Ultrasonic inspection

Claim 1

ULTRASONIC INSPECTION APPARATUS WHICH COMPRISES: RATE GENERATOR MEANS ADAPTED TO GENERATE PERIODIC TIMING PULSES OF ELECTRICAL ENERGY; PULSE GENERATOR MEANS RESPONSIVE TO THE OUTPUT OF SAID RATE GENERATOR MEANS TO GENERATE A RADIO FREQUENCY PULSE IN RESPONSE TO EACH TIMING PULSE; AN ELECTRO-MECHANICAL TRANSDUCER IN ENERGIZABLE RELATIONSHIP FROM SAID PULSE GENERATOR MEANS AND POSITIONED TO DIRECT MECHANICAL WAVE ENERGY INTO A WORKPIECE THROUGH AN ENTRANT SURFACE THEREOF AND TO RECEIVE REFLECTED MECHANICAL WAVE ENERGY THEREFROM TO PRODUCE ELECTRICAL ECHO SIGNALS CORRESPONDING THERETO; A NORMALLY CLOSED INTERFACE GATE AMPLIFIER CONNECTED TO RECEIVE THE ELECTRICAL ECHO SIGNALS FROM SAID TRANSDUCER; INTERFACE GATE CLOSED SIGNAL GATE AMPLIFIER CONNECTED TO RECEIVE THE ELECTRICAL ECHO SIGNALS FROM SAID TRANSDUCER; INTERFACE GATE CONTROL MEANS CONNECTED TO OPEN SAID INTERFACE GATE AMPLIFIER; DELAY MEANS CONNECTED TO RECEIVE TIMING PULSES FROM SAID RATE GENERATOR MEANS AND ENERGIZE SAID GATE CONTROL MEANS A PREDETERMINED TIME AFTER EACH OF SAID TIMING PULSES; BISTABLE SIGNAL GENERATING MEANS RESPONSIVE TO SAID RATE GENERATOR MEANS TO PRODUCE A FIRST STABLE OUTPUT UPON RECEIPT OF A TIMING PULSE THEREFROM AND RESPONSIVE TO SAID INTERFACE GATE AMPLIFIER TO PRODUCE A SECOND STABLE OUTPUT UPON RECEIPT OF TRANSDUCER ELECTRICAL ECHO SIGNALS PASSED THERETHROUGH; SIGNAL GATE CONTROL MEANS CONNECTED TO OPEN SAID SIGNAL GATE AMPLIFIER IN RESPONSE TO A SECOND STABLE OUTPUT FROM SAID BISTABLE GENERATING MEANS; UTILIZATION MEANS ACTUABLE BY ELECTRICAL ECHO SIGNALS FROM SAID TRANSDUCER PASSED THROUGH SAID SIGNAL GATE AMPLIFIER; AND TRANSDUCER SCANNING CONTROL MEANS RESPONSIVE TO THE OUTPUT OF SAID BISTABLE SIGNAL GENERATING MEANS TO VARY THE RELATIVE SCANNING PATTERN BETWEEN SAID TRANSDUCER AND SAID WORKPIECE AFTER CONTINUATION OF A FIRST STABLE OUTPUT FOR A PRESELECTED TIME PERIOD.