US Patent 6917013 Copying welding equipment

In the tracking welder, left and right side wheels are supported rotatably by a pair of bearing units that are pivotally attached on a carriage, and this carriage is provided with a driving source for running the carriage, a transmission system for transmitting a rotational motion of the driving source to the left and right side wheels, a welding torch, a sensor for detecting a route to be welded, a track-controlling motor to be rotate in forward and backward directions in response to a detection signal of the sensor, and a steering system for turning the bearing units in an amount corresponding to a rotational amount of the track-controlling motor. According to this tracking welder, it is possible to automatically perform various kinds of welding including not only fillet welding of a corner between horizontally placed steel plate and web plate erected on the steel plate, but also butt welding of steel plates, for example.