Which term refers to the device that couples a tractor to a trailer?

• A. Fifth wheel.
• B. Disconnector.
• C. Absorber.
• D. Relay.

Answer: (A)

The device that couples a tractor to a trailer is the fifth wheel. It sits on the rear of the tractor and forms a locking hitch that accepts the trailer’s kingpin. When the kingpin sits into the fifth wheel throat, a locking mechanism clamps around it, securing the connection while still allowing the trailer to pivot for turning. This pivot is essential for steering the combination and for the trailer to follow the tractor smoothly. Proper height and secure locking are crucial for safe towing, and uncoupling involves releasing the lock and backing the tractor to release the kingpin.

Disconnector, absorber, and relay refer to other systems or components not involved in the tractor-trailer coupling, so they don’t serve the towing connection.