pic: Team 3647: Rebound Rumble take 2



West Coast Drive
-ToughBox internals
-6inch KOP wheels with Hex Hubs
-3/16 Drop on the center wheel
-Chain is tensioned with C-C, tensioners well be added later

Tower holds 3 balls.
Powered by a custom 36:1 gearbox with WCP Gears and a FP motor.
Shooter is powered by a FP with a 5:1 reduction using CIM-CIM gears.

As seen: 87.5lbs

Bridge manipulator will be added soon…

We will be at Battle at the border and the Fall Classic.

Looking nice, just a couple of questions for you.

(1) Are you delivering the balls straight into the shooter via your belts?

(2) I can’t tell if its the perspective, but it looks like your chassis might be bowing in the middle. Is that just me?

(3) Did you guys machine the tubing + things in house?

(4) What tips/advice would you recommend using the gussets? Do they provide enough rigidity?

  • Sunny G.

I like the rebuild!

It looks kinda like your wheels are sticking out of the frame. Is this going to be a problem once you add bumpers?

How consistent is the shooter?

I like the 973-style hole pattern. I wish we did something like that, but we don’t exclusively use 1 wide tubing so it’s less elegant.

More Photos at: https://www.facebook.com/media/set/?set=a.413566872026496.90696.196719503711235&type=1

(1) Are you delivering the balls straight into the shooter via your belts?

(2) I can’t tell if its the perspective, but it looks like your chassis might be bowing in the middle. Is that just me?

(3) Did you guys machine the tubing + things in house?

(4) What tips/advice would you recommend using the gussets? Do they provide enough rigidity?

  1. We are delivering the balls straight into the shooter, so far it is working well for us; the hand off from belt to shooter is pretty smooth.
  2. Hm I am pretty sure that is just the way the photo is taken, the frame is pretty rigid.
  3. Yes the entire robot was machined by students; we have an local machine shop sponsor us and I was allowed to use the CNC mill to run all the parts.
  4. The gussets on the frame are 1/8 thick and the tower ones are 3/32. So far we have no issues and from what it looks like from other teams as well 1/8 thick on the frame is more then plenty.

The bumpers are a work in progress at the moment, the mounts may not be 2012 Legal but it’s off season :stuck_out_tongue:
The shooter so far is very consistent, we have an encoder with a PID control loop on it. In the following weeks we plan to test the crap out of this bot.

The hole pattern was so we could add/change elements as we see fit, it’s consistent pattern though out.

Nice work but I look at all that hardware and think how much lighter you could be with rivets holding it together instead bolts.

Looks great guys. Interested in seeing which manipulator for the bridge you choose to go with.

Ditto, most of your hardware seems like your never going to take it apart. Even if you were, rivets are pretty easy to drill out.

You can use High strength or Normal Rivets with no issues. 3/16" Rivets and 10 bolts are interchangeable.

-RC

I would like to congratulate your team on doing a great off-season project.

Thanks everyone for the nice comments, we are quite proud of this little guy and hope it performs well at off season.

We considered using rivets however we had an bad experience with rivets before and decided that bolts are safer. Are pop rivets really suitable to replace 1/4 bolts?

Depending on how they are loaded (i.e. mainly in shear), rivets can absolutely replace bolts. Based on the pattern of gussets on the robot, it almost looks like the robot was designed to be primarily riveted.

Cause they really needed to save weight eh? :wink: If anything they should add some steal plates to make it heavier.

Looks great, it just proves to al of us how small and light we could have made our bots.

Even 1/4in rivets can be overkill but since rivets are so light it doesn’t really matter. My biggest peeve with the kitbot is the 32 nuts and bolts we have to use its like dead weight! :rolleyes:

Is your shooter designed to hit the top basket or is it a mid/low?

Overall your redesign looks great! Best of luck to you guys!

Talk to us at the fall classic and I’ll show you how we utilized rivets.

We actually standardize on 3/16" rivets, and they are plenty strong if used right.

This year we used 3/16 Rivets. IMO the best decision we made was going to Rivets, so much better then bolting everything together.
Do you think we would have a problem switching over to 1/8" Rivets? I was considering doing that this year, but if 3/16" would be a better choice I will stick with those.

We have used 3/16 rivets and gussets for years without a single failure. For higher stress areas we also add epoxy.

I won’t speak to their relative strength, but one of the neat features of using 3/16 rivets everywhere is that you can standardize on a 9 clearance hole everywhere, which can be drilled out to 10 clearance really easily if you want to bolt something instead of riveting. This assumes you currently standardize on 10 bolts.

Thanks guys, we will look into rivets for future use.

Though for this robot weight wasn’t really an issue :wink:

If you are worried about being too light, you can add weight where you want. Perhaps you can add a steel plate to the bottom. This will lower your center of gravity and give some protection.