Duct connecting system

In a method for connecting the ends of sheet metal ducts wherein a frame is provided for each duct end, corner connectors defining perpendicularly extending arms are associated with the frames, and means are provided to interconnect the frames of adjacent duct ends, the improvement comprising the steps of forming each said frame by roll-forming a section of the duct whereby the frame comprises an integral part of the sheet metal duct, each said roll-formed section comprising a first portion extending perpendicularly outwardly from a duct wall, and a second portion bent rearwardly into a position opposite an end portion of the duct wall, the distance between said second portion and said end portion substantially corresponding to the width of an arm of a corner connector, forming a retainer means in said second portion, introducing the arms of the corner connectors between respective second portions and end portions whereby the side edges of each such arm are received in engagement with the respective surfaces of a said second portion and end portion to hold the corner connectors in position relative to a frame, said retainer means assisting in the holding by said second portion, and thereafter fastening the respective connectors together to provide an assembly.

In a system for connecting the ends of sheet metal ducts wherein a frame is provided for each duct end, a plurality of corner connectors defining perpendicularly extending arms are associated with the frames, and means are provided to interconnect the frames of adjacent duct ends to form an assembly, the improvement wherein each corner connector in the assembly includes an offset ear formed on the end of each of said arms, and including a stiffener member extending between the ears on the ends of adjacent connectors mounted on said frames, said stiffener member being held in the space defined by the said ears and the adjacent frame surfaces.

In a system for connecting the ends of sheet metal ducts wherein a frame is provided for each duct end, corner connectors defining perpendicularly extending arms are associated with the frames, and means are provided to interconnect the frames of adjacent duct ends, the improvement wherein each said frame comprises a first portion extending perpendicularly outwardly from a duct wall, and a second portion bent rearwardly into a position opposite an end portion of the duct wall, a first channel formed in said second portion for receiving a side edge of an arm, and a second channel formed in said end portion of the duct wall for receiving the opposite side edge of an arm, the distance between said channels of said second portion and said end portion substantially corresponding to the width of an arm of a corner connector, the side edges of each such arm being received in engagement with the respective bottom surfaces of said channels whereby the corner connectors are held in position relative to a frame.

In a method for connecting the ends of sheet metal ducts of the type having a frame located at each duct end, corner connectors defining perpendicularly extending arms associated with the frames, and means for interconnecting the frames of adjacent duct ends, the improvement comprising the steps of roll forming each said frame to provide a first frame portion adapted to extend perpendicularly outwardly from a duct wall when the frame is located in position, a second portion bent rearwardly relative to said first portion, and a third portion opposite said second portion, the distance between said second portion and said third portion substantially corresponding to the width of an arm of a corner connector, forming a retainer in said second portion of said frame, attaching said corner connectors to said frames by locating one side edge of each arm in the space between said second and third portions and driving the opposite side edge of that arm into said space whereby the respective side edges of each such arm are received in engagement with the respective surfaces of said second portion and said third portion, said retainer means assisting in the holding by said second portion whereby the corner connectors are held in position relative to a frame.