| 摘要 |
PURPOSE:To improve the durability of a shearing cutter by making a groove along the trim line of a steel bad through the compressive deformation thereby increasing the local stress when shearing at the rear stage and reducing the load applied on the shearing cutter. CONSTITUTION:Wedged grooves 11, 11' are formed by the grooved conical and trapezoidal rotary members 6, 6' at the front stage from the front and rear along the trim line through the plastic deformation, and to remain a narrow section 12 between them. Thereafter the upper and lower rotary round cutters 7, 7' at the rear stage are engaged at the narrow section 12 between the wedged grooves 11, 11' or on the line where the local stress is most concentrated, then said narrow section 12 is sheared by said rotary round cutters 7, 7' to produce a fine and smooth plane having no slack or warp. |
