Transmission apparatus of all-terrain vehicle

1. A transmission apparatus of an all-terrain vehicle comprising:

a non-stage transmission disposed in a power transmission path from an engine to drive wheels;

a forward and backward movement switching device capable of switching to a forward movement position, a neutral position, and a backward movement position, said forward and backward movement switching device being disposed in said power transmission path at a position near said engine;

a shift operation device for switching forward and backward movements disposed on a handle bar at a position adjacent to a handle grip, said shift operation device and said forward and backward movement switching device being interlocked with each other, said shift operation device being a rotary type and having a rotary member which is rotatable about an axis of the handle bar;

a locking mechanism mounted on said rotary member to releasably lock said rotary member; and

a stopper mechanism mounted on said forward and backward switching device to prevent said forward and backward switching device from shifting from said neutral position to said backward movement position, said stopper mechanism being interlocked with a brake of said vehicle so that said stopper mechanism is operated to allow said forward and backward switching device to shift from said neutral position to said backward movement position when a brake operation of the vehicle is performed.

2. A transmission apparatus of an all-terrain vehicle according to claim 1 , wherein said rotary member is positioned inward with respect to said handle grip fixed on an end of said handle bar in a manner that said rotary member can be rotated independently of said handle grip, and

wherein said locking mechanism includes a knob which is mounted on said locking mechanism in a radially movable manner so that said locking mechanism can be unlocked by pushing said knob radially inward.

3. A transmission apparatus of an all-terrain vehicle according to claim 1 , wherein said stopper mechanism is configured to prevent a switching rotary part of said forward and backward switching device from shifting from said neutral position to said backward movement position.

4. A transmission apparatus of an all-terrain vehicle according to claim 3 wherein said stopper mechanism has a stopper member capable of entering and leaving a moving track between said neutral position and said backward movement position of said switching rotary part of said forward and backward movement switching device, said stopper member being configured so as to be kept in a state that said stopper member enters said moving track by elastic means and leave said moving track by said brake operation,

wherein said forward and backward movement switching device includes a case, a shift lever shaft rotatably mounted on said case to perform a shift operation, said switching rotary part being fixed to said shift lever shaft and operatively connected to said shift operation device.

5. A transmission apparatus of an all-terrain vehicle according to claim 4 wherein said forward and backward movement switching device comprises a forward movement input gear, a backward movement input gear, a shift sleeve, and a shift rod operably connected to said shift operation device, said forward movement input gear and said backward movement input gear including dog pawls capable of independently engaging said shift sleeve, said shift rod operably connected to said shift sleeve.

6. A transmission apparatus of an all-terrain vehicle according to claim 4 wherein said stopper mechanism includes an adjustment bolt and a stopper pin.

7. A transmission apparatus of an all-terrain vehicle according to claim 4 wherein said knob includes a locking pawl and said shift operation device includes three locking notches corresponding to said forward movement position, said neutral position, and said backward movement position.

8. A transmission apparatus of an all-terrain vehicle according to claim 1 , wherein said brake is a foot brake.

9. A transmission apparatus of an all-terrain vehicle comprising:

a non-stage transmission disposed in a power transmission path from an engine to driven wheels;

a forward and backward movement switching device capable of switching to a forward movement position, a neutral position, and a backward movement position, said forward and backward movement switching device being disposed in said power transmission path near said engine;

a shift operation device located on a steering device of said all-terrain vehicle and operatively connected to said forward and backward movement switching device and capable of switching said forward and backward movement switching device into said forward movement position, said neutral position, and said backward movement position; and

a stopper mechanism connected to said forward and backward switching device and operatively connected to a brake of said all-terrain vehicle, said stopper mechanism adapted to only allow said forward and backward switching device to switch to said backward movement position when said brake is operated.

wherein said forward and backward movement switching device includes a switching rotary part and a moving track, said switching rotary part movable in said moving track, said forward and backward movement switching device being switched from said backward movement position, said neutral position, and said forward movement position by movement of said switching rotary part in said moving track, said stopper mechanism including a stopper member capable of entering and leaving said moving track to prevent said switching rotary part from switching said forward and backward movement switching device from switching from said neutral position to said backward movement position, said stopper member being configured so that said stopper member enters said moving track by elastic means and leaves said moving track when said brake is operated, and

wherein said shift operation device comprises a rotary member rotatively mounted on said steering device, said rotary member operatively connected to said switching rotary part.

10. A transmission apparatus of an all-terrain vehicle as in claim 9 wherein said rotary member is positioned near a hand-gripping area of said steering device, said rotary member capable of being rotated independently of said hand-gripping area.

11. A transmission apparatus of an all-terrain vehicle as in claim 10 further comprising:

a locking mechanism connected to said rotary member, said locking mechanism capable of preventing said rotary member from rotating, said locking mechanism including a knob, said knob when pressed releasing said locking mechanism so that said rotary member can rotate.

12. A transmission apparatus of an all-terrain vehicle according to claim 11 wherein said forward and backward movement switching device comprises a forward movement input gear, a backward movement input gear, a shift sleeve, and a shift rod operably connected to said shift operation device, said forward movement input gear and said backward movement input gear including dog pawls capable of independently engaging said shift sleeve, said shift rod operably connected to said shift sleeve.

13. A transmission apparatus of an all-terrain vehicle according to claim 11 wherein said stopper mechanism includes an adjustment bolt and a stopper pin.

14. A transmission apparatus of an all-terrain vehicle according to claim 11 wherein said knob includes a locking pawl and said shift operation device includes three locking notches corresponding to said forward movement position, said neutral position, and said backward movement position.