Incorporating the vex ball shifter into a WCD Drive

[AdamHeard]

Originally Posted by Adam.garcia

The main problem is that there are no internal sprockets inside the gearbox to provide power to the front and back wheels.

This isn't necessarily a problem, be creative. The solution we're posting in a few days isn't innovative or crazy at all.

[Walter Deitzler]

The main problem is that there are no internal sprockets inside the gearbox to provide power to the front and back wheels.

I feel like you could just run a sprocket off of the shaft, then chain the front and back axles to it, then direct drive the middle wheel. As long as the sprockets have the same number of teeth, I do not think that there would be a problem with this.

[MichaelBick]

Last year we used supershifters on our WCD. We just made an adapter plate to mount the supershifter to our drive. If I were to run the Vex ball shifters this year I would mount in this same way.

[AlecMataloni]

In 2011, Team RUSH (27) used 221's "Super Light Rolling Chassis" with the chains mounted outside the chassis perimeter. Would this work for you?

[BJT]

The two stage version has that nice curve on the bottom, which looks like it would be nice especially with small wheels, but, at least in our wcd, we would need the 3rd stage which makes the whole package a lot harder to work with.

[connor.worley]

Originally Posted by LedLover96

I feel like you could just run a sprocket off of the shaft, then chain the front and back axles to it, then direct drive the middle wheel. As long as the sprockets have the same number of teeth, I do not think that there would be a problem with this.

Remember: WCD chains the front and back wheels separately.

[Walter Deitzler]

Originally Posted by connor.worley

Remember: WCD chains the front and back wheels separately.

I was thinking either two separate sprockets or one of those double-sprockets.

[Nemo]

I'm picturing a wider custom version of the 3rd stage add-on that Vex sells. Put your two sprockets inside and change the 3rd stage ratio to be appropriate for direct drive. Sounds like a fun winter break project.

[Brian Selle]

If you are able to remove the hex output shaft pressed into the ball shifter shaft and replace it with your own, you could just add some pulleys/sprockets and a couple standoffs like the attached picture. The picture shown has 30 tooth pulleys and the clearance with the 4 standoffs is close... to get more clearance with smaller pulleys/sprockets you could rotate the entire gearbox slightly about the output shaft and use the 2 standoffs in the upper left/lower right corners (2nd picture). Would be good to work in some more support for the cantilevered gearbox.

[MichaelBick]

Originally Posted by btslaser

If you are able to remove the hex output shaft pressed into the ball shifter shaft and replace it with your own, you could just add some pulleys/sprockets and a couple standoffs like the attached picture. The picture shown has 30 tooth pulleys and the clearance with the 4 standoffs is close... to get more clearance with smaller pulleys/sprockets you could rotate the entire gearbox slightly about the output shaft and use the 2 standoffs in the upper left/lower right corners (2nd picture). Would be good to work in some more support for the cantilevered gearbox.

Attachment 13286
Attachment 13288

If I remember correctly, the output speed of the ball shifters without the third stage is a bit too fast to direct drive.

[AdamHeard]

Posted CAD of the implementation here.

This is a real rough model showing our concept for mounting the ballshifter only, it's a bit clunky now and if we ran with this we'd likely refine the mount a bit more.

Don't interpret this as a specific decision by 973 to do 8wd with that spacing, those wheels, etc... but rather focus on the ball shifter interface, and that we're switching to 1/2" hex all around in hex bearings.

Hopefully this helps a few people.

[MattC9]

Originally Posted by AdamHeard

Posted CAD of the implementation here.

This is a real rough model showing our concept for mounting the ballshifter only, it's a bit clunky now and if we ran with this we'd likely refine the mount a bit more.

Don't interpret this as a specific decision by 973 to do 8wd with that spacing, those wheels, etc... but rather focus on the ball shifter interface, and that we're switching to 1/2" hex all around in hex bearings.

Hopefully this helps a few people.

Adam, unfortunately my cad is not working could you add a picture or rendering of what y'all have come up with? Also... I see Hodgepodge and Viper, what are those? Again my Solidworks isn't working so I can not see these models.

P.S. I didn't mean to put that purple smiley next to the post... and I don't know how to take it off.

[JB987]

Adam,
Can you post a screen shot or two?

[AdamHeard]

Sheesh, nobody is ever satisfied

Here is an iso with the frame supressed, and then with the mount plate made transparent.

[BJT]

Thanks for the pic. thats essentially what we do with supershifters, but this got me past a mental block I had with implementing the 3 stage ball shifter.