Sensor apparatus
US4637265A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1985 |
| Grant date | Jan 20, 1987 |
| Priority date | — |
| Expiry date | Jul 22, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L3/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Sensor apparatus which uses non-contacting, inductance coil sensors to transfer information about a parameter being monitored from a moving member to an indicator mechanically isolated from the moving member. The inductance coil sensors each have a stationary tank circuit and a movable tank circuit which are inductively coupled to produce a double resonance curve for the stationary tank circuit. The parameter is sensed by a unit having inductively coupled components. This unit is connected to the moving tank circuit to change the inductance of the moving tank circuit in accordance with changes in the inductive coupling of the sensing unit which, in turn, are dependent upon the parameter being monitored. As the inductance of the moving tank circuit changes, the relative frequency, amplitude and phase characteristics of the resonance peaks of the stationary tank circuit change. The degree of change of these characteristics is a measure of parameter. In order to reduce or eliminate common mode errors, the sensing unit is arranged to develop oppositely directed signals which are time multiplexed to produce difference signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.