8 inch bumper rule and other
 

In the rules it says that bumpers do not need to be attached to the chassis but just touching it. the photo below shows how we have only attached it on the sides. Is this legal?

Also we attached our pool noodles to the board with tape (SHHHHH don't tell the inspectors!) but do you think they will ask about them or do we have to take apart the bumpers and attach them with zipties.(refer to pictures)

Re: 8 inch bumper rule and other
 

In my opinion you probably won't be asked about the tape. However a team mentor and team captain are going to have to attest to the following statement on the inspection sheet.

It really depends on if your comfortable signing that or not. Do you believe you have followed all the rules?

Re: 8 inch bumper rule and other
 

Is there any reason why you would feel your bumpers are not legal? Are they mounted in accordance with R21(F)?

If that is a press-fit, then you are illegal.

Also, it's the inspectors you have to worry about satisfying, not the judges.

Re: 8 inch bumper rule and other
 

Zipties are no more allowed than is tape. In fact, zipties could be considered more of a violation because they are not as soft. Lots of teams have built bumpers without using anything to fasten noodles to plywood or fabric. Its really not that hard to do, though it usually takes an extra set of hands.

As to fastening the bumper to the robot, I can't really tell where fasteners are located, but it would probably come down to how much 'give' the bumpers have at the midpoint (assuming this is furthest from any attachment point) As an inspector, I'd want to see very little give here, and also would want the robot to be able to be safely picked up off the floor by lifting from these same points on the bumpers only. So in the picture, if the bumpers are only secured at the extreme end points of the C shaped bumper, I would not consider that to be robustly fastened.

Re: 8 inch bumper rule and other
 

the mounts are located 1 on each short side of the bumper

Re: 8 inch bumper rule and other
 

That will invite very close scrutiny and likely a need to add more fastening points.

Re: 8 inch bumper rule and other
 

Thank you. If I add one support in the middle of the long side will that be rules compliant.

Re: 8 inch bumper rule and other
 

The rules call for a "rigid fastening system to form a tight, robust connection to the main structure/frame". Does your mounting meet that requirement?

In generally, inspectors look for two things to determine if it is a robust connection: What will happen during normal game play (we don't want to see your bumpers falling off!), and what will happen when a student picks up the robot by the bumper (We don't want to see it breaking off!)?

IMO, mounting with just those short sections of angle on the sides is probably not robust enough.

And as for the tape... a lot of inspectors and LRI's read Chief Delphi here. If a team at one of my regionals posted on here that they used tape in the bumpers and I saw the post, I would feel obliged to ask them about it at the regional.

Re: 8 inch bumper rule and other
 

I must say, however, you have very nice looking bumpers.

A fastening technique we have used in the past is to use T-nuts (available at your local hardware store) installed on the inside face of the plywood (you'd have to disassemble for this) and then hex head bolts that go through the frame into the T-nuts (short enough to not go poke through the plywood!). Very tight connection, can be removed quickly with a socket wrench or if in a tight spot just a box end wrench)

https://www.google.com/search?q=t-Nut

Re: 8 inch bumper rule and other
 

Thanks

Re: 8 inch bumper rule and other
 

Do they ask you to pick up your robot by the bumpers at your event or at Championships? This is an honest question as the event we attend asks you not to pick up your robot by the bumpers.

If this is something they do at Championships or other events we would like to know as we hope to attend other events in the future.

Re: 8 inch bumper rule and other
 

The only time would be during inspection as a test. We have never been ask to do that. It is the inspector's call as to what a "robust attachment" really is.

Re: 8 inch bumper rule and other
 

The fact that you're willingly breaking a rule disappoints me, and the fact that you're telling the internet baffles me. I can all but guarantee that at least one inspector at Chesapeake and/or DC has read this thread by now, and will be asking you to take your bumper apart at an event.

Something cannot be "more of a violation," a violation is absolute. Either something is a violation or it is not. That's like saying something is "more than perfect."

Where in the manual does it state this practice?

R21F (quote below for your convenience) does not specify that the bumpers must be able to support the weight of the robot. Bumpers must "withstand vigorous game play." No where does it state they must withstand being lifted up.

Re: 8 inch bumper rule and other
 

You shouldn't lift by bumpers (and you shouldn't be asked to do so) because too many robots have bumpers that aren't secured robustly, and it is dangerous. But they ought to be able to be lifted by the bumpers if they are robust enough.

Consider an electrical junction box that you just wired and energized. You ought to be able to poke your fingers in there because there should be no exposed live wires, but you should not do so, for I hope what are obvious reasons. Sort of the same idea.

Re: 8 inch bumper rule and other
 

OP, you will need to fix this. Here is the official ruling on exactly what your team has done.

If you are attending Chesapeake, please don't show up with this uncorrected.

Re: 8 inch bumper rule and other
 

jlee and other members of your team,
What John and the others are addressing is the belief that the long section of bumper has nothing to lock it to the frame. Depending on it's height compared with another robot, that contact might just lift it causing a failure to the two attachment points on the short sides. If a section or two of "C" channel that fit over the frame were included on the long side, there would be no way for the bumpers to be lifted and therefore, cause a failure in the attachment points on the short sides. Alternately, any fastening point (aluminum angle attached to frame and bumper) on the long side would also work. Lifting the bumper system would be a valid test for an inspector to try and determine the robust nature of your attachment. That is the likely stress that your robot will incur during match play. As inspectors, we want to help you play every match.

Re: 8 inch bumper rule and other
 

It is in your best interest (and the best interest of the alliances you are on) for you to have robust bumper connections. The ultimate test of this occurs on the field where you want your bumpers to stay on your robot.

Look at rule G-20. If you lose a bumper or have it jacked up out of the bumper zone, your robot will be disabled.

Don't know why you want to do a minimal job of attaching your bumpers when it isn't that much more work to do a good job that you can be proud of.

Dr. Bob
Chairman's Award is not about building the robot. Every team builds a robot.

Re: 8 inch bumper rule and other
 

You are correct in the wording of the rule. However, having been around FIRST for some time now, I can tell you that every robot from every team will at some point during the season be picked up by its bumpers. Our interest in making sure there is a robust mounting that won't break in this situation is purely for the safety of the students on the team, and thus falls under R8.

Re: 8 inch bumper rule and other
 

Thank you all for the feedback! We added another support for the bumpers, and we're now able to pick up the robot by the bumpers.

Also, what I said about the tape came out wrong -- we put them together before we realized it was illegal (it's not in the manual). We're planning on fixing the problem.

Re: 8 inch bumper rule and other
 

Thank you all for the feedback! We added another support for the bumpers, and we're now able to pick up the robot by the bumpers.

Also, what I said about the tape came out wrong -- we put them together before we realized it was illegal (it's not in the manual). We're planning on fixing the problem.

Re: 8 inch bumper rule and other
 

Ursa Major,

Please heed the advice of those who have commented on your bumper construction and attachment points. There is nothing more I can add that hasn't already been said.

We look forward to seeing you in DC and Chesapeake.

Bill Landin
Lead Robot Inspector, 2014 FIRST FRC Chesapeake Regional