Synthetic resin cap

Abstract

A synthetic resin cap having excellent tamper evidence properties, simultaneously achieving both good sealing ability and easiness of opening of the cap, and capable of reliably preventing leakage of container contents before a bridge is cut. The synthetic resin cap has a top wall, a skirt wall, and a tamper evidence band connected to the skirt wall via the bridge. A middle leg, an annular protrusion, and an outer leg are formed integrally with the inner surface of the top wall. The thickness in lateral cross sections of an intermediate section of the middle leg is substantially constant in the vertical direction. The inner and outer peripheral surfaces of the intermediate section are circular arc curved surfaces protruding radially inward so as to have substantially the same curvature in a vertical cross section of intermediate section. A guide surface for guiding a container mouth section is provided on the outer peripheral surface of the tip of the middle leg. The intermediate section is tilted radially outward so that, when the middle leg is inserted into the container mouth section, the upper end of the guide surface moves radially inward by 0.1 - 0.6 mm.

Description

technical field [0001] The present invention relates to a one-piece synthetic resin cap that can be detachably mounted on the mouth of a container for drinking water, wine, etc. The anti-theft cover (pilfer-proofcap) of the function that has not been opened). Background technique [0002] As an existing synthetic resin cap of a single structure, there is a plastic cap having the following characteristics: a top plate of a substantially circular shape and a skirt (skirt) hanging down from the periphery of the top plate are integrally formed with plastic, The inner peripheral surface is provided with screw threads and other fastening parts for fastening with the container. Among them, a non-deformable annular bracket is provided at the inner corner of the top plate and the tooth edge, and the bracket should be compatible with the The portion from the upper edge of the container mouth to the outer peripheral edge is tightly engaged; and at least one sealing protrusion is locat...

AI Technical Summary

Problems solved by technology

[0004] However, in the above-mentioned cover, when the tamper evidence band (tamper evidence band) is connected to the lower part of the above-mentioned tooth edge via a breakable connecting bridge (bridge) and used as an anti-theft cover, it may be caused by a small angle. The opening operation, which removes the seal before the connection bridge is disconnected, is not enough in terms of tamper evident (or unopened proof function)

[0005] In addition, not limited to the above-mentioned caps, in conventional caps with a single-body structure, it is generally difficult to achieve both sealing and opening performance (ease of opening), and the sealing part also rotates with opening, so there is the following problem : The content is easy to leak before the bridge is broken, and it is not practical to open it if the fitting of the sealing part is strengthened so that the content does not leak

[0006] In addition, in the case of the conventional one-piece structure cap, if only a part of the connecting bridge is disconnected, it is easy to leak.

That is, along with the opening operation, before becoming the state where all the connecting bridges are disconnected, only a part of the connecting bridges will be disconnected or elongated, while the other parts of the connecting bridges will remain as they are, and the cover in this state is easy to tilt, And if the cover is tilted, there is a problem of easy leakage

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