Apparatus for ultrasonic testing

Claim 1

APPARATUS FOR ULTRASONIC ECHO TESTING OF A BODY HAVING A RIB ON A SURFACE THEREOF, COMPRISING: (A) A FIRST TRANSDUCER IN OPERATIVE RELATION WITH THE BODY ON ONE SIDE OF THE RIB FOR DIRECTING A PULSED BEAM OF ULTRASONIC WAVES THROUGH THE BODY TOWARD THE RIB AND FOR RECEIVING REFLECTED PULSES FROM DISCONTINUITIES IN THE BODY OR FROM THE OPPOSITE SIDE OF THE RIB; (B) A SECOND TRANSDUCER ALIGNED WITH SAID FIRST TRANSDUCER IN OPERATIVE RELATION WITH THE BODY ON THE OPPOSITE SIDE OF THE RIB FOR DIRECTING A SECOND PULSED BEAM OF ULTRASONIC WAVES THROUGH THE BODY TOWARD THE RIB FROM SAID OPPOSITE SIDE AND FOR RECEIVING REFLECTED PULSES FROM DISCONTINUITIES IN THE BODY OR FROM SAID ONE SIDE OF THE RIB; (C) INDICATING MEANS RESPONSIVE TO PULSES RECEIVED AT SAID TRANSDUCERS; (D) MEANS FOR ALTERNATELY ENERGIZING THE TRANSDUCER AT SEPARATED INTERVALS, COMPRISING: (1) A BISTABLE CIRCUIT HAVING A PAIR OF COMPLEMENTARY PULSES OUTPUT TERMINALS SUCH THAT PULSES ARE GENERATED ALTERNATELY AT THE TERMINALS; (2)TWO DRIVERS, ONE FOR EACH OF THE TRANSDUCERS; AND (3) TWO CONNECTIONS FROM SAID PAIR OF COMPLEMENTARY PULSE OUTPUT TERMINALS TO SAID DRIVERS, SO THAT THE TRANSDUCERS ARE ALTERNATELY ENERGIZED BY THE DRIVERS AT SEPARATED INTERVALE DETERMINED BY THE SPACING OF THE PULSES GENERATED BY THE BISTABLE CIRCUIT; (E) BLOCKING MEANS EFFECTIVE UPON THE ENERGIZATION OF EACH TRANSDUCER AND UNTIL THE ENERGIZATION OF THE OTHER TRANSDUCER TO PREVENT RESPONSIVE OF THE SAID INDICATING MEANS TO PULSES RECEIVED AT THE OTHER TRANSDUCER, COMPRISING: (1) A PAIR OF COMPLEMENTARY SQUARE WAVE OUTPUT TERMINALS FORMING A PART OF SAID BISTABLE CIRCUIT AND GENERATING ALTERNATE SQUARE WAVE SIGNALS BY SAID BISTABLE CIRCUIT; AND GENERATED BY SAID BISTABLE CIRCUIT; AND (2) TWO COINCIDENCE CIRCUITS EACH HAVING TWO INPUTS AND AN OUTPUT, ONE INPUT OF EACH COINCIDENCE CIRCUIT BEING CONNECTED TO ONE OF THE TWO TRANDUCERS, AND THE OTHER INPUT OF EACH COINCIDENCE CIRCUIT BEING CONNECTED TO ONE OF THE SQUARE WAVE OUTPUT TERMINALS OF THE BISTABLE CIRCUIT, SO THAT UPON ENERGIZATION OF ONE TRANSDUCER THE TRANSMISSION OF PULSES FROM THE COINCIDENCE CIRCUIT CONNECTED TO THE OTHER TRANSDUCER IS BLOCKED UNTIL ENERGIZATION OF SAID OTHER TRANSDUCER.