METHOD AND DEVICE FOR INCREASING DIAMETER OF METAL SHAFT MATERIAL

摘要

Method and apparatus for diametrically expanding a desired part of a metal shaft which can be a rod or a pipe, wherein the apparatus includes a driving rotary section (4) and a driven rotary section (6) arranged at a predetermined distance (D), each of the rotary sections (4) and (6) including a holder for holding a work, a pressing device (8) for pressing the work held by the holders along the length of the apparatus, and a biasing device (7) for declining the axis of the work, so that the work held by the holders at the distance (D) is rotated around its axis, and one of the holders is forced by the pressing device toward the other to carry out the diametral expansion, and then the work is bent back and straightened up.