Abstract: A speed change gear device is disclosed. A speed change gear box has an input gear. The lower gear is firmly secured with a gear shaft. A speed change disk is installed between two gears mounted on a gear shaft. A movable piece is placed in the annular groove of a speed change disk. A lower connecting plate is mounted at one side of the movable piece. Another end of an upper connecting plate is installed to a driving rod. Another end of the driving rod is connected to a linkage. Another end of the linkage is firmly secured to a gear switching rod. Thereby, by moving the gear switching rod, a switching rotary shaft can rotate so that the movable piece move the speed change disk. Thus the gears are switched to move forwards, move rightwards or to an idle gear.

Abstract: A speed change gear device is disclosed. A speed change gear box has an input gear. The lower gear is firmly secured with a gear shaft. A speed change disk is installed between two gears mounted on a gear shaft. A movable piece is placed in the annular groove of a speed change disk. A lower connecting plate is mounted at one side of the movable piece. Another end of an upper connecting plate is installed to a driving rod. Another end of the driving rod is connected to a linkage. Another end of the linkage is firmly secured to a gear switching rod. Thereby, by moving the gear switching rod, a switching rotary shaft can rotate so that the movable piece move the speed change disk. Thus the gears are switched to move forwards, move rightwards or to an idle gear.