Patent ID: 7299999

Claim:
A rotating stream sprinkler, comprising: a sprinkler body adapted for connection to a supply of water under pressure; a spray head rotatably mounted on said sprinkler body and having a first spring contact surface, the spray head carrying a nozzle having a nozzle port formed therein for outward projection of an irrigation water stream when said sprinkler body is connected to a supply of water under pressure, said nozzle port being offset relative to an axis of rotation of said spray head whereby the outwardly projected water stream produces a reaction drive torque for rotatably driving said spray head; a bearing assembly rotatably supporting said spray head relative to said sprinkler body, said bearing assembly including a second spring contact surface and at least one rotatable friction washer rotatable with said spray head and disposed in friction-producing bearing engagement with at least one substantially stationary friction washer carried by said sprinkler body to produce a friction brake torque resisting spray head rotation; said reaction drive torque and said friction brake torque being maintained in a substantially constant ratio for relatively slow and approximately constant speed rotational movement of said spray head throughout a normal operating range of water supply pressures; and a thrust spring positioned against the first spring contact surface and the second spring contact surface above the first spring contact surface, the spring expanding when the supply of water under pressure is turned off to apply a spring force for retaining said rotatable and stationary friction washers in bearing engagement and to apply a spring force for assisting in retraction of the spray head for seating the spray head with the sprinkler body.