Patent ID: 8776567

Claim:
A method of manufacturing an arm material comprising: providing a parts material made of metal extending in a lengthwise direction and having a flat, hollow, closed cross-sectional shape, the cross-sectional shape having a pair of long sides which are parallel to each other; supporting the parts material at a first position while relatively feeding the parts material in the lengthwise direction; locally heating the parts material being fed at a second position downstream of the first position in the feed direction of the parts material; at a third position downstream of the second position in the feed direction of the parts material, water-cooling the portion of the parts material which was heated at the second position; supporting the parts material by a chuck mechanism supported by a vertical articulated industrial robot provided in a region downstream of the third position in the feed direction of the parts material; and imparting a bending moment to the heated portion of the parts material by two-dimensionally changing the position of the downstream chuck mechanism in a first plane roughly parallel to the pair of long sides of the parts material.