Roll coupling trailer hitch assembly

A roll coupling assembly for roll coupling the drawbar of a trailer to the rear of a tow vehicle, the assembly comprising:

• a roll torque transfer structure including at least one first load bearing surface on a first load bearing structure mountable to the rear of the tow vehicle and adapted to be mounted closely adjacent thereto, and at least one second load bearing surface on a second load bearing structure mountable to the front of the trailer drawbar, wherein said first and second load bearing surfaces cooperate so as to releasably mate with one another for towing of the trailer behind the tow vehicle and, when the trailer is so mated to the tow vehicle, are distributed across a substantially planar interface between the rear of the tow vehicle and the front of the trailer drawbar so as to distribute torque imparted to the drawbar by relative rolling motion between the trailer and tow vehicle to the rear of the tow vehicle by distribution of resulting moments which are transferred to the tow vehicle so that the cumulative combined roll resistance of the tow vehicle and trailer resist the rolling of the trailer about the drawbar,
• a coupling alignment mechanism to adjust the relative orientation of said first and second load bearing surfaces in said substantially planar interface so as to align said first and second load bearing surfaces for said mating with one another.