Automatic welding apparatus for long workpieces

An automatic welding apparatus comprising:

• a welding torch;
• a composite frame adapted to movably mount said torch such that said torch may be located at a predetermined position within a work space;
• said composite frame adapted to move said torch in a longitudinal direction, a lateral direction, and a vertical direction as well as being rotatable around a vertical axis;
• a workpiece holder for securing a workpiece thereto such that said workpiece or portions thereof are located within the limits of said work space;
• said workpiece holder including a pair of spaced apart fixtures which are rotatable around a horizontal axis;
• means for controlling the angular position of said pair of spaced apart fixtures;
• a movable base for supporting either said frame or said workpiece holder such that said frame and said holder are movable with respect to one another along a longitudinal axis;
• said movable base including a truck provided with a reversible motor adapted to drive said truck along a pair of spaced apart, parallel tracks;
• positioning means for positioning said truck along said longitudinal axis such that all portions of said workpiece may be brought within the limits of said work space of said automatic welding apparatus;
• said positioning means capable of locating said truck at a plurality of work stations situated at predetermined points along said tracks;
• said positioning means including a plurality of locating means positioned along said longitudinal axis for selectively engaging said truck only when said truck is in the vicinity of the respective predetermined positions and moving said truck to said predetermined positions and thereafter locking said truck at said predetermined positions.