I had the same issue with mine. Once you get the fan off, the whole gear train should lift out without anything going "boing". With mine, the handle shaft was spinning inside its gear. There seems to be no key- what it had was a small roll pin that went thru the hub (?) of the gear into a hole on the shaft. Over time the roll pin loosened up and shifted out of the shaft. I lined the holes up and reinserted the roll pin, good to go! Not so fast, bucko- before long the pin came loose again. Grrrrr! I pulled everything apart, tapped the pin back in place, setting it below the surface of the hub. I then peened the hole just a little bit with a center punch to close up the hole and locking the pin in place. No issues since. Hope this helps.
Steve