slack in safety chains

Ron Gratz wrote:

LarryJM wrote:
Maybe Ron might see this and do his magic with some guesstimates on the forces expected.

Larry, is this what you had in mind?

Ron

Close enough and re reading that I think JBarca's description of what might happen in a breakaway event is what I also think should/might/could and most importantly hopefully HAPPEN.

Larry

Monaco, you're crazy. It takes at least two to cradle the tongue.

I use a bungee cord, works for me, and its cheap too.now its all happy-camping

LarryJM wrote:
Maybe Ron might see this and do his magic with some guesstimates on the forces expected.

Larry, is this what you had in mind?

Ron

nomad297 wrote:

mosseater wrote:
And, in addition, we're all trying to be safe and do the right thing and have the correct chain, hooks, latches, etc., but have you ever looked at the chain anchors and the welding quality at the attachment point? I believe the chain and attachments are the least of our worries. Probably going to pull that welded loop right off the "A" frame, IMO.

I have thought the same thing. That loop sure looks like a weak point on all trailers.

Bruce

I'm sure no ME, but you need to remember that in a breakaway scenario it's a dynamic situation and the trailer and TV are both moving in the same direction and while the forces on things like the chains and attachment points are going to be high I question just how high they are really going to be. Let's say a 10K trailer were to separate from a vehicle going 60mph I would think the forces from the trailer brakes being applied full strength might only result in a "force" of like 1/2 the weight of the trailer and that scenario would only last for well under 60 seconds until the trailer and TV are basically stopped. One could get a feel for this by simply manually activating their brake controller full tilt while going 60mph with their foot off the TV "go pedal".

Maybe Ron might see this and do his magic with some guesstimates on the forces expected.

WRT the single attachment point and crossing the chains I'm one that thinks crossing them is still the way to go since it does provide IMO more of a cradle to at least provide a "skid plate" from the chains to keep the tongue from "catching on the pavement" and it keeps the trailer tracking basically straight behind the TV. It might not provide a 100% cradle scenario from the tongue from ever touching the ground, but is that "really" needed to be effective. I would think what you wouldn't want is the tongue "digging into" the pavement and trying to "swerve" off to one or the other side of the line of travel of the TV and putting HUGE side forces on the rear of the TV.

When this subject comes up I wonder if all of us "arm chair" engineers wander too far off into the weeds in our novice thinking of "WHAT IFS".

Larry

mosseater wrote:
And, in addition, we're all trying to be safe and do the right thing and have the correct chain, hooks, latches, etc., but have you ever looked at the chain anchors and the welding quality at the attachment point? I believe the chain and attachments are the least of our worries. Probably going to pull that welded loop right off the "A" frame, IMO.

I have thought the same thing. That loop sure looks like a weak point on all trailers.

Bruce

And, in addition, we're all trying to be safe and do the right thing and have the correct chain, hooks, latches, etc., but have you ever looked at the chain anchors and the welding quality at the attachment point? I believe the chain and attachments are the least of our worries. Probably going to pull that welded loop right off the "A" frame, IMO.

Never quite understood the crossed chain idea, since all my trailers have always had both chains attached to the frame from the exact same point. Crossing? Cross what? So, I do the best I can. I give them an extra "one over the other" a couple times. It shortens the chain a little, but still, in all reality, won't form a cradle. Now if the chains were attached to the A-frame of the trailer a few inches apart from each other (two points) then crossing would definitely form a cradle. But when they are both attached at the same point, the best I can do is simply twist them one over the other.






Slack? yea, just enough you can make the sharpest turn (actually a jack-knife) and the farthest chain does not have any tension on it. That will automatically create the distance to "cradle" in the event of a disconnect.

Edit:
But you know, sometimes even with the best set-up, safety chains and break-away cable, it won't matter anyway! This actually happened to us several years ago:







FYI, we survived, had new A frame attached, and the world was wonderful after that! Thank goodness we did not have actual separation on the road.

downtheroad wrote:
Long enough so they don't bind when turning or backing.
Short enough so the tongue won't drag on the road of it is disconnected from the hitch.

Also have to consider the length of the brake-away cable in the equation.

X 2...same non-bind logic applied to breakaway cable.

Per crossing:

State requirements aside, practical instructions from most trailer makers re. safety chains require crossing them. This since crossing the chains forms a cradle for the tongue to rest on. Uncrossed chains do not.

If they crossed like they should be, they can be shorter then if not crossed. They will become more slack when you turn.