8 inch bumper rule and other

[jlee0119]

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)

[AllenGregoryIV]

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.

We, the Team Mentor and Team Captain, attest by our signing below, that our team’s robot was built after the 2014 Kickoff on January 4, 2014 and in accordance with all of the 2014 FRC rules, including all Fabrication Schedule rules. We have conducted our own inspection and determined that our robot satisfies all of the 2014 FRC rules for robot design.

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

[protoserge]

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.

[jvriezen]

Originally Posted by jlee0119

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 judges!) 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)

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.

[jlee0119]

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

[jvriezen]

Originally Posted by jlee0119

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

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

[jlee0119]

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

[Jon Stratis]

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.

[jvriezen]

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

[jlee0119]

Thanks

[rsegrest]

Originally Posted by jvriezen

...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.

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.

[FrankJ]

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.

[Gregor]

Originally Posted by jlee0119

Also we attached our pool noodles to the board with tape (SHHHHH don't tell the inspectors!)

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.

Originally Posted by jvriezen

In fact, zipties could be considered more of a violation because they are not as soft.

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."

Originally Posted by jvriezen

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.

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.

R21
BUMPERS must be constructed as follows

F-must attach to the FRAME PERIMETER of the ROBOT with a rigid fastening system to form a tight, robust connection to the main structure/frame (e.g. not attached with hook-and-loop or tie-wraps). The attachment system must be designed to withstand vigorous game play.

[jvriezen]

Originally Posted by rsegrest

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.

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.

[protoserge]

Originally Posted by Gregor

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.

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.