| 摘要 |
A rotating joint for a sprinkler that provides a substantially constant rate of rotation regardless of water pressure and flow rate fluctuations. The joint includes a stationary lower portion that is in fluid communication with a pipe that delivers pressurized water to the sprinkler, and a moveable upper portion rotatably connected to the stationary lower portion about a substantially vertical axis. The moveable upper portion rotates in response to tangential forces that are applied by an impulse arm carried on a barrel from which pressurized water is discharged. The rate of rotation of the moveable upper portion is controlled by a braking mechanism that includes a pair of disks rigidly attached to the stationary lower portion and a pair of breaking elements mounted on the moveable upper portion. The pair of disks are located between and are in frictional engagement with the pair of braking elements with the pair of disks being secured against rotational and axial displacement with respect to the stationary lower portion. Variations in water pressure axially displace the moveable upper portion with respect to the stationary lower portion so that a braking element exerts a frictional force on a disk that is proportional to the water pressure to result in a self-adjusting braking force.
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