Wall Automation With Pneumatic Cylinders. University of Cincinnati Project

Here is how I pneumatically motivated a set of walls in a play to be pushed downstage.

I will list the steps and supplies I used, but keep in mind all of this was for a very large wall, 13'x15'x1'-6". Your needs will probably vary, but the schematic and the principles are easily applied on different scales!

Some verbiage I will use in this Instructable:

The "bottom" is the back-end of the cylinder and the "top" is the end the cylinder extends from.

To extend the cylinder, air flows into the bottom of the cylinder, and exhausts from the top.

To retract the cylinder, air flows into the top of the cylinder, and exhausts from the bottom.

When I refer to "air flow in", I mean when the cylinder is extending, air is flowing in this direction. Yes, technically air will flow out through the hose too to extend, but to save all our brains a bit of a jumble, lets just talk about the cylinder extending since that is what we are here to do, shall we?

Last note: Color coding is important!

In these pictures you will see the black hose is air to the bottom of the cylinder.

White hose is air from the Valve to the Tee fitting leading to the bottoms of the cylinders.

Blue and Red hose is air from the tops of the cylinders.

--

Featured in the Double Bill at Ensemble Theatre Cincinnati 2022. Scenic Design by Brain C. Mehring

vvv Check out this vid of the wall moving! vvv

2 - Double acting no cushion 8 foot stroke Hydro-Line Pneumatic Cylinders With 1/2" push-to-connect fittings on Top and Bottom.

Lots of 1/2" hose. I used approximately 230 feet of hose in total.

1 - 3/4 Pneumatic Valve. (3 position, 4 port, 4 way, closed center).

2 - NITRA pneumatic inline flow control valve with push-to-connect fittings.

2 - 1/2" Tee Union Fittings with push-to-connect fittings.

1 - Pneumatic Muffler.

1 - Inline Lubricator Mist oiler

This is my schematic of this project.

Taking this into the setup was necessary to plumb all my hose and know it was correct in the orientation I needed.

Feel free to use or adapt this schematic if you'd like!

Here is a picture of the Tee Fitting and Flow Control Valves.

When Cylinders are extending, this white hose line is air input. The black hose lines split at the Tee fitting and go through Flow Control valves to each cylinder. The flow control placement lets you meter the air flow in to get the cylinders extending at the same rate.

You will need to:

Connect your hose from the bottom of your cylinder, through a flow control valve, then to a tee fitting. Same with the other cylinder. Then, the top of the tee fitting connects to a hose which goes to your control valve.

Make sure you have put this into the port of your control valve which will connect to air in on one switch and air exhaust when it switches to the other.

You will do the same for the top of your cylinder, except this time without the flow control.

As I mentioned in the last step, which port you plumb your hose to is important. Review the schematic of your valve to make sure you plumb it correctly.

For example, here is the schematic of the valve I used.

Here I show you what each state and port of the valve connects to, and how I plumbed my hose to get each reaction.

I also included pictures of the valve itself and how I labelled it. This was important for the operator to have! Then all they have to do is turn the switch to "extend", when the cylinder is extended as far as it needs, they switch it to "X". This is all ports blocked so that the cylinder stays extended at the desired length. When they were ready to retract the cylinders they simply swap the switch to the "retract" side and let the air flow so the cylinders can retract. Then, when not in use the operator will set the switch back to "X" and the all air flow will stop in the system.

Sometimes working with older materials brings problems. As we tested the cylinders extension we found the stroke would 'jolt' slightly as it extended. To fix this so that you can not tell its jumpy from the front, we added foam pads for the cylinder to push. This cushioned the jolts and let the push become more of a gradual bounce. It appears very smooth from the front and made a beautiful show, so this was a quick and easy solution to the problem!

We also added an inline lubricator to try to reduce sticking. I have no pictures of this as we added it later, but I included it's placement in the schematic. This isn't a bad idea for yourself trying this as it can make your move smoother!

After you have all of your hose from your cylinders plumbed, You will need your system pressure in and exhaust.

From the port you have decided will be pressure in, run a hose. Connect one end to your air compressor. Simple as that! This air pressure will now only fill your other hoses when you activate your valve switch!

From the port you have decided will be exhaust, run a hose. Depending on your preference, you can either have a very long (100'+) hose , or a muffler, or Both! (I did both). The length of hose and the muffler both quiet the sound of air exhausting, and since all of this system was directly backstage, I needed this to be silent.

The only thing to note, is that if you include the lubricator like I did, eventually this oil will work its way out the exhaust. You may want to add a rag to the end of your hose to catch any drips.

Now every port in your valve is ready for use!

Make you and your friend's lives easier!

Label your hose, let everybody know what it is doing. I labelled my hose with the direction of air flow when the cylinder is extending. This lets anyone easily fix if a hose breaks/gets unplugged they can replace it no problem!