Pop-up rotor type sprinkler with subterranean outer case and protective cover plate

A method of retrofitting a subterranean sprinkler unit that includes an upwardly opening cylindrical mounting case having an impact drive sprinkler mounted in an upper section thereof on an extensible riser assembly mounted in a lower section thereof, and including a protective disk-shaped cover plate mounted on top of the impact drive sprinkler, comprising the steps of:

• removing the impact drive sprinkler, the riser assembly and the protective cover plate from the subterranean case without digging around the subterranean case;
• inserting a pop-up rotor-type sprinkler inside of a cylindrical adaptor sleeve and coupling an upper end of the sleeve to an upper ring-shaped upper end cap of the rotor-type sprinkler, the rotor type sprinkler including a riser that encloses a nozzle at an upper end thereof, a lower riser retraction spring retainer on the riser, an upper riser retraction spring retainer beneath the end cap, and a riser retraction spring surrounding the riser and having its ends contained by the retainers;
• and
• screwing a male threaded segment of a lower end of the adaptor sleeve into a female threaded segment connecting the upper and lower sections of the mounting case so that a lower portion of the riser extends into the lower section of the mounting case when a source of pressurized water connected to the lower section is turned OFF and so that an upper portion of the riser containing the nozzle will extend above the upper section when the source of pressurized water is turned ON.

A sprinkler unit, comprising:

• an upwardly opening generally cylindrical vertically extending mounting case injection molded out of plastic as a single unitary structure and adapted for subterranean location, the case having a tapered lower smaller diameter section forming a pressure vessel with an inlet, a tapered upper larger diameter fluted section forming a sprinkler housing, an upper lip formed at an upper end of the upper section and normally positioned at the level of a grade, a female threaded segment at a junction of the upper section and the lower section of the mounting case, a plurality of circumferentially spaced first reinforcing ribs that extend radially and vertically between the upper lip and the upper section of the mounting case, a plurality of circumferentially spaced second reinforcing ribs that extend radially and vertically between the lower section of the mounting case and the upper section of the mounting case, a first vertical female threaded inlet formed in a bottom wall of the lower section of the mounting case and communicating with the pressure vessel and a second horizontally extending female threaded inlet formed in a side wall of the lower section of the mounting case and communicating with the pressure vessel;
• a pop-up rotor-type sprinkler including a turbine driven rotating nozzle, a ring-shaped upper end cap, an upper riser retraction spring retainer below the upper end cap, a cylindrical riser vertically extensible through a central opening in the upper end cap, a lower riser retraction spring retainer intermediate a length of the riser, and a riser retraction spring surrounding the riser and held between the upper and lower retainers;
• a generally cylindrical vertically extending adaptor sleeve surrounding the riser and having a male threaded upper end screwed into a female threaded inwardly facing surface of the end cap, and a lower end with a male threaded segment screwed into the female threaded segment of the cylindrical mounting case at the junction of the upper and lower sections;
• an O-ring surrounding the lower end of the adaptor sleeve above the male threaded segment of the lower end of the adaptor sleeve and providing a water-tight seal between the adaptor sleeve and the cylindrical mounting case;
• the adaptor sleeve being formed with a downwardly facing shoulder that mates with a corresponding upwardly facing shoulder of the mounting case to provide a stop that limits the extent to which the male threaded segment of the lower end of the adaptor sleeve can be screwed into the female threaded segment of the mounting case and limits the amount of deformation of the O-ring;
• and
• a generally horizontally extending protective cover plate rotatably mounted to the upper end cap of the rotor-type sprinkler and extending generally horizontally across a gap between the upper end cap of the rotor-type sprinkler and the lip of the cylindrical mounting case.

A method of retrofitting an already installed impact drive sprinkler in a can previously buried in the ground, the method comprising the steps of:

• locating an upwardly opening cylindrical mounting case, the case being buried in the ground and having an upper lip positioned at grade level, the case including an impact drive sprinkler mounted in an upper section of the case on an extensible riser assembly that extends into a lower section of the case, the lower section of the case being connected to a water supply pipe, and the upper section of the case having a protective disk-shaped cover plate mounted on top of the impact drive sprinkler;
• removing the impact drive sprinkler, the riser assembly and the protective cover plate from the case without removing the case from the ground or disconnecting the water supply pipe from the lower section of the case;
• providing a portion of a turbine driven pop-up rotor-type sprinkler, the rotor-type sprinkler having an extensible riser that has a nozzle at an upper end thereof;
• installing a riser retraction spring around the riser;
• inserting the portion of the pop-up rotor-type sprinkler and the spring inside of the case;
• and
• threadably coupling a lower end of the portion of the rotor-type sprinkler to a segment of the case connecting the upper and lower sections of the case so that a lower portion of the riser extends into the lower section of the mounting case when a source of pressurized water connected to the lower section is turned OFF, an upper portion of the riser containing the nozzle extends above the upper section of the case and the nozzle rotates and discharges a stream of water when the source of pressurized water is turned ON, and the riser retraction spring will retract the riser back into the case when the source of pressurized water is turned OFF.