Abstract: An improved electro-pneumatic monitor for double safety valves controlled by solenoid-operated pilot valves. The monitor comprises a relatively short spool centrally held by oppositely disposed captive springs. The sensing passages are provided with relatively small orifices which help to de-sensitize the monitor. The resulting construction is resistant to shifting in response to minor double valve irregularities which otherwise could create undesired lockout conditions.

Abstract: A double safety valve for stamping presses and the like having a monitor responsive to asynchronous pressures, to disenable a press. The assembly comprises two valve stems each being radially supported by a piston at one end and by an outboard bearing at the other end. Each valve stem carries an inlet poppet valve adjacent one end, a spool valve on an intermediate portion and an exhaust valve adjacent the other end. Cross passages connect the inlet poppet valve of each valve stem in series with the spool valve of the other valve stem. A common outlet chamber receives pressurized fluid from both spool valves, this outlet chamber being connected in parallel to both exhaust valves. The assembly thus has the advantages of a double safety valve in which the inlet valves are in series and the exhaust valves in parallel, but is capable of being monitored by a monitor responsive to asynchronous pressures or movements.

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.

Abstract: A double valve of the safety type for the control of equipment such as the clutch/brake of a press. The double valve comprises two four-way valves each having two supply and two working ports and an exhaust port. The valves are shiftable by fluid controlled means through a shuttle check valve. The arrangement is such that when either main valve is faulted, pressure will be removed from the clutch/brake motor and the fluid controlled shifting means will be disenabled due to the lack of synchronism between the main valves. This self monitoring function will prevent repressurization of the clutch/brake motor regardless of whether the unfaulted main valve continues to operate. The main valves are of the open center crossover type to prevent trapping of air at the working port for the clutch/brake motor in intermediate positions of the valves.

Abstract: A safety valve for use in a compressed air line having a supply valve and a control valve, to prevent inadvertent sudden shifting of the controlled part when the line is exhausted and later repressurized. The safety valve comprises a normally closed piston-operated poppet valve, the piston chamber and outlet port being connected to the supply port through a bypass with an adjustable restriction upstream of the valve member. In one embodiment, the adjustable restriction comprises a replaceable plug threaded in the valve body. In a second version, the adjustable restriction comprises a needle valve mounted in a housing cover.

Abstract: A method and construction for the formation of an internal thread for fluid or other ports which may receive NPT, BSP tapered, or BSP parallel external threads. The port configuration varies with different nominal tube bore diameters, but comprises one or more of the following:Adjustment of tooth form.Adjustment of pitch.A tapered entry and parallel inner portion.The invention applied at least to nominal diameters between 1/8 and 11/2inches.

Abstract: A four-way spool valve controls a double acting fluid motor for locking or unlocking a part such as a tailgate. The valve is spring-urged to a locking position and hand-operable to its unlocking position. A position at the end of the valve is pressurized when in the unlocking position to counteract the spring. This piston monitors supply pressure so that the valve will be automatically shifted to its locking position when pressure drops. This will insure a locked position of the part when pressure is reapplied.

Abstract: A system for disconnecting a compressed air control system from a main supply line if the system is not used with a predetermined frequency. A normally closed solenoid-operated three-way reset valve is controlled by a normally open hand-operated switch which simultaneously operates a control valve in the system for a working cylinder. When the working cylinder valve is actuated, the three-way valve charges the operating chamber of a normally closed three-way air saver valve in series with the main line, thus opening the air saver valve. The operating chamber of the air saver valve discharges at a controlled rate through the reset valve when the latter returns to its closed position by opening the switch. If the operator closes the switch again before the pressure in the operating chamber is depleted, the air-saver valve is held open.

Abstract: A safety valve for use in a compressed air line having a supply valve and a control valve, to prevent inadvertent sudden shifting of the controlled part when the line is exhausted and later repressurized. The safety valve comprises a normally closed piston-operated poppet valve, the piston chamber and outlet port being connected to the supply port through a bypass with an adjustable restriction upstream of the valve member. In one embodiment, the adjustable restriction comprises a replaceable plug threaded in the valve body. In a second version, the adjustable restriction comprises a needle valve mounted in a housing cover.