Patent ID: 8690197

Claim:
A bearing structure apparatus for a pivoting irrigation system, the bearing structure apparatus comprising: a rotatable vertical section of a water-carrying conduit, the rotatable section including a first cylindrical sidewall presenting an inner surface and an outer surface, and defining a first longitudinal axis; a non-rotatable vertical section of the water-carrying conduit, the non-rotatable section including a second cylindrical sidewall presenting an inner surface adjacent to the outer surface of the rotatable vertical section, and defining a second longitudinal axis coaxially aligned with the first longitudinal axis; a first annular assembly including a first race mounted on the rotatable vertical section and a second race mounted on the non-rotatable vertical section, the first race rotatably connected to the second race; and a second annular assembly including a third race mounted on the rotatable vertical section and a fourth race mounted on the non-rotatable vertical section, the third race rotatably connected to the fourth race, wherein the first cylindrical sidewall defines an outside diameter and the second cylindrical sidewall defines an inside diameter, the outside diameter of the first sidewall is smaller than the inside diameter of the second sidewall, and the rotatable vertical section is housed substantially within the non-rotatable vertical section; and wherein the inner surface and the outer surface of the rotatable vertical section have inwardly tapered ends.