Patent ID: 9597745
Date: 2017-03-21
CPC Classifications: B23K

Claim:
1. A tungsten inert gas (TIG) welding torch comprising: (a) a cylindrical torch body for providing a shielding gas; (b) an electrode collet that is screwed and inserted into the torch body so as to be movable up and down and be rotatable, and the electrode collet attachably and detachably holds a tungsten electrode rod; (c) a collet handle attached to an upper end of the electrode collet and that moves the electrode collet upwardly and downwardly with respect to the torch body while rotating the electrode collet in normal and reverse directions; (d) a gas lens having a holder that is attached to a lower end of the torch body and formed in a cylindrical shape having a first gas passage for inserting the tungsten electrode rod and for flowing the shielding gas around the tungsten electrode rod from the torch body, a plurality of gas flow holes for dividing the shielding gas flowing through the first gas passage, and an annular filter for laminarizing a first shielding gas flowing through the plurality of gas flow holes; (e) a constricting nozzle having a nozzle body attached to a center portion of the annular filter and formed in a cylindrical shape having a second gas passage for inserting the tungsten electrode rod and for flowing a second shielding gas around the tungsten electrode rod from the first gas passage without flowing through the plurality of gas flow holes, a plurality of positioning projections provided on an inner peripheral surface of the nozzle body for slidably holding the tungsten electrode rod in a center position of the second gas passage, and a plurality of gas-flow regulating grooves arranged between the positioning projections and that regulate the second shielding gas; and (f) a cylindrical shielding nozzle that is attached to the gas lens or to the torch body so as to surround the constricting nozzle and discharge the first shielding gas laminarized by the annular filter through a gap between an outer face of the constricting nozzle and the inner surface of the cylindrical shielding nozzle, wherein a tip of the constricting nozzle projects from an opening of a lower end of the cylindrical shielding nozzle; wherein the constricting nozzle is constructed such that the second shielding gas discharged from the constricting nozzle is faster than the first shielding gas laminarized by the annular filter and discharged from the shielding nozzle.