A Trap Door Forage Wagon is a type of wagon used in farming that can unload without the operator having to stop. It earned top honors in the American Farm Bureau Federation's 14th annual Farmer Idea Exchange in the annual convention.
Operation
Two doors are located at the bottom of the wagon. Normally these are locked at a 45 degree angle downward to hold the haylidge inside the wagon. When the farmer drives over the pile he releases the doors from inside the cab of the tractor to instantly unload the wagon. This design offers greater safety, less wear from moving parts and most importantly greater efficiency.
References
Trap Door Forage Wagon Wikipedia(Text) CC BY-SA