DIRECTIONAL MULTI-BLADE BORING HEAD

摘要

55 DIRECTIONAL MULTI-BLADE BORING HEAD Directional multi-blade boring heads (1000, 1050) are disclosed which have first and second blades (1030, 1032) which each define a deflecting surface (1036, 1038) for deflecting the boring head when the head is advanced without rotation. At least one intermediate blade (1034) extends between the deflecting surfaces in a three blade design. In a four blade design, a second intermediate blade (1042) extends on the side opposite the first intermediate blade (1034). The boring head is particularly effective in drilling a straight borehole through a variety of soil conditions when the boring head is simultaneously rotated and advanced along the direction of boring.