Abstract Means for sensing a discrepant position between two normally closed valves of a double valve assembly used to control an industrial machine such as an air-operated press clutch and brake. The indicating means comprises switch means responsive to the movement of each of the valves and so positioned that the switch means is actuated very close to the closed position of each valve. The switch means controls power to solenoid-operated pilot valves for the two main control valves of the double valve assembly. By controlling the switch means immediately adjacent the closed valve positions, the safe or closed part of the cycle is monitored for these valves, which are in themselves stable because of their normally closed nature. The switch means may be either cam-operated mechanical switches, proximity switches, photoelectric sensors, or contacts directly engageable by the inlet valve elements and utilizing the valve body itself as part of the electrical circuit. The invention is applicable to a double valve assembly in which both inlet and exhaust flow is in parallel through the two valves, or one in which the inlet flow is in series and the exhaust flow in parallel.
In combination with a poppet valve element movable toward and away from a seat, switch means comprising a spring-like conductive element mounted adjacent said seat and interposed between said element and seat, whereby said valve element will deflect said spring-like conductive element when it approaches said seat, and means connecting said conductive element to an electrical circuit.
Claim 2
Dependent Claim
57 words
In combination with a poppet valve element movable toward and away from a seat, switch means comprising a spring-like conductive element mounted adjacent said seat and interposed between said element and seat, whereby said valve element will deflect said spring-like conductive element when it approaches said seat, and means connecting said conductive element to an electrical circuit.
Claim 3
Dependent Claim
19 words
The combination according to claim 1, said conductive element comprising an annular disc member, said valve element being non-conductive.
Claim 4
Dependent Claim
22 words
The combination according to claim 2, said seat being conductive, said conductive element engaging said seat when said valve element is closed.
Claim 5
Dependent Claim
40 words
The combination according to claim 1, said conductive element comprising a member which is separated from said seat when said valve element is away from said seat, and is pressed against said seat when said valve element approaches said seat.