| 摘要 |
A borehole drilling apparatus 10 with in-line extending wings 200, comprising a guide device 100, wings 200 for extending a borehole, and a pilot bit 300, wherein the guide device 100 is configured to be a cylindrical structure through which an air hole 20 is passed along a centre axis thereof; and includes an upper shaft portion, a piston portion and a lower shaft portion, wherein the piston portion is formed on the outer circumferential surface thereof with a plurality of sludge discharging grooves; and the lower shaft portion is formed at the lower surface thereof with spiral projections, the spiral projections each having a curved surface whose radius increases from the centre, and formed at a side thereof with a retaining protrusion and pin 400 engaging means; wherein the extending wing is wholly configured to be a rectangular structure, and is formed at a side thereof with a guide groove for engaging slidably with the curved surface of the spiral projection below the guide device 100; and wherein the pilot bit 300 is configured to have a concave structure in which the lower shaft portion of the guide device 100 and the extending wings 200 are received, the pilot bit 300 being formed at a side thereof with an advancing and retracting window for the extending wing, formed at the inner circumferential surface thereof with a retaining step and pin 400 engagement means for restricting the rotation of the guide device 100 by the retaining protrusion, formed at the lower surface thereof with an air hole 20, and formed at the outer circumferential surface thereof with a plurality of sludge discharging grooves.
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