Abstract: The present invention involves a central pivot assembly for a self-propelled, center-pivot irrigation system. The assembly includes an hydraulic slip ring arrangement, a pivot arrangement, and a support arrangement for the pivot pipe of the irrigation system. The hydraulic slip arrangement includes first and second concentrically positioned rings which permit hydraulic fluid to continuously flow along out and return paths between a stationary source and the moving, pivot pipe. The pivot arrangement of the present invention includes a pivot bar, sleeve member slideably positioned about the pivot bar and fixedly secured to the pivot pipe, and pillow blocks which slideably receive the ends of the pivot bar. This arrangement allows the pivot pipe to move in vertical planes to accommodate the up and down motion of the distribution pipe as it revolves about the central axis of the system.

Abstract: An alignment control for a self-propelled irrigation system. The alignment control maintains adjacent pipe segments of the irrigation system in a predetermined alignment and includes an elongated actuation arm pivotally mounted near its center for movement about a substantially vertical axis. One end portion of the arm is spring biased against one of the pipe segments and the other end is operably connected to a control valve which runs one of the self-propelled support towers of the irrigation system. In the preferred embodiment, the end portion abutting the pipe segment is bifurcated into two legs which vertically straddle a section of the pipe segment. The spring means biases one of the legs toward an abutting relationship with the pipe section making the actuation arm very sensitive and responsive to misalignments of the adjacent pipe segments.