VEX Ball Shifting into Neutral
 

Okay I know there is a big thread about this but I was a bit afraid that my post would get lost since there are so many posts, so I am posting here. My team and I had the idea of putting a ratchet on the low gear of the gear box so while in that gear it could not back drive without putting stress on the CIM motors. Then the high gear would be made a neutral gear as described in the other thread. This would make it so the pawl would not have to be pulled out just the sifter would shift to neutral. What my question is when the low gear has so much torque on it will the sifting mech be damaged or hurt in any way when it is pulled into neutral?

Re: VEX Ball Shifting into Neutral
 

I just cleaned up the CAD a bit and rendered out a few views for you guys to see what I am talking about.

Re: VEX Ball Shifting into Neutral
 

No, mechanically the Ballshifter construction is very well suited to releasing under high loads, due to the geometry of the shifting mechanism the shifter shaft sees a much smaller load and may be pulled free with much lower amounts of force than DOG shifters.

Re: VEX Ball Shifting into Neutral
 

Awesome thank you for the reply I really appreciate it.

Re: VEX Ball Shifting into Neutral
 

you can also use a 1/2" ratchet wrench on the output shaft to achieve the same non backdrive characteristic, but with much much less work.

Re: VEX Ball Shifting into Neutral
 

The only problem we ran into with that is that if we put it on the final output it will never be able to fire unless we could disengage the wrench some how.

Re: VEX Ball Shifting into Neutral
 

You need to put the rachet somewhere before the neutral, so an extended shaft is needed, which calls for the wcp gearbox, which has dogs (o noes, dogs!). Fabricating a custom longer shaft could also work, may need some new bearings.

Re: VEX Ball Shifting into Neutral
 

very good point... didn't think about that. :yikes:

looking at the cad, you could extend the first shaft (the 3/8 hex one with the gear the 3 cim pinions drive) using a 3/8 hex bearing on the case instead of a round one. then you could put the wrench on the outside of the case. would just need something to keep the shaft from walking out of the case.

other than that, the solution you have there should work, don't see why not.

Re: VEX Ball Shifting into Neutral
 

You could also try removing the gears for the low gear stage and put the wrench through a similar hole to what you have now replacing the smaller gear
.

Re: VEX Ball Shifting into Neutral
 

We considered what you have and thought about making the cogs of the ratchet much less steep--almost perpendicular to the center. With a small pneumatic cylinder to activate the pawl you could easily control it.