Most impact sprinklers comprise a sprinkler body with a sprinkler nozzle, and a sprinkler arm mounted hingedly to the body to revolve about a central axis. The sprinkler arm (also known as ‘hammer’) is adapted to be operated by a jet emitted from the sprinkler nozzle. The hammer is generally formed with a curved portion designed such that impact of the jet upon this portion causes the hammer to perform a reciprocal rotary motion about the central axis, the rotary motion having enough momentum on the return, added with power of the directional jet, so as to cause rotation of the entire sprinkler body about the central axis.
It should be appreciated that during rotation of the sprinkler, the extent of each angular increment of rotation of the sprinkler is erratic/random, i.e. one increment is not equal to the next, whereby the nozzle of the sprinkler rarely returns to the same position upon completing a full 360° turn.
In the field of irrigation, especially irrigation by sprinklers, adapted to provide water to a predetermined area, it is usually desired to have a uniform spread of the irrigated substance, e.g. water, across the entire area. For this purpose, many sprinklers are provided with a splitter or deflector, adapted to split the water jet emitted from the sprinkler nozzle.
In some sprinklers, the hammer itself serves as a deflector, since upon impact of the jet on the curved portion of the hammer, deflection and/or splitting of the jet takes place.
In more advanced sprinkler, additional deflectors and splitters are employed to gain a wider spread of water along the horizontal plane, across the area to be irrigated. One example of such a sprinkler may be found in U.S. Pat. No. 4,453,673.
Several constructions have also been devised to deflect the water jet along the vertical plane as may be found in U.S. Pat. Nos. 7,014,125, and 5,671,886 to the Applicant, as well as U.S. Pat. Nos. 4,632,312, 5,267,689, and a product by Irritrol systems (code 1015005, model AR3-LA)