[posix]

Ok, here's another couple of cut-away drawings. Also note that little (planetary) rollers have little pinions at both ends and the nut has a corresponding large toothed ring on each end. My guess is that's to discourage the rollers from "sliding" across the screw and nut surfaces but to turn properly. I've caught mention of gearing somewhere as well.

Could any of you solidworks gurus out there make up a solid model of this which could help us visualise the whole system. Also mechanical engineers among you could come up with a spreadsheed which could be used to calculate the exact screw, roller and nut diameters and thread depths and pitch of each component since this mechanism isn't using any standard threads.