Fifth wheel coupling
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(Redirected from Fifth wheel)
"Fifth wheel" redirects here. For other uses, see Fifth wheel (disambiguation).
The fifth wheel coupling provides the link between a semi-trailer and the towing truck, tractor unit, leading trailer or dolly. Some recreational vehicles RVs are in a fifth wheel configuration, requiring the coupling to be installed in the bed of a pickup truck as a towing vehicle. The coupling consists of a coupling pin (or king pin) on the front of the semi-trailer and a horseshoe-shaped coupling device called a fifth wheel on the rear of the towing vehicle.
The term fifth wheel comes from a similar coupling used on four-wheel horse-drawn carriages and wagons. The device allowed the front axle assembly to pivot in the horizontal plane, to improve turning.
It was invented in the UK by Clive Henderson[citation needed]
