Amplitude measuring devices for high frequency vibrations

Claim 1

A DEVICE FOR MEASURING THE AMPLITUDE OF VIBRATION OF A MEMBER WHICH IS VIBRATED SUBSTANTIALLY AT A SELECTED ONE OF A PLURALITY OF PREDETERMINED HIGH FREQUENCIES; SAID DEVICE COMPRISING A HOUSING HAVING A PICKUP COIL AND A COAXIAL ANNULAR PERMANENT MAGNET THEREIN WHICH COOPERATE WITH THE HOUSING TO DEFINE A BORE OPENING AT ONE END OF THE HOUSING, A MAGNETOSTRICTIVE ROD SELECTED FROM A PLURALITY OF INTERCHANGEABLE MAGNETOSTRICTIVE RODS EACH BEING RESONANT AT A CORRESPONDING ONE OF SAID PREDETERMINED HIGH FREQUENCIES SO THAT A SELECTED ROD WHICH IS RESONANT AT THE SELECTED HIGH FREQUENCY WITH WHICH THE MEMBER IS VIBRATED WILL BE SIMILARLY VIBRATED BY RELATIVELY LIGHT CONTACT, AT ONE END, WITH THE VIBRATED MEMBER, SAID SELECTED ROD BEING INSERTED IN SAID BORE, MEANS AXIALLY LOCATING THE SELECTED MAGNETOSTRICTIVE ROD WITH RESPECT TO SAID HOUSING SO THAT SAID ONE END OF THE ROD PROJECTS FROM THE HOUSING AND SAID MAGNET AND COIL ARE IN SURROUNDING RELATION TO THE SELECTED ROD TO POLARIZE THE LATTER AND TO HAVE AN ALTERNATING VOLTAGE INDUCED IN THE COIL WHICH IS A FUNCTION OF THE AMPLITUDE OF VIBRATION OF THE CONTACTED MEMBER, AT LEAST SAID SELECTED ROD HAVING A REDUCED DIAMETER PORTION WHICH EXTENDS THROUGH SAID PICK-UP COIL WHEN THE ROD IS INSERTED IN SAID BORE TO PROVIDE A MAGNIFICATION FACTOR INCREASING THE RELATION BETWEEN THE OUTPUT OF SAID PICK-UP COIL AND THE AMPLITUDE OF THE MEASURED VIBRATIONS, A MICROAMMETER CALIBRATED TO INDICATED AMPLITUDE OF VIBRATION, AND A METER CIRCUIT CONNECTING SAID AMMETER TO SAID PICK-UP COIL AND HAVING CURRENT RECTIFYING MEANS THEREIN, SAID PICK-UP COIL HAVING A LARGE NUMBER OF TURNS MATCHING THE IMPEDANCE OF SAID AMMETER AND CIRCUIT.

Claim 2

A DEVICE FOR MEASURING THE AMPLITUDE OF VIBRATION OF A MEMBER WHICH IS VIBRATED SUBSTANTIALLY AT A SELECTED ONE OF A PLURALITY OF PREDETERMINED HIGH FREQUENCIES; SAID DEVICE COMPRISING A HOUSING HAVING A PICKUP COIL AND A COAXIAL ANNULAR PERMANENT MAGNET THEREIN WHICH COOPERATE WITH THE HOUSING TO DEFINE A BORE OPENING AT ONE END OF THE HOUSING, A MAGNETOSTRICTIVE ROD SELECTED FROM A PLURALITY OF INTERCHANGEABLE MAGNETOSTRICTIVE RODS EACH BEING RESONANT AT A CORRESPONDING ONE OF SAID PREDETERMINED HIGH FREQUENCIES SO THAT A SELECTED ROD WHICH IS RESONANT AT THE SELECTED HIGH FREQUENCY WITH WHICH THE MEMBER IS VIBRATED WILL BE SIMILARLY VIBRATED BY RELATIVELY LIGHT CONTACT, AT ONE END, WITH THE VIBRATED MEMBER, SAID SELECTED ROD BEING INSERTED IN SAID BORE, MEANS AXIALLY LOCATING THE SELECTED MAGNETOSTRICTIVE ROD WITH RESPECT TO SAID HOUSING SO THAT SAID ONE END OF THE ROD PROJECTS FROM THE HOUSING AND SAID MAGNET AND COIL ARE IN SURROUNDING RELATION TO THE SELECTED ROD TO POLARIZE THE LATTER AND TO HAVE AN ALTERNATING VOLTAGE INDUCED IN THE COIL WHICH IS A FUNCTION OF THE AMPLITUDE OF VIBRATION OF THE CONTACTED MEMBER, AT LEAST SAID SELECTED ROD HAVING A REDUCED DIAMETER PORTION WHICH EXTENDS THROUGH SAID PICK-UP COIL WHEN THE ROD IS INSERTED IN SAID BORE TO PROVIDE A MAGNIFICATION FACTOR INCREASING THE RELATION BETWEEN THE OUTPUT OF SAID PICK-UP COIL AND THE AMPLITUDE OF THE MEASURED VIBRATIONS, A MICROAMMETER CALIBRATED TO INDICATED AMPLITUDE OF VIBRATION, AND A METER CIRCUIT CONNECTING SAID AMMETER TO SAID PICK-UP COIL AND HAVING CURRENT RECTIFYING MEANS THEREIN, SAID PICK-UP COIL HAVING A LARGE NUMBER OF TURNS MATCHING THE IMPEDANCE OF SAID AMMETER AND CIRCUIT.