JP7370290B2 - resin cap - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin cap that is attached to the mouth of a container that accommodates contents such as drinks, for example.

In a resin cap (for example, see Patent Document 1) that includes an outer ring (outer leg) for sealing the container mouth from the outside, a weld line is placed at the sealing location of the outer ring to improve sealing performance and a sense of security. It is desirable that no formation occurs.

Therefore, the applicant proposed that the outer ring (outer annular seal piece) be divided into an upper main area that is in close contact with the container mouth and serves as a sealing area, and a lower sub-area that is spaced apart from the container mouth and does not serve as a sealing area. Patent Document 2 proposes a technique in which the formation of the weld line is limited to the lower sub-region.

JP2009-29498A Patent No. 5554604

However, there is still room for improvement in preventing the formation of weld lines at the sealing location of the outer ring.

The present invention has been made with the above-mentioned considerations in mind, and an object of the present invention is to provide a resin cap that helps ensure the prevention of weld line formation at the sealing location.

In order to achieve the above object, the resin cap according to the present invention is a resin cap equipped with an outer ring for sealing the container mouth from the outside, and the outer ring is attached to the outer peripheral surface of the container mouth. It has an annular seal part that makes close contact, and a tip ring part that is provided on the tip side of the annular seal part and is configured so as not to impede the close contact, and the length of the tip ring part is made uneven in the circumferential direction , and the top a skirt wall that extends downward from the outer periphery of the top wall and has a female thread that engages with a spirally extending male thread of the container mouth, and the outer ring includes an area of the top wall that is inside the skirt wall. The length of the tip ring portion is changed stepwise or continuously in the circumferential direction according to the distance from the annular seal portion that protrudes downward from the capping state and differs in the circumferential direction to the upper end of the male thread (Claim 1) .

The present invention provides a resin cap that helps ensure the prevention of weld line formation at the sealing location.

That is, in the resin cap of the invention according to claim 1 of the present application , since the length of the tip ring portion is configured to be non-uniform in the circumferential direction, for example, the annular seal portion is located above the tip ring portion, and When resin is poured into a mold so that the annular seal part is molded horizontally (the center axis of the annular seal part is vertical), even if a weld line is formed at the tip ring part, the The weld line is more likely to form in the relatively long part of the tip ring part (relatively located on the lower side), which means that it is difficult for the weld line to reach the annular seal part, which improves the sealing performance and sense of security. can be increased.

In particular, when making the length of the tip ring portion uniform in the circumferential direction, the length must be based on the shortest distance from the annular seal to the top of the male thread at the container mouth, which increases the length of the tip ring portion. However, in the resin cap of the invention according to claim 1 , in which the length of the tip ring portion is changed in the circumferential direction according to the distance from the annular seal portion to the upper end of the male thread, the tip ring portion is made longer. This also leads to an improvement in the effect of avoiding weld line formation at the sealing location.

(A) is a vertical cross-sectional view schematically showing the structure of a resin cap according to an embodiment of the present invention, and (B) is an enlarged view of part B in (A). (A) is a bottom view schematically showing the configuration of the resin cap, and (B) and (C) are schematic views of the configuration near the tip ring portion in ranges R1 and R2 shown in (A), respectively. Partially enlarged vertical sectional view, (D) is a developed view schematically showing the configuration of the tip ring portion near range R3 shown in (A).

Embodiments of the present invention will be described below with reference to the drawings.
A resin cap (hereinafter referred to as a cap) 1 shown in FIG. 1(A) is used by being attached to the mouth M (see FIG. 1(B)) of a container such as a PET bottle, and is used by compression molding. Alternatively, it is integrally molded from polyethylene by injection molding. Note that the material forming the cap 1 is not particularly limited, and in addition to the polyethylene used in this embodiment, polypropylene and the like are suitably used.

Further, as shown in FIGS. 1A and 2A, the cap 1 includes a top wall 2 that is approximately circular in plan view, and a substantially cylindrical skirt that extends downward from the outer periphery of the top wall 2. It has a wall 3. Here, a knurled groove 4 is provided on the outer circumferential surface of the skirt wall 3, and a female thread 5 is provided on the inner circumferential surface, and this female thread 5 is a male thread M1 (FIG. (See (B)).

