Rope Power

[TreeSpyder]

http://www.mytreelessons.com/bent%20line%20load.jpg

[slowzuki]

I voted 400 lbs but I can't really tell what is the rainbow load...

[beenthere]

I'll bite. What is "bent line" ?

Does the question have anything to do with the drawing in the following link?  That drawing is equally challenging to me, as to what is the weight and what isn't. Looks like the weight is held under a pulley with one end of the line tied to the upper end of the weight. Kind of like picking oneself by his 'bootstraps'. 

Maybe this is only confusing to me, of which I will understand.

[beenthere]

Still confused about the question in the "poll" on rope power.

But I did find some info on "bent line" so think I understand it a tiny bit.

http://www.arboristsite.com/attachment_11649.php


I helped pull an elk up a mountain slope using the "bent line" principle, I think. Could get that elk to move about 1" at a time, but it took a lot of 'line bending' to get the elk 100' to the top.

[TreeSpyder]

i mean for the poll to refer to the drawing.  The 200# weight is free hanging, line bent on that load.

http://www.mytreelessons.com/Bent%20Line.htm

[caryr]

Ken,

You are better off connecting the rope directly to the carabiner or eye and skipping the extra 200 lbs of internal tension/compression, but you already knew that didn't you.

Take care,

Cary

[iain]

The load on the biner is 200#
the load on the anchor is split between it, and what ever is on the other end of the rope


 iain

[caryr]

Iain,

You may want to rethink that. There is 200 lbs on the left rope since it is the only thing tied off to the outside world. Ken likes to make people think a bit, so I won't spoil the fun with an exact analysis.

Cary

[TreeSpyder]

The multicolored device is the weight and the framework the bent line is run on.

This device/load weighs 200#; it has 1 support; so the line tension must be 200#.

The line is bent, so we get 2- 200# legs of line pulling.

The angle the 2 lines meet in, determines what percentage of the total of both of the the pulls is inhheritted by the bend( and also the median direction of the bend's pull is given byt he angle).  The angle of the bend is Zer0, so the full impact of both lines is realized at the bend (all other degrees of angles will take on less of the sum of the 2 pulls on the bend), and the angle of that force is Zer0.

This gives more usable power and change in direction, that i use for rigging turns in branches.  i brought it here because it works on getting more power like the Ship's Rig getting 13x not 10x; and being able to increase power with pulley on anchor and not load as in More Power to Ya etc.  They all work by taking the equal and opposite reaction and using it on target, rather than terminating it on an anchor, to just pull on something that doesn't need to move!  Usually we just take our leveraged force and place it on the work target, and assume the equal and opposite reaction must always be spent, or terminated on an anchor of no focus towards the work target.

Many times these last tweaks have made the day shorter, possible or even saved it.

[iain]

I thought the weight was free hanging, and the tied off bit on the right, was not connected to the weight, or is the multi coloured bit all one piece?



 iain

[caryr]

Iain,

I am assuming it is all one piece, though Ken has the final answer on that. I am also assuming he is not bothering with how the two moments may rotate the piece since he did not specify the CM (center of mass) or any distances. My previous interactions with Ken suggest he has a good intuitive understanding of the subject. I just wish his descriptions and setups were a little better.

Cary

[TreeSpyder]

It is meant to be a 1 piece 'load' on the line, it is jsut that the shape of the multi-colored load (piece) allows for the line force to be ushered in a bend on the load.  i've maid a multi pulley system that puts 4x, not 2x on that same point, to further test/explain/prove force pattern.  We did it with scales, but just strumming the black link holding the pulley to the load tells the story, anyone can try it.

This is a school puzzle i made up to expalin different techniques of rigging, pulling trees over, little guy getting more power etc.  i also think this is the part of the power behind knots, carrying the same physics, into the microcosms of the same patterns of bending lines etc.

Choke Grip Forces

[iain]

I refer back cary's answear, whats the point in the pulley?
i think any one who sets up like that, has way to much time and money on there hands



      iain

[iain]

Also can you give the height from the bottom to the top of the weight
height of pulley pivit point above the bottom
pulley mass
rope mass
step heights and widths
crab mass
black eye mass
is it flat plate or a 3D object? if flat then how thick?

above needed to work out the amount of tilt, when pull is applied to the rope on the left
the amount of tilt will change the answear a lot


 iain

[beenthere]

What was the 'final' conclusion to this thread?  Seems there was more confusion than conclusion, but maybe I just missed it because of my 'confusion'.  
Not even the poll was very conclusive.