Rigid elongated member for use in vehicles and producing method and apparatus therefor

摘要

A method of producing an elongated member having a main body portion and terminal portions extending form ends thereof includes bending an elongated strip between circumferential faces of first forming rolls and second forming rolls having parallel central rotational axes. The circumferential faces of the first forming rolls include annular main body portion bending sections that form the main body portion in the strip and adjacent transition portion bending sections that form adjacent transition portions in the strip, thereby forming an intermediate stage elongated member. The transition portions have a cross-section that changes continuously from the annular cross-section of the main body portion to a different cross-section of the terminal portions. The intermediate elongated member is further formed by annular main body portion and transition portion bending sections of the second forming rolls corresponding to the respective bending sections of the first forming rolls in circumferential length but having a different axial dimension such that the intermediate stage elongated member approaches a shape of the fully-formed elongated member.