Automatic curing cycle control system

A control system for controlling the opening of the mold at the end of the curing cycle of a molding machine comprising:

• a. at least one means in said mold for sensing the temperature of resin in the mold cavity and for producing a temperature signal representative of the sensed temperature;
• b. rate means connected to each temperature-sensing means to receive the temperature signal therefrom and generate a rate signal representative of the rate of change of the temperature signal as a function of time;
• c. circuit means connected to each rate means to receive the rate signal therefrom and adapted to be connected for transmission of signals to means for opening the mold in response to reception of a command signal, said circuit means including means for establishing first and second reference rates, detecting when each sensed rate exceeds the first reference rate and thereafter when it falls below the second reference rate, generating a command signal at a time determined by the time at which the last sensed rate falls below the second reference rate after it has exceeded the first reference rate, and transmitting the command signal to the means for opening the mold when connected thereto, the mold thereby opening in response to the termination of curing as determined by the falling of the last sensed rate below the second reference rate after having exceeded the first reference rate.