| 摘要 |
A direct boring bit is provided to prevent the discharge channel of the inner bit from being clogged by soil produced during drilling of the ground, by injecting air through the air injection hole. A direct boring bit comprises an outer bit(10), a bushing, and an inner bit. The outer bit has a tip mounting unit(110) in which a tip(112) is mounted, a coupling part(120) connected to the inner bit, and a coupling groove(130) in which a C shaped ring is inserted. The coupling part includes an insertion groove(121) and a locking groove(122). The coupling groove includes a seating groove(135) formed deeper in the middle. The bushing is combined in the outer bit by the C shaped ring, and includes a mounting groove for the C shaped ring and a protrusion coupled to the leading end of a direct boring rod. The inner bit is separably combined inside the outer bit.
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