Teams: Check Your Bumpers

[ThirteenOfTwo]

I just found out that our team's bumpers, which are already bagged and tagged, are illegal as per rule <R35>.

A cursory trawl through the Robot Showcase subforum allowed me to find pictures and video of more than a half-dozen teams with illegal bumpers on the first page alone.

<R35>: Teams shall display their team number on the Bumpers in four locations at approximately 90° intervals around the perimeter of the Robot. The numerals must be at least 4 in. high, at least ¾ in. in stroke width, and be either white in color or outlined in white. Team numbers must be clearly visible from a distance of not less than 100 ft, so that judges, referees, and announcers can easily identify competing Robots.

Question on 2/8/12 by Team 1619:

Originally Posted by Official Q&A

Q. Does R35 limit the team number quantity to exactly four locations? For instance, if one side of the robot has two short bumpers separated by a gap, can the complete team number be put on both of those bumpers? Thus, there'd be two complete team numbers on one side of the robot.
A. Rule [R35] requires that the team number be displayed in four locations, no more or fewer.

Teams, check your bumpers now to make sure that they aren't illegal! If you know of any teams with illegal bumpers, please remind them of this rule. We don't want anyone to end up in a position where they find out at inspection that they need to rework their bumpers!

[AdamHeard]

It's sad that the bumper rules are far more arbitrary and restrictive than many other sections of the rules.

[AllenGregoryIV]

Thursday of everyone's first competition is going to be a lot of fun, <sarcasm> sewing and painting is what I want to be doing during that time </sarcasm>

We will be fixing bumpers as well, but we shouldn't have to do too much.

I am inspecting at two events and I don't want to be the one to stop people from passing because of bumpers but I feel like that is going to happen a lot.

[Billfred]

Originally Posted by AdamHeard

It's sad that the bumper rules are far more arbitrary and restrictive than many other sections of the rules.

This. I'm glad we have a 1 in our number, otherwise we'd probably have to increase our bumper length on one side of our intake strictly to fit the number. I'm tolerant of only showing the numbers, but letting the four-digit teams break them up (I think most of the sub-1000s could fit their number in eight inches comfortably) would've been helpful.

[Cal578]

It amazes me how much misunderstanding there is regarding fitting the team number on the bumper. It's easy to fit your number, even if you have a 4-digit number with no 1's, without compromising your design.

The minimum size of a bumper, as measured at the surface where the team number goes, is 11.25". It's not 8", as many people post. You have 8" of frame per [R27], plus 3/4 inches for the overlapped plywood (see figure 4-4 under [R28]), plus 2.5" for the noodle in the corner space per [R31]. Even if you use the vertical noodle as shown in the lower left of figure 4-6 and you don't want your team number to go into the rounded corner, you have 10.5 inches you can realistically work with.

There have been several posts (like this one and another) that offer fonts that make it easy to fit your team number within 10.5-11 inches. If you need to work on your bumpers at competition to pass inspection (my team has done that, but I hope not this year), then I hope this advice helps you get to a direct and fairly easy solution. Good luck!

[topgun]

Originally Posted by Cal578

The minimum size of a bumper, as measured at the surface where the team number goes, is 11.25". It's not 8", as many people post. You have 8" of frame per [R27], plus 3/4 inches for the overlapped plywood (see figure 4-4 under [R28]), plus 2.5" for the noodle in the corner space per [R31]. Even if you use the vertical noodle as shown in the lower left of figure 4-6 and you don't want your team number to go into the rounded corner, you have 10.5 inches you can realistically work with.

You are assuming that people are overlapping with the shorter bumper. If the connection/overlap is coming from the adjacent bumper, then you only have 8 inches.

I agree with Adam about the bumpers.

Furthermore, the whole "at the ends" in R33 is going to be a bigger problem for teams than R35. We modified our bumpers to meet this "at the end" section in R33 following Saturday's pre-ship event and it resulted in more weakly mounted bumpers than what we had before we met the R33 compliance. This problem is especially acute for teams using the KOP chassis since there are so many bolts already in the corners of the chassis. Our nice pinning solution doesn't work at the ends.

An inordinate amount of time and money is spent on bumpers, when the focus should be on the main robot.

[Brandon Holley]

Originally Posted by Billfred

This. I'm glad we have a 1 in our number, otherwise we'd probably have to increase our bumper length on one side of our intake strictly to fit the number. I'm tolerant of only showing the numbers, but letting the four-digit teams break them up (I think most of the sub-1000s could fit their number in eight inches comfortably) would've been helpful.

I won't complain too much because we are a 3 digit team with a 1 in our number, but even that was a pain. We have a specific "font" we use for all our number/lettering. It's become part of our image so we like to stick with it. Our font will not satisfy the stroke width requirements while staying inside 8" length. We had to go back and "squish" our numbers for the front and back to make them fit, which makes them look silly to me.

I cannot imagine what it is like for 4 digit teams.

-Brando

[pyroslev]

Originally Posted by AdamHeard

It's sad that the bumper rules are far more arbitrary and restrictive than many other sections of the rules.

Amen to that. We might have to cover up one of ours cause there is an open space on the front and we painted both. Cover it up and we should be ok.

We did the usual extruded aluminum frame with the sliders mounted on the middle and ends of the bumpers. Doing a Nascar style pit stop, we can change them in about a minute with three people, satisfying that 10 minutes or less rule.

