BOOM STRUCTURE FOR CONSTRUCTION MACHINE OR THE LIKE

PURPOSE:To enhance the durability by forming a boom body composed of split sections which are separated from each other along a sectional neutral axis, longitudinal of the body, so as to prevent high stress caused by a waking load, from concentrating to a welded part. CONSTITUTION:The body 12 of the boom structure 10 is vertically split into an upper boom body 12A and a lower boom body 12B by a split line 22 along a neutral axis along which a vertical neutral plane in the cross-section of the body and a boom side wall surface cross together, and the upper boom body 12A and the lower boom body 12B are integrally welded together. Then, the structure 10 is installed on a working vehicle so as to perform working, and accordingly, a load is exerted to the structure 10, resulting in that high strength is induced at a corner part of the body 12. However, since the corner part of the body 12 has a structure which is formed by bending a one sheet, and since the welded position is located on the split line 22, no high stress is induced in the welded part. Accordingly, a stress reducing effect in the welded part is enhanced, thereby it is possible to enhance the durability of the structure 10.