US Patent 8100465 Trailer rear door frame with angled rear sill

A rear frame of a trailer has an elongated horizontal sill having a closed cross-section which is rigid in bending and in torsion. The elongated horizontal sill is formed of a fantail and a base plate attached to an underside of the fantail. The base plate has front and rear sections that are not notched as notching of the sill can weaken it. The front section is horizontal and the rear section is angled upwardly relative to the horizontal front section at a predetermined angle of approximately 22 degrees. The angling of the base plate provides a specialized geometry for accommodating a tuck-under lift gate. The sill also has minimal vertical dimensions to aid in the non-interference with legs of the tuck-under lift gate.