Abstract: A sensor and valving system for controlling the flow of liquid coolant in a welding electrode cooling circuit using coolant under pressure in supply and return lines. The system is responsive to loss of coolant to the welding electrodes by pressure response upon loss of coolant detection, the coolant supply is cut off and effective lines are isolated allowing for repair or replaceable without additional loss of coolant from the system.

Abstract: A multiple port valve body has a cylindrical bore with at least two pairs of oppositely disposed inlet and outlet ports communicating therewith and a cylindrical valve member rotatably positioned in said cylindrical bore. Transverse passageways in the cylindrical valve member register with the inlet and outlet ports in a first position and oversize resilient elastic rubber plugs under compression are positioned in oppositely disposed pockets in the cylindrical valve member register with said inlet and outlet ports when the cylindrical valve member has been rotated on its axis approximately 90.degree. to a second position, the resilient elastic rubber plugs acting to bulge into the inlet and outlet ports to insure positive sealing thereof.

Abstract: A valve for controlling the flow of a liquid coolant in a circuit interconnecting several hollow welding electrodes with a pressurized coolant source has dual ball check valves in the supply and return lines respectively and a spring and pressure responsive device for holding the ball check valve in the supply line open when the fluid pressure of the coolant in the cooling circuit is maintained. The device is responsive in operation to loss of pressure in the coolant supply line and the hollow electrodes to permit the dual ball check valves to close upon a loss of pressure as occasioned by the burn out of one of the electrodes or the removal of the electrode from the circuit. The device may also originate an appropriate signal which may be directed to a remote electrical switch controlling the welding current.

Abstract: A cylinder piston rod coupler for misaligned shafts attaches one shaft to a housing and an annular flange on a stud attached to the other shaft is positioned in the housing between a pair of guide members. A retaining ring in the housing holds the guide members and stud in movable relation and a floating seal closes the housing about the stud and retaining ring. The guide members and the stud are impregnated with TEFLON so as to form slippery surfaces thereon.