Forces...

[crackoff]

Looking at another pulley involved...

 

 

A and D are now 0.5 each, whilst B and C are now 1 ton each...

 

(I think:lol:)

[Arbtech Tree Services]

Looking at another pulley involved...

 

 

A and D are now 0.5 each, whilst B and C are now 1 ton each...

 

(I think:lol:)

 

[Pete Mctree]

That doesn't make any sense, if you add more pulleys the weight will be distributed throughout those pulleys

 

Depends on how you use the pulley.

If you suspended the system illustrated from another identical system you would double the loading again. Therefore quadrupling the force applied by the weight at the anchor point.

 

(Sorry I don't know how to draw pics to illustrate my point)

[crackoff]

is that the sort of thing you mean Pete???

 

[crackoff]

Its the thought that adding the first pulley up the tree actually doubles the force that messes my head. Tie the weight straight to the tree and it is just the mass ie 1ton in this case, that is taken by the tree...

[Pete Mctree]

I will try & explain the picture. It illustrates the theoretical force on the anchor point "A" when a block "I" is suspended from it. From that a block "II" is suspended. Not that uncommon occurrence when you want your rigging point to be set & retrievable from the ground.

We already know that the load at "B" is twice the load suspended, but what about the load at "A" ?

If you work it out as before - it is Double the load, so the force will be twice that exerted at "B", which is twice that exerted by the load.

 

Four times the load at the anchor point "A" is a lot of force if you do not manage it !!!

 

Hope that makes sense

[crackoff]

Not what I thought you meant there then... lol

 

Same end result, I just wasted more time getting to 4 ton...