Eddy current nondestructive testing device using an oscilloscope to identify and locate irregularities in a test piece

Claim 1

A DEVICE FOR NONDESTRUCTIVELY TESTING A SAMPLE COMPRISING: (1) A PROBE INCLUDING FIRST AND SECOND INDUCTIVE IMPEDANCES; (2) MEANS FOR PROVIDING RELATIVE MOTION BETWEEN SAID PROBE AND SAID SAMPLE; (3) SAID FIRST AND SECOND INDUCTIVE IMPEDANCES OF SAID PROBE BEING FIXEDLY SPATIALLY MOUNTED WITH RESPECT TO EACH OTHER ALONG THE DIRECTION OF RELATIVE MOTION BETWEEN SAID PROBE AND SAID SAMPLE; (4) MEANS, INCLUDING REFERENCE OSCILLATOR MEANS ENERGIZING SAID FIRST AND SECOND INDUCTIVE IMPEDANCES WHEREBY SAID IMPEDANCES ELECTROMAGNETICALLY COUPLE WITH SAID MATERIAL, FOR GENERATING A SIGNAL REPRESENTATIVE OF THE DIFFERENCE IN CURRENT FLOWING IN SAID INDUCTIVE IMPEDANCES, SAID DIFFERENCE SIGNAL VARYING IN PHASE AND AMPLITUDE WITH RESPECT TO SAID REFERENCE OSCILLATOR WHEN SAID IMPEDANCES TRAVERSE AN IRREGULARITY IN SAID MATERIAL; (5) MEANS FOR DETECTING SAID DIFFERENCE SIGNAL INCLUDING: (A) MEANS RECEIVING THE OUTPUT SIGNAL OF SAID REFERENCE OSCILLATOR FOR GENERATING FIRST AND SECOND DETECTING SIGNALS IN PHASE QUADRATURE, AND FOR SHIFTING THE PHASE OF SAID FIRST DETECTING SIGNAL SUCH THAT IT IS IN PHASE WITH THE NOISE ON SAID DIFFERENCE SIGNAL WHEN SAID PROBE WOBBLES RELATIVE TO A FLAWLESS MATERIAL; (B) MEANS RECEIVING SAID DIFFERENCE SIGNAL AND SAID QUADRATURE DETECTING SIGNALS FOR ADDING SAID DIFFERENCE SIGNAL TO EACH OF SAID QUADRATURE DETECTING SIGNALS; (C) MEANS RECEIVING THE OUTPUT SIGNALS OF SAID ADDING MEANS FOR GENERATING UNIDIRECTIONAL VOLTAGES REPRESENTATIVE OF THE AMPLITUDES OF THE ADDED SIGNALS; AND (6) RECORDING MEANS INCLUDING A SCREEN AND A LIGHT SPOT ADAPTED TO MOVE ON SAID SCREEN, SAID RECORDING MEANS RECEIVING THE OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS AND MOVING THE LIGHT SPOT IN ONE DIRECTION ON SAID SCREEN RESPONSIVE TO ONE OF SAID OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS AND IN A TRANSVERSE DIRECTION RESPONSIVE TO THE OTHER OF SAID OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS; WHEREBY THE LOCUS OF SAID LIGHT SPOT GENERATES A DISPLAY WHICH SERVES TO IDENTIFY AND DETERMINE THE LOCATION OF IRREGULARITIES IN SAID MATERIAL AS THEY ARE TRAVERSED BY SAID PROBE.

Claim 2

A DEVICE FOR NONDESTRUCTIVELY TESTING A SAMPLE COMPRISING: (1) A PROBE INCLUDING FIRST AND SECOND INDUCTIVE IMPEDANCES; (2) MEANS FOR PROVIDING RELATIVE MOTION BETWEEN SAID PROBE AND SAID SAMPLE; (3) SAID FIRST AND SECOND INDUCTIVE IMPEDANCES OF SAID PROBE BEING FIXEDLY SPATIALLY MOUNTED WITH RESPECT TO EACH OTHER ALONG THE DIRECTION OF RELATIVE MOTION BETWEEN SAID PROBE AND SAID SAMPLE; (4) MEANS, INCLUDING REFERENCE OSCILLATOR MEANS ENERGIZING SAID FIRST AND SECOND INDUCTIVE IMPEDANCES WHEREBY SAID IMPEDANCES ELECTROMAGNETICALLY COUPLE WITH SAID MATERIAL, FOR GENERATING A SIGNAL REPRESENTATIVE OF THE DIFFERENCE IN CURRENT FLOWING IN SAID INDUCTIVE IMPEDANCES, SAID DIFFERENCE SIGNAL VARYING IN PHASE AND AMPLITUDE WITH RESPECT TO SAID REFERENCE OSCILLATOR WHEN SAID IMPEDANCES TRAVERSE AN IRREGULARITY IN SAID MATERIAL; (5) MEANS FOR DETECTING SAID DIFFERENCE SIGNAL INCLUDING: (A) MEANS RECEIVING THE OUTPUT SIGNAL OF SAID REFERENCE OSCILLATOR FOR GENERATING FIRST AND SECOND DETECTING SIGNALS IN PHASE QUADRATURE, AND FOR SHIFTING THE PHASE OF SAID FIRST DETECTING SIGNAL SUCH THAT IT IS IN PHASE WITH THE NOISE ON SAID DIFFERENCE SIGNAL WHEN SAID PROBE WOBBLES RELATIVE TO A FLAWLESS MATERIAL; (B) MEANS RECEIVING SAID DIFFERENCE SIGNAL AND SAID QUADRATURE DETECTING SIGNALS FOR ADDING SAID DIFFERENCE SIGNAL TO EACH OF SAID QUADRATURE DETECTING SIGNALS; (C) MEANS RECEIVING THE OUTPUT SIGNALS OF SAID ADDING MEANS FOR GENERATING UNIDIRECTIONAL VOLTAGES REPRESENTATIVE OF THE AMPLITUDES OF THE ADDED SIGNALS; AND (6) RECORDING MEANS INCLUDING A SCREEN AND A LIGHT SPOT ADAPTED TO MOVE ON SAID SCREEN, SAID RECORDING MEANS RECEIVING THE OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS AND MOVING THE LIGHT SPOT IN ONE DIRECTION ON SAID SCREEN RESPONSIVE TO ONE OF SAID OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS AND IN A TRANSVERSE DIRECTION RESPONSIVE TO THE OTHER OF SAID OUTPUT SIGNALS OF SAID UNIDIRECTIONAL VOLTAGE GENERATING MEANS; WHEREBY THE LOCUS OF SAID LIGHT SPOT GENERATES A DISPLAY WHICH SERVES TO IDENTIFY AND DETERMINE THE LOCATION OF IRREGULARITIES IN SAID MATERIAL AS THEY ARE TRAVERSED BY SAID PROBE.