Bumper Latch Legality

We’re building bumpers to fit the AM14U. Since it has no mounting points on the cross brace, we made our bumpers like so:
The latches between each bumper slide into one another to support the bumpers in the middle, where there’s no support. The exposed wood at the end of each bumpers would be covered with fabric, but wouldn’t have a pool noodle backing:

Does R21 mandate pool noodle everywhere? Is our current bumper setup legal?

Picture does not seem to be loading. Is it uploaded to a secure website?

Loads fine for me.

That’s not a legal bumper per R21 if it has wood without noodles.
It doesn’t follow the prescribed bumper profile of wood backed pool noodles covered by fabric.

The section between the pool noodles will have to be the robot frame perimeter.
You need to attach the bumpers directly to the frame perimeter, and the latch itself probably shouldn’t protrude.


Not an inspector, but mounting the latches like that looks like significantly altering the bumper cross section, which would be illegal.

I agree. Not legal. The only thing that can be outside your frame perimeter is bumpers. Bumpers have the cross section in the figure, so what you have there is not a bumper at that point. Effectively you have a ‘hard’ part, that is not recessed a bumper’s width from the adjacent bumpers, which means you use that to your advantage.

For me the first challenge here is hard parts > 1" from frame perimeter (R21B) looking at the combined depth of your wood and latches, although I can’t tell from this whether you’re definitely over.

I’m not seeing anything explicit in the rules on excess wood tangent to and supported by the frame perimeter on non-corner ends within the R21B depth, as the rules focus a lot on the corners, but the cross section problem is probably enough to mean you need a new plan.

The excess wood is not a BUMPER, so it can’t be outside your Frame Perimeter at the start of the match.

What if we covered the latches with pool noodles? Would this still be considered modifying the bumper cross section?

It would be hard parts over 1". Still illegal.

Now, if you moved 'em inside and then covered the outside with pool noodles and fabric, you’d have a pretty decent shot at passing–assuming those latches are strong enough to keep the bumpers mounted when paired with the rest of the system.

Thanks. Could you elaborate on “inside”? Do you mean the other side of the plywood, facing the AM14U chassis itself?

Yes, that is exactly what he is saying.

Although if you added latches between the frame and your bumpers you’d be violating the “direct contact with the frame” portion of the rule.

Thanks for the help everyone, we’ve worked out an alternative now.