| 摘要 |
A vertical-axis water sprinkler with a reversibly rotating spray head has an internal control shell rotating with the spray head in a fixed housing. Adjustably fixed in the housing are a plurality of pattern defining plates. A pattern sampling disk with a specially contoured aperture therein is carried on a control shell within the housing and communicates from a water inlet in the housing to the spray head. The aperture sweeps across the face and edge of each of the pattern defining plates as the control shell rotates in the housing. The positions of the pattern defining plates control or limit the volume of water flow to the spray head, thereby generating a ground coverage pattern conforming to the relative positions of the plates. The speed of rotation of the spray head is made constant despite changes in the output flow rate by design selection of a friction bearing and of the surface areas of the control shell exposed to pressure forces in upward and downward directions. Water supply pressure variations are accommodated in one embodiment by a plurality of pattern sampling apertures in a sampling disk coupled to a pressure selector disk having a single aperture radially aligned with the spray nozzle of the sprinkler head. Momentary engagement of the sampling disk to the housing permits rotating the spray head affixed to the control shell to change the aperture selected.
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