Self-leveling and grade setting laser apparatus

摘要

A pivotally-mounted laser or other collimated light beam source is maintained in a level position by means of a thermal motor capable of precise small movements. Actuation of the motor is accomplished by a control amplifier whose inputs are responsive to the output of a level-sensitive transducer. Pre-selected grades may be established and maintained by means of a second thermal motor which is employed to change the angular relationship between the pivotally mounted laser or light source and the level-sensitive transducer.