Flat Hose
 

Our team would like to know if it would be against the rules to use a flat hose as an air bladder for our lifting mechanism.

Thanks.

Re: Flat Hose
 

It would be a pneumatic component. It would also not be one of the specifically allowed items in <R72>. Therefore, it would be illegal under <R71>.

Re: Flat Hose
 

What makes this considered to be a pneumatic component?

Re: Flat Hose
 

Pressurized air. At least, if you're using it to hold air, or cause movement with air, it's pneumatic.

Re: Flat Hose
 

Thank You.

Re: Flat Hose
 

Thanks Eric,

I'd like to ask a follow up question.

What if the hose and connectors were rated at 125 psi, and it was a COTS item, generally available to other teams.

Are there other characteristics that would make it illegal?

Re: Flat Hose
 

Given that it was COTS rated to 125 PSI, I'd look at the following Q&A:

http://forums.usfirst.org/showthread.php?t=13703
http://forums.usfirst.org/showthread.php?t=14242 << Especially this one...

If you can't answer it that way, ask it to Q&A and see what they think.

Re: Flat Hose
 

Not sure either of those help me, or maybe it is my ability to read the rules, I don't know. Could be the six week zombie syndrom :D

Anyway, if the hose is considered a pneumatic cylinder, then why is it not permitted under <R72>D

If the hose is considered a storage cylinder then it is excluded under <R72>A:

I will submit to the GDC Q&A once I figure out if I can get the hose I need. Thanks for your input

Re: Flat Hose
 

The second one refers to a diaphragm, or flexible membrane, to convert air force into mechanical force. I think this the type of device that you're asking about. The GDC has specifically pointed to that as not legal.

There was one--in fact, the first one in the pneumatics--about using inflatable items. However, it doesn't cover inflatables that are inflated using the compressor's air.

http://forums.usfirst.org/showthread.php?t=13703

You might reference it when you ask, something to the effect of, "Regarding [previous link], does the answer change if the inflatable item is COTS, pressure rated to at least 125 PSI, and inflated using the onboard FRC pneumatics system? If not, which rule does it violate?"

Re: Flat Hose
 

Richard,
The two Q&A answers do cover your question. The GDC's response is related to devices that produce movement. The hose expansion produces movement by the introduction of air pressure. The only devices that may do that are defined in R72 as cylinders up to a specific size and rotary actuators.

The last paragraph of section 8.3 gives you a little statement from the GDC that might help.

"In addition, another intent of these rules is to have all energy sources and active actuation systems on the ROBOT (e.g. batteries, compressors, motors, servos, cylinders, and their controllers) drawn from a well-defined set of options. This is to ensure that all teams have access to the same actuation resources, and to ensure that the inspectors are able to accurately assess the legality of a given part."

Re: Flat Hose
 

I see that the explanation of what we are intending to do is not clear.

We are thinking of putting a hook on the end of a flexible tube/hose that is deflated. We would inflate the hose with air from the accumulator(s) which would raise the hook to the point we could grab the bar. Then we would use a winch to lift the robot, probably deflating the tube once the hook is on the bar.

So there is no piston in the hose.

I'm still unclear whether the hose would be considered a cylinder or accumulator. It's intended use is closer to that of a cylinder.

Based on Al's last comment about the last para. of 8.3 it looks like the intent of the rules is to have a well-defined set of energy sources/actuation systems would probably exclude what we are thinking of doing, but...

...once we get specifics on the hose and fittings, I'll submit the question to the GDC for a final ruling.

Re: Flat Hose
 

Someone wanted to do the same thing with PVC. GDC said no. http://forums.usfirst.org/showthread.php?t=14194

Re: Flat Hose
 

I don't think PVC is rated at 125psi. The hose I am looking at is rated at 125psi by the manufacturer, including fittings. The hose could be custom made so no modifications need to be done.

Re: Flat Hose
 

Yeah, that's a bit tricky to call. Q&A it; if it's good for you, I'll try to remember to grab a digital copy of the Q&A in case you guys forget to do so. You'll be at Arizona, right?

Re: Flat Hose
 

Would coiling up a thin (like 1/16" or 3/32") strip of polycarbonate with the hook at the end and a servo/pneumatic release pin work?

Re: Flat Hose
 

We have tried other things, didn't know you could get polycarb to coil like that. Certainly worth a look.

The students on both teams I am working with are pretty stubborn about trying to make the air filled hose work, but may have to go with an alternative as time is running out.

Eric,
2493 will be in San Diego, 3295 will be in LA. I will be in Phoenix but not the team.

Re: Flat Hose
 

Richard,
I would be interested in knowing some more about this hose. You can PM me with reference if you wish.

Re: Flat Hose
 

I'm not 100% sure the miracle hose exists yet. One of the team members is going to http://www.hose-man.com/sys-tmpl/colton/ to check it out today.

The site allows you to select characteristics of the hose. The on site visit should confirm what they can do for us, how flexible the hose will be, how much it will cost, if 60psi or less can make it stand erect, etc.

As soon as I get details, I will post it.

Re: Flat Hose
 

OK, generally a non-flex hose under pressure is not a desirable effect.

Re: Flat Hose
 

Here is the question as posted on the Q&A

Now to wait for the answer.....

Re: Flat Hose
 

Richard,
While you are waiting, have you calculated the volume of supply air you would need for such a device?

Re: Flat Hose
 

we did the math with a lighter material and slightly larger diameter and had plenty of air in one Clippard at 60psi.

I'm estimating we can do the same with the new material, 2" rather than 2.5" with one maybe two Clippards.

With the first material we calculated 2psi would do the work we needed. Even if we double or triple that psi, we still have enough Clippards to do the work.

The rookie team is using no other pneumatics, so they have all 4 Clippards available.

2493's available air may be an issue.

So, unless my math or theory is wrong, we should be OK.

Re: Flat Hose
 

The GDC has spoken... denied. On to plan B

Re: Flat Hose
 

Too bad, it might have been interesting to see.

Re: Flat Hose
 

We may try it at an off-season event. If we do, we will post pictures.