We’ve received a lot of questions about our robot and we think making the CAD public is a fun way to showcase our design to teams around the world. For teams or individuals attending the championship next week, feel free to stop by the pit and ask questions.
This is a snapshot of the current working CAD model so there are plenty of broken things in the model or things that don’t match the actual robot. I think this is a good representation of what a well-organized but practical FRC CAD model can look like.
The 3D prints are all almost exclusively PLA or PLA+. There are a very small number of markforged onyx prints where it matters like supporting the e-chain on the telescoping part of the arm.
As far as the “why” side versus a rigid mount, this ended up being a little easier. We wanted the cross member for structural support anyway. We knew chain tension would be something we’d need to tweak (lot of force with how fast the arm moves). It also gives us a little side to side play to adjust for tracking. The mount to the cross member is just a slip fit, with collars to hold it in place axially along that tube.
Spent a bunch of time looking through this model last night— so many cute details between the tension members, the chain tensioning system, the intake/rotational wrist, wire routing, the linear extension gearbox built into the sprocket… there’s a ton here for anyone to learn something new.
So you essentially tension the chain by moving the gearbox?
Really cool engineering here. Would not have occurred to me to just let the gearbox slip fit around the cross-tube and give it rigidity with the turnbuckles.
Yep, the whole gearbox pivots around the round tube.
This is a little trick pulled from the heavy equipment industry where this is a pretty common way of belt tensioning.
The advantage is that it’s a lot easier to keep the shafts parallel while making the adjustment. As opposed to some sort of linear adjustment, The other main advantage is rotational motion is typically simpler with lower part count and simpler parts in general.
Do you need to do any modifications to the
Slide-Snap latches - 1872A111 to get them to work with #10? I haven’t used these before but this is a much more elegant solution to the bumper mounting issue that caused us some issues this season.
We drill out the bushings to use #10-32 bolts to mount to the frame. You could use smaller sizes, but keeping bolt sizes to a smaller selection makes it easier for the pit crew. For the bumper side brackets, we use M3 hardware.
Also, we buy them from here to save some money over McMaster
Red: bumper side brackets, M3
Blue: frame side, drilled #10-32
