Remote control system for positioning a motor driven load

Claim 1

A REMOTE CONTROL DEVICE FOR A POWER UNIT TO DRIVE AN OUTPUT SHAFT WITH THE DEVICE AND POWER UNIT INTERCONNECTED BY A PLURALITY OF ELECTRICAL CONDUCTORS, COMPRISING IN COMBINATION, AN ELECTRIC MOTOR IN SAID POWER UNIT, A VARIABLE IMPEDANCE IN SAID POWER UNIT DRIVEN IN ACCORDANCE WITH ROTATION OF SAID MOTOR TO VARY THE IMPEDANCE THEREOF IN ACCORDANCE WITH ROTATION OF SAID MOTOR; SAID CONTROL DEVICE INCLUDING A MANUAL KNOB ROTATABLE TO EFFECT ENERGIZATION OF SAID MOTOR, AN INDICATOR MOVED WITH SAID KNOB TO PROVIDE INDICATION OF THE DESIRED POSITION OF THE OUTPUT SHAFT, A LOST MOTION CONNECTION BETWEEN SAID KNOB AND SAID INDICATOR, SWITCH MEANS CONNECTED TO BE ACTUATED IN ACCORDANCE WITH SAID LOST MOTION CONNECTION, TRANSFORMER MEANS HAVING SECONDARY WINDING MEANS, A BRIDGE CIRCUIT, MEANS TO ENERGIZE SAID BRIDGE CIRCUIT FROM SAID SECONDARY WINDING MEANS IN ACCORDANCE WITH ACTUATION OF SAID SWITCH MEANS, A SECOND VARIABLE IMPEDANCE, MEANS INCLUDING SAID PLURALITY OF CONDUCTORS TO CONNECT SAID FIRST AND SECOND VARIABLE IMPEDANCES AS PART OF SAID BRIDGE CIRCUIT, OUTPUT TERMINALS ON SAID BRIDGE CIRCUIT, AMPLIFIER MEANS CONNECTED TO THE OUTPUT TERMINALS OF SAID BRIDGE CIRCUIT SO THAT WHEN SAID BRIDGE CIRCUIT IS UNBALANCED THE AMPLIFIER MEANS IS EFFECTIVE, AND MEANS INCLUDING SAID PLURALITY OF CONDUCTORS CONNECTING SAID AMPLIFIER MEANS IN CIRCUIT WITH SAID SECONDARY WINDING MEANS AND SAID ELECTRIC MOTOR TO EFFECT ROTATION OF SAID MOTOR.