Servo control apparatus

Claim 1

IN A SERVO SYSTEM, THE COMBINATION OF MEANS RESPONSIVE TO A VARIABLE INPUT FORCE, MEANS RESPONSIVE TO A VARIABLE OUTPUT FORCE, MEANS FOR CONTROLLING SAID VARIABLE OUTPUT FORCE AS A FUNCTION OF SAID VARIABLE INPUT FORCE INCLUDING A LEVER OPERATIVELY CONNECTED TO AND LOADED BY SAID FIRST NAMED MEANS TO PROVIDE AN INPUT TORQUE, SAID LEVER BEING ROTATED ABOUT AN AXIS, RESILIENT MEANS PROVIDING A CONSTANT REFERENCE FORCE, FORCE TRANSMITTING MEANS OPERATIVELY CONNECTED TO SAID LEVER AND SAID RESILIENT MEANS THROUGH WHICH SAID CONSTANT REFERENCE FORCE ACTS IN OPPOSITION TO SAID VARIABLE INPUT FORCE, AND FOLLOW-UP MEANS ACTUATED BY SAID OUTPUT FORCE RESPONSIVE MEANS OPERATIVELY CONNECTED TO SAID FORCE TRANSMITTING MEANS FOR ACTUATING THE SAME, SAID FORCE TRANSMITTING MEANS BEING MOVED BY SAID FOLLOW-UP MEANS RELATIVE TO SAID AXIS TO CAUSE AN INCREASE OR A DECREASE IN THE EFFECTIVE LEVER ARM OF SAID LEVER IN ACCORDANCE WITH AN INCREASE OR A DECREASE, RESPECTIVELY, OF SAID VARIABLE INPUT FORCE WHEREUPON SAID INPUT TORQUE IS BALANCED BY AN EQUAL AND OPPOSITE TORQUE DEVELOPED BY SAID CONSTANT REFERENCE FORCE ACTING THROUGH SAID LEVER.