# Thread: Calculations for a Scissor Lift

1. ## Calculations for a Scissor Lift

Alright, so in the other threads regarding scissor lifts it's just about always referring to industrial scissors where the actuators either use the center or outer pins with hydraulics. For my purposes, my scissor will be on a much smaller scale and will not be using any hydraulics. This scissor will have to be within 18 inches in length when fully contracted, and extend out to be able to lift something 48 inches when fully extended.
The equations I've found have all assumed that the force would be coming from the side, but all of my force would instead by coming from the base or from springs built into the lift itself.
The equation is as follows for normal lifts : F=(n(Weight of load +Weight of the lift)/2)/tan(theta)) where n is the number of levels, and theta is the angle of the actuator to the pin.
In my lift, all of the force would be from a spring pulling the lift straight up from a a pin on the first level of the scissor its fixed side, and must simply lift a 38.9 ounce ball.
I'm trying to figure how strong my spring must be, and how the equation would change if all of the forces are only vertical.

2. For greater context, i'm looking to make a 2 stage scissor where each of the four lengths in the scissor formations is 9 inches long.

3. A free body diagram would go a long ways to develop and verify and appropriate equation..

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