pic: Compressor Fan Mount



This is the compressor fan mount I made today :slight_smile: I’m really happy with how it turned out, and it’s probably the first thing I have made all year. I have the CAD file (Google Sketchup) if anyone wants it.

We were going to do the same thing mounting with the three bolts on the compressor until our LRI mentor informed us that removing those bolts to attach the fan and replacing them was considered modifying pneumatics and thus make the compressor illegal. We are now attaching with a custom bracket that zipties on.

I’d consider that to be legal per R65-C, but if your mentor is an LRI…

Last year we had a fan for the compressor (mounted to the electrical board, not altering the compressor), and were told to take it off by our inspector at Orlando. Not sure if that is really against the rules, or if most inspectors would care… But regardless, nice design!

I could see the reasoning why that wouldn’t be kosher.

You are removing the three screws that hold the head onto the cylinder. If you don’t re tighten the screws enough (secure them to a likely undisclosed torque spec / thread locker / etc), there is a chance the head could come loose with 120psi behind it.

Ya our LRI said the same thing.

Your LRI and his LRI are the same LRI… You’re from the same team!

Personally, I would make the same argument with my team and tell them not to do it. I could understand the argument for R65-C, but I don’t this this is what the GDC had in mind for that particular rule. This is also something that I think most inspectors wouldn’t notice or think about when inspecting. But as an LRI, I feel I have to hold my team to a very strict interpretation of the rules during build. It keeps them from having problems during inspection, and avoids any risk of an inspector thinking “i didn’t think that was legal, but it’s the LRI’s team and I don’t want to look like an idiot…”

You were told to take it off? Did they cite the rule that it was breaking? We had a fan pointing at our compressor and made it through 2 Regional inspections and the Championship inspection with no problems.

Being asked to remove it could come from two sources: first, the inspector may not realise it was a legal fan for the robot, and it would be an ideal time to respectfully ask for a second opinion from the LRI and make your case for it being legal. Second, without actually seeing the fan that was used, it’s possible that the fan was NOT one of the ones that has been distributed in the KoP over the years - those, and any that are integral to a COTS computing device or constructed from a legal motor are the only ones that are legal for use on a robot.

My LRI said the same thing too. What a coincidence!:smiley:

That could very well be the case, which is why I was curious of the reasoning.

It’s a nice design, but you are definitely reducing the amount of thread engagement those bolts have.

Having a fan pointed at your compressor, and having a fan mounted on your compressor, are not the same thing. We have a fan pointed at our compressor also, it’s mounted on a bracket which is attached to the robot belly pan.

Last year we had a fan for the compressor (mounted to the electrical board, not altering the compressor)…

That’s what I was referring to.

I’ll throw my opinion in here (and as I am the LRI at your week 1 event, you may want to know what it is… )

Removing the bolts on the compressor, installing your bracket (which is very nice, by the way) and then re-installing the bolts, is a no-no.

There is a simple test for if something relating to “modifying” a pneumatics component is allowed: Did you pick up a tool? If so, it’s probably not allowed unless it’s on the specific list in R-65. R-65c allows you to assemble components together, such as installing a COTS threaded coupling into a threaded orifice in the COTS cylinder. If you are claiming you are assembling pneumatic components under R-65c, then R66 lists the allowed components, and your fan bracket is not listed. So R-65c does not apply.

I highly recommend mounting a legal fan next to the compressor, my team does that most years. Not sure why an inspector would have required a team to remove a fan. That’s one of those situations where you should always respectfully and graciously request a second opinion from the LRI at the event.

Ya It was suppose to be a joke. :smiley:

Somehow we got away with this last year, except it was a different design. I didn’t realize it was breaking the rules, shoot… And I was proud of it! I think I’m going to try and re-use it, except not mount it under the bolts, but instead on top of them. I’ll try some stuff.

I don’t remember exactly, I wasn’t in the pit during the inspection. I believe the inspector said it was an “unfair advantage,” which doesn’t make sense because anyone could do it… But our compressor wasn’t too stressed last year, so it wasn’t something that really mattered.