PURPOSE: To bend a special form hollow material, etc. at high work efficiency without causing deformation by inserting bars made of a synthetic resin into the hollow parts to be bent of a long sized hollow material.
CONSTITUTION: Bars 7 made of a synthetic resin such as polypropylene, etc. are inserted to the parts to be bent of a special form material 1 such as a window frame, etc. having 2 continuous hollow part 2. This special form material 1 is set to a bending die 5, and both ends are grasped by chucks 4. Bending is performed by moving the chcuks in the X-Y direction, and bent parts having radii of curvature R1, R2 are formed at the parts where bars 7 are inserted. By this way, bending is performed without causing deformation of the sectional form of hollow part 2. As the special form material 1 has a large slip factor against the bars 7, cracking does not take place. After working, welding is made without taking out the bars 7, and painting, baking etc. are performed.
TAMURA YOSHINAO
SUGIHARA SHIYOUJI
FUKUCHI HIROYUKI
