Abstract: A guidance system for positioning a welding apparatus with respect to a seam or joint to be welded by sensing changes in the surface of the seam. The torch of the apparatus is mounted upon and positioned by a motor-driven cross-slide providing both horizontal and vertical movement.A probe is adapted to follow the reference surfaces. Two variable resistors within the probe detect horizontal and vertical deviations of these surfaces. A voltage on each variable resistor is used to generate pulses which are applied to a SCR network through which power is supplied to the corresponding slide positioning motor. The voltage supplied to the motor corresponds in magnitude and polarity to the deviation in the direction of the path being followed by the probe and welding apparatus.The invention also includes a circuit for disabling the motors when the respective cross-slides reach the limits of their travel.

Abstract: A guidance system for seeking, following, and maintaining the position of a welding apparatus with respect to a seam or joint to be welded by sensing changes in the surfaces, hereinafter called reference surfaces, at or adjacent to the seam. The system includes a probe adapted to detect and follow the reference surface(s) and to detect changes and deviations in the vertical and/or horizontal components of these surfaces, respectively. The torch of the welding apparatus is mounted upon and positioned by a motor-driven cross-slide providing both horizontal and vertical movement. The probe is mounted on the torch or on its own slide, which may be either on the torch or separate therefrom.

Abstract: A propelled tractor, for welding or cutting apparatus and the like.The tractor has drive and steering wheels and is adapted to support necessary welding or cutting equipment including a guidance system. The guidance system includes a probe mounted on a slide and adapted to follow a seam, template work path or the like and to respond to denotions therein in proportion to the amount of the deviation. The drive and steering wheels are driven by separate motors. The drive motor is adjustable to a predetermined speed so that a wide range of welding or cutting rates are provided and means is provided to selectively disconnect the drive train so that the tractor may be free wheeled. The steering motor is controlled in response to the probe and steers the tractor to return the probe to a predetermined null position, the turning rate being proportional to the magnitude of the deviation sensed by the probe.