1.
is provided integrally with the lid body or by a liner or packing forming means known per se.

This plastic cap is provided with a pilfer-proof mechanism known per se, which in this embodiment is provided at the lower end of the circumferential side wall 2 via a circumferential perforated score 6. It consists of a narrow annular piece 8 which is connected with a bridge part 7 arranged, and on the inner surface of this annular piece 8 there are a number of flap pieces 9 which are to be engaged with the jaws of the container and which are fixed inwardly. It is installed at an angle of inclination of

In the cross section shown in FIG.
is shown in sealing engagement with the
The lid threaded portion 4 engages with the threaded portion 11 of the container, so that the container mouth portion 12 tightly engages with the liner portion 5 of the container lid for sealing. Moreover, the flap piece 9 of the annular piece 8 engages with the jaw part 13 of the container, so that opening of the container lid by pivoting becomes possible only after the bridging part 7 is severed.

In the present invention, as shown in FIG. 1, an annular protrusion 14 is provided on the inner surface of the top plate part 1 to define the outer edge of the sealing part 5, and the annular protrusion 14 and the circumferential side wall 2, and a plurality of gas vents 16 reaching the annular space 15 are provided in the side wall portion 2 adjacent to the top plate portion 1. This annular protrusion 14 is provided integrally with the top plate part 1 so as to have flexibility, and preferably has a tapered cross-sectional shape. In the present invention, the gas vent 16 is arranged vertically from the edge of the top plate 1, and the inner circumferential surface of the notch is connected to the side wall 2.
It is formed by providing notches 17 at small intervals so as to be substantially flush with the inner circumferential surface of the side wall portion 2, and the portion where the notches 17 and the inner circumferential surface of the side wall portion 2 coincide becomes the gas vent hole 16. ing. As shown in FIG. 2, the inner circumferential surface of the annular protrusion 14 is tightly fitted to the outer circumferential surface of the container mouth 12. As shown in FIG.

Thus, according to the invention, the gas vent 16 is
Although the annular protrusion 14 is provided at the part closest to the sealing engagement part between the container mouth part 12 and the liner part 5, the annular protrusion 14 is in close contact with the outer periphery of the container mouth part, and dirt is not allowed to enter this part through the gas vent. This has the effect of reliably preventing foreign matter such as adhesion. Furthermore, when opening the container, as soon as the container opening 12 and the annular protrusion 14 are disengaged, the pressurized contents gas will be released.
The cap is immediately opened to the outside of the lid through the annular space 15 and the gas vent hole 16, effectively eliminating problems such as the contents blowing out and the cap flying off.
In fact, in the results of experiments conducted by the present inventors in which a plastic cap with an outer diameter of 30 mm was opened, it was confirmed that degassing was carried out extremely smoothly by opening the cap at only 10 to 30 degrees.

In addition, in the plastic container lid of the present invention, the female mold for injection molding is provided with a protrusion corresponding to the notch 17, and this protrusion and the male mold are fitted, so that the gas can be removed at the same time as the injection molding. There is also the distinct advantage that the molding of the male mold and the female mold can be performed very easily as well as the formation of the punching hole.

In addition, in the specific example shown in FIG.
By forming the lower surface of the notch 18 into a surface 18 that is inclined outwardly and downwardly, it is possible to effectively prevent foreign matter such as dust from accumulating in the space within the notch 17 .

In the present invention, in order to prevent the intrusion of foreign substances such as dust as much as possible, it is preferable to provide a large number of relatively small notches. For example, the width of the notches is 0.2 to 1 mm. Depending on the situation, it is preferable to provide 4 to 36 pieces at approximately equal intervals. In the lid of the invention, the release of gas occurs through the annular space 15, so that the release of pressure occurs uniformly over the entire circumference.
The protrusion dimension of the annular protrusion 14 varies depending on the dimensions of the lid, but is generally preferably in the range of 0.5 to 3.0 mm.

In one preferred embodiment of the present invention, when the sealing part 5 of the container lid is not engaged with the container opening 12, the annular space 15 is clearly formed; When engaged with the mouth portion 12 and sealed, the annular space 15 or the gas vent hole 16 is substantially closed by the annular protrusion 14 . According to this configuration, it is possible to provide a container lid that is highly hygienic and completely prevents foreign matter such as dust from entering the inner surface of the container lid.

In FIGS. 3 and 4 showing this specific example, a jaw-shaped protrusion 19 is provided on the inner surface of the circumferential side wall 2 facing the annular protrusion 14 and slightly protrudes inward. In the sealed engagement state shown in FIG.
The annular protrusion 14 is pushed slightly outward due to forced fitting with the container opening, and the enlarged protrusion 14
The outer circumferential surface thereof engages with the jaw-like protrusion 19 of the circumferential side wall portion 2, thereby substantially closing the annular space 15 or the gas vent hole 16. At the opening stage shown in FIG. 4, the annular protrusion 14 and the container opening 12 are disengaged, and the expanded annular protrusion 14 returns to its original state due to elastic recovery. A communicating annular space 15 is formed, and internal pressure gas is smoothly released through this space 15 and the gas vent hole 16.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view of the container lid of the present invention, FIG. 2 is a partially sectional side view showing the container lid of FIG. 1 engaged with the container mouth, and FIG. FIG. 4 is a partial sectional view showing another example of the container lid of the invention in a state in which it is engaged with the container mouth; FIG. 4 is a partial sectional view showing the container lid of FIG. 3 in a state in which it is disengaged from the container mouth. . 1 is a top plate part, 2 is a circumferential side wall part, 4 is a screw part, 5
14 is a liner, 14 is an annular projection, 15 is an annular space, 16 is a gas vent hole, and 17 is a notch.

Claims (1)

[Scope of Claims] 1. A top plate part and a circumferential side wall part are integrally molded of plastic, and a screw for engaging a container mouth part and a sealing part is provided on the inner surface of the side wall part, and The container lid has a gas vent hole between the side sealing part and the threaded part to release the internal pressure when the cap is opened, and the inner surface of the top plate has an annular shape defining the outer edge of the sealing part. A protrusion and an annular space between the protrusion and the side wall are provided, and the side wall adjacent to the top plate includes:
A plurality of notches are formed at small intervals vertically from the edge of the top plate so that the inner circumferential surface of the notch is substantially flush with the inner circumferential surface of the side wall, and the notches and the inner circumferential surface of the side wall A plastic container lid characterized in that the matching portion is a gas vent hole that is connected to the annular space.