PILOT VALVE OPERATED MAIN VALVE WITH LOST MOTION CONNECTED AND TANDEM OPERATED VALVES

摘要

A solenoid actuated three-way valve to admit air under pressure to a spring biased piston in a cylinder and, alternatively, to exhaust the cylinder to the atmosphere. Two pilot valves are operated substantially in tandem. The operator has a lost motion connection with the valves for positive valve actuation in the event of pressure failure. A framework between one main valve and one pilot valve for the other main valve causes the one pilot valve to close when the one main valve opens, and vice versa. Both main valves are oriented so that fluid pressure biases them in a closing direction. Small closing bias springs and a small solenoid may thus be utilized. Good valve seating is thus obtainable. The overall size of the valve is also reduced.