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Rank: Advanced Member Groups: Member
Joined: 12/13/2005 Posts: 1,321 Location: Latrobe,Pa.
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Looking at pics on internet of 4100 extender.Just curious of design and the how and why. Just guessing 'leverage' you give up distance for force.Is my thinking correct?Thanks Bob.
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Rank: Member Groups: Member
Joined: 1/16/2014 Posts: 13
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I can only make an educated guess but I would think that with the extender you gain extra capacity by taking the load off the tracks / carbody & house of the base machine & shift them out to the " extender " . By doing this it also means that you can use a larger boom section , due to the space available for the width of the boom foot , therefore more capacity & a larger back mast to handle greater compression loads .
It also means that the base crane has now become the counter weight & has effectively increased the amount of force required to tip the crane forwards , due to the extra leverage , as you said . The capacity limits on the crane would now be structural rather than tipping .
This design also meant that Manitowoc now had a large capacity machine that could travel & swing , a big step forwards for them at the time when they had to compete with the likes of the American Skyhorse .
hope that this helps a bit .
Jack
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Rank: Advanced Member Groups: Member
Joined: 12/13/2005 Posts: 1,321 Location: Latrobe,Pa.
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Thank you. I'm not an engineer just wondering.Makes sense. I also wondered do the engineers know from math exactly how new designs will work,or do they engineer the crane then experiment with a design until it is perfected,ie safe.Lattice boom cranes always fascinated me.
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Rank: Advanced Member Groups: Member
Joined: 5/20/2006 Posts: 1,591 Location: Jacksonville, FL
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Engineers use computer analysis to determine the stresses in every member and joint of a crane to make sure there are no overloads. Load tests are required to confirm that the design of the crane works as intended.
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Rank: Advanced Member Groups: Member
Joined: 12/13/2005 Posts: 1,321 Location: Latrobe,Pa.
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Thanks. Before computers? ?
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Rank: Advanced Member Groups: Member
Joined: 5/20/2006 Posts: 1,591 Location: Jacksonville, FL
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Before computers, they would have to design the crane using hand calculations. But it wouldn't have been quite as thorough. Testing was more critical then. I imagine they would have to build them more stout just to be safe. But I have no evidence to prove it.
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Rank: Advanced Member Groups: Member
Joined: 12/13/2005 Posts: 1,321 Location: Latrobe,Pa.
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Thanks.I remember using a slide rule in college. Only can imagine the calculations. Thanks again.
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