Patent attributes
Portable friction stir welding apparatus having a crawler which supports a motor for rotating a Friction Stir Welding tool and is coupled to a drive mechanism for urging the crawler along a predefined weld path on work pieces. The crawler can comprise one member or a set of two or three physically separated members each rotatably coupled to the friction stir welding tool. The friction stir welding tool for making the weld is rotatably coupled to each member and restricts axial displacement of the physically separate members relative to each other. The members are adapted to engage rails on the work pieces which provide at least one of guiding, alignment, fixturing, torque compensation for the members as the friction stir welding tool is rotated and the crawler is moved along a joint.