Abstract: A back gage is provided for use with a bending brake of a type that comprises a generally flat bed and a brake edge. In use, the bending brake receives the leading edge of a sheet metal member and bends a portion of the member around the brake edge in order to form a shape therein. The back gage of the present invention broadly comprises a movable carriage assembly arranged on the bed of the bending brake, a drive assembly for moving the carriage assembly relative to the brake edge of the bending brake, and a measuring device mounted to the bed of the bending brake and coupled to the movable carriage assembly. In practice, when the leading edge of the sheet metal member engages the movable carriage assembly, the measuring device conveniently displays the distance between the leading edge of the member and the brake edge of the bending brake.

Abstract: A portable, hydraulically operated punch-die unit for fastening together sheet metal members without the use of separate fasteners. The unit is used in a hydraulic system utilizing a two-stage high pressure hydraulic pump having a retractor valve arrangement which allows the punch to be driven at high pressure and then retracted by generation of a vacuum. This eliminates the complexity of other ways of retracting the hydraulically driven punch, and the simplicity of the unit and the relatively few number of parts that comprise it, allow the unit to be made small and lightweight and thus easily handled.

Abstract: A method and apparatus for automatically and continuously producing multiple blanks from a coil of sheet material with a minimum of scrap. The apparatus utilizes pinch rolls to advance and retract the sheet material from a coil, while simultaneously a cutter, such as plasma torch, moves transversely to the moving sheet material. Movement of the cutter and sheet material is controlled and coordinated so as to make the desired cuts in the sheet material and produce the blanks of the desired configuration.

Abstract: A method and apparatus for forming the locking bend on a Pittsburgh type seam used in joining the sections during assembly of box-shaped sheet metal ducts. The apparatus provides a means for securely holding the duct without the use of a mandrel to permit the sheet metal along the seam to be bent over by a forming roller moving along the seam so as to complete the joint and lock the seam.

Abstract: A method and apparatus for forming the locking bend on a Pittsburgh type seam used in joining the sections during assembly of box-shaped sheet metal ducts. The apparatus provides a means for securely holding the duct without the use of a mandrel to permit the sheet metal along the seam to be bent over by a forming roller moving along the seam so as to complete the joint and lock the seam.

Abstract: A hand-held power tool for installing the corners of transverse duct systems. The tool has powered jaws that, when placed over a standard corner piece and one of the flanges of the duct, will first clamp the corner piece in place on the flange and then crimp the flange over the corner piece to complete the installation. Both operations of clamping and crimping are accomplished with a single stroke of the operating rod of an air cylinder.