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Mowers and Sprinkler Heads: Keeping the Peace

A flag marks a sprinkler for maintenance at Yale University in New Haven, Conn. This rotor head appears to be installed correctly but erosion has lowered the ground level around it. Photo by Erik Skindrud

The clash that occurs when mowers meet sprinkler heads is nothing new. The damage produced can add up to hundreds of dollars a season in replaced hardware.

The infuriating thing about mower damage is that it's--for the most part--avoidable. The bottom line is that careful installation will leave the retracted sprinkler head at or near ground level, where mower blades can pass harmlessly over. Of course, differences in soil density and other factors can result in uneven settling, meaning that protruding heads need to be re-installed later.

A piston-driven water cannon, Underhill's M-160 is mounted on the sidelines and provides full or part-circle operation. Six M-160s are capable of irrigating an entire football field from outside the playing area. When not in use, the big rotor retreats beneath the field surface to avoid players, mowers and utility vehicles. Photo by Underhill

Problem with mowers date back to the days of brass sprinkler heads--when damage to lawn mowers was likely more severe than it is in today's plastic age. In 1979, Florida resident Steven W. Soos registered a patent for a ramped ring designed to keep blades away from brass spray nozzles.

Concrete rings around sprinklers are a proven way to protect irrigation hardware from lawn mowers. These rings are positioned next to a driveway and are intended to protect rotors from errant car tires too. This solution to sprinkler damage is an obvious one that was mentioned in the 1970s patent text at right and is still in use today. Photo by IB Clickin'

The patent document--part of which is reproduced below--is still instructive for anyone who has to deal with the issue. In fact, most modern sprinkler heads employ a plastic ring or housing that provides protection using the same principles as Soos' invention.

-- Erik Skindrud

Clonk! The clash between a sprinkler head and mower blade is accompanied by a sudden thud that jars and startles the mower operator. The realization that digging must be done soon sets in. (This above-ground-level head has had repeated run-ins with mowers.) Notice, however, that this sprinkler's plastic ring has prevented damages to the nozzle itself. Photo by Erik Skindrud

Call For Inventions

Experience has shown that protection of the sprinkling heads from lawnmowers, and particularly rotary lawnmowers is necessary. A commonly-employed guard ring is a cast concrete "doughnut" which serves as a protective collar. This requires the ground to be cut away around the sprinkler head to provide a recess for the doughnut so that the cap of the doughnut is close to ground level to permit lawnmower wheels to roll over the doughnut.

The present invention as compared to concrete doughnuts more readily accommodates and protects sprinkler heads which, after installation and perhaps after the sodding of the surrounding ground, or because of settling ground after installation, end up above the ground level rather than being flush. The flared skirt provides a ramp for the lawnmower and enables the wheel to more readily ride over a guard ring and thus minimizes the wheel obstruction and tipping or dislodging problems in using a guard ring to protect a sprinkler head which is somewhat above the level of the surrounding ground. Obviously, neither the guard ring or sprinkler head can be high enough to interfere with the passage of the reel or blade of a lawnmower over the ring and head.

The invention provides a low-cost guard ring which can be easily installed and is self-positioning with respect to ground level and which is constructed so that the guard ring may project a greater distance above the ground level than the conventional concrete doughnut and yet without creating an objectionable obstruction to lawn mower wheels and the like.


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May 24, 2019, 7:01 pm PDT

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