I think the drawbar was first created before they had come up with hitch balls. I can remember when trailers had a split tongue that went over-under a hitch and you dropped in a pin to attach them. This type of hitch works very well with a drawbar, because if you want to lift the tongue, the drawbar can rotate and not spread the split hitch. I think the drawbar lock and various other "gadgets" were introduced after the superiority of the hitch ball made it universal. ...this info isn't worth much, but it is free./w3tcompact/icons/laugh.gif