Think I am missing something *DELETED*

Re: Think I am missing something

Wow thats small, ok what is in it is piggy backed pulley all 2:1. at the end the pic is saying there is 1600 force on the brown line. I do know it is a 8:1 but if there is 100lbs pulling on an 8:1 will that equal out to 1600 lbs of force on the brown line?
 
Re: Think I am missing something

Although the pic, which is now gone, is small, it does have the features of a piggy-back configuration and Fairfield referred to it as a piggy back system.

I'm going by memory here, but if there were four piggy-backed pulleys, it is a 16:1. 100 lbs on the pull line, assuming 100% efficiency, would produce 1600 lbs on the load side.

However, you won't realize that in reality even with 95% efficient ball bearing pulleys. About the best you'd get with 95% efficient pulleys is about an effective 14.5:1. The odd thing is, the amount of rope you'd have to pull to move the load one foot is exactly 16 feet (16:1) disregarding rope stretch. But that's because friction doesn't effect the length/pull relationships, only the forces.
 
Re: Think I am missing something

what is awesome is that that system will out pull an eight part block
 
Re: Think I am missing something

[ QUOTE ]
Ya had a brain fart as to what I was looking at.

[/ QUOTE ]
You showed a pic of a four pulley, piggy-back system and asked if 100 lbs were applied would 1600lbs be generated.

I said yes with frictionless pulleys, and even gave a comparison of what could be expected in a real system with 95% efficient ball bearing pulleys.

How's that a brain fart?
 
Re: Think I am missing something

[ QUOTE ]
what is awesome is that that system will out pull an eight part block

[/ QUOTE ]
True, but it takes a separate rope for each section, and the rope lengths and multiple anchor point locations makes it complicated to get right.
 
Re: Think I am missing something

When I had posted the pic I for some reason was thinking it was something other then a 16:1. Right after I wrote it I had seen where I was going wrong.
 
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