pic: 971 Friction Clutch Transmission Insides

[Travis Schuh]

Originally Posted by s_forbes

Neat!

It looks like with a drum on each second stage gear, that you would need air pressure to engage either gear set, regardless if it is low or high gear, is that correct? Seems like a big plus to that is you can shut off your air pressure after a match and the robot would roll freely with no motors engaged.

You are correct that you need pressure to engage the gear sets and our initial thinking was exactly along the same lines as you outline, however we found that this didn't turn out to be the case. When you drain the pressure on the robot, the transmission stayes engaged in gear to the point where the motors spin as you push it and it wasn't possible to dis-engage it by hand. We took appart one of the transmissions to check wear, and found that the shoes were wedged into the drum pretty well. We are not sure of the exact mechanism of this or how strong the engagement is, as we got everything together at the last minute and have been so busy with other projects since that we haven't gotten a chance to dig into this further. The nice thing about the linkage approach rather than say a taper lock is that whatever lock we have dissengages pretty smoothly because the shoes pull away from the face as you pull on the selector.

-Travis