| 摘要 |
The pivot connection member of a two-piece boom comprising a first boom having a pivot connection member pivotally connected to a boom support part on the base end side and a second boom the base end side of which is pivotally connected to the tip end side of the first boom and to the tip end side of which an arm is pivotally connected can be made in common with a standard boom. The lateral width of the body portion (51) of the second boom (18B) is so set that the second area (Y) of the second boom on the base end side is smaller than the first area (X) of the second boom on the tip end side. The base end side of the second area (Y) of the second boom (18B) is inserted between the right and left side walls (29) on the tip end side of the first boom (18A). Thereby, the second boom (18B) is so pivotally connected to the first boom that the second boom can be rotated around a lateral axis. |
