ALARM SYSTEM FOR THE SAFETY OF NON-SWIMMERS
An alarm system for the safety of non-swimmers comprises a portable
transmitter which is adapted to be attached to the body of the non-swimmer
and to be activated on immersion in water, and a receiver adapted to
operate an alarm on receiving the transmitted signal. The transmitted
signal is a mechanical wave having a frequency which is ultrasonic.
Lieb; Solomon Nathan (Johannesburg, ZA) |
December 13, 1972|