Method of and apparatus for detecting damage to a frangible object
OwnerErnst Spiriginventor
Life of this patent
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Abstract
Damage to a frangible article, particularly a glass window is detected by sensors responsive to oscillations in different frequency bands. Only when all the sensors are simultaneously responsive is an alarm signal, denotive of damage to the article, developed. Piezo-ceramic transducers respond to frequencies within the range of 30 kHz to 1 MHz. The sensors are connected in parallel with inductors to provide resonant amplification of the voltage developed. The resultant signals are amplified and applied to an AND gate yielding the required output signal.
Claims12
The method of detecting breakage of a frangible object which comprises detecting ultrasonic oscillations occurring in said object in each of a plurality of mutually distinct frequency ranges, and developing a signal denotive of said breakage when oscillations are detected simultaneously in all said frequency ranges.
Apparatus for detecting breakage of a frangible object, comprising a plurality of ultrasonic transducers coupled to said object to respond to ultrasonic vibrations in different respective frequency ranges occurring therein, circuit means yielding a breakage-denotive output signal in response to the simultaneous application of signals to a plurality of inputs thereof and means applying the signal from each said transducer to a respective input of said circuit means whereby said breakage-denotive output signal is developed.
Dependencies are inferred from the claim text.