CORE BIT AND EXCAVATOR

摘要

PROBLEM TO BE SOLVED: To maintain excellent drilling efficiency by smoothly discharging chips generated at the place of excavation and smoothly supplying a cooling fluid. SOLUTION: The core bit 13 is composed of a cylindrical tube 14 with a through-hole 14a and a bit 15 installed at the front end section of the tube 14. A spiral groove section 10a towards the front end side towards the front side of the direction of rotation is formed to the inner circumferential surface 14' of the tube 14. A spiral groove section 10b towards the rear end side towards the front side of the direction of rotation is formed to the outer circumferential surface 14" of the tube 14. When excavation is conducted by abutting the bit 15 against concrete under the state in which the bit is connected to a shaft for a DC motor and turned, cooling water is forwarded forcibly to the place of excavation at the front end section by the groove section 10a while the chips generated at the place of excavation are discharged forcibly to the outside by the groove section 10b.