The yellow input shaft may change rotation direction but the rotation direction of the orange output gear keeps unchanged because of ratchet mechanisms placed between the yellow shaft and the big gears. Friction overrunning roller clutch can be used instead of ratchet mechanism to avoid noise and backlash.
Pictures of every part of this mechanism are available at:
http://www.mediafire.com/view/?sqdbcy6m08mm2c8
STEP files for this mechanism are available at:
http://www.mediafire.com/?yfu5jm3u221sna7
آی-ویدئو