| 摘要 |
<p>A down reaming apparatus (10) has an upper stabilizer (14) which supports the down reaming apparatus (10) in bored hole. A plurality of wheel assemblies (46) are radially attached to the hub (32) of the upper stabilizer (14). Each of the wheel assemblies (46) has rotatable tires (54) oriented against the bored hole wall, and a rotatable overload wheel (60) which contacts the tunnel wall upon compression of the tires (54). A weight assembly (90) comprising a plurality of stacked plates (16) is secured to the frame of the down reaming apparatus (10) and has manways (108) therethrough. A lower stabilizer (30) provides additional support for the down reaming apparatus (10). A plurality of wheel assemblies (130) are radially attached to the hub (122) of the lower stabilizer (30). Each of the wheel assemblies (130) has a rotatable wheel (144) pivotally attached to the lower stabilizer hub (122) and spaced therefrom by a compressible bumper (138) which reacts against the bored hole wall to stabilize the down reaming apparatus (10).</p> |
