Abstract: An electronic control unit is disclosed for a stud welding device having a movable electrode mounted on a solenoid armature, for moving the electrode away from the workpiece. The control includes a timing circuit providing a plurality of timer outputs in accordance with the preselected time intervals. A pilot arc circuit and an electrode movement circuit connected to the solenoid are activated by a timer output for establishing a pilot arc between the electrode and the workpiece and for moving the electrode from the workpiece. A welding power circuit is activated by another one of the plurality of timer outputs to establish welding current between the electrode and the workpiece. The electrode movement circuit is deactivated by another one of the plurality of timer outputs to enable the electrode to contact the workpiece by the urging of a spring. Means are provided for terminating the welding current. The control is suitable for use in a direct current welding power circuit.

Abstract: A capacitance discharge stud welding apparatus which comprises a housing. A coil is positioned in the housing and an armature is located within the coil and is movable between first and second positions relative to the coil. A stud chuck is provided for the purpose of holding a stud and is connected to the armature for movement therewith. A relatively light spring constantly urges the armature and the stud chuck toward the first position of the armature in the direction of a metal member to which a stud held by the chuck is to be welded. Engagement of the stud held by the chuck with a metal member causes the armature to move to the second position relative to the coil and against the urging of the light spring. An electrical welding current circuit is provided and electrical connection means connect the welding current circuit to the chuck and to a stud held thereby.