It is in the nozzle above the rocker shaft, set with a front end with a deflector plate (baffle) and guide plate rocker pressure water from the nozzle of the nozzle when sprayed, the deflector plate impact guide plate, so that the rocker arm produces tangential motion force around the cantilever rotation of an angle, and then return under the action of the torsion spring and hit the nozzle, so that the nozzle turn an angle, and so on repeatedly, the nozzle can make a full-circle rotation. If the nozzle is equipped with a limiting device and a reversing mechanism, so that the nozzle in the rotation of a certain angle after the reversal of rotation, you can carry out fan sprinkler irrigation. Suitable for fixed medium pressure sprinkler systems.