A sprinkler includes a housing having a tubular axle, a control device including a base coupled at the housing, a bridge upwardly extended from the tubular axle, a first cover including a top platform and an assembling unit downwardly extended from the top platform, and a second cover, having a center through hole, coupled at a top rim of the base. The bridge has two or more bridge ribs and the assembly unit has two or more corresponding windows. The first cover is coupled at the second cover at a position that the assembling unit is downwardly extended through the center through hole until the in center through hole is covered by the top platform, such that the bridge ribs of the bridge are engaged with the windows of the assembling unit of the first cover to securely couple the control device with the housing in a screw-less manner.
