Coupling and Uncoupling Trailers Flashcards

What is a 'fifth wheel' coupling on a heavy goods vehicle?

Answer: The coupling device on the tractor that locks onto the trailer kingpin

The fifth wheel is the horse-shoe-shaped coupling plate mounted on the rear of the tractor unit that receives and locks around the trailer's kingpin.

Before uncoupling a trailer on a public road, you must ensure:

Answer: The trailer is on level, firm ground with the brakes applied

Level, firm ground ensures the trailer will not roll or tip when uncoupled, and applied brakes prevent any unintended movement.

What is the purpose of the landing gear (dolly legs) on a semi-trailer?

Answer: To support the front of the trailer when uncoupled from the tractor

The landing gear is cranked down before uncoupling to support the nose of the trailer and keep it level when not connected to the tractor unit.

Which of the following would indicate a faulty fifth wheel coupling?

Answer: The locking jaws do not fully close around the kingpin

If the fifth wheel locking jaws do not fully close around the kingpin, the trailer is not properly secured and could detach from the tractor.

When coupling a trailer in poor visibility conditions such as at night, what is recommended?

Answer: Use a banksman or spotter to guide the reversing driver

A banksman provides real-time guidance and can communicate obstacles or misalignments that cameras or mirrors may not clearly show in poor visibility.

Before driving away after coupling a trailer, what must you confirm about the trailer brakes?

Answer: That the trailer brakes function correctly and are released for travel

The trailer brakes must be tested to confirm they work, then released so the vehicle can move; driving with trailer brakes applied causes overheating and damage.

At what point should you stop reversing the tractor unit when coupling to a trailer?

Answer: When you hear or feel the fifth wheel jaws lock onto the kingpin

The audible click and physical resistance indicate that the fifth wheel jaws have engaged and locked around the kingpin, confirming a successful coupling.