Passive and wireless displacement measuring device
US6656135B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2001 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Feb 20, 2021 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B90/06
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A system that remotely measures displacement between two objects. A passive sensor is affixed between the objects. The internal sensor uses magnetic coupling between two sensor elements to measure their relative displacement. The sensors are either a) a permeable rod and a complimentary coil in parallel with a tuning capacitor; or b) two permeable rods, each having its own surrounding coil and a tuning capacitor. One of the sensor elements is affixed to each object which is to be monitored. When an interrogating device is placed near the sensors, a resonance can be measured whose frequency characteristics change in a reproducible manner with the relative displacement of the sensors. The resulting resonance characteristics can be calibrated in such a way as to enable the displacement of the objects to be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.