An operating mechanism includes a main shaft rotatably mounted on a side plate, and a swinging member arranged on the main shaft. The side plate has a limiting shaft blocking the rotation of the swinging member. A rotatable blocking member and an elastic member connected to the blocking member are arranged on the swinging member. The swinging member drives the blocking member to rotate around the main shaft. The elastic member drives a blocking portion of the blocking member to rotate toward the main shaft to locate, the limiting shaft outside a path of the blocking portion. An impacting member is inside the main shaft on the side plate and has two limiting portions arranged at intervals and in limiting fit with the main shaft. The impacting member pushes the blocking portion to rotate away from the main shaft to locate, the limiting shaft on the path of the blocking portion.