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Thread: Rigging Physics 101 -- Redirect Pulley

  1. #1
    Treehouser Sponsor rfwoody's Avatar
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    Default Rigging Physics 101 -- Redirect Pulley

    This is a very simple question, but I would much appreciate a "sanity check" on my thinking and other pairs of eyes....

    thanks for looking.

    I hope this diagram is pretty clear and self-explanatory:

    Click image for larger version. 

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    Just to reiterate the questions:

    1) Will the redirect pulley (significantly) reduce the force applied to the victim tree?

    2) Will the force on the victim tree increase significantly since all the horizontal movement of the truck will be applied to horizontal pull instead of some of the force being lost to vertical pull if the pull line was connected directly to the truck hitch?

    3) AND possibly additionally(?) ... because *traction* of truck tires will not be reduced because of vertical pull... trying to pull the back of the truck up?

    hope I haven't hopelessly confused this simple question.

    Thanks a lot for your consideration and input!
    - Robert
    Slowly trying to make a profit in tree work with my neighborhood tree service.
    Thinking I want to become a Certified Arborist.
    www.PoagvilleTreeService.com

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    Treehouser Sponsor SeanKroll's Avatar
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    Try to get the redirect pulley AS LOW AS POSSIBLE AND SECURE. This will ideally lead upward to the truck, increasing traction.


    If your pulling directly with the truck, the rope will be above-horizontal, negatively.





    You really need throw line skills to get higher.

    A load in bed does a lot for traction.




    Try to find a YouTube explanation of vector forces.

    Read Mark Chisholm's Engineering a Tree Removal article.
    If it looks like I asked a question, but put a period, it's probably a question.
    Don't know why I'm question-mark challenged online. 😀 New Year's Resolution, better proof reading.

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    Treehouser Sponsor rfwoody's Avatar
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    Thanks Sean!
    - Robert
    Slowly trying to make a profit in tree work with my neighborhood tree service.
    Thinking I want to become a Certified Arborist.
    www.PoagvilleTreeService.com

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    Woods walker Sponsor Burnham's Avatar
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    It's worth noting that tire chains can make a world of difference in traction on off road surfaces, not just snow and ice. Don't spin the tires, throttle control is critical.
    "Confidence is the feeling you sometimes have before you fully understand the situation."

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    Treehouser Sponsor SeanKroll's Avatar
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    One on the gas, one with a little pressure in the brake... Two-foot driving.

    Manuals aren't good for pulling slow and steady, like an automatic or winch.
    If it looks like I asked a question, but put a period, it's probably a question.
    Don't know why I'm question-mark challenged online. 😀 New Year's Resolution, better proof reading.

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    Woods walker Sponsor Burnham's Avatar
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    Of course, a winch beats all.
    "Confidence is the feeling you sometimes have before you fully understand the situation."

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    THE CALM ONE!!!! Sponsor squisher's Avatar
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    Depends on the manual. Just got to know how to use a clutch. All my work trucks have been manuals. Every bucket, my old ghetto 1ton, 550, couple of different 350's. You can certainly pull decently with a manual if you have the slightest bit of skill with a clutch.

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    Woods walker Sponsor Burnham's Avatar
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    I'm with Squish on this one...although maybe somewhat more than "the slightest bit of skill" is needed .

    I'd even argue that on some of the newer trucks with drive by wire throttles, an automatic transmission can be somewhat erratic in delivery of power as expected. This I know from both my personal pickup, and a couple of work rigs.
    "Confidence is the feeling you sometimes have before you fully understand the situation."

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    TreeHouser Mick!'s Avatar
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    Bloody yanks! Put them in a stick shift and they haven’t a clue!

    Seriously though, manuals are absolutely fine as a pulling device.

    To answer the questions directly.

    1: not significantly.

    2: never really thought about it before but yes, it’ll keep your wheels on the ground.
    Im condescending, that means I talk down to people.


    Mick

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    Woods walker Sponsor Burnham's Avatar
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    Agreed, per Mick's answers . Otherwise...bloody Brits, so condescending. Especially the expats .
    "Confidence is the feeling you sometimes have before you fully understand the situation."

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