DOWN REAMING APPARATUS

摘要

A down reaming apparatus (10) has an upper stabilizer (146) which supports the down reaming apparatus (10) in the bored hole. A plurality of shoe assemblies (164) are radially attached to the hub of the upper stabilizer (146). The shoe assemblies (164) are biased against a bored shaft wall by pressurized cylinders (162) which allow limited return movement with resistance of the shoe assemblies (164). 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 which allow passage of workers. A lower stabilizer (186) provides additional support for the down reaming apparatus (10). The lower stabilizer (186) also includes shoe assemblies (188) that are biased against the bored shaft wall by a pressurized cylinder (194).