Automatic level control system for earth moving machines

Claim 1

An apparatus in combination with a bulldozer blade for the automatic control thereof comprising a horizontally rotatable support means, an image receiving device rotatably mounted on said support means for varying the angle of elevation of said image receiving device wherein a light source is mounted on said blade and the image of said light source mounted on the blade is formed on an image receiving surface of said image receiving device having photoelectric converter elements provided thereon within a longitudinal bandlike space therebetween and a second image receiving surface is provided at said image receiving device having photoelectric converter elements provided thereon with a lateral bandlike space therebetween, means for detecting deviation of the actual height of the blade on a moving bulldozer from a desired excavation locus, said means further converting the deviation into an electric signal in accordance with the relationship between the lateral bandlike space of said second image receiving surface and the position where the image of said light source is formed and transmitting said electric signal, a blade operating cylinder being operatively connected with said blade, a hydraulic circuit being connected with said blade operating cylinder, a solenoid valve being arranged in said hydraulic circuit for control of the desired raising and lowering of said blade, means receiving said electric signal to control said solenoid valve in said hydraulic circuit means for detecting the difference between the actual visual direction of the moving bulldozer and the optical axis of the image receiving device in accordance with the relationship between the longitudinal bandlike space of the first image receiving surface and the position where the image of said light source on said blade is formed and converting it into an electric signal to thereby control a servomotor for rotating the support means, a potentiometer operatively associated with said image receiving device for detecting the angle of elevation thereof, an external commanding device operatively associated with said image receiving device for externally commanding The angle of elevation thereof, and means for changing the angle of elevation of said image receiving device in accordance with signals from said potentiometer and said external commanding device.

Claim 2

An apparatus in combination with a bulldozer blade for the automatic control thereof comprising a horizontally rotatable support means, an image receiving device rotatably mounted on said support means for varying the angle of elevation of said image receiving device wherein a light source is mounted on said blade and the image of said light source mounted on the blade is formed on an image receiving surface of said image receiving device having photoelectric converter elements provided thereon within a longitudinal bandlike space therebetween and a second image receiving surface is provided at said image receiving device having photoelectric converter elements provided thereon with a lateral bandlike space therebetween, means for detecting deviation of the actual height of the blade on a moving bulldozer from a desired excavation locus, said means further converting the deviation into an electric signal in accordance with the relationship between the lateral bandlike space of said second image receiving surface and the position where the image of said light source is formed and transmitting said electric signal, a blade operating cylinder being operatively connected with said blade, a hydraulic circuit being connected with said blade operating cylinder, a solenoid valve being arranged in said hydraulic circuit for control of the desired raising and lowering of said blade, means receiving said electric signal to control said solenoid valve in said hydraulic circuit means for detecting the difference between the actual visual direction of the moving bulldozer and the optical axis of the image receiving device in accordance with the relationship between the longitudinal bandlike space of the first image receiving surface and the position where the image of said light source on said blade is formed and converting it into an electric signal to thereby control a servomotor for rotating the support means, a potentiometer operatively associated with said image receiving device for detecting the angle of elevation thereof, an external commanding device operatively associated with said image receiving device for externally commanding The angle of elevation thereof, and means for changing the angle of elevation of said image receiving device in accordance with signals from said potentiometer and said external commanding device.