| 摘要 |
PURPOSE:To prevent any unexcavated remnants from occurring in a tunnel formed in a noncircular section such as an oval or the like by forming a section of an excavator into noncircularity, installing plural numbers of spoke cutters in front of this excavator, and giving a rotating motion to a drive shaft at the center of these cutters, while giving a revolving motion as well. CONSTITUTION:A rotary plate 3 is installed in the inner part of a shield excavator body 1 whose section is noncircularity. In addition, a cutter 2 is attached to a position other than a circular center of this rotary plate 3 free of rotation, and a drive shaft of this cutter 2 is attached to the rotary plate 3. Then, the side of the body 1 and a spoke 22 are coupled with a link 24, and this spoke 22 is installed free of opening or closing motion with the drive shaft as the center by expansion or contraction of a cylinder 25. |
