BOX BOOM LIFT ARM ASSEMBLY

摘要

The box boom lift arm assembly (18) of the present invention includes a single plate steel top wall (30) and a bottom wall (50) connected with a substantially non-transverse weld to a pair of single plate steel inner side walls (22, 26) and a pair of single plate steel outer side walls (94, 96) to define a closed box section having a rectangular cross section along the entire length, varying only in height and width. The unique configuration and shape of the plates and the use of non-transverse weld during manufacturing improve the fatigue characteristics, load distribution and strength of the box boom lift arm assembly (18) without increasing the weight of the machine.