| 摘要 |
An engagement member (33) prevents the mounting and removal of a plug (12) when at a third engagement position, and permits the mounting and removal of the plug (12) when at a third extraction position. A prevention member (61) retains the engagement member (33) at the third engagement position when at a second engagement position, and permits the movement of the engagement member (33) when at a second extraction position. An operation member (62) permits the movement of the prevention member (61) when at a first engagement position, and retains the prevention member (61) at the second extraction position when at a first extraction position. |
