Not applicable. 
Not applicable. 
Not applicable. 
The present invention relates generally to a gardening sprinkler, and more particular to a mechanism to work the rotation of the spray head of the gardening sprinkler. 
The conventional gardening sprinkler comprises a main body and a spray head which is rotatably fastened with one end of the main body by a mechanism comprising a plurality of locating holes and a locating device.  The locating holes are disposed in a pivoting end of the spray head.  The locating device is disposed in the one end of the main body and is formed of a retaining hole, a plunger steel ball, and a spring.  The plunger steel ball and the spring are disposed in the retaining hole such that the plunger steel ball is urged by the spring, and that the plunger steel ball is partially jutted out of the open end of the retaining hole.  The one end of the main body is provided with a projection acting as a pivot on which the spray head turns.  As the spray head is turned in relation to the main body, the plunger steel ball moves into one of the locating holes of the pivoting end of the spray head, so as to locate the spray head at a desired angle.  However, the spray head can not be securely located at the desired angle by a joint effort of the locating hole and the plunger steel ball, due to the fact that the joint effort fails to provide a locating force strong enough to locate securely the spray head.  As a result, the spray head is vulnerable to dislocation by impact of the water pressure or external force. 
The primary objective of the present invention is to provide a gardening sprinkler with a revolving mechanism capable of locating securely a spray head of the gardening sprinkler. 
In keeping with the principle of the present invention, the foregoing objective of the present invention is attained by a revolving mechanism comprising an arcuate rack and an elastic locating piece.  The arcuate rack is disposed in a pivoting body which is fastened with a connection end of the spray head.  The elastic locating piece is secured to a fastening end of a main body of the gardening sprinkler.  As the pivoting body is turned on a projecting of the fastening end of the main body, the elastic locating piece plunges into one of the gullets of the arcuate rack so as to locate securely the spray head at a desired position.