Safety control for two handed press - has valve so that system failure causes press to stay in lower position

摘要

The control system for the two-hand operated press consists of a computer which receives the control signal and transmits a signal to the control unit which in turn controls safety valve. A return signal from the safety valve ensures that a new operational cycle is only possible if the input to the control unit has been correctly transmitted. The control unit consists of a number of protective relays which will allow the press to function only if both the hand operated switches are operated. In addition, the control unit retains the press in the button dead centre position in the event of any failure of the system.