Abstract: A nozzle for a plasma arc torch has a longitudinal nozzle axis, a nozzle orifice with a generally cylindrical orifice sidewall centered on the nozzle axis, and an orifice inlet that is formed as a surface of rotation about the nozzle axis; a gas-directing surface may also be provided. The orifice inlet has a variably-curved surface generated by rotating a variably-curved element about the nozzle axis, where the variably-curved element can be a portion of an ellipse, parabola, or hyperbola, and can join to the orifice sidewall and to the gas-directing surface, if provided. Both the orifice sidewall and the gas directing surface can each join the variably-curved element in a substantially tangential manner. Using an elliptical contour for the orifice inlet was found to increase stability for the plasma arc, providing improved cut quality and faster cutting speed for the torch.

Abstract: A power transfer assembly for supplying electrical power to an electrode of a contact-start plasma arc torch has two conductive elements biased by a compression spring. The conductive elements are provided with mating structures that are defined by parallel surfaces that can be slidably engaged with each other. The conductive elements are configured to engage the spring such that positioning the mating structures to slidably engage each other generates an off-axis force in the spring that biases the mating structures together along at least one line of contact to assure an electrically conductive path through the mating structures from one conductive element to the other. One conductive element is a static element that is positioned against a power supplying element of the torch, while the other is a movable element that engages or is attached to the electrode.

Abstract: An electrode-supporting assembly for a contact-start plasma arc torch has an insulator that partially houses an electrode, and employs a spring-loaded plunger to bias the electrode to a forward position. The spring is engaged between the plunger and a contact element attached to the insulator, and may conduct electrical current to the electrode. The plunger, spring, and contact element are retained in the insulator when the torch is opened to replace the electrode, which is a consumable part. The electrode and the plunger have axially-engagable mating surfaces to assure good thermal and electrical conductivity therebetween. Conductivity can be further enhanced by forming the plunger of silver or a silver-bearing alloy. In some embodiments, a passage through the insulator is partitioned into forward and rear chambers, with the plunger, spring, and contact element trapped in the rear chamber.

Abstract: A nozzle for a plasma arc torch is provided with a distal region sidewall formed by rotation of a variably curved element about a nozzle axis. The distal region sidewall has an inclination to the nozzle axis that increases at an increasing rate as it approached a nozzle terminal plane that terminates an orifice of the nozzle. The distal region sidewall is substantially tangent to the nozzle terminal plane where it intersect the same. The desired curvature can be formed by rotation of a portion of an ellipse or parabola. The curvature of the distal region sidewall appears to draw a portion of the shield gas along the nozzle to provide improved cooling and greater stability to the plasma arc, which can improve the quality of cuts made by the arc and can increase nozzle life.

Abstract: A connector assembly for coupling a plasma arc torch or a welding torch to a power supply having a receiving mechanism. The connector assembly includes a connector body, a plug, and a locking key assembly. The connector body has distal and proximal ends, and the plasma arc torch is affixed to the distal end. The plug extends from the proximal end of the connector body and may include a keyseat. The locking key assembly includes an adapter key and a latch. The adapter key is disposed within the plug keyseat and is configured for receipt within a keyway of the receiving mechanism. The latch retains the locking key assembly to the connector body or connector assembly. The locking key assembly releasably couples the connector assembly to the receiving mechanism and the plasma arc torch to the power supply.