Pattern-changing structure for a projection light system

A pattern-changing structure for a projection light system comprising a base plate, a rotating disc, a motor, a patterned disc, the base plate having a shaft hole at the center thereof, and a light transmissive hole being provided adjacent to the shaft hole and a center hole being provided to the center of the rotating disc, a plurality of circular hole being located at the rotating disc surrounding the center hole, a plurality of screws being provided on the surface of the rotating disc, the motor being mounted at one lateral side of the base plate and the shaft center of the motor being mounted with a cam passed through the base plate, and the center of the rotating disc and an engaging and a disengaging mechanism being combine to form integrally as a unit, characterized in that one lateral side of the base plate is provided with a stopping crankshaft having two ends, one end being mounted with a stopping region and the other end being a spring hook, the spring hook is connected to a pulling-spring, and a cavity hole is provided on the base plate such that the stopping region of the crankshaft is protruded out of the cavity hole, and the circumferential edge of the rotating disc is provided with a plurality of positioning teeth, each teeth being spaced apart at equal distance, thereby, when the motor rotates, the cam controls the extending or retraction of the stopping crankshaft to either release or restrict the positioning teeth so that the rotating disc rotates intermittently and the patterns are changed and various patterned images are obtained.