Re: Cutting corners (on the robot!)
 

That's not quite what the rule says. R21 specifies how the bumpers are to be constructed and what materials you can use. For example, R21 does NOT allow you to bolt a big hunk of steel to the bumper "just to add weight". It does, however, allow you to construct your fastening system (how you attach to the robot) however you like. So if your fastening system is a big hunk of steel with some holes through it that let the bumper mount to your frame, it's fine by R21.

Bumpers do have their own weight limit (20 lbs), though, as seen in R20.

Re: Cutting corners (on the robot!)
 

That's what I was trying to get at. You're allowed to choose your own fastening system and construct it with as much (or as few) materials as required. Any weight beyond what is required to construct your bumpers (however you want) is not allowed.

Re: Cutting corners (on the robot!)
 

What rule says this? I just read through the rules on bumpers, and didn't find anything that limits parts or weight based on the intention of those parts or weight. There's a 20 pound limit total (R20).

I doubt Al will give a ruling here on CD, but he will likely give great advice, and history.

Re: Cutting corners (on the robot!)
 

R21 says how bumpers must be constructed. Plywood, pool noodles, cloth, optional angle as a cloth clamp, and a "robust fastening system". No other items are allowed to be used to construct bumpers as that would go beyond the guidelines specified in R21.

The term "robust fastening system" is vague and generally inclusive. You are allowed to design your own fastening system using any parts you wish. Once you have your fastening system, you can't add any additional materials to bumpers even if you're under the 20 lb bumper weight limit.

The bottom line is you can use steel as part of your fastening system if you can meet the weight limit. If your fastening system doesn't involve steel, you aren't allowed to add it even if you're under the weight limit.

Re: Cutting corners (on the robot!)
 

R21 says that certain materials must be used (wood, noodles, fabric). But I don't see any thing that says only these materials, or prohibits other materials.

Re: Cutting corners (on the robot!)
 

R21 says how bumpers must be constructed. Adding additional weight is not part of those guidelines.

Re: Cutting corners (on the robot!)
 

The rule doesn't say anything about reversible bumpers or velcro, yet year after year both are legal.

Outside of that, I can tell you that the ten pounds of steel I used on my "robust fastening system" are integral to it.

After three years in our pit, I have yet to see an inspector rule against added weight on the bumpers. Might just be a regional thing though...

Re: Cutting corners (on the robot!)
 

Reversible bumpers and velcro are included in the "fabric" requirement in combination with R27 which requires robots to able to display red or blue bumpers and be able to switch between them fairly quickly.

Re: Cutting corners (on the robot!)
 

If you can convince the inspector that everything on your bumper is essential, you are fine. If you screw steel plates onto your bumpers which serve no other purpose besides weight, you are in violation of bumper rules.

Re: Cutting corners (on the robot!)
 

Last year, inspectors were disallowing bumpers because teams put metal weights inside the pool noodles. Don't try that. Use the fastening system as your extra weight, as you can't add non-functional pieces and be compliant in the rules.

But, if you have a metal piece fitted to support the bumpers around the short side/cut corners, then you should be good insofar as obeying both the spirit and the letter of the rules.

Not the easiest way to do it, but it should satisfy the inspectors.

Re: Cutting corners (on the robot!)
 

I did not intend to suggest simply adding weight for the sake of weight. What I intended to say is that if you needed to fill the gap of a cut corner, you could add angle iron to reinforce the inside corner of the bumper, maintain contact with the last 1/2" of frame and that added weight would count against the bumper weight, not the robot. I have never seen bumpers that came anywhere near the 20lb limit and I would put forth that if they do, the added mass was not integrally required.

Re: Cutting corners (on the robot!)
 

While no one can "rule" on a description here, I can tell you the rule of thumb inspectors use is examining the bumper construction using the bumper rules as a reference. Those parts that are and should be part of the bumper are thought of as "bumper'. Those parts that should be robot structure are thought of as 'robot". Those things that are "robot" should be weighed and sized (Frame Perimeter determination) with the robot. Steel weights, metal rod filling the pool noodles, lead sheet, (depleted uranium?!?) etc. can be pointed at by anyone in the pit and labeled "robot". Ballast is "robot" That is not to say creative ways of bumper mounting will be automatically rejected. Our LRIs are well versed in making the determination.
Please remember that all key volunteers do not operate in a vacuum or rule from on high. They will discuss a problem as a group when needed and come to a consensus. If they can't make a ruling, each of them has a contact at HQ that is available for phone consult.

Re: Cutting corners (on the robot!)
 

Wouldn't that violate R8 (prohibition on hazardous materials)? As far as I know, depleted uranium is still toxic.

Re: Cutting corners (on the robot!)
 

And radioactive!:D