| 摘要 |
<p>A reamer bit for reaming in earth formations. In one embodiment, the bit provides a plurality of levels (80) of stems onto which may be disposed semi-spherical reamer cutters. The cutters (86, 88) are arranged such that they are circumscribable within a sphere. The levels of stems may include as few as two stems or several. This arrangement provides for a significantly larger cutting area which, in turn, prevents premature bit wear. As a further advantage, the bit may include several levels with roller cutters having progressively increasing diameter to provide an arrangement which subscribes to a generally triangular formation.</p> |
