| 摘要 |
<p>A door system (11, 12, 21, 22), in a frame (10, 20), that uses any wind pressure to keep the door shut, insted of blowing it open. This is achieved by-when at its limit of travel in the shut position-presenting a greater effective surface area on (21) than on (22). The other side of the door system has the same properties.</p> |
