BIT FOR PERCUSSION EXCAVATION AND RETRACTING BIT

• Main Authors: MARI TAKESHI, ENDO TETSUYA
• Format: Patent
• Language: English
• Published: 31.05.2002
• Edition: 7
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

PROBLEM TO BE SOLVED: To provide a bit for percussion excavation, in which only the edge of a blade easy to wear can be exchanged, which is economical, in which the constitution of the edge of the blade can be changed easily in conformity with a stratum at a site and which is configured so as to improve excavation efficiency. SOLUTION: The bit for percussion excavation is composed of a plurality of cutter pieces having tips consisting of a rigid material at front end sections and the bit on which the cutter pieces are mounted, the cutter pieces are installed detachably to a mounting section secured on the excavating surface of the bit, and the cutter pieces having different blade-edge shapes are arranged at required positions without receiving a constraint in the shapes of the edges of the blades and a cutting blade is constituted. In a retracting bit with the bit for percussion excavation, the cutter pieces are arranged to a plurality of the bits while being directed in different positions and directions.