[Taylor]

For those of us who have already made the numbers on each bumper - five total - Would it be permissible to cover over the numbers with red/blue gaffers tape to be compliant with the 4 and only 4 ruling?

[Cal578]

Originally Posted by topgun

You are assuming that people are overlapping with the shorter bumper. If the connection/overlap is coming from the adjacent bumper, then you only have 8 inches...

No, I made no such assumption. It doesn't matter which direction the plywood overlaps, there is still another 3/4 inch added to the first 8 inches (see figure 4-6 under [R31]. Then add the noodle filling the corner area (same figure); that adds another 2.5". This adds up to 11.25" for the team number.

If you have a bumper with only 8" of fabric where the team number goes, I think it's illegal. It either doesn't cover the 8" of frame from the vertex per [R27], or it doesn't have the corner filled per [R31].

If you disagree, please give us a picture or drawing of a shorter bumper that is legal.

[JosephC]

I'm agreeing with Cal on this one. Bumpers need to be 3.25'' thick. If you have a 8 inch bumper that lines up with the exact corner of your frame perimeter, you still need the additional 3.25" on the corner of your robot. Making it 11.25" for your team number.

Being a 2-digit team, we don't have to worry about fitting our number in.

Thanks for the heads-up ThirteenofTwo, going to check if we violated R35 after school today.

[MrForbes]

If you put the corner noodle on the side bumper instead of the short front bumper, then you could make the front bumper only about 8" wide. But why would you do that, if you need to make the number fit the short front bumper?

We used longer noodles on our short front bumpers, so they would be the thing that filled in the corner. No problem fitting our 4 digit number on there. But we didn't get the stroke width right....it's almost 3/4". I think they'll pass?

The rules are kind of complex, and they do kind of dictate how you can design parts of the robot. Of course it turns out that if we'd have played with the balls more at the beginning of build season and discovered how they behave, we probably would not have split the front bumper, we would have just made our intake under the bumper, as wide as possible....since it's so easy to drive over the balls.

[Jon Stratis]

Originally Posted by Taylor

For those of us who have already made the numbers on each bumper - five total - Would it be permissible to cover over the numbers with red/blue gaffers tape to be compliant with the 4 and only 4 ruling?

I imagine that would be fine. You could also get some additional fabric to wrap around that specific bumper, and staple it in.

Originally Posted by Cal578

No, I made no such assumption. It doesn't matter which direction the plywood overlaps, there is still another 3/4 inch added to the first 8 inches (see figure 4-6 under [R31]. Then add the noodle filling the corner area (same figure); that adds another 2.5". This adds up to 11.25" for the team number.

If you have a bumper with only 8" of fabric where the team number goes, I think it's illegal. It either doesn't cover the 8" of frame from the vertex per [R27], or it doesn't have the corner filled per [R31].

If you disagree, please give us a picture or drawing of a shorter bumper that is legal.

i think he was implying that the pool noodle in the corner would be attached to the side bumper, not the front bumper. In that case, I've seen teams put a single digit on the end of the side bumper such that it lines up with the other numbers on the front bumper, and it's worked that way for them.

[Jon Stratis]

Originally Posted by squirrel

If you put the corner noodle on the side bumper instead of the short front bumper, then you could make the front bumper only about 8" wide. But why would you do that, if you need to make the number fit the short front bumper?

We used longer noodles on our short front bumpers, so they would be the thing that filled in the corner. No problem fitting our 4 digit number on there. But we didn't get the stroke width right....it's almost 3/4". I think they'll pass?

The rules are kind of complex, and they do kind of dictate how you can design parts of the robot. Of course it turns out that if we'd have played with the balls more at the beginning of build season, we probably would not have split the front bumper, we would have just made our intake under the bumper, as wide as possible....since it's so easy to drive over the balls.

IMO, your numbers are very readable from a distance, and the stroke width isn't so much smaller that it's noticeable. have a plan if you need to, but i'm going to guess no one will notice, unless the inspector actually measures the numbers!

[Kevin Sevcik]

Originally Posted by topgun

Furthermore, the whole "at the ends" in R33 is going to be a bigger problem for teams than R35.

This. I asked the GDC two pretty specific questions on this. The answers were less than helpful.

Q. How much tolerance is for attaching at the "end" of the bumper? Do we need to attach within 4" of the physical end? 1"? At the infinitesimal point at the end of the bumper? Physical constraints may make it difficult to place two perpendicular fasteners at the same infinitesimal point in space.
A. If it appears that a Bumper is rigidly attached at the end to a reasonably astute observer, it will be considered attached "at the end".

Q. Where is the end of a Bumper? We have bumpers that are two 8" pieces of plywood rigidly attached perpendicular to each other at the corner, plus noodle cloth, etc. Do we have to attach to the frame perimeter at just the two end points of this L shaped bumper, or at the corner as well?
A. If it appears that a Bumper is rigidly attached at the end to a reasonably astute observer, it will be considered attached "at the end".

I especially like how the second one completely fails to answer the question. But I'll whip it out when if inspector points out that we're not attaching our L bumpers in the corner. Then at least attempt to argue that the ends of the L actually are the ends of the bumpers.

I'm thinking about asking if they want to comment on what "attached" means. Specifically if they're going judge by whether the bumper is stiffly and securely held against the frame perimeter, or whether they want to see a physical fastener "at the end" of the bumper. I think the former option makes a lot more sense than the latter.