Lifting Set Flat from Ground

[jstroming]

I am trying to figure out a way to raise a vertical set flat (15' wide x 12' high) about 10' in the air. I have to do this from the ground (no overhead points), and I need to have the lifting mechanism be BEHIND the set flat so that it isn't seen from the audience when the flat is down on the deck. I am somewhat concerned about noise, I just dont want it to be TOO loud from the audience....but I don't need it to be completely silent. Also, I would like to achieve a 10' height (from deck to BOTTOM of flat) in less than 10 seconds. This will go up and down repeatedly throughout the course of the show.

What I was thinking was 2 hydraulic cylinders of some sort, one close to each L/R side of the flat behind it, that lift the flat up "guillotine style". I think the scissor-lift style lifts are too obtrusive for this, and don't know if I can get a 10' height with them. Electric is also an option.

My last option was building a goal-post truss structure over the decks, with a pully and wire rope electric winch system from behind the set. But Oy Vey! Thats a lot of trouble, and it will most likely be too long of a span with downlegs.

Rental is an option, but I would most likely be looking at purchasing.

Anyone have any ideas? Perusing McMaster just led to dead ends....

 

[DuckJordan]

I am trying to figure out a way to raise a vertical set flat (15' wide x 12' high) about 10' in the air. I have to do this from the ground (no overhead points), and I need to have the lifting mechanism be BEHIND the set flat so that it isn't seen from the audience when the flat is down on the deck. I am somewhat concerned about noise, I just dont want it to be TOO loud from the audience....but I don't need it to be completely silent. Also, I would like to achieve a 10' height (from deck to BOTTOM of flat) in less than 10 seconds. This will go up and down repeatedly throughout the course of the show.

What I was thinking was 2 hydraulic cylinders of some sort, one close to each L/R side of the flat behind it, that lift the flat up "guillotine style". I think the scissor-lift style lifts are too obtrusive for this, and don't know if I can get a 10' height with them. Electric is also an option.

My last option was building a goal-post truss structure over the decks, with a pully and wire rope electric winch system from behind the set. But Oy Vey! Thats a lot of trouble, and it will most likely be too long of a span with downlegs.

Rental is an option, but I would most likely be looking at purchasing.

Anyone have any ideas? Perusing McMaster just led to dead ends....

I'm not sure about your experience as far as rigging but anything thats hung above heads makes me cringe. I'm sure there is a safe way to do this but I don't think your going to find a ton of good help on this forum... I am hoping to be proven wrong.

May I ask what the purpose of this is?

 

[jstroming]

This is going to be used for stage crew to pass through during an awards show to bring props through from an upstage holding pen. There is no fly system installed in the theater.
I proposed a hangar-door style flat that went up on an angle, but this was shot down. They want straight up and down.

I understand it's going to be tough to get answers in an open forum with no credentials. Eventually I will figure out the best way to do it, but thought someone here might have some expereince or at least point me in the direction of some type of system that might fit the bill. If no one can answer for liability reasons I completely understand. I figure for something this basic I don't need to go to an engineer. I wont be building it, but have to go to the carpenter and rigging supervisor with ideas. Let's just say they're not too creative.

 

[derekleffew]

A pair of Self-Climbing Truss Towers with appropriate outriggers? The chain hoist would probably prove too loud, but it might work with a cable hoist.

...I figure for something this basic I don't need to go to an engineer. I wont be building it, but have to go to the carpenter and rigging supervisor with ideas. Let's just say they're not too creative.

Ah, but Sapsis, Tait, Hudson, Feller, and others can be fairly creative.

 

[MPowers]

You're in NY, NY?????? There are a multitude of shops that can do this for you in an instant, ...... for a price.

What is your budget and time frame?

 

[TheatrePros]

Mcmaster has hydraulic cylinders, but I would use grainger. With a large enough throw you should be able to achieve what you want, but with it moving often and such a large piece, pneumatics might be the more reasonable option unless you already are set up with the valves and hydraulic pump. There are a TON of linear actuators if you go the electric route, but once again, based on control you may find yourself getting expensive very quickly. let me know if you want ideas, I have done a fair amount of hydraulics, pneumatics, etc. in my day for automation. Have you considered a motor with a pillow block system? Below is a link of a video from Ravenswood Studio. I used to be a carpenter there and may be able to find the specs if you are interested in how they did this, although it is a smaller piece than you are describing, with a good lightweight frame the concept will apply.

YouTube - ‪RavenswoodStudio's Channel‬‏

 

[mstaylor]

Why not a set of Genie lifts, ST25s, and either box or antenna truss, then install block and falls?

 

[jstroming]

OK, I have taken Derek's idea and done a mock-up rendering;

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There will be some counterweight issues I will have to address. The proscenium covers the top of the towers, I will have to use masking drape to cover the vertical truss.



I have also done a pneumatic version;

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The pneumatic version seems a lot better of a solution, but I'm sure it's also going to cost 10x the price if I have to get it outsourced. Cost really isn't an issue at this point. We'll spend the money on the pneumatic lifts if they really are that much better and less noticeable. I have 90% of the items needed for the Truss Tower setup, will just have to rent the electric winches.

Any thoughts on these? I figure i'll get some quotes from local companies, but half the fun for me is building it myself.

 

[garethconner]

Fun project!

I would steer clear of a pneumatic solution. Syncing air is tough and the movement will not be smooth. Hydraulic cylinders would work, but 10' of stroke is massive. You would need to get a much smaller stroke (maybe 24") and then rig a pulley system to give you some mechanical disadvantage, like a 5:1 the hard way so it produces much more travel.

If you can setup a goal post with the truss, using either chain motors or a pair of winches would be simple and easy. Chain motors are loud and slow, but come built with all the appropriate redundancy for hoisting. If you are building your own winches, you'll have to make sure to build in a redundant brake, excess capacity, etc. If you can counterweight the wall, so much the better.

Another option that we've done on occasion when making pop-up walls is to put a long piece of spur rack (from McMaster) on the back of the wall. Actually, two pieces of rack, one on either end of the wall. Then, mount gearmotors (SEW is what we use) on the truss towers behind the wall. The gearmotors have spur gears that mate with the rack, when the motor turns it push the wall up or down. You'll need to build a linear guide system to capture the wall and let it slide up and down. The rack & pinion just act as a linear actuator.

Just like any solution, you need to watch out for single points of failure. Each motor should be capable of holding the entire load. If one motor system fails, nothing should fall. Depending on the safety implications, you may need to insure the wall can continue to function even if one motor system fails (eg. you may need to raise the wall or disconnect it completely quickly to open an exit path in case of machine failure).

Hope that helps a bit. All the normal disclaimers apply, if you need more help hire a shop etc.

Gareth Conner
Creative Conners, Inc.