Boom of bucket type excavator and method for making same

Abstract

A boom body (23) comprises a boom front member (20), a boom intermediate member (22) and a boom rear member (21). An arm-connection bracket (24) is jointed to the boom front member (20) and a vehicle body-mounting bracket (25) is jointed to the boom rear member (21), thereby forming a boom. With this structure, a cross section of the boom body (23) is less prone to be deformed and therefore, the plate thickness can be reduced, the rigidity of the boom body (23) can be increased without mounting a cross section restraint material and the cross section of the boom is not deformed. Therefore, it is possible to reduce the boom in weight.

Dependencies are inferred from the claim text.