Abstract: An assembly for coupling a truck tractor to a semi-trailer. The assembly comprises an upper coupling plate, an intermediate plate, and a back plate. The upper coupling plate has an opening for receiving the kingpin. The intermediate plate is positioned on an upper surface of the upper coupling plate and has a portal for receiving a portion of the kingpin. The back plate is positioned adjacent the intermediate plate. A double shear attachment means joins the upper coupling plate, the intermediate plate, and the back plate are along a first shear plane and a second shear plane.