Touch-up welding apparatus for motorcar body

Claim 1

A touch-up welding apparatus for welding such portions of a motorcar body which remain unwelded after the body has passed along a main welding portion of a motorcar body assembly line comprising: a welding station including means for moving a motorcar body into the station after passing along a main welding portion of an assembly line and means for setting the motorcar body at a predetermined setting position; plural welding gun magazines for supporting respective differing welding guns disposed adjacent said setting position; a framework surrounding said welding station and supporting horizontally spaced guide rails above said setting position and a frame member mounted for movement along said guide rails above said motorcar body in one of a lateral or longitudinal direction relative to said motorcar body; and a welding robot including a robot main body mounted to said frame member for movement along said frame member in the other of said lateral or longitudinal direction relative to said motorcar body, means for moving said frame member in said one direction, means for moving said robot main body in said other direction, a robot arm extending downwardly from said robot main body, means for rotating said robot arm about a vertical axis, means for moving said arm upwardly and downwardly, a wrist portion provided on a lower end of said robot arm, and means for rotating said wrist portion about a horizontal axis for swinging said wrist portion up and down, and means for rotating said wrist portion about a vertical axis for turning movement of said wrist portion independently of said robot arm, said welding guns being selectively attachable to said wrist portion, whereby selective replacement of the welding guns on the wrist portion of the welding robot arm from the plural welding gun magazines and movement of the robot main body laterally and longitudinally relative to the motorcar body and the robot arm upwardly and downwardly permits access to all areas of the motorcar body and enables welding of the remaining unwelded portions of the motorcar body.