pic: Demo Transmission 222

[henryBsick]

As far as all the extra waterjet discussion is going... we don't have access to one, a laser mill either. We were also looking into gear cutters to make our own gears once the 06 build rlls around, but we do not have one now.
The tolerances can't be too wrong, polycarb has a hardness that is measured on the Rockwell scale, so it isn't exactly going to wear in very easily, but it is after all just a demo transmission. I did like the idea of epoxy or rubber cement. We could probably use the normal tolerances with the 05 transmission plates and use the depth of the rubber cement applied to account for the missing teeth on polycard wheels.

The servo shifting idea was discussed. The shifting is definitly possible with servos, and I bet it could be done reliably with one servo per transmission, but 2 servos per side would be the only safe way to go about it IMHO. That leads to the battery drain. The servos are run entirely off of the backup battery (correct me if I am wrong) so we didn't want to take the risk of running a low backup and not being able to shift. In the end our discissions boiled down to simplicity. Powerful air BAM one way BAM the other; physical stops each way. Done.
I believe 469 used a leadscrew setup with a globe motor powering the single screw which shifted both of the joined transmissions. I also believe that 571 and 1143 used pneumatics like us. The only other team with this transmission setup is 476 (??) and I am not sure what they use.

-Henry

[Arefin Bari]

I have always looked up to team 222 for the way they build their transmission. Specially the shifter.

Just like Henry pointed out before me, that you can shift with globe motors. Team 233, The Pink Team used globe motor to shift or I was told. Take a look at their machine if you get a chance. Or get in touch with someone from their team.

[sanddrag]

I got it. Don't bother with rubber cement or anything. Just put wide rubberbands on your polycarb/acryllic gear-wheels. Make sure you get your center to center distance right though for good contact between the rubber bands. Enough contact to hold, but not excessive friction/binding.