US Patent 9505280 Trailer hitch structure

A trailer hitch connected to rear frames has, on each side, a fixed member fixed to a rear end surface of the corresponding rear side frame. The rear surfaces of the fixed plates are connected to each other by a cross member. A hitch support for supporting a hitch ball is provided at the center of the cross member. A front surface upper portion of each of the fixed members is supported by an arm of a fixed bracket fixedly installed to the corresponding rear frame, so as to swing freely in a longitudinal direction.