Patent ID: 8258424

Claim:
A plasma arc torch comprising: a main torch body; an electrically conductive nozzle defining an orifice for gas flow therethrough towards a work piece; an electrode holder arranged within the main torch body; an electrode releasably attached to the electrode holder and projecting from the electrode holder in a forward direction towards an opposing surface of the nozzle, the electrode defining an end face and an axial length L, the length L decreasing as the end face of the electrode is worn away during use of the plasma arc torch; and an electrically non-conductive wear stop fixedly mounted within the main torch body, the wear stop defining a first engaging surface that is axially spaced from the opposing surface of the nozzle by a predetermined axial distance D, wherein one of the electrode and the nozzle is axially movable with respect to the other of the electrode and the nozzle, and wherein the one of the electrode and nozzle that is axially movable defines a projection, wherein the projection defines a second engaging surface, wherein the wear stop is positioned such that prior to any wear of the end face of the electrode, when the end face of the electrode is in electrical contact with the opposing surface of the nozzle, there is an axial clearance C between the first engaging surface of the wear stop and the second engaging surface of the projection, the clearance C decreasing as the end face of the electrode is worn away during use of the plasma arc torch, and wherein the clearance C decreases to zero and the first engaging surface of the wear stop abuts the second engaging surface of the projection so as to prevent the end face of the electrode from making electrical contact with the opposing surface of the nozzle when the wear exceeds a predetermined amount.