| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling tool having high strength and capable of drilling a hole by applying rotation force and hitting force to a bit at a tip of the tool by leaving the bit in the drilled hole after drilling the hole and drilling a hole in even a hard rock-bed satisfactorily. SOLUTION: This drilling tool 11 has rods 21, 21a for transmitting power for drilling a hole and a drilling bit member 31 provided at a tip of the rod 21a to drill the hole and is provided with an attaching and detaching structure for connecting the rod 21a with the drilling bit member 31 detachable between the tip part of the rod 21a and a rear end part of the drilling bit member 31. The attaching and detaching structure has an engaging cylindrical part 25 and an engaged cylindrical part 62 which are mutually engaged in the direction of length, and a core member 35 is inserted into inner sides of these engaging and engaged cylindrical parts 25, 62 to enhance the rigidity of the tool. COPYRIGHT: (C)2008,JPO&INPIT
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