legality of bolt and screw heads breaking plane of chassis meeting bumpers

[sgreco]

If in fact a robot had bolt head extending out of the frame perimeter, but inside the bumper zone, then when the bumpers were removed and the robot were pushed against a wall, the bolt head would hit the wall and not the frame perimeter, which would make this note not make sense.

Note: This means no “mushroom-bots.” If a ROBOT is designed as intended, in normal operation you should be able to push the ROBOT (with BUMPERS removed) up against a vertical wall, and the FRAME PERIMETER will be the only point of contact with the wall.

[Mr. Lim]

Originally Posted by sgreco

If in fact a robot had bolt head extending out of the frame perimeter, but inside the bumper zone, then when the bumpers were removed and the robot were pushed against a wall, the bolt head would hit the wall and not the frame perimeter, which would make this note not make sense.

I think the note was a good example in illustrating the general application of the FRAME PERIMETER, which was its original intent. It's not as good in illustrating the protruding bolt head exclusion, which was added later in a Team Update(?).

The note clarification does make more sense if you interpret that the protruding bolt heads in the bumper zone "simply disappear" because they are excluded from the FRAME PERIMETER. By magically pretending the excluded bolt heads no longer exist, your FRAME PERIMETER should be the first thing to touch a wall.

(That also means any protruding bolt heads above or below the bumper zone will cause a problem - they are NOT excluded, and still have to be taken into account in the example)

Kind of a weird assumption, and I've already shown in this thread that making assumptions is generally a bad idea. However if you do this, the scenario seems to better the reflect the actual rules as written.

[sgreco]

I'm sorry to keep dwelling on this topic, but does anyone know the intent of this rule? What changed from last year to this year, or any other year that made this rule need to be changed?

I can't see anything harmful about having a bolt extend a little underneathe the bumpers. The only thing I can see is if they were sharp, but that is covered in R-04 and thus shouldn't make a difference in the determination of this rule.

(That said the rules are the rules and we have to follow them, I'm just curoius if anyone knows the intent)

[Bharat Nain]

What is the reasoning behind this rule?

[Proud2BeaGeek]

Originally Posted by sgreco

Ok, I'm a bit confused.


Frame Perimeter



R-16



Note Under R-16



These Three parts of the rules completely contradict each other.

The definition of frame perimeter is consistent with the first part of R-16, which would make bolts protruding perfectly legal.

The note under R -16 completely contradicts everything. I would be more inclined to believe that a part of rules would be more correct than a note underneathe, and I would also be more inclined to believe that something that appears in the rules twice would be more correct than a note that occurs once. Based on what I've seen and read I have no reason to believe that protruding bolts are illegal; true there is some gray area, but since two distinct sections say it is legal, I would think that I can fairly assume that it is legal.

To me the rules pretty clearly allow the bolts to protrude as neither of the first two quotes I posted have been removed from the rules.

It appears to me that the note does not contradict the rules, but rather clarifies them; the "minor protrusions such as bolt heads, fastener ends, rivets, etc... within the BUMPER ZONE" (in my view) are allowed in order to attach the bumpers to the robot, and when the bumpers are removed, so are said protrusions. Then "you should be able to push the ROBOT... up against a vertical wall, and the FRAME PERIMETER will be the only point of contact with the wall."

So, if my reasoning is correct, the only protruding bolts allowed are the bolts holding the bumpers on.

[sgreco]

Originally Posted by Proud2BeaGeek

It appears to me that the note does not contradict the rules, but rather clarifies them; the "minor protrusions such as bolt heads, fastener ends, rivets, etc... within the BUMPER ZONE" (in my view) are allowed in order to attach the bumpers to the robot, and when the bumpers are removed, so are said protrusions. Then "you should be able to push the ROBOT... up against a vertical wall, and the FRAME PERIMETER will be the only point of contact with the wall."

So, if my reasoning is correct, the only protruding bolts allowed are the bolts holding the bumpers on.

The Protruding bolts most certainly are not the ones holding the bumpers on. They are attached to the frame, see my second post for some clarification on where the note doesn't line up with the rules.

I understand what the rules are saying, but the intent of the rule is still somehwere outside of my knowledge base.

[Coach Tom]

I'm only speculating -- since this year's game has the bumpers very high off the carpet, R16 helps to limit perturbing fasteners, bolts etc. below the bumper zone.

Team Overdrive is already planning a quick fix to our robot since our wheels currently have bolt heads perturbing outside our frame perimeter. We already fit into the allowable dimensions.

I still predict that more than 50% of the robots will arrive at their first regional out of spec per R16. This will delay the regional for sure.

[Vikesrock]

Originally Posted by Coach Tom

I still predict that more than 50% of the robots will arrive at their first regional out of spec per R16. This will delay the regional for sure.

I'm going to guess about 1/3 of the robots will have trouble with this rule, although I wouldn't be surprised for it to be as high as 50%.

The thing I definitely disagree with is that it will delay regionals. The events will go on, even if some robots have not passed inspection.

[Coach Tom]

Team Overdrive is assuming that welds at perimeter joints (or below) are not protrusions -- otherwise we will be grinding down some metal. What fun!

[IndySam]

Originally Posted by Coach Tom

Team Overdrive is assuming that welds at perimeter joints (or below) are not protrusions -- otherwise we will be grinding down some metal. What fun!

I'm afraid your assumption will be wrong. It might be easier to make shims to move your perimeter out a bit to cover your welds.

[martin417]

There has been much discussion about this topic in this thread.

As for why, there has been much discussion about the why of rules in this thread.

[Coach Tom]

Thank you for steering me to the prior threads. Woo ... What a discussion.

I noticed that Team Overdrive's Rules Captain "Scout Master" (a student) chimed in on the thread in late January. At the time, it appeared that bolt heads could protrude beyond the vertical perimeter below the bumper zone (at least that was her conclusion). So, we proceeded with our design. By sheer luck, I stumbled onto this thread today. Team Overdrive can fix our robot to comply within the strictest compliance, but it will take about one hour of valuable time at the regional. We will grind down our welds and counter sink our shaft bolt heads.

I agree with the Mentor from Wildstang (111), clarification of this issue came way to late in the build season. Team Overdrive gives 100% of rule compliance responsibility to our students. After week four, they thought this issue was settled -- especially since common sense seemed to be obvious. Fortunately, we have a relatively quick fix. Many other teams will not. Also, depending on a team’s bumper design, "adding a shim" is not always possible.

I sure hope the local regionals give some grace on this otherwise I still see a lot of out of spec robots.

Respectfully, Coach Tom (FRC 2753)

[Vikesrock]

Originally Posted by Coach Tom

I sure hope the local regionals give some grace on this otherwise I still see a lot of out of spec robots.

After installing shims to expand our frame perimeter on our wide dimension to deal with this issue I strongly hope that regionals DO NOT give any grace on this issue.

The rule is certainly obnoxious (and perhaps a bit confusing), but it is obnoxious for everyone and I see no reason why other teams should be excused from following rules we put in the time and effort to adhere to.

[Hawiian Cadder]

we have a low frame that is 27.5 by 37.5, then a foe frame made out of velurite (corrugated lexan) glued to C channel to avoid this problem.

[3286]

Without pointing fingers or fanning flames, in my humble opinion, and we all know what opinons are worth in todays market, this is an example of an area in the rules where graphics would be extremely helpful.

I know the GDC is probably up to here with opinions and I respect what they have to do each year, and I have no doubt they put a lot of time and effort into this to ensure that the playing field is level for all, but this would probably remove a lot of the questions that inevitably arise from taking ideas that are expressed in text only and the resulting confusion from interpreting these ideas.

Mike