Plural motor process drive

Claim 1

IN A SPEED CONTROL SYSTEM FOR PROCESS OF MATERIAL: A SERIES OF PROCESS ROLLERS FOR DETERMINING THE SPEED OF THE MATERIAL IN PROCESS AT SUCCESSIVE STAGES; A SERIES OF POWER UNITS FOR OPERATING THE PROCESS ROLLERS AT INTERMEDIATE STAGES, AND EACH INCLUDING A VARIABLE RATIO TRANSMISSION HAVING AN OUTPUT SHAFT CONNECTED TO ITS PROCESS ROLLER AND HAVING AN OUTPUT SHAFT MOVABLE TO ADJUST THE RATIO OF TRANSMISSION, A MAIN MOTOR FOR OPERATING THE VARIABLE RATIO TRANSMISSION, AND A MECHANICAL DIFFERENTIAL HAVING AN OUTPUT SHAFT FOR PROVIDING AN ERROR SIGNAL CONNECTED TO SAID MOVABLE MEMBER WHEREBY THE RATIO OF TRANSMISSION, IS ADJUSTED IN A DIRECTION TO REDUCE SAID ERROR SIGNAL, SAID DIFFERENTIAL HAVING A FIRST INPUT SHAFT DRIVEN IN PROPORTION TO THE SPEED OF THE CORRESPONDING PROCESS ROLLER TO PROVIDE A SIGNAL TO BE CONTROLLED, SAID DIFFERENTIAL HAVING A SECOND INPUT SHAFT, SUPPLEMENTAL MOTOR FOR OPERATING SAID SECOND INPUT SHAFT, MEANS OPERATIVELY ASSOCIATED WITH THE PRECEDING PROCESS ROLLER FOR GENERATING ELECTRICAL ENERGY FOR SAID SUPPLEMENTAL MOTOR TO DRIVE SAID SUPPLEMENTAL MOTOR AT A SPEED PROPORTIONAL TO THE SPEED OF THE PRECEDING PROCESS ROLLER WHEREBY THE SAID ERROR SIGNAL CORRESPONDS TO THE DIFFERENCE BETWEEN THE SPEED OF SAID MAIN MOTOR AND A PROPORTION OF THE SPEED OF THE PRECEDING PROCESS ROLLER, AND MEANS FOR ADJUSTING THE PROPORTIONATE EFFECT OF THE SPEED OF SAID PRECEING PROCESS ROLLER ON SAID SECOND INPUT SHAFT RELATIVE TO THE PROPORTIONATE EFFECT OF THE SPEED OF SAID PROCESS ROLLER OF THE CORRESPONDING STAGE ON SAID FIRST INPUT SHAFT WHEREBY THE SPEED OF SAID PROCESS ROLLER IS MAINTAINED AT A SET PROPORTION OF THE SPEED OF THE PRECEDING PROCESS ROLLER INDEPENDENTLY OF THE SPEED OF SAID PRECEDING PROCESS ROLLER.