Magnetoacoustic proximity sensor
US4709210A · kind A · utility
Inventor
Key dates
| Filing date | May 2, 1985 |
| Grant date | Nov 24, 1987 |
| Priority date | — |
| Expiry date | May 2, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/952
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A new form of proximity sensor is described which enables sensing of magnetic and/or metallic objects over an extended region of space. The time-varying magnetic field necessary for proximity sensing is provided by a strain wave propagating at acoustic velocity in a waveguide composed of magnetized magnetostrictive material. The propagating strain wave carries with it a disturbance in the magnetic field in the region of the waveguide. A single, elongated sensing coil is located in the same plane as the acoustic waveguide and senses changes in the flux passing through the coil when magnetic and/or metallic objects or targets are present near the waveguide. The spatial location of the targets along the length of the proximity sensor can be determined by measuring the time interval from the initial application of the strain wave until the signal corresponding to the target is induced in the sensing coil. Multiple objects can be sensed by measuring the time interval for each signal. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.