Then, when the cap 1 is rotated and attached to the container mouth M so that the female thread 5 of the skirt wall 3 is connected to the male thread M1 of the container mouth M, an annular ring connected to the inner surface (lower surface) of the top wall 2 is attached. The middle leg (inner ring) 6, the annular rib 7, and the annular outer leg (outer ring) 8 are brought into close contact with the container mouth M, thereby sealing the container mouth (see FIG. 1(B)). ). That is, when the cap 1 is attached to the container mouth M, the middle leg 6 is inserted into the container mouth M and comes into close contact with the inner peripheral surface of the container mouth M, and the annular rib 7 is attached to the container mouth M. The outer leg 8 is configured to be in close contact with the upper end surface of the annular shape, and the outer leg 8 is in close contact with the outer peripheral surface of the container mouth M.

In addition, the cap 1 is a pilfer-proof cap that has the function of proving that it is unopened (that it has never been opened), and when the unopened cap 1 attached to the container mouth M is opened (first When opening the cap), when the cap 1 is rotated so that the connection between the male thread M1 and the female thread 5 is released, the cap 1 separates from the container opening M, but the tamper evidence connected to the lower part of the skirt wall 3 The band (hereinafter simply referred to as "band") 9 is configured to remain in the container mouth M.

That is, the band 9 is connected to the lower part of the skirt wall 3 via an annular weakened part 10 that extends over the entire circumference of the skirt wall 3 (see FIG. 1(A)). It is composed of a plurality of bridges 10a existing on the inner peripheral side of the boundary between the skirt wall 3 and the band 9, and slits 10b extending in the circumferential direction of the skirt wall 3 and the band 9 so as to vertically define the skirt wall 3 and the band 9. A portion (outer circumferential portion) of the bridge 10a is also cut with a slit 10b so that the bridge 10a breaks when pulled with a predetermined force.

Further, on the inner peripheral side of the band 9, a plurality of locking pieces (flaps) 11 that project inward are provided at intervals in the circumferential direction (eight pieces in this example) (see FIG. 1(A)). ). When the cap 1 is attached to the container mouth M, each locking piece 11 is positioned approximately below an annular projection (not shown) formed on the outer periphery of the container mouth M below the male thread M1. position, and is locked to the annular protrusion by opening the cap. That is, the locking piece 11 is configured to be able to lock onto the annular protrusion from below, and when the cap is opened, the cap main body (skirt wall 3 and top wall 2) located above the annular weakened portion 10 is connected to the container opening M. The band 9, which is separated from the annular weakened part 10 and is located below the annular weakened part 10, remains in the container opening M, and the annular weakened part 10 is broken accordingly.

In this example, as shown in FIG. 1(B), the outer leg 8 for sealing the container mouth M from the outside includes an annular seal portion 12 that is in close contact with the outer peripheral surface of the container mouth M, and an annular seal portion 12 that is in close contact with the outer peripheral surface of the container mouth M. 2 (A) to (C). As shown in , the length of the tip ring portion 13 (the length in the vertical direction) is made non-uniform in the circumferential direction (however, a portion where the length of the tip ring portion 13 is zero or less is not formed).

Specifically, the outer leg 8 protrudes downward from a region of the top wall 2 that is inner than the skirt wall 3 (see FIG. 1(A)), and the length of the annular seal portion 12 is uniform in the circumferential direction. . Here, since the male screw M1 provided on the outer circumferential surface of the container mouth M extends spirally, the height position of its upper end differs in the circumferential direction. M), the distance from the annular seal portion 12 (lower end) of the outer leg 8 to the upper end of the male thread M1 varies in the circumferential direction. In this example, the length of the tip ring portion 13 is changed in the circumferential direction depending on the distance from the annular seal portion 12 (lower end) to the upper end of the male thread M1.

