A question about log trailers

[Frickman]

A little background for this question.  I am a retired logger who cut Appalachian hardwoods in Southwestern PA and Northern West Virginia.  I have seen plenty of log trailers on TV and YouTube you fellows run in the Pacific Northwest.  They are what we would call a "pole trailer". The trailer is one log pole with wheels and a log bunk on the back.  It is disconnected at the mill and rides on the truck back to the woods.  At the landing the loader operator lifts the trailer off the truck and reattaches it to the front half of the trailer.  The driver then has to hook everything up.  I don't know how best to describe the trailers, or even what they are called.  That's the best I can do.

Now here is my question.  On the trip back to the woods, how do you keep the trailer stationary on the truck and prevent it from slewing side to side? I can see there is a notch in the headache rack to place the pole.  What keeps the back end of the trailer that is resting atop and behind the fifth wheel from moving back and forth?

[Ljohnsaw]

I've seen them with the tandem axles riding each side of the forward log bunk. Then some binders holding it down.

"My" Logger has a self loader. There is a double hinge beam of sorts that is connected to the trailer pole. The pole slides through the tandem axle/bunk. He lets the trailer roll forward when empty, grabs a cable loop on the rear bunk and lifts. The hinges fold up and the trailer sets in a pair of wells just behind the front bunk for the wheels. He only has to pull the one pin that locks the hinge down. All cables and air lines stay attached. He can haul as short as 15' and longer than 33' if needed.

[sawguy21]

I saw a similar system in the 70's that used a winch to load the jack knife trailer, it worked but weight was a problem as it cut the payload. The lift on Frickman describes is tied to the truck with a wrapper to keep everything together. 

[Skeans1]

A little background for this question.  I am a retired logger who cut Appalachian hardwoods in Southwestern PA and Northern West Virginia.  I have seen plenty of log trailers on TV and YouTube you fellows run in the Pacific Northwest.  They are what we would call a "pole trailer". The trailer is one log pole with wheels and a log bunk on the back.  It is disconnected at the mill and rides on the truck back to the woods.  At the landing the loader operator lifts the trailer off the truck and reattaches it to the front half of the trailer.  The driver then has to hook everything up.  I don't know how best to describe the trailers, or even what they are called.  That's the best I can do.

Now here is my question.  On the trip back to the woods, how do you keep the trailer stationary on the truck and prevent it from slewing side to side? I can see there is a notch in the headache rack to place the pole.  What keeps the back end of the trailer that is resting atop and behind the fifth wheel from moving back and forth?

Simplest answer is when the trailer is piggybacked up on the truck the truck bunk has what are called rides for the trailer tires to rest on as well as keeping it centered. Depending on how the truck is setup if it has a set of rearward ride bars that's where the trailer will set or on most standard long loggers the trailer will sit on the rides of the bunk. Some use a chain with a binder to keep the trailer down on the truck well others will use a winch and strap.

[Ianab]

Slightly different setup to what the OP is describing, but similar idea. This is the "standard" local log truck setup. The "H" rated trucks will have an extra axle on the trailer, but it works the same way.

Loaded.



On the empty trip the bunks are folded down and the trailer is loaded on some auxiliary bunks and chained down with the regular chains and binders. 



I imagine the pole style trailers work the same way. 

As well as making the empty rig drive better, truck road taxes as based on hub meters. There is one on the truck, and another one for the trailer. Carrying the trailer back when empty basically cuts the road taxes by ~25%. 

Another thing I noticed about some of the new rigs is the 5 axle trailer overhangs the truck considerably. I think they hook up the trailer lights when it's being carried, to get around the "overhanging load" problem. If the trailer hangs 6ft out behind the truck, it's still legal if the lights are working.

[Frickman]

Thank you for all the answers.

[CCCLLC]

Thanks guys. Very informative. Always wondered but didn't  know who to ask.

[DCT2021]

Trailer sets on the truck bunk the reach sits between the ears of the cab guard and you have a chain usually with no binder or anything that hooks to the trailer so it can't bounce around to much, they weigh enough they don't really move, been taking them off trucks and throwing logs on them for about 30yrs.