| 摘要 |
PROBLEM TO BE SOLVED: To reduce a shearing force in a multiple thread cutting of each shape steel by deviating a cut-in timing of a moving blade to the shape steel in each shape steel in the case where a plurality of shape steels are simultaneously sheared using a fixed blade and the moving blade having a plurality of aperture molds adapting to a cross section shape of the respective shape steels. SOLUTION: A clearance between each starting surface a1-c1 to be sheared of a shape steel 1 and each cut-in surface a2-c2 of each aperture mold 4a, 4b is provided at a predetermined range against a flange thickness t2 regarding each shape steel 1 such that each aperture mold 4a, 4b of a moving blade 3 subsequently shears a plurality of shape steels 1 when it is pushed down by a knocker, inclinedly advances and shears them. In the case where a clearance of a flange portion is made to CF1, CF2 regarding each aperture mold 4a, 4b and a clearance of a web portion is made to CW1, CW2, a value is set to CF1<CF2 and CW1<CW2. Thereby, a shearing is subsequently started from the shape steel 1 at a left side and a shearing force at the time of multiple thread cutting is reduced.
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