| 摘要 |
PURPOSE:To permit the outside diameter of excavated face to be varied as well as obtain sufficient structural strength by a method in which many rotary cutters are provided around a central cutter in a back and forth movable manner along the inner sloped face of a housing chamber. CONSTITUTION:A cap-shaped partition wall 12 is positioned in the excavating front face skin plate 11 of a shield excavator 1. A central cutter 2 is set on the center of the wall 12 and turned to excavate the front face of the projection 13 of the wall 12. Many cutters 3 are set around the cutter 2 and turned to excavate the front face of the recession 14 of the wall 12. The cutters 3 are designed to be slid back and forth along the inner sloped face of a housing chamber 31, and the interval between the peripheral edge of the cutters 3 and the tail plate is varied. |
