| 摘要 |
A method is disclosed by which duct sections made of sheet metal can be joined, especially transversally, and which is based on the known art of providing the edges to be joined with bends, which are held together by a correspondingly bent strip, which is pushed over said bent edges. The improved method of the present invention ensures superior tightness of the seams as well as greater rigidity of the duct entities than before, and it is particularly characterized in that the bends made on the duct edges are half-closed (bent at an angle between 90 DEG and 180 DEG ) as opposed to fully closed (180 DEG ) bends in prior art, that a strip of a packing material is placed in the seam, and the seam is secured with a push-on strip having a substantially triangular cross section. This latter operation is performed with the aid of a special tool, which urges the central part of the strip against the packing and simultaneously supports the lateral components wings of the seam from below or even raises them. |
