Starting and stabilizing apparatus for a gas-tungsten arc welding system

Claim 1

Apparatus for starting and stabilizing a welding arc in a gas-tungsten arc portable welding torch comprising: a torch body formed of electrically conductive material, a nozzle formed of dielectric material threadedly connected to said body, a main electrode connected to said body within said nozzle with its tip located rearwardly of the mouth of said nozzle, an auxiliary electrode secured to and carried by and within said nozzle and axially movable when said nozzle is threaded toward and away from said body between a position contacting said main electrode and a position spaced from said main electrode to establish an auxiliary arc between said electrodes, a main power source connected between said main electrode and the work for establishing a main-welding-arc-sustaining electrical potential difference between said main electrode and the work to be welded, an auxiliary power source for establishing an auxiliary-arcsustaining electrical potential difference between said electrodes, and means for directing a flow of shield gas through the space between said nozzle and said main electrode and a portion thereof past said auxiliary arc, whereby said auxiliary arc ionizes said portion of said gas to establish a plasma flame; said plasma flame providing a conductive path for starting and stabilizing said main arc.