| 摘要 |
<p>The door lock uses an aerosol can which when contacted by the bolt (3) of the lock (1) discharges gas so as to cause a whistle (13) to sound. Attached to the frame (6) adjacent to the edge of the door (2) is a strip (4) bent into a U shape, acting as a door catch. One arm (7) is secured to the door frame by screws, and the parallel arm (9) carries an externally threaded tube (10) locked by a ring nut (11). Inside the tube, the aerosol can is inserted, with its base (15) projecting towards the bolt, spaced from it by a short gap (d). When the door is forced from the outside, the bolt is pushed against the aerosol can so that it is operated at the valve end, and gas is expelled into the whistle which is mounted onto the can by a flange (14). In another design, the bolt is forced against a crank arm which is tilted about an axis to operate against the aerosol can which is supported vertically, with an adjusting screw underneath.</p> |
