Help with Automation

[ecocrest]

I am working on a show that the director would like a box that is 7'hX7'wX7'd. She wants it to open "magically" I was thinking of using pneumatic actuators or something along that line. does anyone have some websites, books, or ideas of where i can get more information. I need the sides to open 90 degrees.

[mstaylor]

I would start with a Grainger's book, get some ideas and then search the internet for other suppliers.

[epimetheus]

Depending on the opening time required, you could look into linear actuators.

[Van]

When you say open to 90 degrees, what is your raference point ? Each wall opens to 90? The sides fall down to paralle witht he ground ? Is it just a reveal? < open only> or does it close again too ? Grainger is an excellent source for actuators as is McMaster&Carr. A little more detail and we can zero in on a better solution.

[ecocrest]

When you say open to 90 degrees, what is your raference point ? Each wall opens to 90? The sides fall down to paralle witht he ground ? Is it just a reveal? < open only> or does it close again too ? Grainger is an excellent source for actuators as is McMaster&Carr. A little more detail and we can zero in on a better solution.

gonna answer out of order a bit...
It will open and stay open for the majority of the show, then closes close to the end and opens one last time.

Time is not too big of an issue.. if it takes 10 seconds or so the director is ok with that.

The back wall of the box will stay where it is an not move. there will be two sides that move 90 degrees to make a giant wall and when the box is open it will have a white background so that we can project onto it. the front of the box is in 2 peices (one attached to each side) so that the side peice and 1/2 of the front look like an L.

I hope this helps and thanks for all the input.

[soundman]

How Thick can the sides be?

From my understanding it the front is two pieces and each piece is attached to the side so it can open up fully, is that correct?

[Footer]

No top?

When you do this, you need to put more time into the hinges then the door (SL and SR Sides) themselves. From the sounds of it, you are really only going to have two actions. Does the box rest on a platform or is it just on your stage proper?

If you can get the resistance of the doors down to as little as possible, your life will be much easier. If you can, put casters in the door that will take some of the weight. Best case scenerio, it will only take a few lbs of pressure to open and close. You will then need some type of arm and actuator to open/close. Ideally, this would be buried in the deck. IF you can't do that, you can instead do it as low to the ground as possible. You will need to push some type of arm outside of the box to grab onto with an actuator. Tie that actuator back to the deck and that should pretty much do it. If you clear up what the box will be sitting on, we can give you a bit more help.

I would suggest electric actuators if you can. They are easier to work with and can be quiet. Some are, some are not. Pneumatic actuators are almost always loud unless you do a lot of muffling and venting.

[ecocrest]

Yes there will be a top, but i got that worked out. I have a few electric actuators that are used to lift up a truck taunu cover. I only have to lift the top about 2 feet.

Out stage deck is concrete. So i am going to elevate our stage about 1' to get some hardware under it. I can put casters on the downstage ends of the sides of the box. The thickness of the walls is not important. I would like to keep them thin so the whole thing is lighter.

I was looking at McMaster-Carr
Adjustable-Angle Rotary Air Actuators






I was hoping that the biggest one with 172 ftlbs of torque would be enough. If I got one for each side of the box and had the sides pivot with casters on the far end.

I am not too worried about noise because there will be music over the opening of the box.

[coldnorth57]

I was hoping that the biggest one with 172 ftlbs of torque would be enough. If I got one for each side of the box and had the sides pivot with casters on the far end.

I am not too worried about noise because there will be music over the opening of the box.[/QUOTE]

I am sorry that dose not say 172 ftlb it say 172 inlbs very very small amount of torque.

Torque, in.-lbs.
@ 70 psi Port Pipe
175.2 1/8" NPT 11.03" 4.72" 4.17" 1/2"-20 3.54" 3.15" 1/2"-20 0.50"

[Footer]

Your not going to want to open it from the pivot. That gives one no mechanical advantage. Best thing to do would be to cut a slot in the deck for a shaft to stick though that connects to a point a few feet out from the pivot. Connect that shaft to an actuator and you should be set. If will require that you build the deck keep in mind the space needed, but it should give you what you want. Think of how an automated door opens.

[bobgaggle]

Why use actuators at all? The more complicated the system the higher likelihood of failure. Have you considered using some sort of line system? Pull a rope and the side swings open. The rigging might be tough to figure out, but it leaves a much smaller margin for error.

[ecocrest]

Why use actuators at all? The more complicated the system the higher likelihood of failure. Have you considered using some sort of line system? Pull a rope and the side swings open. The rigging might be tough to figure out, but it leaves a much smaller margin for error.

yes that was my first idea... but i couldn't find a way close it without having ropes visable. the whole thing needs to be an "magically" opened without any visable help.

[MPowers]

Fair Warning, this is close to a commercial advertisement.

There a hundred ways to do this. How much do you want to spend? How many man hours do you have available? What is the skill level of your builders and what is the capability of your shop?

If I interpret the OP, I suspect that a clever use of trick line and pulleys is the answer, for both price and resources.

If you have specific questions, contact me off list.

If the Orange County you are from is in California, you have a wealth of sources available.

[CrisCole]

No Automation needed. I'd just rig up a system of quick-release pins and fishing lines, and yank them all at once. But that's just me.

I agree with bobgaggle. If you don't need an elaborate system of automation, then don't use it. Theatre is magical in that way-everything is duct-tape and fishing wire, but as long as the audience doesn't see it, and it's safe, then it works just as well.

[soundman]

No Automation needed. I'd just rig up a system of quick-release pins and fishing lines, and yank them all at once. But that's just me.

How would it close back up?

[CrisCole]

How would it close back up?

Attach another set of fishing lines to the sides, and pull it back up?

You've got me there. I suppose that answer wasn't well though through at all.

Either way, I'd still stay away from animatronics. It's a lot of work, and lots of room for error. Perhaps a tech can use a long black stick from behind to push it open via it's pivot point.

From what I understand, you want it to open like a book? The frame is still their but the actual sides open. I'd think it would be easier to make it in two peices, and hinge it so that the entire thing splits in half.

Perhaps use Chinese puppetry?

We needed a small platform to split in half once, for B&B I believe, and I disemboweled a radio-controlled car, and used the motor for that. The cars I used had little boxes that received the radio signal and rotated a gear, which rotated one on the wheel, making it go.
^^Can you tell I'm not mechanically inclined? :P

I just taped the motor in the middle of the split, and a gear to the one side of the box, and used the remote to move it. (It was of course, on casters). Opened and closed (without any weight) in about 8.5 seconds

Even that was a bit to mechanical for me. I'd much rather rig up some sort of pulley system for it.

[mstaylor]

Is the riser going to only be under the box or will it go the width of the stage? Look at cutting a curve in the deck and attach ropes and pullies under the deck in an arc to follow the swing of the door. Run the rope to the other side of the deck to get it to close. The actual mechanics of either direction can be better seen by looking at a curtain traveler. Basically a knot or retainer to limit travel either way.