| 摘要 |
PROBLEM TO BE SOLVED: To increase a degree of freedom of design for the turn working part and to enable the part to have a dihedral width function and a knurling function about the writing utensil with turn working part. SOLUTION: A plug 3 is fixed by means of screwing at the opening of a tube 2. A turn working part 31 is installed on the outer spherical surface of the plug 3 (tail plug or pen holder). The turn working part 31 consists of a dihedral width part where a spanner can be used. The dihedral width part consists of plural projection parts 31a arranged on the outer spherical surface of the plug 3 at a proper interval in the circular direction. |
