Electrical primary flight control system

Claim 1

A PRIMARY FLIGHT CONTROL SYSTEM FOR AIRCRAFT COMPRISING: A CONTROL SURFACE; A TRIPLE-COMPARTMENT HYDRAULIC POWER CYLINDER HAVING A PISTON IN EACH COMPARTMENT AND A PISTON ROD CONNECTING SAID PISTONS TO SAID CONTROL SURFACE; A PLURALITY OF CONTROL VALVES EACH HAVING A CONTROL LEVER AND FLUID PRESSURE CONNECTIONS WITH ONE OF SAID COMPARTMENTS FOR CONTROLLING FLUID PRESSURE ADMISSION TO AND EXHAUST FROM SAID CYLINDER; A RECIPROCALLY MOVABLE BAR MECHANICALLY COUPLED TO SAID CONTROL LEVERS; SAID CONTROL LEVERS UPON BEING MOVED IN ONE DIRECTION ESTABLISHING IN SAID VALVES A FLUID-PRESSURE PATH WHICH ACTS TO OPERATE SAID CONTROL SURFACE IN ONE DIRECTION AND WHEN MOVED IN THE OPPOSITE DIRECTION SIMILARLY ESTABLISHING A SECOND FLUID-PRESSURE PATH WHICH ACTS TO OPERATE SAID CONTROL SUR FACE IN THE OPPOSITE DIRECTION; THREE ALTERNATING CURRENT TORQUE MOTORS EACH INCLUDING A CONTROL WINDING, A REFERENCE WINDING ENERGIZED BY A REFERENCE SOURCE OF ALTERNATING CURRENT, AND A ROTATABLY MOUNTED ARMATURE ADAPTED FOR ANGULAR DISPLACEMENT FROM A REFERENCE POSITION IN ACCORDANCE WITH THE CURRENT IN SAID CONTROL WINDING; MEANS FOR MECHANICALLY COUPLING SAID ARMATURES TO SAID BAR THEREBY IMPARTING TO SAID BAR LINEAR MOVEMENT WHICH OPERATES SAID CONTROL LEVERS UPON TURNING OF SAID ARMATURES FROM SAID REFERENCE POSITION; A PILOT''S CONTROL MEMBER; A PLURALITY OF ELECTROMECHANICAL TRANSDUCERS MECHANICALLY COUPLED TO SAID CONTROL MEMBER; EACH OF SAID TRANSDUCERS HAVING OUTPUT TERMINALS AT WHICH AN ELECTRICAL COMMAND SIGNAL HAVING CHARACTERISTICS APPROPRIATE TO THE SENSE AND MAGNITUDE OF DISPLACEMENT OF SAID CONTROL MEMBER IS DEVELOPED; THE OUTPUT TERMINALS OF EACH OF SAID TRANSDUCERS BEING CONNECTED IN SERIES RELATION WITH ONE OF SAID CONTROL WINDINGS; INDICATING MEANS FOR VISUALLY PRESENTING TO THE PILOT THE MAGNITUDE AND DIRECTIONAL CHARACTERISTICS OF EACH COMMAN SIGNAL; AND A PLURALITY OF INDUCTIVE SWITCHES EACH INTERCEPTING THE ELECTRICAL COMMAND SIGNAL TRANSMITTED TO THE RESPECTIVE CONTROL WINDINGS AND HAVING A MOVABLE MEMBER ADAPTED BY CHANGE FROM A FIRST TO A SECOND POSITION TO LEAVE UNAFFECTED OR REDUCE SUBSTANTIALLY TO ZERO THE LEVEL OF CONTROL COMMAND CURRENT FED TO SAID CONTROL WINDINGS, RESPECTIVELY.