Aluminum angle on bumpers

Is there any limit to how much you can have? Or can you just put it on the corners? Our bumpers only weigh 12.5 pounds, so we want to add another 5 pounds onto them in order to maximize our weight at the bottom of the robot to have an even better low center of gravity.

Any and all help is appreciated!

You could use steel angle instead to add weight. You can add whatever material you’d like in that 1" deep “hard parts only” zone.

Russ

I was thinking about this…we might need to reduce the length of our plywood bumper backing if we add angle, to keep the hard parts from extending past the bumper perimeter on the adjacent side, that is, into the corner.

I’ve been smacking my head on the wall about this. What is the point of the aluminium? Last year we just stapled the cloth in place. I know it isn’t really my place to contridict the allmighty GDC, but I’m flipping out about this because it is making my job of building the bumpers somewhat more complicated. Also, it says to attach the aluminium with wood screws, but won’t the screw heads stick out a bit from the bumpers? Or do the screws go in from the top of the bumper, in which case the plywood has a better chance of cracking from the screws?

Argh, I wish this hadn’t been thrown on me so late in the game. Oh well.

FYI, http://forums.usfirst.org/showthread.php?t=11394 says those angles are optional.

:open_mouth: Now I feel dumb. Thanks a lot, that helps. Disregard my sillyness, we’re hectic here over other things.

That is definitely NOT the case. You CANNOT add “whatever material you’d like” in the “hard parts only” zone. Please do not do this!

If there is any question about what can or cannot be incorporated into the bumpers, please be sure to ask that question on the official Q&A forums. Remember, any answers found here (including this one) are unofficial and will not carry any weight with the inspectors.

-dave

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Dave,
My understanding of the rule is that, as long as there are the 2 stacked noodles + durable cover that’s securely fastened to a 3/4" thick x 5" tall plywood backing, there is no reason why teams can’t add a 1/8" thick steel plate all around the plywood. That was the rationale behind my “add whatever material you’d like” comment (emphasis on “add”).

Russ

Perhaps the point Dave is trying to make is that you cannot add whatever you want inbetween the robot and bumper if it is non-functional from an attachment point of view?

But… if your multi-part bumper attachment system (R08-H) uses thick steel brackets for strength there is no reason why that is illegal.

Unless we are to interpret Figure 8 - 1 as a definition, whereas Figure 8 - 2 is only an example.

Gary–that might be the case, because

<R08> … BUMPERS must be constructed as described below and illustrated in Figure 8 – 1.

The angle shown in Fig 8 - 1 is labeled “aluminum”, not “steel”, and it does not appear that the angle is optional…???

Time for me to read up on more Q&As…

edit: apparently the angle is optional

http://forums.usfirst.org/showthread.php?t=11394

As opposed to

I. BUMPERS must protect all exterior corners of the BUMPER PERIMETER (see Figure 8 - 2).
J. Corners and joints between BUMPER segments may be filled with short pieces of vertically oriented pool noodle, by wrapping the pool noodles around the corners, or by beveling the ends between adjacent segments so they form a tight and complete protective surface (see Figure 8 – 2).

And, as you’ve found in Q&A, the clamping brackets are optional. (Although an earlier post http://forums.usfirst.org/showthread.php?t=11219 said they are required; that’s OK, the GDC can change.) If 8 - 1 is to be definitive a note indicating the brackets are optional should be added.

Exactly! :slight_smile:

So are steel brackets okay or not? :stuck_out_tongue:
I’ll try and ask on the Q&A but what do you all think?

I know we could add weight by sticking steel robs in the noodles. It’s brilliant. jk. :stuck_out_tongue:

See this Q&A forum answer. No steel angles. No steel plates. No lead weights. No small rodents. No Chinese food from lunch. You have to make the bumpers out of the items that they have always said they must be made from - plywood, pool noodles, fabric covering, aluminum angles, and fastening system. Nothing else.

-dave

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I really don’t mean to derail this thread, but I’d like to point out for future GDC consideration that this is an excellent demonstration of how defective the wording of bumper rules was this year. Calling the rules unclear is inaccurate; they are very clear… the only problem is that everyone seems to find them clear in a different way. If there are any two people on this planet who should accurately understand these rules, they are Dave Lavery, a guy who helped write the rules, and Russ Beavis, the guy in charge of telling inspectors how to enforce them. For there to be this substantial of a disagreement this late in the season is really troublesome.

I don’t think there’s any question that literally hundreds of teams are going to show up to competition with illegal bumper configurations this year. For many of them, it won’t be because they didn’t read the manual, but rather because they read it, applied a reasonable degree of logic, and still ended up with a different interpretation than the one intended. I’m afraid it’s going to be a huge mess, I feel like it could have been avoided, and I’m very hopeful for vast improvements next year.

Since this opinion was on Chief Delphi, it is not necessarily correct or even accurate. Only those views expressed from the GDC (or FRCOPS) on the official Q&A are to be regarded as gospel. Quite frankly, I don’t trust this “dlavery” fellow.

would it be considered illegal if steel brackets are used as part of the robust attachment system seeing as how there are no definitions on what a robust attachment system is?

ummmmm…how about you ask on the Q&A? :slight_smile:

My wild guess it that you could use steel brackets and large steel bolts as part of your robust fastening system. Last year we used 5/16" coupling nuts (they’re over an inch long) as part of our nut-and-bolt fastening system, they’re much easier to hold onto that normal nuts.