I am curious as to how these work. The 18' section swivels and the back end touches the ground when the 4' section is stationary. Well, my question is, how is the swivel action controlled. Just by gravity or is there a hydraulic assist? If there is not an assist, doesn't the trailer slam down when you drive up with a car or whatever it is you are loading. Must be a violent touchdown, in either direction.

 

Usually there is a hydraulic cylinder on the part that tilts, and that cylinder has a hose running form the fitting at the top of the cylinder to the fitting at the bottom. Somewhere in the hose there is a turn valve that will control how fast the hydraulic fluid travels from one end of the cylinder to the other, thus controlling how fast the bed will go up/down.

chaikwa.