US Patent 7097742 Door for a vehicle

A vehicle door body outer panel includes a lower frame arranged in a lower portion of the door body, extending in the longitudinal direction of the vehicle, an outside plate forming a surface of the vehicle body outside the lower frame, and an inside plate folded back at a lower end portion of the outside plate, extending to the inside of the lower frame. When the lower frame and the outer panel are joined to each other, a closed cross section is formed in the lower portion of the door body.