Abstract: A nutating sprinkler assembly includes a sprinkler body having one end adapted to be coupled to a water supply conduit and an opposite end supporting a nozzle; at least one arm extending from the sprinkler body for supporting a removable cap assembly downstream of the nozzle, the cap assembly having a center body supporting a rotor plate having off-center grooves for distributing a stream exiting the nozzle and impinging upon the grooves. A spool bearing assembly having upper and lower bearing flanges is supported in the cap center body, and the center body mounts an interior ring loosely confining the spool bearing assembly and the rotor plate. The center body has an end wall formed with a post extending toward and received within a cavity of a lower spool bearing component of the spool bearing assembly when the rotor plate is in an at-rest position, thereby creating an unstable arrangement causing the rotor plate to tilt to an off-center position.

Abstract: A nutating sprinkler assembly includes a sprinkler body having one end connected to an adapter; a nozzle mounted in the sprinkler body captured between the adapter and the sprinkler body; at least one arm extending from the sprinkler body for supporting a removable cap assembly downstream of the nozzle, the cap assembly having a center body supporting a rotor plate having off-center grooves for distributing a stream exiting the nozzle and impinging upon the grooves; a hub having one end secured in the rotor plate and an opposite end supporting a load disc, the load disc loosely captured between opposed rings provided in the center body; the center body having an end wall formed with a tilter button extending toward and engaging a center portion on an underside of the load disc when the rotor plate is in an at rest position, thereby creating an unstable arrangement causing the rotor plate to tilt to an off-center position.