pic: 6 speed?? Great in theory - lets see how it works!

[Sean Schuff]

Here's what I can tell you so far - not that we're trying to keep secrets, but like I said before, this is in the very preliminary stages and I was looking for some input from the CD community (which is exactly what I got). Thanks to all of you!!

1. The drill motor and CIM motor are geared directly to one another. Drill to CIM ratio is roughly 3.2:1.

2. The gear on the CIM motor drives the first in a chain of gear reducing double gears. We are going to see if we can purchase them to our specs otherwise we'll have to mate two gears together face-to-face. Each gear reduction is a step down of 1.67:1. (I will post a screen capture of an end view of the gear train so you can see how they reduce from one to the other)

3. The gears in the gear train all ride on bearings and a simple shaft with thrust bearings separating each pair. The reduction is a stair-step effect from one end to the other. The gears can be replaced by simply removing the plate on the end (clear in the original screen shot) and sliding each gear set off the end of the shaft.

4. The pink object is the shifting mechanism with a gear in the middle that drives the hex shaft and ultimately the cog on the outside of the gearbox. The jury is still out on how to move to six specific positions consistently but I'm getting some great ideas here!!

Theoretical speed and torque are as follows:
First gear - 16.63fps - 504lb/ft
Second gear - 9.98fps - 841lb/ft
Third gear - 5.99fps - 1,402lb/ft
Fourth gear - 3.59fps - 2,336lb/ft
Fifth gear - 2.16fps - 3,894lb/ft
Sixth gear - 1.29fps - 6,491lb/ft

In theory (which is what much of this is right now) the entire gear box could be built using a drill press and lathe. The lathe is only needed to turn down the ends of the hex shaft where it meets the bearings.

Hope this sheds some light on this funky contraption.

Sean

p.s. No, JVN, I don't have any insight into this years game. Just playing around with some extreme ideas. I think I've been watching too much of the Discovery Channel lately! Although a 1/4 mile drag race between robots is something they should consider for IRI next year!