Analog automatic slowdown system

Claim 1

In a process line wherein a coil of material mounted on a mandrel driven by a payoff reel motor, is being unwound at a linear speed S, an analog automatic slowdown control system for determining the optimum instant of time to initiate slowdown of the material being payed out, comprising: a. means for determining the instantaneous diameter of the coil of material to derive a signal d; b. means for differentiating, connected to receive said signal d and deliver a signal d', where d' is the derivative of the instantaneous diameter d with respect to time; c. means for deriving a signal s which is a function of said linear speed; d. means for deriving a signal n which is a function of the speed of the payoff reel motor; e. means for determining the desired remaining portion of the coil diameter after stopping, adapted to receive said signals d', s, and to deliver an output signal which is a function of (d'/s); f. means for determining the change in the diameter of the coil of material during deceleration adapted to receive said signals d', s, and to deliver an output signal which is a function of d', s; g. means for deriving an analog signal do which is a function of the diameter of said mandrel, and h. means for summation adapted to receive the signals: d, do, functional signals (d'/s) and d's, and to deliver an initiation signal to begin slowdown when the signal d equals the sum of said other signals.