| 摘要 |
PURPOSE: To obtain a stable hermetical sealing of an inner cap with a writing instrument body by forming an air passage with the atmosphere of a shelf and the protrusion of the end of a space made of the inner wall of a head plug and the end of an inner cap and a space made of the inner wall of an external facing cap and the outer wall of the inner cap. CONSTITUTION: When an inner cap 3 is brought into contact with a writing instrument body, the contact of the protrusion 10 of the end 7 of the cap 3 is removed from the shelf 6 of the inner wall of a head plug 2, and the airs of a space S and a space H are compressed. The compressed air flows to the space H via a trough 9 provided at the shelf 6 and releases to the atmosphere. Eventually, when the body is finished to be mounted at the cap 1, the cap 3 is elastically supported by an elastic member 8, hermetically brought into contact with the hermetical seal part of the body and the hermetical seal part of the lower opening of the cap 3, and the cap 3 is supported at a point. The space H communicates with the space S in such a state, the air smoothly moves, and the air can release on when the air in the cap 3 expands. |
