Are Sleeve Air Bags Allowed?

Our team would like to know if sleeve air bags, such as the product 958K26 on the McMaster-Carr website, are allowed for use in this years event.

https://www.mcmaster.com/#9538k26/=1b8rrue

You would have to ask on the Q&A if these would be considered a “pneumatic linear actuator” in R83 part J. Anything else would just be speculation, I think.

R83 does not allow for them, they do allow for them. Sorry

**R83. **The only pneumatic system items permitted on ROBOTS include the items listed below.
**A. **Items available in the KOP (except as noted in K),
**B. **Pneumatic pressure vent plug valves functionally equivalent to those provided in the KOP, Parker valves PV609-2 or MV709-2 are recommended.
**C. **Pressure relief valves functionally equivalent to those provided in the KOP, Norgren 16-004-011, 16-004-003 or McMaster-Carr 48435K714 recommended. To be considered functionally equivalent the valve must be preset or adjustable to 125 psi (~862 kPA) and capable of relieving at least 1 scfm (~472 cm3).
**D. **Solenoid valves with a maximum ⅛ in. (nominal, ~6 mm) NPT, BSPP, or BSPT port diameter,
**E. **Additional pneumatic tubing, with a maximum ¼ in. (nominal, ~6 mm) outside diameter,
**F. **Pressure transducers, pressure gauges, passive flow control valves (specifically “needle valve”), manifolds, and connecting fittings (including COTS pneumatic Utubes),
**G. **Check and quick exhaust valves, provided that the requirements of R95 are still met.
**H. **Shutoff valves which relieve downstream pressure to atmosphere when closed (may also be known as 3-way or 3-way exhausting valves).
**I. **Pressure regulators with the maximum outlet pressure adjusted to no more than 60
psi (~413 kPa),
**J. **Pneumatic cylinders, pneumatic linear actuators, and rotary actuators,
**K. **Pneumatic storage tanks (with the exception of White Clippard tanks P/N: AVT-PP41), and
**L. **Compressors compliant with R85.

EDIT: Would make for a good Q&A Search and question

According to McMaster’s data, that part is only rated for a maximum pressure of 100psi. Thus it would run afoul of [R81].

However, sometimes McMaster’s data for pressure ratings is meant for 100% duty cycle situations. If you call McMaster, they should be able to tell you the manufacturer, and the part # from the manufacturer. Then it’s up to you to find a data sheet from the manufacturer with the maximum peak pressure. If the pressure meets R81’s needs, then I’d say Q&A is your next step to see how it would be classified under R83.

Alternatively, having a datasheet from the manufacturer which shows it being sold as “pneumatic airbag linear actuator” (or something to that effect) would also answer that question.

Cool device; I hope it works out.

100psi is fine for actuators according to R81 part B, since actuators have to be installed on the low pressure side of the primary regulator.

All pneumatic items must be COTS pneumatic devices and either:
A. rated by their manufacturers for pressure of at least 125psi (~862 kPa), or
B. installed downstream of the primary relieving regulator (see R88), and rated for pressure of at least 70psi (~483 kPa)

While past performance is not a valid predictor for future performance…

According to past rulings, if you filled those with fans or squirrel cage blowers, they would not be considered a pneumatic component, and you could do just about anything with them. If you filled them with air from a proper compressor, they definitely would be, and would have to comply with every pneumatic rule.

My suggestion is that if you’re going to put this question to Q&A, expect a non-answer, especially if asked as broadly as you did here. The odds of getting an answer will increase somewhat as you provide more details as to what it is you plan to do.

A way to use these that would likely make them legal would be to use them as vacuum actuators. A long-standing ruling (this year part of the blue box for R83 reads:

The following devices are not considered pneumatic devices and are not subject to pneumatic rules (though they must satisfy all other rules):

A. a device that creates a vacuum

From a practical standpoint, this makes vacuum actuators non-pneumatic devices.

Why would this have to be submitted to the Q&A? It’s obviously a pneumatic actuator that satisfies R83.J, and it’s rated to above 70psi (satisfies R81.B).

It’s a legal part, you don’t have to over-lawyer it.

No where does it say it’s a pneumatic actuator. It calls itself an air spring. Air springs are NOT directly called out as legal to be on the robot. If you wish to take that risk, go ahead, but I would rater KNOW that it’s legal.

Therefore it will be questioned by a RI.

I would suggest you get Q&A approval and bring it to the competition with you.

Is this part legal? McMaster-Carr

It’s called an “air slide”, but R83 only allows “Pneumatic cylinders, pneumatic linear actuators, and rotary actuators”.

This thing is called a “gripper”, is that allowed? McMaster-Carr

Maybe FIRST should define the word “actuate”, since the rule book isn’t long enough yet.

Are you willing to risk your season on how the phrase “pneumatic linear actuators” is interpreted? It’s easy and quick to ask a question and get clarity for both yourself and the inspectors at your event… Then only reason I could see not doing it is being afraid you won’t like the answer…

Technically, no they are not allowed.
… and I agree that FIRST should better define actuate.

Personally I believe that FIRST is too restrictive with pneumatics, but rules are rules.

I would, though I don’t think other people on my team would.

A COTs pneumatic part that actuates when you apply pressure can be argued to be a “pneumatic actuator”, and that’s a fairly easy argument to win.

Asking for all of these details from the Q&A isn’t always beneficial. In 2013 the design rules for the climbing challenge were effectively changed a week into build season when the Q&A response to a question altered the common sense interpretation of the rule.

About that “past performance is not a valid predictor for future performance”…

Anybody reading the quoted post can feel free to disregard the second paragraph of said post, given the Q&A response linked in this post.

But they do not use the term ‘Pneumatic actuator’. They use the terms ‘Pneumatic linear actuator’ and ‘Rotary actuator’.

As a RI I would bring it to my LRI … just sayin’

I had the same thought initially when I read that. Reading it again though, it specifies “**contained **air under pressure”. In practice, securing a bag to a fan and using the fan to “inflate” the bag doesn’t create a situation where you have contained air - all of the air can flow right out through the fan easily enough. Add in some other components to trap the air and maintain pressure, however, and you do then have “contained air under pressure” and a pneumatic system. I think that’s the distinction that Q&A was going for. And it makes sense from the wording of the question - inflating a bag to a specific, low PSI, a COTS device not capable of overpressure… if you don’t go look at the device mentioned and understand how it works, that description sounds like a pneumatic system.

In the past, fans were not considered a source of “pneumatic” air. If Q&A thinks otherwise, they should review the list of allowed compressors (R85 & R81). If the fan does meet the rules, remember you are allowed only one of them, Anything attached to them will be required to meet the pneumatic rules including relief valves, switches etc. The rabbit hole gets deep fast.

It looks like this question has been answered on the Q&A.

Q: Are only items explicitly marketed/labeled as a “pneumatic cylinder”, “pneumatic linear actuator”, or “rotary actuator” allowed per rule R83 J? For example, McMaster-Carr part 9538K25 is called an “adjustable air spring”, but it is fundamentally a COTS pneumatic linear actuator.

A: Yes, a COTS item must be sold by the VENDOR as that item in order to be considered that item. For the purposes of the FIRST Robotics Competition, air springs are not cylinders.

So… if they’re not cylinders, are they linear actuators? :rolleyes:

This is a good time to open up my new vending service, where I resale McMaster parts as “Pneumatic Cylinders ™”

UGH!