My guess is they’re coaxial. The shaft is a live (driven) shaft, but the intake roller+pulley are on bearings (as if the shaft as a dead shaft), using mechanical coupling (outside the shaft) between the pulley and intake roller. Thus the shaft and the intake roller can be independently driven, even though they’re coaxially aligned.
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This is correct! We call it a “zombie axle” - both live and dead 
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Is the roller-connected pulley the dead or live axle part of the system? What is gained by doing this here? Does that axle go the length of the intake or just cantilevered there? I’m assuming there is more hidden that area but I’m not sure.
This was a space-saving technique for packaging tightly integrated mechanisms. The live axle goes across the entire robot and drives both sides of the elevator. The 3” intake roller is a couple inches shorter than the full robot width and is driven as if it was on a dead axle.
We knew that we needed to drive our elevator from both sides since it is very wide and driving from one side could easily result in racking. This requires a jackshaft across the robot to drive both belt runs together.
At the same time, we had determined that we liked the larger 3” OD roller for bringing the ring around a 90deg curve up into the Amp Mechanism and had manufacturing familiarity here from our 2022 intake rollers.
Originally the intent was to not tightly integrate here - even though this is a cute implementation we normally like to keep subsystems self-contained to enable them to be more easily upgraded or fixed. The tight integration only happened after our designers had been banging their heads against a wall for quite a while trying to make both of these mechanisms fit. (Once the robot is done it seems obvious that everything is the way that it is, but this year definitely caused a lot of designer headache along the way 🫨 )
Cheers,
Bryan
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Thanks that answers a lot of my questions!
If I may ask one more, what does the pulley on the zombie axle (the one powered by the 3" roller pulley) power? Does it go to the bottom roller? If so how does it reverse its direction?
Edit (I understand now nevermind, Thanks again!)
Last question tonight (probably not) Where does this belt path go? I cant seem to follow it.
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I love how your robots follow the blue and black branding every year, and how great they end up looking. I was wondering how y’all decided what color to make each part? Is it already planned out going into the season, for example tubes will be __ and gussets will be __. Or do you just try different things until it ends up looking good.
In general, we try to do the following:
- Blue powdercoated shiny tubes
- Blue powercoated plates if gussets of a weldment (less done these days)
- Black anodized matte plates if holding bearings / part of gearboxes
- Smoked grey polycarbonate
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