| 摘要 |
A sleeve (1) has breakable wings (11) directed inwardly. A piston (5) has an external projection (12) which rests on the wings. The piston with a puncturing tip is slidably mounted in the sleeve. A drive spring (9) is positioned between a pushing piece (2) and the piston. A return spring (10) is positioned inside the sleeve between one end of the sleeve and the piston. |
