Blade level control apparatus for a grading machine

Claim 1

BLADE LEVEL CONTROL APPARATUS FOR A GRADING MACHINE OF THE TYPE HAVING MAIN SUPPORTING FRAMEWORK MEANS INCLUDING A DEPENDING MAIN FRAMEWORK PORTION HAVING A REARWARDLY FACING SWIVEL CONNECTOR MEANS TAKING THE FORM OF A BALL AND SOCKET JOINT MEANS PROVIDED WITH AND EFFECTIVELY SWIVELLY INTERCONNECTING A REARWARDLY SUBSTANTIALLY LONGITUDINALLY DIRECTED AUXILIARY MOVABLE CIRCLE FRAME MEANS WITH RESPECT TO SAID DEPENDING MAIN FRAMEWORK PORTION, SAID AUXILIARY CIRCLE FRAME MEANS BEING PROVIDED ADJACENT TO ITS REAR END WITH A SUBSTANTIALLY COPLANAR CIRCLE MEMBER CARRYING THEREUNDER A SUBSTANTIALLY COPLANAR AND NORMALLY TRANSVERSELY DIRECTED EARTH SCRAPING AND LEVELING BLADE MEMBER AND BEING PROVIDED WITH ROTORY MOUNTING MEANS AND CONTROLLABLY POWERED DRIVING MEANS FOR EFFECTIVELY ROTATING SAID CIRCLE MEMBER AROUND THE CENTER THEREOF WITH RESPECT TO SAID CIRCLE FRAME MEANS, SAID MAIN SUPPORTING FRAMEWORK MEANS AND LEFT AND RIGHT REAR SIDE PORTIONS OF SAID CIRCLE FRAME MEANS BEING EFFECTIVELY PROVIDED WITH AND ARCUATELY MOVABLE INTERCONNECTED BY A PAIR OF CONTROLLABLY AND INDIVIDUALLY OPERABLE EXTENSION AND RETRACTION ACTUATOR MEANS FOR CONTROLLABLY RAISING AND LOWERING CORRESPONDING REAR SIDE PORTIONS OF SAID CIRCLE FRAME MEANS WITH RESPECT TO SAID MAIN SUPPORTING FRAMEWORK MEANS, COMPRISING: A BLADE-POSITION SIMULATOR MEANS COMPRISING FIRST, SECOND, AND THIRD RELATIVELY MUTUALLY PERPENDICULARLY ROTATIVELY INTERCONNECTED PORTIONS, SAID FIRST SIMULATOR MEANS PORTION BEING EFFECTIVELY PROVIDED WITH FIRST ROTARY MOUNTING EFFECTIVELY FOR MOUNTING SAME ON A REAR SURFACE OF SAID DEPENDING PORTION OF SAID MAIN FRAMEWORK MEANS FOR ROTATION AROUND A LONGITUDINAL FORE AND AFT FIRST AXIS PASSING CENTRALLY THROUGH THE CENTER OF SAID SWIVEL CONNECTOR MEANS, SAID FIRST AND SECOND SIMULATOR MEANS PORTIONS BEING EFFECTIVELY PROVIDED WITH AND RELATIVELY ROTATIVELY INTERCONNECTED BY A SECOND ROTARY MOUNTING MEANS EFFECTIVELY ROTATIVELY MOUNTING SAME FOR ROTATION AROUND A SECOND AXIS SUBSTANTIALLY PERPENDICULAR TO SAID LONGITUDINAL FIRST AXIS, SAID SECOND AND THIRD SIMULATOR MEANS PORTIONS BEING EFFECTIVELY PROVIDED WITH AND RELATIVELY ROTATIVELY INTERCONNECTED BY A THIRD ROTARY MOUNTING MEANS EFFECTIVELY RELATIVELY ROTATIVELY MOUNTING SAME FOR ROTATION AROUND A THIRD AXIS SUBSTANTIALLY PERPENDICULAR TO BOTH SAID LONGITUDINAL FIRST AXIS AND SAID SECOND AXIS PERPENDICULAR THERETO, SAID SIMULATOR MEANS BEING PROVIDED WITH AN OUTPUT BLADE-POSITION SIMULTATING PORTION AND EFFECTIVE COUPLING MEANS EFFECTIVELY COUPLING SAME WITH RESPECT TO SAID BLADE MEMBER FOR CAUSING CORRESPONDING MOVEMENT OF SAID OUTPUT PORTION, IN AN EFFECTIVE ERROR AND CORRECTION SIGNAL-PRODUCING MANNER, IN RESPONSE TO MOVEMENT OF SAID BLADE MEMBER AWAY FROM A DESIRED HORIZONTAL ANGULAR POSITION WITH RESPECT TO SAID LONGITUDINAL FIRST AXIS.