Stretch-shrink indicating and tension motor control apparatus

Claim 1

IN AUTOMATIC ELECTRIC STRETCH-SHRINK INDICATING AND CONTROL APPARATUS FOR CONTINUOUSLY RUNNING WEBS AND THE LIKE, THE COMBINATION OF FIRST AND SECOND VOLTAGE GENERATORS DISPOSED AT POINTS SPACED LONGITUDINALLY OF THE RUNNING MOVEMENT OF THE WEB, THE VOLTAGE OUTPUT OF SAID GENERATORS BEING DIRECTLY PROPORTIONAL TO THEIR RESPECTIVE SPEEDS, FIRST AND SECOND LOGARITHMIC FUNCTION PRODUCING MEANS CONNECTED RESPECTIVELY IN CIRCUIT WITH SAID FIRST AND SECOND VOLTAGE GENERATORS FOR CONVERTING THE OUTPUT VOLTAGES OF SAID VOLTAGE GENERATORS TO LOGARITHMIC FUNCTIONS THEREOF, A METER IN CIRCUIT WITH SAID FIRST SECOND LOGARITHMIC FUNCTION PRODUCING MEANS FOR MEASURING THE DIFFERENCE IN THEIR VOLTAGE OUTPUT, A PAIR OF CURRENT LIMITING AMPLIFIER MEANS CONNECTED RESPECTIVELY IN THE CIRCUIT BETWEEN SAID FIRST VOLTAGE GENERATOR AND SAID FIRST LOGARITHMIC FUNCTION PRODUCING MEANS AND IN THE CIRCUIT BETWEEN SAID SECOND VOLTAGE GENERATOR AND SAID SECOND LOGARITHMIC FUNCTION PRODUCING MEANS, AND SPEED CONTROL MEANS RESPONSIVE TO VARIATIONS IN THE DIFFERENCE VOLTAGE OUTPUT OF SAID FIRST AND SECOND LOGARITHMIC FUNCTIONS PRODUCING MEANS FOR MAINTAINING THE STRETCH-SHRINK FACTOR OF THE WEB WITHIN PREDETERMINED LIMITS.