| 摘要 |
<p>A lock for a door comprising a casing, a bolt operable to extend from or retract into the casing and manually operable bolt retention means to retain the bolt in its retracted state even when an automatically operating bolt holding member is released by inwards movement of a bolt release member. The bolt retention means comprises a snib having a part receivable in an opening in the bolt when the bolt is manually moved into the case from its normally retracted position. Once the snib part is in the opening and the inwards force on the bolt removed, the spring acting on the bolt moves the bolt to its normally retracted position, where it is then retained by the snib. To release the retention, the bolt is again moved further into the case, whereupon the snib part is moved clear of the bolt opening under spring bias, and the unretained bolt is moved by its bias to its normally retracted position.</p> |
