| 摘要 |
PROBLEM TO BE SOLVED: To accurately assure verticality by reducing a frictional resistance with a preceding core drilling hole and to suitably pour water to cool a drilling bit. SOLUTION: In a process for cutting a large sectional concrete C by drilling a plurality of drilling holes partly duplicated with each other in one row at the concrete C by using a drilling tube 20 of a core drilling machine, a fixture for guiding the core drilling machine includes a guide plate 26 installed at an upper part of the preceding core drilling hole 1, a guide rod 28 to be inserted into the preceding drilling hole 1 through the plate 26 in a vertically movable and rotation inhibiting state, and a coupling pipe 30 coaxially coupled to an outer periphery of a lower part of the rod 28 and in parallel with and relatively rotatably to a lower end of the tube 20. Further, a plurality of guide rollers 46 are radially disposed on an outer periphery of a roller support pipe 32 so as to be rotated along an inner wall 1a of the preceding drilling hole 1. COPYRIGHT: (C)2004,JPO
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