Alarm box with compressed gas fog-horn - has spring-loaded actuating mechanism released by breaking small piece of glass with hammer

摘要

The fog horn comprises a support (1) to which a lever (2) is attached. The free end of the lever presses against a small piece of glass (11) held between two runners (6, 7). The support also holds a striker (3) which is biased by a spring (4). A second spring (5) urges the lever against the glass (11). When the piece of glass is broken by a hammer which is provided, the lever is able to move in the direction determined by the second spring (5). This releases the striker which operates the fog horn. The horn may be powered by a compressed gas cylinder and requires no electrical supply. The horn is stopped by opening the door of the housing.