Abstract: A method and apparatus for automatically sensing the configuration of a damaged surface area and wherein the apparatus is provided with an arc gouging tool, a welding tool, and a grinding tool to gouge damaged areas and fill them with weld material to at least the surface profile of the surface in the working environment and to grind the filled areas flush with the surface of the working environment. A track is bent to a profile enabling the apparatus to work without any collision with its environment while keeping full access to the work area. The geometry of the track is generally unknown to the control circuit of the robot. A motor-actuated robot member is connected to the track and is displaceable on the track by a motorized element. A working arm is displaceably coupled to the robot member and has one or more working tools connected thereto. A control circuit displaces the robot and operates the working arm and tool.

Abstract: A circuit for controlling the power supply to an electrode of the shielded type, such as that used in a shielded metal arc welding process (SMAW) whereby to protect a user from electric shocks. The control circuit is a protection circuit which serves to protect welders against electric shocks by decreasing the circuit voltage between the electrode tip and the workpiece to be welded. An AC or DC power supply may be used to feed the electrode. The control circuit is comprised of a high impedance voltage source applied to the electrode, a detection circuit for determining the level value of the impedance appearing between the electrode and the workpiece. The detection circuit compares the impedance thus detected with a threshold impedance and generates a control signal when the detected impedance is lower than the threshold impedance. The control signal operates a driver circuit which energizes a power feed device serially connected between the electrode power supply and the electrode itself.