Inventors:
Robert D. Herman - Chicago IL
International Classification:
G01C 906
Abstract:
An angular orientation detector and indicator has a plumb bob suspended in a vertically extending chamber of a housing. A beam of radiation is emitted across the chamber from a beam emitter to a beam receiver and the plumb bob is swingable through a beam path extending between the emitter and receiver. When the housing of the detector is positioned in a preselected angular orientation the plumb bob comes to rest blocking the beam path to substantially reduce or prevent the radiated beam from being received by the receiver. An electrically actuated signal, such as an audible or visual signal, or both, is thereby actuated to indicate that the detector is at a preselected angular orientation. Such detectors may be mounted on builder's levels to indicate when the level is in a preselected angular orientation, such as a horizontal or vertical orientation. Other embodiments and useful applications of such detectors are also disclosed.