If I design and employ a bracket for attaching bumpers to my robot such that the bracket is always attached to the bumper, is that bracket then considered part of the weight of the bumper?
i.e. you remove the bumpers by removing the bracket.
According to which year’s rules?
By 2008 rules, I would say that it would count with the bumper, assuming the attachment method was legal.
Assuming the most current rule set.
I agree, I think the bracket goes with the bumpers.
That is how we did bumpers this year… the bracket stayed with the bumper and was weighed as part of the 15 lbm allowance.
Now if somone would only come up with a universal bumper bracket. :rolleyes:
Why do you need to design a bracket?
We just mounted clevis pins on the wood backing on the bumpers and ran the clevis pins inside, through the chassis and captured them using quick release pins. We’ve been able to attach and detach our bumpers in under a minute the past couple of seasons.
The only problem with the clevis pin method is if an inspector takes the “bolt and nut system” rule literally (which they probably should).
Chassis design can incorporate bumper attaching points, if you plan ahead.
The only place to look for an authoritative interpretation of FRC rules is the official FIRST Q&A forum. The pertinent section of that forum for 2008 can be found here.
The attachment method described by the OP would comply with <R08> as written and officially interpreted on the forum linked above; however, the bracket(s) would have to be attached to the standard bumper using strong stiff (threaded) fasteners, and be removed from the bumpers when they are weighed during inspection. The weight of the bracket(s) would count as part of robot weight, not bumper weight. See this Q&A response, among others.
We did brackets the two out of the last thee years and the inspectors always required them to be weighed with the robot.
Even though a quick release pin is the best way to mount bumpers, it’s technically been illegal since bumpers have been around.
I wish the bumper rules were changed a little bit to allow methods of retaining the bumpers that are strong and quick to be released, yet are not strictly bolt and nut interfaces.
I do, too. It is not fun for robot inspectors to tell a team that has devised a clever solution that it must be changed to match the less-elegant one that is required by the rule book.
However, I have also seen some quick-release bumper mounts that were not-so-elegant, nor very robust. Teams that built them were better served by changing to the standard mounting method shown in the rules. IMO it will be a challenge for FIRST to write a new standard bumper rule that allows cleverness in the mounting scheme, while preserving safety, robustness, and fairness.
The worst kind of specification is “I’ll know it when I see it” (IKIWISI). I’d rather enforce a rule that is clear, even if it disallows some solutions that I think are cool.
This discussion misses the point-the bumpers!!!
Who cares how they are mounted as long as it is safe and there is no unfair advantage?
Consider this more- if you built the bumpers exactly to the specs in the rule book last year they could not make the specified weight.
This is a VERY sore subject since I spent most of a day dealing with a x**&*^ inspector at Nationals who seemed to think there is only one right way to do things. Apparently the rumors of the CD community weigh a lot with some inspectors over others. Sometimes enforcing the spirit of the rule book is more important than enforcing the letter of it.
Mark these words- the day is coming when all FIRST robots will be clones of each other with little or no freedom for individual innovation of design.
**Lets hope that this year’s game will encourage a diverse array of innovative designs and materials uses. Otherwise we might as well eliminate the Xerox Creativity Award. **
WC 
(yeah- this ticks me off)
Interesting point Wayne…I don’t quite agree that the bumpers will be overweight if built to the specs, since one of the specs is that they will not weigh more than 15 lbs (please pardon they lawyerspeak). Ours weighed about 12 lbs and went all the way around the robot, which was only 26 x 36", and we used heavy attaching nuts/bolts, and no aluminum angle. I did not find a size specification for the aluminum angle, but I think that if we had used 1/2" x 1/16" angle it might have met weight. I can imagine that it would be very easy to make the bumpers overweight if you were to make them as large as possible and use the angle, or if they were a bit smaller but used more substantial angle.
Overall I think there is a lot of room for creative use of materials and design…the bumpers, motors, electronics, and pneumatics seem to be areas that are limited, but there is good reason for most of the limits.
The other problem is that many inspectors are not calling teams on it. We spent a lot of time (wasted a lot of time, really) making sure our bumpers would be legal. We would have very much liked to use a quick release pin, but decided it did not meet the letter of the rules. Once we got to the events we saw many teams who had used non bolt-nut fasteners, and were never told to change their bumper configuration.
what’s even worse is when you have a setup, and told from regional to regional that its legal, its not legal, and then its legal again (in terms of where the fasteners weight count towards).
