Terms Used In Wisconsin Statutes 347.47
(1) No person shall operate a vehicle towing or drawing another vehicle or vehicles on a highway if the drawbar or other connection between any 2 vehicles exceeds 12 feet in length.
(2) No person shall operate a motor vehicle drawing a trailer, semitrailer, recreational vehicle, or mobile home upon a highway unless the hitch and coupling attaching the trailer, semitrailer, recreational vehicle, or mobile home to the vehicle by which it is drawn is of such construction as to cause such trailer, semitrailer, recreational vehicle, or mobile home to follow in direct line with the propelling vehicle without dangerous side swing or wobble. The hitch and coupling, the surface to which they are attached, and the connections, shall be of sufficient strength to prevent failure under all conditions of operation. The hitch is that part of the connecting mechanism, including the coupling platform and its attaching members or weldments, which is attached to the towing vehicle. The coupling is that part of the connecting mechanism, including the coupling and its attaching members or weldments, which is attached to the trailer, recreational vehicle, or mobile home and by which connection is made to the hitch. If a device is used between the trailer proper and the coupling such as a pole, such device shall also meet the requirements of this section.
(3) In addition to the hitch and coupling specified in sub. (2), every towed vehicle shall be coupled to the towing vehicle by means of safety chains, leveling bars or cables. This requirement does not apply to a semitrailer having a connecting device composed of a 5th wheel and kingpin assembly, nor to a pole or pipe dolly. The safety chains, leveling bars or cables shall have only the necessary slack to permit proper turning and safety chains or cables shall be so connected to the towed and towing vehicle to prevent the drawbar from dropping to the ground if the hitch or coupling disengages. Two separate lengths of safety chain, leveling bars or cable shall be required on all trailers and mobile homes; however, the department may authorize use of such other appropriate equipment or methods approved by nationally recognized organizations which recommend safety standards for motor vehicles.
(4) Trailer, semitrailer, recreational vehicle, and mobile home couplings and the safety chains, leveling bars or cables shall be of such minimum strength, design and type as established by published rule of the department.