| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw joint structure of an excavation tool that enables an unskilled operator to easily recognize the use limit of a screw of the screw joint structure and securely prevents the tool from being broken, and the excavation tool using the same.SOLUTION: There is provided a screw joint structure 1 of an excavation tool that connects a drilling bit and a drilling rod, drilling bits, or the drilling rod and a coupling to each other, and is constituted by threadably engaging a male screw 5 having a male screw part 6 formed thereon and a female screw 21 having a female screw part 22 formed thereon with each other. The female screw 21 has a skirt part 23 having the female screw part 22 formed at an inner periphery, and the skirt part 23 has a detection hole 27 formed to be open at an outer periphery of the skirt part 23 and to extend toward the female screw part 22, a bottom surface 28 of the detection hole 27 being arranged in the proximity to the female screw part 22 without being open in the female screw 21. |
