What is the function of the kingpin in a chassis?

The kingpin serves a critical role in connecting the chassis of a trailer to the towing vehicle (tractor) and allowing for pivoting movement during turns. This connection enables the two units to articulate relative to each other, which is essential for maneuverability and safe operation. The ability to pivot around the kingpin means that the trailer can follow the path of the towing vehicle, enhancing steering capabilities and stability while on the road.

The design of the kingpin accommodates the forces and stresses experienced during towing and turning, making it a key component in the design of both trailers and their coupling systems. This functional aspect ensures that the trailer can navigate sharp turns and adapt to changes in direction while maintaining a secure attachment to the tractor.