Patent ID: 8573852
Filing Date: 2013-11-05
Classification: E02F,F16C

Abstract:
1. An earth-moving machine comprising: a lower structure; a ring gear mounted on the lower structure; an upper structure rotatably supported by the lower structure for rotation about an axis; a drive mounted to the upper structure; a pinion gear mounted on the drive and engaging the ring gear, wherein rotation of the pinion gear by the drive rotates the upper structure about the axis; a substantially circular lower rail mounted on the lower structure and having an inclined lower surface, the lower rail substantially concentric with the axis; a substantially circular upper rail mounted on the upper structure and having a substantially planar upper surface oriented substantially perpendicular to the axis; a plurality of tapered rollers supporting the upper rail above the lower rail for rotation of the upper rail about the axis, each roller engaging both the upper surface and the lower surface, wherein the ring gear includes a contact surface that maintains alignment of the rollers with respect to the upper rail and the lower rail.