Sprinkler Gear Adjusters


This nonferrous grand prize winning brass adjustment gear assembly is a key component in commercial underground pop-up irrigation sprinklers.  The assembly weighs 5.4 grams and has a typical density of 7.6 grams/cc, a minimum yield strength of 13,000 psi (90Mpa) and a 14% elongation.  The design consists of a serrated flange assembled to an 18 tooth gear hub and then sintered to achieve a strong bond.  The material composition of the two parts is engineered to provide shrink characteristics that assist the sinter-bonding.  Critical tolerances on the gear include a diametral pitch of 64, a 25 degree pressure angle, a total composite tolerance of .006”, a tooth to tooth composite of .0025” and concentricity of .002” to the stepped inside diameter.  The design allows on-site adjustment to regulate the pattern and dispersion of water and the rotation of the sprinkler head.  Adjustment is achieved by depressing the gear and disengaging the serrated pattern of the locking clutch plate.  Manufacturing production volumes of the complex part using methods other than P/M would have been prohibitively expensive.