Originally Posted by sanddrag

Is there a picture of the real thing? That would serve us both better than me asking a bunch of questions. Thanks.

Originally Posted by Paul H

Sam, I know that some teams shift the drill transmission with servos, and to the best of my knowledge, these cannot be shifted on the fly.

Originally Posted by dlavery

Thank you very much for the kind words. Working with the team to design that transmission was a lot of fun, and we learned a lot!

-dave

Originally Posted by Elgin Clock

BTW, Dave and the rest of the crew over on Team 116, here is our version of your designed gearbox and tranny!

http://www.pbase.com/image/26818929

Originally Posted by Jim Zondag

Thanks, I'm glad everyone likes our design.
We have made two speed transmissions for the past several years. Each year we try to make them simpler and smaller. I found that with the kind of high/low shift range that I like to have (3:1 or more) that the robot would tend to lurch severely if you downshifted at high speeds. I really want to make a 3 speed with an intermediate gear to help this. It turned out it was easier to build a 4 speed than a 3 speed ( its really two small two-speeds in series). We focused the design around reliablity and ease of construction, the demo unit on display was made entirely by high school students in a few evenings using no special tooling.
Once I had a design with 4 gears I was pretty much forced to automate the shifting in order to keep from overloading the driver. I talked with a few Automatic Transmission experts at DaimlerChrysler on how to do a shift scheduler and viola....a fully automatic electronic robot transmission.
It really is pretty neat, providing a nearly flat power output across a very wide RPM band with a 5:1 total shift span.
I plan on posting the design and engineering here as soon as I get a good set of drawings made up (I'm not a CAD guy, I made the ones in the robot from a napkin sketch).