| 摘要 |
A bottom roller drive mechanism for a subterranean soil processing tool is provided. The tool is connected to a string of Kelly bar sections. Each Kelly bar section has a preferably square, or other polygonal, cross-section. A plurality of roller wheels is mounted in a drive assembly connected to the bottom rotary drive plate. The roller wheel assembly engages the faces of each Kelly bar section and rotates the Kelly bar around a vertical axis A-A. The upper and lower ends of each Kelly bar section are tapered to form a reduced cross-section at each joint. The roller drive assembly is free to rotate at each joint without rotating the Kelly bar. This allows misaligned Kelly bar sections to pass through the drive mechanism. |
