# Gas Spring Equation?

#### bobgaggle

##### Well-Known Member
I've had to do a few gas springs on some set pieces and I'm wondering if there's an easy way to figure out placement. Is there some sort of equation, given stroke length, compressed length etc? I've been doing my figuring in CAD, playing with placement but it seems like a sloppy way to go about it. Example:

Black rectangles are the hinged pieces, Magenta is the spring with the ends and compressed length marked with the points. The circles trace the path of the spring. If they overlap, the placement won't work because it will be compressed beyond its capacity. This takes a lot of fiddling to figure out in CAD, is there an easier way?

#### BillConnerFASTC

##### Well-Known Member
Triple problem.

Have you called the gas spring manufacturers? Got to be the best applications engineering source.

#### bobgaggle

##### Well-Known Member
wow that posted three times. I have not called manufacturers, guess that would be the way to go...

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#### bobgaggle

##### Well-Known Member
from gecea
"
FORCE = (W x Y) / (Z x N)
W = Weight of object to be moved.
Y = Distance from fixed mounting point to center of the object (mm).
Z = Distance from hinge point to moving mounting point (mm).
N = Number of springs."

So this gives me everything I need related to the forces involved, but Y and Z are unknown in my scenario. If I had at least one of those I could rearrange the equation, and this doesn't account for stroke length and angle of rotation either...