Reversible Bumper Update
 

G'day Chief Delphi!

I woke up this morning and read the team update for R21. My first thought was this didn't change anything, two layers of fabric, and two colors. After looking at our team's prototype reversible bumper, (based upon this design: http://www.youtube.com/watch?v=BUDMB-aiBpo#t=29 ) I realised it has 3 layers on one side of the fold and 1 layer on the other. We have already shipped our real bumpers that follow this same approach.

It appears to me that the new wording of R21 inadvertently makes these reversible bumpers illegal. I'm sure FIRST's intention was not to make reversible bumpers illegal. We assume a lot of teams use a similar approach to bumpers. If your team does, how are you planning to accommodate this update?

G'luck at the competition! We can't wait to see you all there.

Re: Reversible Bumper Update
 

The best option here might be to submit a question to the official FIRST Q&A (https://frc-qa.usfirst.org/Questions.php) for official help answering this question, as answers here are regarded as opinion unless a proper source is given. If asked there, the answer can be used as a reference for inspection in the event that your team's bumpers are ruled illegal. If you do not feel that asking the Q&A is necessary, it might be a good idea to make a second set of bumper covers that are completely legal in addition to a second set of other materials that can be ready to assemble. Depending on which event you attend, I am sure there will be many teams that would be happy to help your team out if they don't pass inspection.

-JTN
FRC 16

Re: Reversible Bumper Update
 

I agree, ask on the Q&A. When I read it, I read the intent as allowing reversible bumpers - the flip portion, while technically two layers of fabric, can be thought of as one. When you look at the folded over seam on a shirt or pants cuff, you don't think of it as 2 layers - it's two layers that are permanently joined with stitching to make a single unit.

I'll also mention that I don't see a way to use two strict layers of cloth to make reversible bumpers - you would need a single piece of cloth that has different colors on each side. Sounds like a very complicated dye job!

Re: Reversible Bumper Update
 

I asked a follow up question this morning. I think they are saying reversible bumpers are ok, but why not just say three layers is ok.

Re: Reversible Bumper Update
 

Can you post the question number?

As for 3 layers versus 2, it's starting to look like they are saying add-on covers are ok (2 layers), but reversible are not (3 layers).

Re: Reversible Bumper Update
 

Also, Q17 seems to imply that reversible bumpers are allowed.

https://frc-qa.usfirst.org/Question/...10-competition

Re: Reversible Bumper Update
 

Q377

Re: Reversible Bumper Update
 

OK so Q377 was asked specifically mentoning "3 layers", the answer was "see update 2-21". That update specifically mentions 2 layers.

So if I am reading this correctly, folding the fabric over (thus creating 3 layers) is not legal.

Oh crud.

Other opinions?

Re: Reversible Bumper Update
 

I agree, seems like it is being ruled illegal. Has that rule been similarly phrased all season? I think a lot of teams, including 694, may be in big trouble as the rules are phrased right now.

Re: Reversible Bumper Update
 

I would agree with Jon that the flip portion should be counted as one layer since they are permanently joined (not that my opinion matters vs. the GDC's).

Wouldn't permitting only 2 strict layers of fabric also prevent a team from folding in the raw edges of the base fabric if they intended to use any covers, or creating a folded pocket on covers/reversibles for elastic material?

I don't see how having a few extra layers would significantly alter the cross section either, and hope the GDC clarifies soon.

Re: Reversible Bumper Update
 

Note that update 2-21 added "and seams are". The two layers wording was added in update 2-11, in which tape was deemed legal.

Re: Reversible Bumper Update
 

Wondering what in the world made First put the "2 layer" part in the rule anyway. Is there some sort of competitive advantage to having 6 layers or something?

Re: Reversible Bumper Update
 

Q404

Re: Reversible Bumper Update
 

Thanks, but try to either link to or quote the source; everyone having to go hunt it down isn't efficient.
But, again, thanks

Re: Reversible Bumper Update
 

Update 2-25-14 made reversible bumpers legal again.:)

Re: Reversible Bumper Update
 

D. be covered with a rugged, smooth cloth (multiple layers of cloth and seams are permitted if needed to accomodate R27, provided the cross section of Figure 4-8 is not significantly altered).

R27




Each ROBOT must be able to display red or blue BUMPERS to match their ALLIANCE color, as assigned in the MATCH schedule distributed at the event (reference Section 5.1.1: MATCH Schedules). Markings visible when installed on the ROBOT, other than those explicitly required per R28, are prohibited.

Re: Reversible Bumper Update
 

So I didn't have to take our bumpers apart and rebuild them? I should have just left them alone? Is that what you are saying?


Just kidding. I'm good.

Re: Reversible Bumper Update
 

So, this got me to thinking.. Wouldn't an easier design for 'reversible bumpers be as follows:

Secure a red layer to the top backside (not top) of the bumper plywood. This layer is just long enough to reach around the noodles to cover the bottom surface of the plywood.

Secure a blue layer to the bottom backside (not bottom) of the bumper. It too is just long enough to cover the top surfaces of the plywood.


Put velcro on the top and bottom of the plywood, and at the corresponding locations on the fabric.

To show red, you open both layers and wrap the blue layer first, then the red layer. Noodles are held in place with tape.

Avoids need to do complex seaming, having stitching across your numbers, etc.

Red fabric
_________________
/
|__
| |OO
| |OOO
| |OOO
| |OO
|---
\___________________

Blue fabric