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telescopic boom sections

Discussion in 'Cranes' started by Tradesman, Feb 14, 2016.

  1. Tradesman

    Tradesman Senior Member

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    I realize and accept that larger telescopic cranes get there maximum lift capacity by extending different sections fully or partially, as apposed to boom truck that extend proportionally. What is it that makes this work ie: is the weight or the strength of the boom that adds to or detracts from the capacity? Please educate me.
     
  2. Knepptune

    Knepptune Senior Member

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    Basically with a pin and latch boom they are restricted to certain lengths for each section. Since they only have one tele cylinder each boom section has to have latch points. A grove has either 0% 50% or 100% for each section. I think liebherr has more options but your still pretty limited. i don't know that's it better or stronger then each section being proportional but that's pretty much how it has to be for a pin and latch boom. I also assume that kinda like an outrigger beam they are braced in specific places.

    It's a lot more complicated then a simple boom cyl and cables and pulleys but I can't even imagine the inside of a seven section boom that was fully proportional. A 4 section boom is packed full enough.
     
  3. Tradesman

    Tradesman Senior Member

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    can you have different % of each section and do you always put the first section out first then the second .....
     
  4. Knepptune

    Knepptune Senior Member

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    It all depends on what boom configuration you want. Sometimes some sections will be at 50% and others at 100%. You can pick any section you want to run out but you always run your outer sections out first.

    https://m.youtube.com/watch?v=ur8nulpGweI

    That shows the basic concept of it.
     
  5. 95zIV

    95zIV Senior Member

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    Looks to me like you have to do the inner/boom tip section out first then work your way out. If you do any of the outer sections first the cylinder wouldn't be able to reach any of the inner sections.
     
  6. Knepptune

    Knepptune Senior Member

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    Your right. That's what I meant.
     
  7. Tradesman

    Tradesman Senior Member

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    Ahh! It's like a light came on I never dreamt that's the way it works, I've heard mention of locking pins but thought it was just for extra safety. Thanks a bunch Kneppune
     
  8. Tugger

    Tugger Well-Known Member

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    Heres the kind of proportional boom I prefer.What you see is what you get.My trusty 40 ton coming off the barge.
     

    Attached Files:

  9. Tugger

    Tugger Well-Known Member

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    Not to Knock Hydraulics ,I do enjoy running my Manitex to