| 摘要 |
PURPOSE:To excavate a free section easily by forming a rotary body furnishing a center cutter, a driving device, a rotary cutter fixed in front of a rotary member, a guide member responding to the excavation form, and a regulating device. CONSTITUTION:By driving a motor with decelerator 35 in a skin plate 1, a ring 11 and a cutting wheel 2 are rotated, and a forming cutter 7 and the whole body of its driving device are also revolved around a center shaft G. And, since the rotor 28 of a control lever 29 is squeezed to a guide rail 34 by the enforcing power of a flexible member 33, the cutter 7 fixed to a cutter arm 70 connected integrally to the lever 29 is also revolved on a locus responding to the inner form of the rail 34. And the central circular part is excavated by a center bit 4 rotating at the center and cutter bits 5. As a result, a tunnel of a desired section form can be excavated. |
