Step-bending die device

A step-bending die device comprising a die and a punch for forming steps on a workpiece by changing relative position of said die and said punch, wherein:

• said die is to be constituted by having a horizontal surface and an inclined surface, forming a semicircular groove with a semicircular cross section along a longitudinal direction on said horizontal surface and installing a semicircular rotary blade rotatably in said semicircular groove,
• that said punch is to be constituted by having a horizontal surface and an inclined surface, forming a semicircular groove with a semicircular cross section in a longitudinal direction on said horizontal surface and installing a semicircular rotary blade rotatably in said semicircular groove,
• that vertical notches being at positions changing from said horizontal surfaces to said inclined surfaces and communicating with said semicircular grooves are formed in longitudinal directions in said die and said punch, so that top portions of said die and said punch are formed in said longitudinal directions, respectively, and
• that said punch is assembled to a press brake as point symmetry with respect to said die so that said horizontal surface of said punch faces said inclined surface of said die and said inclined surface of said punch faces said horizontal surface of said die.