WORKING ARM FOR CONSTRUCTION MACHINE AND METHOD OF PRODUCING THE SAME

摘要

Thin plate members (28, 29) for a flat plane, thick plate members (30) for angled corners, and thick plate members (31) are alternately joined by butt-welding to form a wide plate-like body (27) whose thickness varies from place to place. Then, the wide plate-like body (27) is pressed at positions of right and left thick plate members (30, 30) for angled corners to form a letter U-shaped member (32) having a letter U-shaped lateral cross section. Further, thick plates (35, 35) are butt-welded to both sides of a thin plate material (34) to form a plate-like member (33), a separate body from the letter U-shaped member (32). After that, the plate like member (33) is joined to the under side of the letter U-shaped member (32) by using means such as laser welding. Thus, an angle cornered tube body having a square lateral cross section and constituting the main part of an arm is formed.