Abstract: An angularity sensor is disclosed for incorporation within center pivot irrigation systems for providing a signal to respective controllers controlling the rotational driving force of respective span units in response to angular deviation between adjacent span units. The angularity sensor disclosed resists erroneous signals from roll, pitch, longitudinal extensions and contractions, and traverse dislocations between adjacent span units. It responds only to angular deviations between adjacent span units regardless of the other movements caused by the terrain being traversed. Parallel extensible members under tension are attached to opposite sides of one span unit and connected on the opposite end to a horizontal member rotatably mounted for rotation in a horizontal plane on the opposite span member. The rotatable member is connected to the input of the controller whereby only rotational forces of the rotating member are transmitted to the controller as angularity deviation signals.

Abstract: The present invention discloses an improved center pivot for a self-propelled center pivot irrigation system. The preferred embodiment is characterized by a vertical pivot pipe supported for rotational movement at both the upper and lower extremities thereof. Additionally, the gasket assembly providing leak-proof rotational movement of the pivot pipe relative to a fixed liquid supply pipe is characterized by a slideable casing which can be moved from a normal operating position wherein the fixed supply pipe and the rotating pivot pipe are bridged by the casing with gaskets disposed between mating surfaces and a second non-bridged position wherein the gaskets are removable so as to allow replacement of worn gaskets without moving or removing any of the major pipe components of the sprinkler system.