3 Cim ball shifter output shaft

[autox_vette]

Yesterday during a practice scrimmage, we lost all drive on one side of our robot. After checking all of the obvious, nothing was found to be out of sorts. After several more minutes of head scratching, I happened to notice that the gear on the output shaft of one of the gearboxes (3 Cim ball shifter WCD output) was shifted. It appeared that the output shaft had shifted out of the gearbox far enough that the gear on the shaft was no longer contacting the gear on the axle. I pushed it back in using my fingers and everything was OK.

I haven't had time to dissect the gear box to see what was going on (and I wasn't part of the team that initially assembled them). Looking at all of the drawings on VexPro's web site, it looks like the output shaft just pushes into the shifter with nothing holding it into place. Is there supposed to be something holding the output shaft in place?

It's something that is going to go onto our pre-flight checklist for sure, but just wondering if it's something wrong with our gearbox or an engineering oversight...

Kenton

[mrnoble]

We had the same problem and contacted VexPro. There was supposed to be a locktite type adhesive shipped with the gearbox that was not included. They shipped us new shafts and adhesive, along with improved gears for the encoder shaft, which we also have had trouble with. They (Paul, I think) have posted on CD about these problems earlier and have been nothing but up front and helpful. Give them a call tomorrow.

[T^2]

They're held in with Loctite shaft retaining compound. (The 2-CIM and 3-CIM shifters use the same output shaft.) Last year many teams had issues with the shaft coming out; IFI claim to have solved the problem this time around. Ours have been fine so far.

[DanBrowne]

Our team had the same problem. We love the ball-shifters, but the output shaft problem is one of the VERY few cons, if not the only one.
We discovered the issue a few weeks before our first competition. Our initial solution was to put one layer of electrical tape on the output shaft and hammer it back into place.
When this solution failed at Championships, we had the machine shop put roll pins into the output shaft. This worked amazingly. When we got our ball-shifters this year, we made this modification before we put the gearboxes together. Zero issues so far, and I don't expect any.