Abstract: A pop-up sprinkler having a nozzle housing threadably coupled to a pop-up stem, and including an axially projecting tab formed on the upper end of the stem which cooperates with spaced ribs formed on the inside of the nozzle housing to prevent over tightening of the nozzle housing relative to the stem during assembly and which resists unthreading of the nozzle housing from the stem to prevent vandals from unthreading the nozzle housing from the stem.

Abstract: An improved rotary drive sprinkler is provided for driving a sprinkler spray head in a rotary stepping motion to deliver irrigation water over a prescribed terrain area. The rotary sprinkler comprises a pop-up stem assembly carrying the spray head and movable within a sprinkler housing between a normal retracted position and an elevated spraying position when water under pressure is supplied to the sprinkler housing. During operation, the water flowing through the sprinkler housing powers a piston drive assembly including a spring-loaded drive piston which is alternately subjected to a predetermined pressure differential and normalized pressure to displace the piston in a reciprocating manner. The drive piston is coupled to a motion converter assembly for converting the reciprocal motion of the drive piston to an oscillatory rotary motion which is coupled in turn via a reversible one-way clutch assembly to the pop-up stem assembly.