Spiral bevel gears in OpenSCAD
I read this question a few months ago, and thought I knew what you wanted.  Re-reading it now confuses me a little.
But, I think you may be asking for a large, flat surface with a spiral in it, like the tightening mechanism in a 3-jaw chuck.  In effect, are you using the large cylinder as a worm gear to drive four gears which ride on it?
I thought you wanted more general bevel gears, and today I found a package in OpenSCAD that looks quite good.  it is found at: https://github.com/dpellegr/PolyGear
If this is the answer you were looking for, great.  If not, please comment here and I will delete this answer.