Fifth wheel for the tractor or the trailer of an articulated truck

Fifth wheel for the coupling of a tractor of an articulated truck with a truck trailer comprising a wheel plate, a kingpin (20) with an inner bore and with an outer coupling or engaging surface (30) as well as with connections for linking electric and pneumatic supply lines between the tractor of the articulated truck and the truck trailer, wherein the supply lines of the tractor of the articulated truck lead to a male connector (100) of a supply unit (10) and the supply lines from a female connector (200) in the interior of the kingpin (20) to the designated places at the truck trailer, the male connector (100) being extendable from the supply unit (10) and retractable into the female connector (200), and wherein the male connector (100) is rotatable with regard to the female connector (200), characterised in that

• the inter-connectable parts belonging to the supply lines of the male connector (11-15) and those of the female connector (21-25) are configured as respective rotational-symmetrical bushes that fit into each other in pairs,
• that the connecting areas of the bushes in the coupled condition are spatially confined to the area situated radially on the inside with respect to the coupling and engaging surface (30) of the kingpin (20),
• that all bushes (11-15, 21-25) are aligned coaxially to one another and to the axis of the kingpin (20),
• that the bushes (15, 25) for the direct voltage supply are arranged radially on the very inside of the kingpin (20) and in the supply unit (10), the bushes (13, 14, 23, 24) for data lines are arranged further towards the outside in the kingpin (20) and in the supply unit (10), and the bushes (11, 12, 21, 22) for the pressurised air supply lines surround the electrical lines, and
• that the radially largest bush (11) and the inner bore of the kingpin (20) each have a diameter that is less than half the outer diameter of the coupling or engaging surface (30) of the kingpin.