A cradle drive mechanism is provided. The cradle drive mechanism includes a drive motor, an intermediate frame and a screw and nut transmission device driven by the drive motor so as to drive linear reciprocating motion of the intermediate frame. The cradle drive mechanism also includes a rotating, shaft having a first driving wheel and a gear, a transmission belt, and a rack meshed with the gear so that, during linear reciprocating motion of the intermediate frame, the rack forces the gear to rotate and drive rotation of the first driving wheel, wherein rotation of the first driving wheel drives rotation of the transmission belt. The cradle drive mechanism also includes a cradle connector fixed on the transmission belt and configured to connect a cradle and to drive linear reciprocating motion of the cradle.
