Angle encoder for encoding the zenithal angle between a variable determined direction and the vertical, in particular for a theodolite

US4664519A · kind A · utility

Assignee

• Societe d'Etudes, Recherches et Constructions Electroniques - Sercel · FR

Inventors

• Francois Hullein · Nantes, FR
• Jacques Bodin · Levallois-Perret, FR

Key dates

• Filing date: Jan 24, 1985
• Grant date: May 12, 1987
• Expiry date: Jan 24, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G01C1/06
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The encoder comprises a pendulum (P) mounted to rotate about a horizontal is (O-O) which is substantially coaxial with a reference axis (R-R) of an index disk and which carries vertical optical detector equipment (T.sub.M.pi.E, T.sub.M.pi.R, T.sub.MOE, T.sub.MOR), optical guidance means (M.sub.1, M.sub.2, M.sub.3, M.sub.4, T.sub.5) fixed to the pendulum and suitable for guiding radiation generated by an optical transmitter (T.sub.M.pi.E) towards an associated optical receiver (T.sub.M.pi.R) along a predetermined optical path intersecting the disk (D), and a liquid level forming device (L) fixed to the pendulum (P) and inserted on the optical path upstream from the said point of interception between the optical path and the disk, the said optical guidance means (M.sub.1, M.sub.2, M.sub.3, M.sub.4, M.sub.5) and the liquid level forming device (L) being adapted to ensure an angular deviation of the point of intersection of the light radiation and the disk relative to the pivot axis (O-O) which compensates the angular shift between the pendulum (P) and the vertical.