Patent ID: 7980488

Claim:
A rotary sprinkler comprising: a shaft having a cam, said cam having at least one radially outwardly projecting cam lobe; a rotatable water distribution plate on one end of said shaft adapted to be impinged upon by a stream emitted from a nozzle causing at least said water distribution plate to rotate; a hesitator assembly including a stationary housing having a sealed chamber at least partially filled with a viscous fluid, with at least said cam and said at least one cam lobe located within said chamber, and a rotor ring located within said chamber in substantially surrounding relationship to said cam, said rotor ring loosely located within said chamber for rotation and translation, said rotor ring provided with at least two hesitator lobes projecting radially inwardly and movable laterally into and out of a path of rotation of said at least one cam lobe, said rotor ring further provided with a first plurality of radially outwardly projecting teeth selectively engageable with a second greater plurality of teeth provided on an inner wall of said housing; and wherein rotation of water distribution plate is slowed during intervals when said at least one cam lobe engages and pushes past a respective one of said at least two hesitator lobes, said cam lobe exerting both rotation and translation forces on said rotor ring, with one of said first plurality of teeth on said rotor engaging one of said second plurality of teeth on said housing wall.