Patent ID: 9551190
Date: 2017-01-24
CPC Classifications: E21B

Claim:
1. An excavation tool comprising: a tool body centered on an axis line; and an excavation tip which is attached to an embedding hole drilled in a distal end portion of the tool body, wherein the tool body is centered on the axis line and is moved forward to a distal end side in a direction of the axis line, the excavation tip has an embedding portion, the embedding portion of the excavation tip having an outer cylindrical shape about a central axis, the embedding portion is formed integrally with a cutting edge portion of a distal end side in a direction of the central axis, the embedding portion is inserted into the embedding hole and the cutting edge portion is protruded from the embedding hole, and at least one excavation tip serves as a rotary excavation tip which is rotatable about the central axis of the embedding portion during excavation, is locked so as not to slip toward the distal end side in the direction of the central axis and is attached to the embedding hole, between an outer peripheral surface of the embedding portion of the rotary excavation tip and an inner peripheral surface of the embedding hole to which the rotary excavation tip is attached, a first surface has a concave groove going around the central axis and a second surface has a convex portion accommodated in the concave groove, and the convex portion is formed integrally with the second surface.