초록 ▼

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 calibr

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. Displays are provided for the operator of the vehicle to show what type of adjustments are being made to the blade, and whether the height of the reference surface is outside the range of sensitivity of the follower. The follower is automatically calibrated for a given blade depth by repeated incrementation of a delay time variable until a zero adjustment command is generated for the blade control.

대표청구항 ▼

In a machine such as a paver or grader carrying a vertically adjustable blade at a chosen depth relative to a reference surface having a variable height, an apparatus for automatically adjusting the blade for maintaining the blade at the chosen depth, including: a follower connected to the blade at

In a machine such as a paver or grader carrying a vertically adjustable blade at a chosen depth relative to a reference surface having a variable height, an apparatus for automatically adjusting the blade for maintaining the blade at the chosen depth, including: a follower connected to the blade at a position above the reference surface; means coupled to said follower for generating acoustic pulses toward the reference surface for reflection thereby; processor coupled to said generating means and including means for controlling said generation of said acoustic pulses; a memory coupled to said processor and storing control words relating to instructions for vertically adjusting the blade; means for detecting said acoustic pulses at said follower after reflection by the reference surface; a counter means coupled to said processor for generating a count related to a length of time taken by said acoustic pulses to be reflected back to said detecting means; means for using said count to retrieve a control word stored in said memory; means for calibrating said adjusting apparatus while said follower is at a selected height above said reference surface, such that, when the blade is at the chosen depth, said count related to a predetermined control word in said control table relating to a zero adjustment instruction for the blade; means coupled to said processor for causing said generating means to repeatedly generate said acoustic pulses after said calibration for repeatedly generating further counts relating to lengths of time taken by said acoustic pulses to be reflected back to the follower, such that said further counts relate to control words stored at locations of said memory corresponding to variations in the height of the reference surface; and further including means carried by the grader for vertically adjusting the blade; and means for providing said control word as instructions to said adjusting means for automatically following said variations in the height of the reference surface.