Control system for establishing predetermined surfaces

Claim 1

A CONTROL SYSTEM FOR CONTROLLING THE POSITIONING OF TWO INDEPENDENTLY MOVABLE MEMBERS WITH RESPECT TO THE TRANSVERSE SLOPT THEREBETWEEN AND TO A GRADE REFERENCE DATUM COMPRISING; MOTOR MEANS OPERATIVELY ASSOCIATED WITH SAID MEMBERS AND ADAPTED TO CONTROL THE POSITION OF THE MEMBERS INDEPENDENTLY, A TRANSVERSE SENSOR BEAM EXTENDING BETWEEN AND SUPPORTED BY SAID MEMBERS, A GRACE SENSOR UNIT MOUNTED IN FIXED RELATION TO ONE OF SAID MEMBERS AND INCLUDING A ROTARY SHAFT, SENSING MEANS CONNECTED TO ROTATE SAID SHAFT IN EITHER DIRECTION RESPONSIVE TO DEVIATION IN ELEVATION OF SAID ONE MEMBER IN EITHER DIRECTION FROM THE REFERENCE DATUM, AN ON-OFF ROTARY SWITCH MOUNTED ON SAID SHAFT AND HAVING A CYLINDRICAL SURFACE, AN ELECTRICALLY CONDUCTIVE MATERIAL ON THE CYLINDRICAL SURFACE, A FIRST WIPER CONTACT MEMBER IN CONTINUOUS CONTACT WITH SAID CONDUCTIVE MATERIAL, OPPOSITELY DIRECTED INSULATION STRIPS FLUSH WITH THE SURFACE OF THE CONDUCTIVE MATERIAL, SECOND AND THIRD WIPER CONTACT MEMBERS ASSOCIATED WITH SAID INSULATION STRIPS, ELECTRICAL CIRCUIT MEANS CONNECTED TO SAID WIPER CONTACT MEMBERS AND TO SAID CONDUCTIVE MATERIAL, SAID SECOND AND THIRD WIPER CONTACT MEMBERS BEING IN CONTACT RESPECTIVELY WITH THE INSULATION STRIPS IN A CENTERED POSITION OF THE SHAFT AND SO ARRANGED AS TO PASS ONTO SAID CONDUCTIVE MATERIAL AS THE SHAFT IS ROTATED IN EITHER DIRECTION FROM THE CENTERED POSITION TO PRODUCE A GRADE CONTROL SIGNAL, SAID MOTOR MEANS BEING ENERGIZED RESPONSIVE TO SAID GRADE CONTROL SIGNAL TO POSITION SAID ONE MEMBER, AND A SLOPE SENSOR UNIT MOUNTED ON SAID SENSOR BEAM AND INCLUDING PENDULUM MEANS, SECTOR PLATE MEANS, MEANS TO MOUNT SAID SECTOR PLATE IN ADJUSTABLY FIXED RELATION TO SAID PENDULUM TO CORRESPOND TO A PRESELECTED SLOPE QUANTITY, A CONTACT ARM FIXED TO MOVE WITH SAID PENDULUM AND POSITIONED TO SWING IN AN ARC ACROSS THE SURFACE OF SAID PLATE, SPACED CONTACT MEMBERS ADJUSTABLY FIXED TO THE PLATE ON OPPOSITE SIDES OF SAID CONTACT ARM, ELECTRICAL CIRCUIT MEANS CONNECTED TO SAID CONTACT MEMBERS AND TO SAID CONTACT ARM, WHEREBY DEVIATION OF SAID BEAM FROM A SET SLOPE QUANTITY WILL PRODUCE A SLOPE CONTROL SIGNAL, SAID MOTOR MEANS BEING ACTUATED IN FURTHER RESPONSE TO SAID SLOPE CONTROL SIGNAL TO POSITION SAID OUTER MEMBER.