Abstract: A round duct and apparatus and method of forming the duct in which the side edges of the duct are formed to interlock when the duct is folded and the flap is secured in place to provide support when the finishing duct tape is applied to seal the flap and complete the joint.

Abstract: A duct closure machine for closing duct board into duct with tape which can close duct having four or more sides. Duct board is moved through the machine by a single source of power driving upper and lower rollers with the lower set of rollers movable to accomodate duct of different size. The tape applicator is shiftable laterally to apply tape to duct of different number of sides such as ten sides. The tape applicator is controlled with a simple power circuit in which power to cut off the tape is only applied for a brief time as the completed duct passes through the machine.

Abstract: Apparatus and method of forming shiplap grooves (21, 23, 25, 26 and 28) in a duct board (12) utilizing a square (35) and measuring indicia (39). The apparatus comprises shiplap groove cutting tools (22) and (24) and an angle square (35) comprising a guide leg (37) and a base leg (36) having indicia (39) indicative of the desired dimensions for a resulting shiplap duct. The shiplap groove cutting tools have sleds (57, 67, 58 and 56) which are placed against the guide leg (37) to be guided by the same to produce shiplap grooves (23, 25 and 26). The length of the spacing between the grooves is equal to the indicated indicia (39) for the narrow sleds (57 and 68) or the indicated indicia plus the thickness of the board for the wide sleds.

Abstract: A machine for fastening the flap of a duct board previously cut in a manner to permit it to be folded into duct form; such machine being capable of stapling the flap to the side edge of the board if desired and of applying a sealing tape to the flap and adjacent other edge of the duct board to complete the forming and sealing of a piece of duct board into a duct.

Abstract: A machine for cutting fiberglass board of the type having an impermeable barrier, such as foil, on one face thereof. As a board of fiberglass moves through the machine, the leading edge of the foil is bent down from it normal plane of travel so that a knife edge which is below this plane of travel will be inserted between the foil and remainder of the board.The board is then maintained in its normal plane of travel and the knife edge being below the board forces the barrier to shear away from the board as the board passes through the machine. The knife edge cleans the loosened foil to remove most of the insulation material that might remain adhered thereto.