Magnetic testing probe with mutually perpendicular energizing and pickup coils, the latter surrounding the former

Claim 1

IN A DEVICE FOR DETECTING NON-HOMOGENEITY IN METALS THE COMBINATION OF: AN ELONGATED PROBE ELEMENT HAVING A CENTRAL LONGITUDINAL AXIS TERMINATING IN AN OUTER PROBE END THEREOF, SAID ELEMENT INCLUDING ENERGIZING AND PICKUP COILS POSITIONED ALONG SAID AXIS WITH THE PICKUP COIL IN ONE END OF SAID ENERGIZING COIL AND AT A RIGHT ANGLE TO SAID AXIS, SAID ENERGIZING COIL FURTHER BEING IN COAXIAL ALIGNMENT WITH AND SURROUNDING SAID PROBE ELEMENT AND SAID PICKUP COIL BEING LOCATED AT THE OUTER END THEREOF, SAID PICKUP COIL THEREBY BEING IN THE CENTER OF THE MAGNETIC FIELD AND FLUX PATH OF SAID ENERGIZING COIL TO RECEIVE MAXIMUM EXCITATION THEREFROM IN RESPONSE TO SIGNAL CURRENT APPLIED THERETO, MEANS CONNECTED WITH SAID ENERGIZING COIL FOR APPLYING SIGNAL CURRENT TO SAID COIL TO ESTABLISH A UNIFORM MAGNETIC FIELD IN SAID FLUX PATH AND THROUGH SAID COIL AND PROBE END, AND MEANS CONNECTED WITH SAID PICKUP COIL FOR DETECTING SIGNAL CURRENTS INDUCED IN SAID COIL BY THE PRESENCE OF METAL AT SAID OUTER END OF THE PROBE ELEMENT AND RESULTANT DISTORTION IN THE MAGNETIC FIELD OF SAID ENERGIZING COIL AND FLUX THROUGH SAID PICKUP COIL DUE TO NON-HOMOGENEITY IN SAID METAL.