| 摘要 |
An adjustable riser for adjusting the elevational position of an irrigation sprinkler with respect to the surrounding ground level and/or with respect to the height of surrounding vegetation to be irrigated. The riser includes a movable cartridge within an internal bore of a housing having a plurality of catches outwardly projecting from the exterior wall of the cartridge and adapted to resiliently snap into or out of notches carried on the inner wall surface of the bore movably supporting the cartridge. The sprinkler is carried on a tube for discharging water while the opposite end of the tube includes an impact plate against which water pressure from the supply impinges. Upon impact, the tube with the sprinkler is forced upward within a housing against expansion of a spring, which normally urges the tube and sprinkler into a storage position within the housing. A linear adjustment of the riser, including the sprinkler and its tube, is effective by incorporating the cartridge with the catches movable within a toothed groove formed in the inner wall of the riser housing. The groove includes spaced-apart spiral teeth which are selectively engageable by the catches of the cartridge. Each of the catches are resiliently mounted in the cartridge and are yieldably urged into the notches or grooves for selective engagement with the teeth thereof.
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