To ensure sufficient rigidity while improving workability in manufacturing and assembling by forming a swing bracket integrally as a cast component to simplify welding work.
The swing bracket 16 of the revolving frame 11 is integrally formed as a cast steel component comprising a cylindrical boss part 17, a lower plate part 18 and an upper plate part 19. A front vertical plate 15 and the like are joined to the boss part 17, the lower plate part 18 and the upper plate part 19 respectively by welding. A front end part 13B of a bottom plate 13 is butt-welded to the rear end side of the lower plate part 18 through a stepped part 18C. A blocking plate 24 extended inclining obliquely downward to the upper face side of the bottom plate 13 from an inclined face part 19B of the upper plate part 19 is provided between the left and right front vertical plates 14, 15. A blocked space 25 of box structure is thereby formed among the bottom plate 13, the front vertical plates 14, 15 and the swing bracket 16.
| JPH11107315 | SLEWING CONSTRUCTION MACHINE |
| JP6413567 | Construction machinery with steps |
YAMADA KAZUNORI
MOTOZU MAKOTO
