| 摘要 |
<p>The double bolt french window lock is housed in two half boxes screwed or riveted together to form a single box. It has two bolts, a fixed frame bolt and a spring loaded bolt which is opened and closed by turning the handle in one direction only. When the handle is turned, a finger engages the shoulder formed at the rear end of the bolt to open it. The bolt is guided by a spindle received in a slot against a spring which returns the bolt when the finger passes the shoulder.</p> |
