Pneumatics piston
 

Can we use a Pneumatic piston that is not hooked up to any tubes or air compressors as a shock absorber?

Re: Pneumatics piston
 

!!!!NOT AN OFFICIAL ANSWER!!!

As I understand it, as log as the ports are not plugged, it would be legal. You could put adjustable needle valves in the ports and adjust them to allow air in at out at a rate that you like, but if you plug either end, you create the potential to compress air to a higher than legal pressure.

Re: Pneumatics piston
 

Thank you very much!

We were also wondering if you would know how we can get an official answer, or get this confirmed.

Thanks,

Re: Pneumatics piston
 

Ask the FIRST Q&A.

Re: Pneumatics piston
 

To get an official answer straight from the GDC go to the Q&A forum on the FIRST website.

http://usfirst.org/roboticsprograms/...nt.aspx?id=456

Re: Pneumatics piston
 

Alternatively you could use a sealed pneumatic (gas) shock as discussed in <R66-H>. They are available cheaply from McMasterCarr:
http://www.mcmaster.com/#gas-shocks/=asncje

Re: Pneumatics piston
 

To expand upon Martin417's answer: You connect one port of the cylinder to the other port, using approved tubing and connectors. One of the connectors can be a needle valve to adjust the force required. You can also then use a spring (such as a length ot latex tubing) to return the piston in the cylinder to some desired position to ready it for another 'hit'.

Re: Pneumatics piston
 

This is the defining rule in part...

<R69> Compressed air for the pneumatic system on the ROBOT must be provided by one and only one compressor...

Compressed air shall not come from any other source.

And R66
H. For the purposes of the FRC, closed-loop COTS pneumatic (gas) shocks are not considered pneumatic devices, and are not subject to the pneumatic rules (although they must still satisfy all other appropriate rules).

Re: Pneumatics piston
 

The FIRST Q&A proves to be very slow. Does anyone have any other suggestions?

Re: Pneumatics piston
 

Ask sooner, rather than later.

They are the ONLY official source of rulings.

Re: Pneumatics piston
 

Slow they may be, but sure they are.

Pneumatic pistons used in the way described are not legal. Reason not given, but I would suspect Al's reasoning is correct. http://forums.usfirst.org/showthread.php?t=16749

Re: Pneumatics piston
 

Yes, thank you. That was me posting it.

Re: Pneumatics piston
 

I question that answer. I haven't seen an answer from the GDC that did not cite a rule before, and I can't find a rule that this would violate. You might post a follow up question asking what specific rule it violates so you can modify your design to alleviate the violation.

Re: Pneumatics piston
 

Exactly, one of my colleagues and I derived another question that follows up our previous question. Referencing the possibilities from this thread, along with the rest of the resources @ Chief Delphi.