US Patent 9168592 Limited vertical access drilling machine

A positive-feed drill motor assembly includes a positive-feed motor, a gearbox, and a drill-bit. The positive-feed motor includes the spindle which rotates around a spindle axis and simultaneously translates in a direction parallel to the spindle axis. The gearbox includes a plurality of gears rotated by the spindle. The plurality of gears is configured to engage and rotate a drill-bit around a drill-bit axis which is offset from the spindle axis. The gearbox and a drill-bit attached thereto are configured to simultaneously translate with the spindle in the direction parallel to the spindle axis as the spindle rotates around the spindle axis.