| 摘要 |
PROBLEM TO BE SOLVED: To provide a curvilinear excavator which can smoothly move its cutters outward, and protects the cutters etc. from excessive application of load. SOLUTION: The curvilinear excavator has a head portion 1 which is formed of a main block 11 and a movable block 12. The main block has an outer peripheral surface 11a which is axially movable along an inner peripheral surface A1 of a leading curved pipe A, and has an engaging groove 11b which is formed in the outer peripheral surface 11a and inclined so as to be located progressively inward toward an axially distal end side of the head portion. The movable block is engageable with the engaging groove 11b formed in the main block 11 so as to be movable along the same, and when moved to the distal end side along the engaging groove 11b, it is located inside the inner peripheral surface A1 of the leading curved pipe A together with roller bits (cutters) 13 arranged at a distal end. When the movable block is moved toward a proximal end side, at least the roller bits 13 are located outside the outer peripheral surface 11a of the leading curved pipe A. COPYRIGHT: (C)2005,JPO&NCIPI
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