An automatic control apparatus having a camming means for operating a series of cam followers, a constant speed electric motor, and clutch and transmission means for selectively connecting the camming means to the constant speed motor to be driven thereby past the cam followers, such followers offering resistance to the movement of the camming means thereby when engaged by the camming means, is provided with rapid advance means associated between the clutch-transmission means and the camming means for storing energy received from the motor during operation thereof and for releasing the same to advance the camming means between engagements with the cam followers more rapidly than the advancement normally caused thereby by the motor. The transmission means has a drive shaft connected to the motor and the rapid advance means has a tubular member connected to the camming means and having an inside bore portion with a predetermined internal diameter, a wound wire spring secured at one end to the transmission means drive shaft and having an enlarged diameter portion adjacent the other end in a press fit in the tubular member to store energy during relative rotation between the drive shaft and tubular member prior to an operating cycle and for releasing such energy to rapidly advance the tubular member and associated camming means relative to the transmission means drive shaft during an operating cycle. The spring means is mounted in coaxial bores in a drive shaft and cam shaft, the latter having mating convex and concave bearing surfaces facilitating relative rotation therebetween during twisting and untwisting of the associated spring means.
