| 摘要 |
FIELD: mining.SUBSTANCE: rock-destroying tool includes casing with pressed-into hard-alloy inserts, between which there are discharge holes. Neighbouring discharge holes located at the opposite sides of hard-alloy insert are made at different depth relatively the casing surface, note that, at least, part of the holes is made with variable cross section, according to the first version decreasing, and according to the second version increasing in direction of tool rotation. At least, part of discharge holes can be completely located in the casing of the tool. Part of discharge holes in cross section can be of elongated shape, note that the large axis of the hole is parallel to the axis of adjacent hard-alloy insert.EFFECT: increase of bit lifetime, increase of reliability of hard-alloy inserts fastening, improvement of bottom-hole cleaning from slug.6 cl, 4 dwg |
