| 摘要 |
<p>An auger for use in drilling into the earth under rotative movement in one direction of rotation, the auger having a cylindrical stem and a helical flight extending along the length of the stem, the helical flight being defined by adjacent segments of opposite flight orientation. The auger of the present invention enables the drilling of fast holes of any conventional size to any conventional depth required in overburden and bedrock. It reduces the tendency of bore hole wall collapse through the use of bore hole material to stabilize the hole and reduces the amounts of drilling muds needed.</p> |
