Abstract: Device for attaching two metal sheets or blanks together for absorbing the forces occurring particularly in ventilating systems to prevent loosening without requiring supplemental sealing means. The sheets or blanks to be fastened to one another are specially shaped and configured and are formed from blanks configured appropriately for the desired purpose. The clamped sheets are deformable in a corrugated-like manner in the region of clamping and within described parameters make it possible to secure previously unobtained extraction forces. The degree of bend and the angle and spacing between the legs determine the transmission of force.

Abstract: A joint assembly for the end of a prismatic duct comprises a frame including a plurality of elongate L-section profiles each formed unitarily of sheet metal with a pair of legs the first of which parallels a corresponding duct sidewall and forms one of two jaws which define a slot receiving that sidewall, the second leg being hollow and forming an open-ended transverse channel accommodating angularly or curvilinearly profiled sheet-metal arms of associated corner pieces. The channel is bounded by two generally parallel walls either or each of which has an extension forming part of the other jaw of the slot. The free edge of at least the second leg forms a bent-over two-ply stiffening rib which could be engaged by a connecting clip. Barb-like formations on either or both slot-forming jaws and on the sidewall bracketed thereby engage each other to lock the frame onto the duct.

Abstract: A gas duct is provided with a flange joint formed of a plurality of sheet-metal profiles each fitted over a respective duct side edge and of a plurality of corner pieces each joining together the two ends of two respective profiles. Each of these corner pieces is made of sheet metal and has a pair of legs formed with reinforcing corrugations. The legs fit into the ends of the profiles at the corners of the ducts. At the corner between the legs of each such corner piece is a hole surrounded by an annular corrugation that ensures proper spacing between two such corner pieces in a bolted-together joint assembly.

Abstract: A joint assembly for connecting at their ends a pair of ducts each consisting of side walls formed of sheet material and having a generally quadrilateral cross sectional configuration is provided by a plurality of joint sections each including a pair of perpendicularly extending flanges formed with double walls. The joint sections are mounted on the ends of each of the ducts with a duct wall extending into engagement between the double walls of one of the flanges of a joint section. Angle plates including a pair of arms and a corner region are engaged with the arms thereof extending into engagement between the double walls of the other of said flanges and by thus mounting a plurality of joint sections and angle plates at the end of each of said ducts, the ducts may be joined together by fastening means which extend through the corner regions of the angle plates.