| 摘要 |
A system for locking a door can: (1) lock the door in dead bolt fashion in three modes, (2) allow the door to open a limited distance, or (3) allow the door to open freely. The system has a door-mounted latch assembly that includes a base plate, an intermediate link pivoted to the base plate, and a mode selection and latching assembly that is pivoted to the intermediate link. A latch plate is mounted on the door frame in juxtaposition to the door-mounted latch assembly. The latch plate has a tubular portion with an opening for receiving the latch member. A sleeve fits inside the tubular portion of the latch plate. When the latch member is engaged in the tubular portion of the latch plate, the sleeve can be rotated so that the latch member is engaged to the sleeve in a secured position. The latch plate includes a locking mechanism to releasably lock the sleeve into the secured position. The locking mechanism may be a spring-loaded pin mounted within the sleeve. When the sleeve is rotated into a secured position, the head of the spring-loaded pin protrudes through apertures in the sleeve and in the tubular portion of the latch plate, thereby preventing the sleeve from rotating. The locking mechanism may alternatively be a protrusion and slot system. A mechanism is also provided for locking and unlocking the locking system from the exterior of the door.
|
