| 摘要 |
<p>The piston of a door control device is assembled from a channel (18) and cups (20, 28) welded on to opposite ends of the channel. A valve assembly (19) is mounted in one of the cups. Rollers (17) extend between opposite sides of the channel and co-operate with teeth (16) on a rotatable member (13) to which a control arm is secured.</p> |
