pic: WCD 3 CIM PTO Ball Shifter Render

[Chris is me]

Originally Posted by Bryce2471

Thank you bringing up the question of CIM support. I think your concern is stemming from the fact that there are several aspects of this gearbox that are not easily visible from this angle.
1. The CIM is resting against 0.25" Al along its entire bottom edge.
2. nestled in between the CIM motors are standoffs that run back to support the pneumatic cylinder that runs the PTO. These standoffs will also help support the CIM motor from below.

These features should really help. You're probably okay since I don't think there are any weird loading conditions that would torque the CIMs away from the center of the gearbox. I'd probably leave the material on, but that's just me being overly cautious.

For this reason, I have never been a fan of the design of the ball shifter shaft from vex. In this design there are two custom simplified one piece shifter shafts.

Any chance you could post a quick screenshot / view of one of these? I'd love to take a look. Might end up doing something similar if it isn't too difficult to make. Certainly easier than doing design gymnastics to make the COTS part work the way I want it to.

There's certainly nothing wrong with the Vex shaft design; it does what Vex is trying to accomplish and it works for their COTS product, but it definitely isn't tailored for WCD use.

This is a cool idea in my opinion, Even though it would cause a few problems. The only issues I see with it right now are that it would make gearbox assembly difficult, and cause there to be an unused gap in the gearbox unless the first stage was cantilevered.

Yeah, the first stage would need to be cantilevered. The idea here being that the extra space taken up between the gears by the coupler isn't such a big deal if it's going through a plate in that area anyway.

I sketched this out last night and the biggest difficulty with it is clearance between the motors and the middle gears. You end up with a really big gearbox if you go 3 CIM unless you use idler gears (not necessarily out of the question).

[Bryce2471]

Originally Posted by Chris is me

Any chance you could post a quick screenshot / view of one of these? I'd love to take a look. Might end up doing something similar if it isn't too difficult to make. Certainly easier than doing design gymnastics to make the COTS part work the way I want it to.

Yes. I'll probably just post another render with only the shifting components visible.

There's certainly nothing wrong with the Vex shaft design; it does what Vex is trying to accomplish and it works for their COTS product, but it definitely isn't tailored for WCD.

Their shifter shaft definitely does the job they want it to, but I still think it could have been designed in a way that woud have made their gearbox more versatile and the shifting components more useful. The way they have it set up makes two stage drive systems impractical. Wheather it's in custom gearboxes or their COTS box.

I sketched this out last night and the biggest difficulty with it is clearance between the motors and the middle gears. You end up with a really big gearbox if you go 3 CIM unless you use idler gears (not necessarily out of the question).

I agree with this, but another option you should consider is using belts in the first stage to relocate the CIMs. This would turn out similar to 192's gearbox, but you could possibly get the pneumatic cylinder out of the belly pan as well.