Stopper for beverage container

1. A stopper for a beverage container comprising:

a stopper main body that attaches to an upper opening of a beverage container main body and comprises a liquid through hole on the inside thereof;

a lid that is axially supported by a hinge shaft that is provided at an end of the stopper main body, and which opens and closes the liquid through hole in a rotational manner;

wherein the hinge shaft connects a hinge portion of the stopper main body with right and left hinge portions of the lid, wherein the hinge portion of the stopper main body is axially aligned between the right and left hinge portions;

a storage portion is provided in the hinge portion of the stopper main body;

a torsion spring is housed in the storage portion;

a cover member covers an opening of the storage portion;

the torsion spring and the cover member are integrated with the hinge portion of the stopper main body and the right and left lid hinge portions by the hinge shaft, the cover member rotatable with respect to the hinge portion of the stopper main body; the hinge portion of the stopper main body and the cover member enclose the torsion spring; arm portions, which are provided at both end portions of the torsion spring, are respectively freely fitted into a fixed groove which is provided in the storage portion, and a latching groove which is provided in the cover member; and,

the lid is biased toward an opening direction by a connection portion of the cover member abutting against a connection receiving portion of the lid.

2. The stopper for a beverage container according to claim 1 , wherein the latching groove and the fixed groove are not exposed to an outer surface regardless of a position of the lid.

3. The stopper for a beverage container according to claim 1 , wherein an interval between the storage portion and the cover member is less than or equal to a wire diameter of the torsion spring.

4. The stopper for a beverage container according to claim 1 ,

wherein a lid closure prevention projection having a convex shape is formed on a back side of the outer surface of the hinge portion of the stopper main body,

a thin plate-shaped lid closure prevention plate is formed on the lid; and

the lid closure prevention plate abuts against the lid closure prevention projection.

5. A beverage container comprising the stopper according to claim 1 .

6. A beverage container comprising the stopper according to claim 1 , wherein the stopper main body attaches to the upper opening of the beverage container main body.

7. A stopper for a beverage container comprising:

a stopper main body comprising a liquid through hole;

a lid that is axially supported by a hinge shaft that is provided at an end of the stopper main body, and which opens and closes the liquid through hole in a rotational manner;

wherein the hinge shaft connects a hinge portion of the stopper main body with right and left hinge portions of the lid, wherein the hinge portion of the stopper main body is axially aligned between the right and left hinge portions;

a storage portion is provided in the hinge portion of the stopper main body;

a torsion spring is housed in the storage portion;

a cover member covers an opening of the storage portion, the opening of the storage portion positioned on either a right side of an axial direction of the torsion spring or on a left side of the axial direction of the spring, and the hinge portion of the stopper main body and the cover member enclose the torsion spring;

the torsion spring and the cover member are integrated with the hinge portion of the stopper main body and the lid hinge portion by the hinge shaft, the cover member rotatable with respect to the hinge portion of the stopper main body;

arm portions, which are provided at both end portions of the torsion spring, are respectively fitted to the storage portion and the cover member; and,

the lid is biased toward an opening direction by a connection portion of the cover member abutting against a connection receiving portion of the lid.