Crane failure

[classictruckman]

Although shockloading is far more harmful, any actual over load gradual or not, is harmful to your equipment.

 

[whiteyford]

James, are those shots of that 22 ton manitex on a volvo cabover?

 

[classictruckman]

Yep thats our old go anywhere a car can Volvo. Weller Tree Service owns it now.

 

[CleanupPro]

Winch,
I have really never given a second thought to going over a log loader's capacity. Mostly I have never thought about it but now when I am, I realize that a log loader's lift capacity is governed by the hydraulic system's ability to lift the load. I don't know what the design failure load to rated load is, but I would venture to say that it is a pretty safe margin. I have seen a log loader boom fail, but this was from bad fabrication.

If a log loader tries to lift more than it can, either the main or stick boom cylinder will push in because the hydraulic pressure will go over the relief setting.

 

[classictruckman]

That is true for loaders, but even for them there is a point where the metal is fatigued so it is weaker than the hydraulics.

 

[theXman]

[ QUOTE ]
Although shockloading is far more harmful, any actual over load gradual or not, is harmful to your equipment.

[/ QUOTE ]

Okay, i agree, "any ACTUAL over load".

what i was saying was, if the pick is taken gradual, the computer will stop you (on a decent crane) and not actually lift a load that would cause damage. So, if i try to lift something that goes to 100% capacity, the computer will shut me down, then after a hit a OLP button, i can only telescope in or boom up very slowly.

No damage happens.

 

[treehumper]

Maybe this is one for the Mythbusters. Anyone care to write to them?

 

[theXman]

na, if i say it's true it's true, right?

 

[classictruckman]

I think this one is too complicated for Adam and Jamie.

 

[treehumper]

All the better. They'd be salivating over the potential... If the crane didn't fail they'd be sure to take it to the extreme to make sure it did.

Of course they would have "Buster" in the cab and not Grant or Kari (mmmmmm, she's hot!)

 

[classictruckman]

Got that right!!!

 

[CleanupPro]

ClassicTruckMan,

Yes, I definitely agree with you about metal fatiguing after repeated stress so that it has become the weak link not the capacity of the hydraulics. Just wondering, have you seen or heard of instances where this happened and the log loader boom failed?

 

[classictruckman]

Yes, but the loader boom was so old, had been remounted i'm sure more than a couple times and it had several patch welds so failure was to be expected. And to top that they just patched it again and worked with smaller pieces.

 

[classictruckman]

So Rob, any updates on the new crane? Any more conclusions or evidence on the failure?

 

[treedimensional]

The process for detecting cracks in iron is Magni-flux. One problem with the process is that the paint needs to be removed.

If I had any doubts about a piece of iron, repainting is the least of the worries these days. Here, IF a flaw is suspected during the annual inspection, IT MUST be magni-fluxed, marked and properly repaired (by a journeyman welder) prior to the crane being passed , and put back into service.

Sorry it took me this long to respond. I too am waiting to here what happened. Is there any word out on recalls or service bulletins being sent out for this make of crane?

 

[classictruckman]

Even if this model was failing across North America (which it was so you think they would fix it) they wouldn't openly recall them and admit they make a mistake.

When it comes to smaller cranes they all seem to have major problems, I have never talked to an owner or an operator who didn't have some problem with their crane.

 

[treehumper]

They are getting the new unit but nothing further about how or why. That may never come to light. I agree with you James, they'll deal with on a case by case basis.

 

[Jamin_Mayer]

What brand name is that crane?

Was that posted already?

 

[classictruckman]

Its a Manitex 22 Ton