PURPOSE: To secure a cycle for the crank angle of each press, by linking the signal of the switch provided to each press to the velocity control circuit of the main motor.

CONSTITUTION: The position signals of the synchronous transmitters 6 and 7 of the presses No.1 and No.2 are sent to the control transformer 9, and the level DC voltage Vθ equivalent to the phase difference angle signal is delivered to the amplifier 8 to be applied to the press No.2's motor control board 18. Thus the velocity of the press No.2 made equal to that of the press No.1. Under these conditions, the signals of the rotary cam switches 23 and 23' of each press are supplied to the input terminals A and B each. As a result, the OR output of 3 is applied to the terminal 5-1, and then the output of 1 is delivered from the terminal 5-3. The output is then sent back to the terminal 3-1 to give a self-support to the AND of 5. Then in case a shift of position is caused for the pulses to be applied to the terminals A and B, the output 1 is delivered to the terminal 2-3. And then the output 1 is delivered for a fixed time to the terminal 5-3 to make the photocoupler PH conduct. On the other hand, a certain level of voltage is applied between the terminals C and D from the control board 18 to secure a setting to the level of voltage according to the control of velocity. This command voltage functions continuously until the crank shaft of each press has the synchronism.