Photoelectric tension sensing motor control circuit

Claim 1

IN A SYSTEM FOR TRANSFERRING LONG FRAGILE MATERIAL FROM A FIRST LOCATION TO A SECOND LOCATION AT A RATE DETERMINED BY THE SPEED OF A MOTOR, A DANCER ROLL SUSPENDED BY SAID FRAGILE MATERIAL BETWEEN SAID FIRST AND SAID SECOND LOCATION, A SOURCE OF ILLUMINATION, A SOURCE OF VOLTAGE, A PAIR OF PHOTOELECTRIC ELEMENTS SERIALLY CONNECTED ACROSS SAID SOURCE OF VOLTAGE, SHUTTER MEANS COUPLED TO SAID DANCER ROLL AND INTERPOSED BETWEEN SAID SOURCE OF ILLUMINATION AND SAID PHOTOELECTRIC ELEMENTS, SAID SHUTTER MEANS BEING EFFECTIVE TO SELECTIVELY ENABLE ILLUMINATION OF SAID PHOTOCELLS IN ACCORDANCE WITH THE POSITION OF SAID DANCER ROLL, MOTOR SPEED CONTROL MEANS RESPONSIVE TO VOLTAGE TO ADJUST THE SPEED OF SAID MOTOR, AND MEANS CONTROLLED BY THE VOLTAGE APPEARING ACROSS ONE OF SAID PHOTOELECTRIC ELEMENTS FOR SUPPLYING THE CORRECT VOLTAGE TO SAID MOTOR CONTROL MEANS TO MAINTAIN THE RATE OF TRANSFER OF SAID FRAGILE MATERIAL CONSTANT.