The fifth-wheel coupling is used for which purpose?

The fifth-wheel coupling is used for which purpose?

• A. To connect the trailer to the kingpin
• B. To connect the tractor unit to the trailer
• C. To secure the trailer to the road
• D. To brace the trailer during detachment

Answer: (B)

The main idea is that the fifth-wheel coupling serves as the hitch that links the tractor to the trailer. The trailer carries the kingpin, and the fifth wheel on the tractor clamps around that kingpin to form a secure, releasable connection. This setup lets the two units turn together and supports the vertical load of the trailer, while still allowing some articulation for steering and road irregularities. It’s not about attaching the trailer to the road or bracing it during detachment—the wheels, brakes, and road surface handle road security, and detachment is controlled by the locking mechanism and release.

The main idea is that the fifth-wheel coupling serves as the hitch that links the tractor to the trailer. The trailer carries the kingpin, and the fifth wheel on the tractor clamps around that kingpin to form a secure, releasable connection. This setup lets the two units turn together and supports the vertical load of the trailer, while still allowing some articulation for steering and road irregularities. It’s not about attaching the trailer to the road or bracing it during detachment—the wheels, brakes, and road surface handle road security, and detachment is controlled by the locking mechanism and release.