Burns, Doane, Swecker & Mathis
Multiple purpose feedback control system
 Multiple purpose feedback control system comprising and characterized by a detecting means for detecting the controlled variable and converting the detected variable into a feedback signal output; a signal converting means for receiving the feedback signal from the detecting means and amplifying the signal for input into a balancing motor to convert the signal into rotary displacement in proportion to the said signal; a limit control switch for receiving the rotary movement to compare the movement with a desired value; a pair of electro-magnetic devices for transmission actuated or controlled by the limit control switch at upper and lower limits; a pair of electro-magnetic switches actuated by an on/off solenoid; an electro-magnetic device for braking actuated or controlled by the electro-magnetic switch operated by said control switch; a drive means for driving the main shaft of a control gear means; a control gear set moved by the coupling of the pair of electro-magnetic device and braked by the braking electro-magnetic device; a control gear which serves as the last gear of the said gear set, a variable resistor controlled by the said control gear for corresponding regulation of the controlled variable; and a pair of safety switches. 
G
G05B
inventional
Yu-Kuang
Lee