| 摘要 |
<p>A lock for a door comprises a casing, a bolt operable to extend from or retract into the casing, a pivoted operating handle operable at one side of the door to retract the bolt, lock means for key operation at the other side of the door, and blocking means to prevent operation of the handle to retract the bolt. In a locked closed position of the door, the bolt is extended, and with the blocking means operated, key operation of the exterior lock means both retracts the bolt and also de-actuates the blocking means. At the inside of the door further key operable lock means are provided solely to operate and, if required, to de-actuate, the blocking means. A casting secured in the casing mounts the further lock means, provides part-bearings for pivot rods of the handle and a bolt locking element, provides a guide slot for a spring-like connector linking the handle to the bolt locking element, and provides a pair of arms between which slides a bolt release member and against which bears one end of a biasing spring around part of the bolt release member.</p> |
