Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temperature variations as the grading takes place.

Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temperature variations as the grading takes place.

Abstract: A method and apparatus for automaticlly controlling the position of a tool carried by a machine, which in the preferred embodiment may be the blade of a grader or paver for leveling a surface at a chosen depth. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface.

Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temperature variations as the grading takes place.

Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temeprature variations as the grading takes place.