Resistance welding electrode

This invention relates to a resistance welding electrode for welding fasteners to a metallic object, and more particularly, the invention relates to an insulated stop for limiting electrode pin travel. A welding electrode for welding a fastener to an object is provided. The electrode includes a housing assembly with a bore disposed in the housing assembly. A pin is disposed within the bore and is movable along an axis between extended and depressed positions. The pin is retained in the bore by a flange on a lower portion of the pin that extends radially outwardly. A spring is arranged within the bore and urges the pin from the depressed position to the extended position in which a weld nut may be loaded onto the pin. The spring has a compressed length indicative of a spring failure. A stop such as a spring insulator is arranged within the bore adjacent to at least a portion of the spring. The stop extends generally longitudinally in the direction of the pin axis. The stop defines a maximum spring compression length in a fully depressed pin position that may be caused from an improperly loaded weld nut. The maximum spring compression length is greater than the compressed length so that the spring does not become compressed to the point of failure. The stop is preferably constructed from nylon and has a length sufficient to accommodate excessive forces on the stop caused by an improperly loaded weld nut.