Magnetomechanical transducers utilizing resonant frequency shifts to measure displacement of an object
US4710709A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1983 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Nov 4, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/0029
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A target adapted for use in a magnetomechanical transducer system is activated by an ac magnetic field and a variable dc bias field to produce a resonant frequency which corresponds to the effective strength of the dc bias field. The target includes an elongated ductile strip of magnetostrictive ferromagnetic material enclosed in a nonmagnetic container in a manner to allow the strip to vibrate freely. The strip has a magnetomechanical coupling factor, k.sub.1 greater than O, where k=(1-fr.sup.2 /fa.sup.2)1/2, fr and fa being the resonant and antiresonant frequencies, respectfully. The system is economical to construct and affords accurate and efficient measurement of displacements and angles at locations proximate to or remote from the signal source (target).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.