| 摘要 |
Drilling apparatus embodying an elongated boxed-in frame supporting a transmission unit for longitudinal movement therein with the transmission unit connecting a polygonal drive shaft to a driven head which is threadedly connected to a drill rod section. A first drive unit carried by the elongated frame has a drive shaft in axial alignment with one end of the polygonal shaft with the other end of the polygonal shaft being in axial alignment with the drive shaft of a second drive unit. The drive units exert torque concomitantly at opposite ends of the polygonal shaft to rotate both ends of the polygonal shaft in the same direction. The elongated frame is carried by a supporting frame mounted for rotation about a vertical axis on a translatable frame to position the driven head at selected angular positions about the vertical axis.
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