| 摘要 |
PROBLEM TO BE SOLVED: To provide a core collecting device capable of surely collecting a core in a normal state even when the ground is formed of alternate hard and soft layers by discharging a fluid from a fluid passage to the outer surface side of a bit for a hard rock layer to prevent the damage or seizure of the bit, preventing the discharge of the fluid from the fluid passage to the inner surface side for a soft rock layer to prevent the outflow of sediment, and preventing the corotation of an inner pipe with an outer pipe. SOLUTION: The tip part inner surface of the bit 2 mounted at the tip of the outer pipe 1 is fitted to the tip part outer surface of a core taking case (lifter case 31 or shoe 39) mounted at the tip of the inner pipe 3 while keeping a slight clearance 53 so as to substantially block the fluid passage 5. The discharge port 50 of the fluid passage is formed so as to be opened to the outer surface side of the bit.
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