ALARM SYSTEM DEVICE Russian patent published in 1994 - IPC

FIELD: communication engineering. SUBSTANCE: alarm device has contact elements 1, relay 2, power supply 3, signalling unit 4, manual turn-on button 5, switch 6 and voltage indicator 7. When heavy thing falls down onto the helmet (it may be fragment of rock, fragments of crashed buildings, etc. ) the movable part of contact element 1 (at least single of many) adjoins motionless part. As a result, power circuit is closed and signalling unit 4 turns on. If user is in extreme situation, for example, he broke his leg or found himself in rock burst and has no capability to become free, he could manually turn on alarm signal by means of button 5. When a person approaches to the object being under high voltage, the electric current is induced in aerial. As a result, short sonic pulse occurs and contacts of switch 6 have to be closed simultaneously, and power is applied to signalling unit 4 which forms short-time signal. EFFECT: widened functional capabilities of the device. 2 dwg