Specifically, for the outer leg 8 that extends continuously over 360 degrees around the axis of the cap 1, as shown in FIG. The tip ring portion 13 in the range R1 is configured as shown in FIG. 2(B), and the tip ring portion 13 in the range R2 is configured as shown in FIG. 2(C). do. In other words, the length of the tip ring portion 13 in the range R1 and R2 is made different, and as is clear from comparing FIGS. 2(B) and (C), the tip ring portion 13 in the range R1 (FIG. (see B)) is made relatively short, and the tip ring portion 13 in range R2 (see FIG. 2(C)) is made relatively long. Furthermore, in the two ranges R3 located between the ranges R1 and R2 (see FIG. 2(A)), the tip ring portion 13 is made to gradually become longer from the range R1 to the range R2 (see FIG. 2(D). )reference).

In the cap 1 of this example in which the length of the tip ring portion 13 is configured to be nonuniform in the circumferential direction, for example, the annular seal portion 12 is located above the tip ring portion 13, and the annular seal portion 12 is located above the tip ring portion 13. Even if a weld line is formed in the tip ring part 13 when resin is poured into the mold so that the resin is molded in a horizontal direction (the central axis of the annular seal part 12 is vertical), the weld line The weld line is more likely to be formed in a relatively long part (relatively located lower part) of the tip ring part 13, which means that it becomes difficult for the weld line to reach the annular seal part 12, which improves the sealing performance and sense of security. can be increased.

In particular, when making the length of the tip ring portion 13 uniform in the circumferential direction, the length must be based on the shortest distance from the annular seal portion 12 to the upper end of the male thread M1, and the length of the tip ring portion 13 becomes longer. However, in this example, the length of the tip ring portion 13 is changed in the circumferential direction according to the distance from the annular seal portion 12 to the upper end of the male thread M1, making it easy to increase the length of the tip ring portion 13. This also leads to an improvement in the effect of avoiding weld line formation at the sealing location.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, the following modifications can be given.

In the examples shown in FIGS. 2A to 2D, the length of the tip ring portion 13 is constant in each of the ranges R1 and R2, and the length of the tip ring portion 13 is gradually changed only in the range R3. However, for example, the length of the tip ring portion 13 may be gradually (continuously) changed in one or both of the ranges R1 and R2, or conversely, the length of the tip ring portion 13 in the range R3 may be kept constant. You can also do this. In the latter case, the length of the tip ring portion 13 in the range R3 may be the same as the length of the tip ring portion 13 in the ranges R1 or R2, or may be an intermediate length therebetween. In this way, the length of the tip ring portion 13 can be freely changed stepwise or continuously, and the range classification is not limited to the three types R1 to R3, but can also be divided into two or less types or four or more types. good. Note that the case where there is one type of range classification means that the length of the tip ring portion 13 changes continuously (gradually) in the circumferential direction from one specific location according to the height position of the male screw M1, for example, and This is the case when the original position is reached.

In the capping state, it is preferable that the tip ring portion 13 does not come into contact with the male thread M1 from the viewpoints of closure operability, sealing performance, etc., but it may come into contact with it within a range that does not cause any problems.

It goes without saying that the above modifications may be combined as appropriate.

1 Cap 2 Top wall 3 Skirt wall 4 Knurled groove 5 Female thread 6 Middle leg (inner ring)
7 Annular rib 8 Outer leg (outer ring)
9 Band 10 Annular weakened part 10a Bridge 10b Slit 11 Locking piece 12 Annular seal part 13 Tip ring part M Container mouth part M1 Male thread R1 to 3 range

Claims (1)

A resin cap including an outer ring for sealing a container opening from the outside,
The outer ring has an annular seal portion that is in close contact with the outer circumferential surface of the container mouth portion, and a tip ring portion that is provided on the distal end side of the annular seal portion and configured so as not to impede the close contact. The length is made uneven in the circumferential direction ,
comprising a top wall and a skirt wall extending downward from the outer periphery of the top wall and having a female thread that is threaded into a spirally extending male thread of the container mouth;
The outer ring protrudes downward from an area of the ceiling wall inside the skirt wall,
A resin cap characterized in that, in a capping state, the length of the tip ring portion is changed stepwise or continuously in the circumferential direction depending on the distance from the annular seal portion that varies in the circumferential direction to the upper end of the male thread.