US Patent 10040326 Vehicle hitch adapter comprising a pitch lock system

Vehicle hitch adapter comprising a height adjustment post comprising a plurality of pairs of opposed spaced apart height adjustment apertures; a mounting box surmounting the post; a pitch lock system comprising a pitch box having spaced apart pitch plates defining a chamber therebetween for an inferior end of the post to pass therethrough with a pair of opposed spaced apart height adjustment apertures contained within the chamber and the pitch plates comprising a set of spaced apart vertically extending angled end obround shaped slots having a lower surface end defining an at rest position and an upper surface end angled to form a shoulder surface defining a potential energy state; and a pin extending through the obround shaped slots and the apertures contained within the chamber wherein the pin is supported on the shoulder surface in the potential energy state during loading and on the lower surface end during transport.