| 摘要 |
<p>A safety and default valve in which a protective cup-shaped cap (11) incorporating a fixed lock (17) is housed freely rotatably on a control cap (16) with at least one engagement zone (17, 17A) for an ordinary operating wrench. A releasable engagement is provided between the bolt (19) of the lock (12) and a groove-like annular seat (18) in the control cap (16).</p> |
