let me see if i correctly understand what you are talking about.
would a simplified version with only one ring gear be set up like this:
the motor's gear is driving the outside of the ring gear.
the inside of the ring gear is driving the output shaft's gear.
lets put some numbers in this to see if i understand what you are trying to do correctly.
lets say you have a motor connected to a gear with 10 teeth.
a ring gear with 20 teeth on the inside and 40 teeth on the outside.
and a drive shaft (to connect to your wheels or whatever you are trying to drive) with an 10 tooth gear on it.
the motor will drive the ring gear at a ratio of 10/40 = 1/4.
the ring gear will drive the output shaft at a ratio of 20/10 = 2/1.
so, combining these 2, the motor is driving the output shaft at a ratio of 1/4 * 2/1 = 1/2 (or the motor turns twice as fast as the drive shaft).
is seems to me an inefficient way of doing things. stepping up the ratio, only to step it down again.
easier (ie, smaller and more efficient) to just do it with 2 gears.
or am i missing the point?
(anyone know a good, free package for drawing gears? i think we might need it here....)
(will be thinking about gears all day now....)