Abstract: Apparatus and a corresponding method for forming from a strip of sheet metal stock material a length of spiral duct that includes an integral diffuser. A perforator forms perforations in the strip at at least selected intervals. A machine forms the strip, after perforation, into spiral seamed duct.

Abstract: A machine for producing spiral seamed hollow pipe having a central axis from a metal strip having a first side which becomes the inside surface of the spiral pipe, a second side which becomes the outside surface of the spiral pipe, a width, and two outer edges. The machine includes a being roller station wherein the metal strip is formed into a helix using rolling contact. As the strip is driven through the bending roller station the strip is continuously bent on a bending line which is parallel to the central axis of the spiral pipe and which extends across the metal strip at an angle offset from a right angle with reference to the outer edges of the strip. Within the bending roller station there are a plurality of rollers organized as what may be viewed as staggered roller segments extending across the strip along the bending line which is offset from a right angle. At the same time, the rotational axes of the rollers are perpendicular to the strip.

Abstract: An apparatus and method for forming circular, oval and irregularly shaped connectors and other curved or arcuate members from stock material. In one embodiment, the apparatus includes a pair of pinch rollers mounted on a support structure and defining a gap therebetween, an adjustment mechanism to selectively vary the gap between the pinch rollers to vary the amount of compression force being exerted on at least a portion of the stock material, and a containment roller positioned proximate the gap between the pinch rollers. The compression force exerted on at least a portion of the stock material causes the stock material to bend thereby forming the curved or arcuate connector or other member. Adjustment of the pinch rollers controls the amount of compression force applied to the stock material which controls the degree of curvature in the finished product.