Piston Question

Does anyone know if it’s allowed for our robot run an input/output pneumatic piston with only ONE hose on the piston (e.g-a piston with only an input hose or an output hose; the other would just be open).

Why would you want to do that?

The rules don’t specify that each piston has to have both ends connected, but I don’t see a reason to have a 1-way piston, other than that something else would be pulling it back or it’s a 1-shot application.

My team tried that, but it seemed air escaped, although for the life of me I don’t know why. This is second hand, though. Feel free to pull out a hose and try it - it won’t break anything.

As long as you unplug the hose when there’s no pressure.

You will hear air coming out of the open port when the piston moves towards the open port and entering the port when the piston moves away from it.

If air is actually constantly leaking out of the open piston port I believe that the piston is broken as that sounds like a bad internal seal.

Regarding the original question, this is perfectly legal:

Eric, it is often desirable to simply vent one port of a cylinder if it will already be returned by other means in order to save air. Our 2008 robot vented the retract port of our arm raising cylinder through a flow control valve and let gravity bring it down.

It is perfectly fine to run a cylinder this way and I will wager you will see a lot of it this year.

Because a pre-charged piston moves MUCH faster if it doesn’t have to push a lot of air through a small exhaust hole.

You can make an impressive kicker this way.