(625 ILCS 5/1-120.5)
Fifth wheel assembly.
A coupling device connecting 2 or
more vehicles operating in combination. The lower half of a fifth wheel
mounted on a truck tractor or converter dolly must be secured to the frame of
that vehicle with properly designed brackets, mounting plates, or angles and
properly tightened bolts of adequate size and grade or devices that provide
equivalent security. The installation shall not cause cracking, warping, or
deformation of the frame. The installation shall include a device for
positively preventing the lower half of the fifth wheel assembly from shifting
frame to which it is attached.
The upper half of a fifth wheel assembly must be fastened to the motor
vehicle with at
least the same security required for the installation of the lower half on a
truck tractor or converter dolly.
Every fifth wheel assembly shall have a locking mechanism. The locking
mechanism and any adapter used in conjunction with it must prevent separation
of the upper and lower halves of the fifth wheel assembly unless a positive
manual release is activated. The release may be located so that the driver can
operate it from the cab. If a motor vehicle has a fifth wheel assembly
constructed to be readily separable, the fifth wheel assembly locking devices
automatically on coupling.
The lower half of a fifth wheel assembly shall be located so that,
condition of loading, the relationship between the kingpin and the rear axle or
axles of the towing motor vehicle will properly distribute the gross weight of
both the towed and towing vehicles on the axles of those vehicles, will not
unduly interfere with the steering, braking, and other maneuvering of the
towing vehicle, and will not otherwise contribute to unsafe operation of the
vehicles comprising the combination. The upper half of a fifth wheel assembly
located so that the weight of the vehicles is properly distributed on their
axles and the combination of vehicles will operate safely during normal
(Source: P.A. 90-89, eff. 1-1-98.)