US Patent 8061489 Apparatus for controlling movement of four-wheel trailer

An apparatus for controlling movement of a trailer to permit pulling it behind a tow vehicle is disclosed. Mechanical subassemblies can be combined to provide a trailer that can be either guided to a tow vehicle by a winch or simply pulled along behind a tow vehicle at intervals. Thus, the apparatus is constructed and arranged to facilitate guidance to lead the trailer coupler to the tow ball for hitching in the conventional fashion, and is also constructed and arranged to provide a safe, convenient, hands-off approach to pulling the trailer behind the tow vehicle from one position in the field to another without hitching the coupler to the tow bar.