| 摘要 |
PROBLEM TO BE SOLVED: To enable air to pass through to avoid risks such as suffocation, even when a baby happens to swallow a tail plug by mistake and have it caught in the throat. SOLUTION: In the tail plug 5 which is fitted into the rear end of a barrel 2 filled with ink, in order to prevent the ink from vaporizing, on a writing utensil having a writing tip part such as a marking pen or a ball-point pen fitted on the tip of the utensil 2, a collar part 8 coming into contact with the rear end of the barrel 2, a shaft part 6 fitted into the inner face of the barrel 2 forward of the collar part 8 and an inner hole 7 with a blocked rear end are formed on the shaft part 6. In addition, a lateral hole 6a passing through the outer periphery of the shaft part 6 is formed at a specified spot in the inner hole 7, and an annular protruding part 6a which comes into watertight contact with the inner face of the barrel 2, is formed on the outer periphery of the shaft part 6. Further, a hole part 8a for causing the rear end face of the tail plug 5 to communicate with a contact face with the rear end of the barrel 2 is formed at a specified spot in the collar part 8 of the tail plug 5. |
