| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a center beam of an upper frame the necessary part of which is fully reinforced and improved in rigidity, and which is reduced in weight and cost. Ž<P>SOLUTION: A pair of right and left center beams 22 are installed in a fore-and-aft direction on an upper frame bottom plate, and each center beam 22 is equipped with: a vertical plate 23 installed vertically to the bottom plate and elongated in the fore-and-aft direction; an upper plate 24 horizontally installed on the upper end of the vertical plate 23; and a high front part 22f and a low rear part 22r, which are formed in a continuous shape via a bent part 22a. A reinforcing plate 25 having a curved part 26a along the bent part 22a is installed on the lower surface of the upper plate 24 in the part where the front part 22f and the rear part 22r are continuous including the bent part 22a. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
