| 摘要 |
<p>The piston (2) slides in a housing between the open and shut positions and its cone face increases between its ends. The lip (3) in the housing and working against it distorts sufficiently on assembly to allow the larger-diameter portion of the piston to the thrust right through it. Part of the lip can be arranged to distort plastically, and it can be closed and annular. The lip can be of metal, and a spring can be mounted on the piston, thrusting it in the shut direction.</p> |
