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RIKTUBS · Nov 4, 2010, 10:52 AM

I have attached a drawing showing my problem.
First, I want to lift 20 lbs using 5 lbs of force (4:1)
Second, I want to lift that weight 32 inches with only 18 inches max. of cable.
What would this configuration look like? If not gearing, what would the configuration look like?
Can someone help?
Thank you,
Rik

ebaines · Nov 10, 2010, 12:06 PM

There is no drawing attached.

Conservation of energy says that if you want to lift a 20 lb object 32 inches with a 5 pound force, that means that the 5 pounds of force must operate over 128 inches of travel. Do the gears and/or cable in your drawing allow that?

RIKTUBS · Nov 18, 2010, 09:52 PM

Thanks for responding. I uploaded a pdf but I'm not positive where it's showing up. I don't have 128". Basically I want to pull 18" on one side and have the weight come up 32" on the other side using 5lbs of force.

ebaines · Nov 19, 2010, 11:17 AM

Can't be done with just 5 pounds of force. The relationship between the amount of force and travel is this:

$ F_1 D_1 = F_2 D_2 $

Here you have:

$ F_1 = 20\ pounds\\ D_1 = 32\ inches\\ F_2 = 5 \ pounds\\ $

Therefore $D_2$ (the distance over which you must pull with 5 pounds), is 128 inches.

RIKTUBS · Nov 20, 2010, 07:10 AM

Ok, thank you very much for help.