US Patent 7527555 Grain unloader conveyor tube with dribble control door

Dribble control apparatus including a dribble control door hingedly or pivotally connected to an upper portion of a tube of a grain unloading conveyor. The door has a closed position covering a discharge opening of the tube for preventing grain dribbling, and an open position. The door has a shape which positions a center of gravity of the door for urging the door toward the closed position, including when closed, and which enables the door to support itself in the open position on a stream of grain flowing from the discharge opening with at least a substantial portion of the door spaced above the grain stream, while influencing or controlling an outward extent and direction of the flow of the stream.