Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2954250.
Intended to replace a steel spring in a clockwork model.
Energy is stored in multiple rubber bands, on both sides, stretched between shafts through the outer ring and planet gears.
The central drive gear will be attached via some sort of ratchet mechanism to another drivetrain and escapement.
Untested idea. It might just end up being a paperweight or fidget device.
Note: minor design flaw, requires a fixed carrier for the inner planet gears (not included).
Edit: Playing around with clearances to prevent overlap. MCAD/involute_gears was not designed for internal gears and subtracting external gear is only a rough approximation. Slicer usually fixes overlap though. Also some bug fixes with parameterization.