We had different interpretations on whether the nut/bolt fastener counted either towards the weight of the bumpers or the robot which in situations caused us to not meet the 120 and or 15lb requirements.
The whole issue of using bumpers is to protect bots and some inspectors focus more on the wording than the purpose of having them mounted to your bot.
As just mentioned, I hope the rule(s) are revised. It was a pain taking the bumpers on and off.
Thanks for the idea on the clevis pin. If its allowed next year, we may try that.
I wish we could go back to making bumpers optional. While there are many advantages to having them I can think of just as many not to have them. I wish it was a choice instead of a requirement, then people could attach them legally or not at all and still be fine.
Exactly.
Many teams are capable of choosing to not use bumpers, and as a consequence building a robot that has to withstand an impact with another nonbumpered robot.
If bumpers become optional, then no rule should be in place on how to make them exactly. In 2006, I believe they were optional, BUT, if you used them, it had to be according to FIRST specs. I dont see why if you gain no competitive advantage (within 120lbs that year) with them. We made our own type and had to remove them.
If we have the liberty of creating our robot how we want, why cant we make our own provisions for protecting our bot (following the robot construction rules)?
I had the interesting experience last year of inspecting at events on opposite sides of the US (Peachtree [GA] and Minnesota) and also at the Championship.
I observed that plywood does not have the same density, depending on the source. Different parts of the country, it is made from different woods which affect the weight. Of course, the moisture content can make a difference, too.
One of my least favorite parts of inspecting last year was having to try to explain to teams that fact. You would have one team with a set of bumpers that fully wrapped the bot that would just make the 15 lbs, and the next team would be at 15 lbs with only three sides. I had teams tell me that it was impossible to build 4 sides of bumpers that met the rules and the weight, but I also saw many teams that managed to do just that.
And I had a discussion with Russ Bevis, the Chief Inspector for FIRST, about this very subject at the Championship.
I’m not going to touch the attachment discussion, that subject still makes my blood pressure rise…
Point well proven. I kinda liked it without bumpers, the bot looked liked it had a world war when it came back after the comps.
While I have forgotten some of the minuitae of the rules, and didn’t find the confirmation to this even after following Richard’s very helpful links to the Q&A (I didn’t exactly knock myself out doing it… the season IS over, after all), I believe that the mounting brackets would not only have to be weighed with the robot, but also sized with the robot, as they are not, technically, part of the bumper.
On the issue of building and inspecting robots to meet the bumper specifications… the rules were pretty clear. If you just followed the rules, you wouldn’t have any problems. This does require reading the rules, following the Q&A, and recognizing that no matter how brilliant your particular design is, that it is not brilliant in an FRC competition context if it is not FRC legal.
It is disappointing, but not surprising… especially for teams that followed the rules very carefully… to see other teams pass inspection with bumpers that fall outside the specs. This obviously happened at regionals, because when I was doing tech inspection on Galileo, our team of inspectors found several bumpers that did not meet FRC rules. The most common violation was that the plywood had holes in it other than those used for fasteners, but I also came across a team using 5/8" MDF instead of plywood. There were, quite possibly, one or two that slipped past us in Atlanta, too, but we tried… really, really tried… to make sure that *every *robot was competing on a level, FRC-legal footing by Friday morning.
And I have to add, just for Cory, who felt that their time spent making their bumpers legal was wasted, that it most definitely was not. I remember looking at their robot (it is a beautiful machine) and had I noticed bumper configuration that was not “spec”, they would have been having a conversation with the lead tech inspector over what they would have to do to make it legal.
Most tech inspectors are or have been builders, coaches and/or mentors, too. The only thing more painful than seeing a robot not pass tech on a “technicality” that “doesn’t affect performance”, (please don’t even try that argument with a tech inspector… they don’t make the rules!) is missing the violation and ignoring the hard work that all the other teams did to comply with the rules.
Just a few thoughts…
Jason
P.S. Ever tried finding pool noodles in Canada in winter? Now we stock up in the fall.