Automatic duct welding machine

Abstract

A welding gun of an arc welding machine is mounted for vertical reciprocal movement on a movable frame portion. The movable frame portion is connected to a stationary frame portion by piston cylinder assemblies which upon actuation raise and lower the movable frame portion into an out of position for locating the welding gun in position for welding together a pair of longitudinal sheet metal member edges positioned in a preselected relationship on the stationary frame portion. A pair of clamp plates are carried by the movable frame portion. When the movable frame portion is lowered the clamp plates are positioned oppositely of the pair of sheet member edges respectively to move into and out of clamping engagement with the sheet member edges. Once the sheet member edges are clamped in abutting relationship, the welding gun is advanced downwardly on the frame movable portion in a vertical linear path. A welded seam is formed the full length of the abutting sheet member edges to form a welded joint at the abutting sheet member edges. Upon completion of the welded seam, the movement of the welding gun is automatically reversed to return the welding gun to its initial raised position on the movable frame. Followed by release of the clamps against the welded sheet member edges, the movable frame portion is moved to a raised position on the stationary frame portion to permit removal of the welded sheet member edges from the stationary frame portion. In this manner a selected number of sheet members can be welded together at their abutting longitudinal edges to form a duct section of a desired cross sectional configuration, for example polygonal or circular, in which all the welded seams are positioned internally within the duct section.