It would be useful to know a little more detail as to the use of the output
but just a thought as to constant force output perhaps using ineffective
crank angle on a lever attached to the spring could be useful. For instance
as the spring gets shorter its force output will decrease so for constant
output you would need to initially reduce output by a belcrank attached to
say a sprocket and the belcrank initial angle to the spring starting a above
90 degrees to start with.
Elliptical chainwheels on cycles achieve a similar process i.e. radius to
the chain from the chainwheel point of rotation varies.
Good luck with a terminology search
regards Dave Reffin
"Medic" <[Only registered users see links. ]> wrote in message