| 摘要 |
PROBLEM TO BE SOLVED: To relatively stably support a counterweight even when the arrangement of vertical plates is largely biased.SOLUTION: A revolving super structure 3 includes an upper frame 4 supported freely swingably by a lower structure 2 through a swing bearing 33, an attachment 7 supported by the front part of a pair of vertical plates 13, 13 installed thereon, and a counterweight 31 whose intermediate part is supported by an attachment seat 32b installed at the rear part of the upper frame 4. The pair of vertical plates 13, 13 are arranged in a biased manner so that one is separated from the center C of the swing bearing 33 more than the other. The attachment seat 32b is joined with one vertical plate 13 without being joined to the other vertical plate 13. |
