Position indexing of symbol(s) on movable component - using proximity detectors to detect zones of different material

摘要

The position of a symbol or group of symbols on a movable component, w.r.t. a reference point, is decoded, while the component is stationary or moving, using a proximity detector which is fixed w.r.t. the reference point and which detects a zone of predetermined material on the component facing the symbol(s). The component may have a surface of electrically non-conductive material and a zone of metal or the component surface and the zone may be of different metals. The detector allows simple and instantaneous indexing of movable components without using measuring devices which lose their accuracy or are subject to continuous wear.