Dual Acting Cylinder used as a single

[crollison]

Is it legal to use a dual acting cylinder as a single? We would like to let gravity handle the return of the piston instead of air. I wouldn't think this would be any different than a spring loaded cylinder. I can't find anything in the rule book that says so.

Thanks.

[Chris_Ely]

Originally Posted by crollison

I can't find anything in the rule book that says so.

If the rules don't prohibit something, then it is legal.

[EricH]

There are minimal rules governing plumbing of pneumatics, other than the type of tubing used. If the cylinder meets spec, you should be good.

[Chris is me]

Originally Posted by crollison

Is it legal to use a dual acting cylinder as a single? We would like to let gravity handle the return of the piston instead of air. I wouldn't think this would be any different than a spring loaded cylinder. I can't find anything in the rule book that says so.

Thanks.

This is definitely legal. Teams have done this many times in years past, and nothing in the rules changed this year to imply this wouldn't be legal. In many cases it's a smart way to save air. You're good.

[crollison]

Thanks all, went from flipping out this morning b/c not enough air to everything is great.

[GeeTwo]

Not a legal issue, but a reliability issue. Ensure that you have enough return force that you don't end up with the piston getting "stuck" in one position. Also consider situations in which something falls into the wrong place - with a dual-acting cylinder, you have a bit more capability to work the piece free.

If you have enough ports and valves available, you may want to consider using separate solenoid valves for the two cylinders, so you can use this only when needed. If you want to do this using the FRC-standard solenoid valves, plug the unused "A" or "B" ports so you aren't dumping air from your tanks when you're dumping air from the cylinders.

[2508electronics]

One way to get the cylinder to go back is to connect it to one side of a solenoid and connect another (probably smaller) cylinder to the other solenoid output. That is how my team got our catapult from last year's game to come back. We did this because having the cylinder completely controlled with the solenoid created too much resistance. I would also recommend removing the tubing connectors that you will not need if you are trying to get it to move as fast as possible. No issues during inspections!