Method of tire cure control

Abstract

A system for controlling sequence and duration of the operational steps in processes such as vulcanization of a pneumatic tire is capable of operating under two basic modes or parameters. In one mode the operational steps are dictated by elapsed real time, while in the other mode, the operation can be dictated by elapsed cure equivalent factors. The desired length of each step or the cure, whether in time or cure equivalents, is set into an input program means. In the time mode, time generating circuitry provides an output proportional to elapsed time which output is displayed on a counter and electrically compared with the information in the input program means. When a match occurs, the time generating circuitry and displays are reset and the input program means directs the tire vulcanization press to perform the next sequential function. Also disclosed is circuitry which is capable of performing secondary functions such as extending the length of a step, as necessary. If it is desired to operate in the cure equivalent mode, a signal proportional to elapsed cure equivalents is developed by a cure equivalent generating circuitry which performs digital integration of the Arrhenius function. The input to cure equivalent generating circuitry can be a signal proportional to tire temperature developed by internal thermocouples or can be a signal which is directly proportional to the Arrhenius function as generated by a thermistor sensor.