Measuring displacement between two relatively movable structures
US4694690A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1986 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Jul 30, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for use in measuring relative movement between two structures is described. A support (7) having bores for receiving input and output optical fibres (2, 10) is mounted on a plate (24), secured to one of the structures, at a predetermined position using alignment means (50). A filter (8) is fixed relative to the other structure so that light passing down the input fibre (2) passes through the filter (8) to the output fibre (10). The filter comprises a split field filter so that when light of two wavelengths is transmitted via the input fibre (2), the intensity of light at each wavelength transmitted through the filter (8) depends on the position of the filter relative to the support. An analogue output proportional to the displacement is provided using the transmitted intensities. The invention is particularly applicable to measuring displacement of a railway rail with respect to an underlying structure, and a method and installation for this are described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.