Abstract: A method is described for joining the opposite edge portions of a sheet of flexible material to form a durably-joined elongated tubular member. The material is shaped or folded to provide opposite edge flaps, spaced and extending outwardly from the tubular member formed. A strip of connector tape, folded lengthwise to form a pair of leg flaps, is interposed between the edge flaps with its legs confronting and extending oppositely thereto. Each leg flap is bonded to its corresponding adjacent edge flaps, whereby the tape serves to connect the edge flaps and form a longitudinal joint within the elongated tubular member. The tubular member so produced may include an insulating layer and a flexible skeletal structure therewithin.

Abstract: A clamp assembly for flexible duct of a type having a helically wound strip and a form-sustaining helically wound reinforcing member secured between lapping adjacent wraps of the strip. For reducing an end convolution of the duct, a one-piece spring wire clamp is provided having an operating arm and a lever arm connected in offset angular relation, opposite ends of the operating arm being mounted at opposite ends of an end convolution of the reinforcing member of the duct. The lever arm is movable into a closed clamped position engaging the end of the duct for effecting movement of the operating arm to contract the end convolution of the duct.

Abstract: Apparatus for generating wire reinforced tubular duct featuring a cantilever mounted mandrel supported for rotation and serving as a supporting surface about which lapping wraps of flexible strip of duct material are formed along a helical path around and forwardly off the mandrel. A helical guide fixed in relation to the mandrel and an endless drive belt coact to drive the flexible duct material along its helical path with the drive belt serving to advance the flexible duct material axially along the mandrel and to rotate the mandrel.

Abstract: A machine is provided for making flexible tubular insulated duct having multiple wraps formed about a compressible inside core. A sheet forming collar shapes the wraps about the core upstream of a joint sealer which cooperates with an underlying conveyor to draw the core and wrap materials along a linear path of movement through the joint sealer to form a longitudinally extending joint on the outermost wrap of the duct. A second conveyor overlies the first conveyor downstream of the joint sealer, and the second conveyor and the joint sealer are selectively adjustable in height to form duct of selected diameter size and to apply a desired tractive force to the sealed duct. A cutting unit is selectively operable downstream of the second conveyor for cutting the duct into predetermined lengths.