To efficiently execute three-dimensional bending to an extruded shape in the integrated state by executing bending of small radii of curvature by another bending after bending bent parts having a large radius of cuevature and twisted parts by push-through bending.
At the time of executing the three-dimensional bending to the extruded shape 1 the height of the cross-sectional shape, which is crossed orthoganally to the axial direction, of which is taken as D, the bent part R1 the radius of curvature of which is over 5D is bent by inserting the extruded shape 1 into a fixed die and a movable die and bending work is executed by displacing its position by pressurization and movement. And, by imparting turn of a prescibed angle to the movable die, working of the twisted part T is executed. When this bending is completed, in the bending work of the bent parts R2 R3 having the radius of curvature of ≤5D, the bent parts R2, R3 are formed with a press-bender device with which the extruded shape 1 is placed on two receiving dies and the extruded shape 1 is pressed from the upper side with the other receiving die. In this way, the three-dimensional bending of the extruded shape 1 is efficiently executed.
HAKAMATA TADASHI
SASAMOTO TAKASHI
HINO HARUMICHI
SUGIYAMA KEIICHI
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