Friday, May 10, 2013

Keeping Track

Here is a mobile platform which is capable of lifting thousands of pounds up to 40 feet high.  It broke down so they needed it moved elsewhere to be fixed.  
This tracked vehicle is controlled by a handheld wired control and is completely self contained with an engine and hydraulics.
 This is a direct tie down method which only yields 1/2 Working Load limit as the chain goes from the trailer through the tie down point back to the same side of the trailer.  Four 5/16" chains were used yielding 9400 lbs. of total tie down force.  The chains' main purpose is prevent sideways,forward, or backward movement.  Alone, they weren't enough to legally secure the vehicle so straps were used in addition to the chains, but I had put the camera away at that point so they aren't pictured here.
 The snap binders were used although ratchet binders would have been better here.  The snap binder ended up resting against the trailer rub rail.  4 inches of overhanging securement devices is allowed legally.  The snap binder was secured with a small twist link chain that has a spring clip attached to it. 
 The chains are supposed to be wrapped around the stake pockets instead of hooked directly to the trailer, but since this was a prototype trailer, the manufacturer neglected to share this information with me and after doing this load I learned the correct way to attach the chains.  Thanks to MacGyver for sharing this knowledge with me.  
It never fails that no matter how much you think you know, you never stop learning and things never stop changing.  Combine this with the technology that is being invented every day, and you have a busy time ahead of you trying to keep up.  


june in florida said...

Your getting through to the laymen, i saw a flatbed on the way to work loaded with coils and long bars and i checked out the way they had it tied down. The coils looked ok but the 20ft long bars only had straps over them. Should there have been something to prevent them sliding off the rear?

scott said...

Is there a load weight to tie down force ratio you like to keep?

Ed said...

The working load limit rules are the only way to go. So for a 10K lb. load, the tie downs would have to have 5K lb. WLL which is half the weight of the load. Then I add at least one more securement device on top of that, but not more than two more securement devices unless they are required to secure something on the load.