Electrostatic transducer for length measurement system
US4438402A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1981 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Jun 26, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/044
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-contacting electrostatic mark/sense length measurement gauge is used to place discrete areas of electrostatic charge at very accurately spaced intervals along a relatively moving material surface. Special construction of both the electrostatic marking and sensing transducers is employed. To compensate for expected unreliability of the mark/sense length gauge, a conventional highly reliable but less accurate contacting length gauge (such as a tachometer in rolling contact with the relatively moving material) is employed. The output from the electrostatic mark/sense length gauge and from the tachometer length gauge are combined by special electronic circuits to provide a length measurement of the passing material which is both highly accurate and reliable under all expected measurement conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.