Solve 2-D Spring Problem: 21.75 & 22.25 Equations

[morgan82]

http://i.imgur.com/uKydC.png

Here is the problem. I came up with two equations:

Upper Lc: 21.75=k(Lo-Lcu)
Lower Lc: 22.25=k(Lo-Lcl)

I am not sure what to do with this? How do I figure this out?

 

[Len44]

Total weight on spring = 8 + 22 + scale platform + .25 . If you use 1 lb for the platform then total = 31.25 lb. Assuming k = 5 lb/in then d = (.25 + .25) / 5 + .5 = .6 inches. Max spring compression would be 31.25 / 5 = 6.25 inches. Starting with a 13 in. long spring leaves 6.75 for h. I would expect you would need to plan some adjustment for calibration. This also assumes the chosen spring can be compressed the needed amount without bottoming out.