Arrangement for measuring a deviation from its line of a movable web of foil
US5047651A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1990 |
| Grant date | Sep 10, 1991 |
| Priority date | — |
| Expiry date | Mar 27, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The arrangement comprises a tracking sensor with a light source, an optical means and a receiver with two photosensitive detectors, as well as a measuring apparatus with a computing unit. The optical means focuses light to provide a beam which falls on a moving web of foil. The tracking sensor may, for example, be installed in a re-winding installation, and during re-winding of the web, senses by means of the beam a marking track which is embossed in the web in the longitudinal direction of the web and which is composed of two different diffraction grating tracks. Each diffraction grating track projects the light diffracted therefrom in a predetermined direction of incidence to a respective detector. The sensed signals supplied by the receiver are converted into a difference signal by the measuring apparatus, and processed to provide correction signals which are supplied to a control means of the re-winding installation in order to compensate for lateral deviation of the moving web of foil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.