Abstract: A system for connectng the ends of sheet metal ducts wherein each duct end is provided with a frame. Corner connectors defining perpendicularly extending arms are associated with each frame, and bolts or other fasteners are utilized for connecting the connectors and frames. The respective frames comprise integral roll-formed sections at the duct ends. The sections include a first portion extending perpendicularly outwardly from the duct wall and a second portion bent rearwardly from the outer end of the first portion. When the frame is formed in this fashion, it is adapted to receive the side edges of respective arms of corner connectors whereby the ducts may be efficiently assembled by locating corner connectors in place and thereafter applying the fasteners used for maintaining the assembly.

Abstract: An apparatus for producing shaped metal objects such as collars for ventillating systems. The apparatus includes drive means for advancing a flat metal sheet past a rotary tool whereby notches are formed along one side of the sheet. The tool is provided with a stabilizing fitting and spring means to insure consistent notch forming. The notched sheet may be collected and formed into a rectangular configuration by other equipment or a removably attached sheet crimping and deflecting mechansim may be mounted in the path of movement of the notched sheet. This mechanism includes crimping rolls, and the deflecting means positioned beyond the crimping rolls operate to turn the sheet into a circular configuration whereby the product of the apparatus is automatically formed into a circular collar.