Apparatus for detecting the distance between two objects
US5642869A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 1, 1995 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Dec 1, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/931
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical scanner transmits a light beam from the forward end of a moving track vehicle with the beam inclined toward the direction of movement toward another vehicle on the track. A highly reflective retroreflector tape is secured to the rear end of the other vehicle having an effective reflector region offset from the location of the transmission of the beam at the scanner. The angle of inclination and the amount of offset geometry are proportional to the distance between the vehicles. The scanner senses the return beam which is coaxial with the transmitted beam using a Schmitt trigger circuit to sense the threshold level of the returned beam. The resulting output signal is used to stop the moving vehicle at a predetermined spacing from the other vehicle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.