I hope this comes across as a simple explanation for the 6-speed transmission - you know how us teachers can complicate even the simplest of things!
First off, I've posted a new picture of only the gear reduction system of the transmission. The first gear (top red) on the primary shaft (on the left) is an initial input- from the CIM and drill motors. It is a 1.25:1 reduction from the gear on the CIM motor.
From the first double gear there is a simple tranisition of 1:1 to the first double gear (top blue) on the secondary shaft on the right. The overall reduction from the original input is now 1.25:1.
The first doulble gear on the secondary shaft reduces the speed (1.67:1) back to the second red gear on the primary shaft. Overall reduction at this point is now 2.0875:1
The second primary red gear transitions back to the second secondary gear at 1:1.
The second secondary gear reduces back to the third primary gear at 1.67:1. Overall reduction to this point is now 3.486:1.
The reduction continues down the system to the sixth gear.
The gear on the hexed output shaft (shown in the original picture) slides across the six blue double gears and engages at each one of them to provide six different output speeds.
Friction, while a concern, is negligible since all of the gears on the gear train (red and blue) are pressed on bearings and rolling rather freely. Granted the friction between the gears from one end to the next creates quite a bit of friction, I don't think it will be a huge concern. Like I've said before, we're going to start with a two-speed variation and work up from there.
I hope thsi explains how this system works a little better. Once you understand the stair-stepping concept between the gears, it is easy to see how you can set this up with as few or as many speeds as you need without great modification.
I will keep you all posted as we progress with the fabrication, construction and testing. I will also update the model to include gears with actual teeth so it is easier to see what meshes with what and how it all plays together.
Sean