Yes, i know this topic has been hit alot. I really just need help ensuring my math is correct. (its been a while since college) lol. anyways. I'm trying to figure out the optimal set up required to lift a load of approximately 25lbs from completely collapsed scissors to a height of 96" using 2 levels. first, solving for L:

L =(H/4)/sin(theta)

where H = height of platform when lift is extended

theta = angle of L to horizontal

plugging in:

L= 24/sin(45) = ~34"

which means each bar would have to be ~68"

Now to calculate force required

F = n((W +(Wa)/2)/tan(theta))

where n=number of levels = 2

w = weight of load + platform = 25lbs

wa = weight of members = 15lbs

F = force,

1.When lift is collapsed (lets say angle is 5 degrees):

F = 2((25 + 7.5)/tan(5)) = ~149 lbs of force

2. When lift is extended (lets say angle is 45degrees):

F= 2(25 + 7.5)/tan(45) = ~65 lbs of force

Then, the distance, D, the base member moves inward should be equal to the distance the top member moves inward as well and proportional to the height each member travels from the horizontal, correct?

So if im moving the base member via linear actuataor i would need to have it rated for ~150lbs of force with a stroke of 12"? ;?

Also, i did a 3 level lift, the force required would be higher, but the stroke of the actuator and the members would be shorter?

This seems very inefficient when opening the lift from collapse, so am I missing something or are my calculations correct?

Thanks in advance!

update:

see attached image for visual[ATTACH=CONFIG]537[/ATTACH]