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Stage curtains - economical motorised system


gotty
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I'm helping sort out a small community stage which has nice fairly heavy curtains. But they can only be opened and closed by pulling them by hand, so they're never used (except to shut off the stage from other events in the hall).

 

A manual pulley/winch system is not possible as the stage is the stage is basically a box with the 6m proscenium at one end and doors at the other to gain access. So there is no place to put a winch or ropes that aren't in full view of the audience (although there are seep and 1m high recesses at both sides at track level that would allow space for a motor)

 

I've been looking around and can't find much within a budget of about £2k, other than a system that will open and close the curtains in 15 seconds, which is rather slow.

 

Are we on a hiding to nothing?

Edited by gotty
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Unless infinitely thin the curtains must occupy a width at each side even when fully open. Does this not provide sufficient masking for a rope or winch system? Some years ago I installed a cinema curtain system for a c10m proscenium that cost around £1k for parts, so your £2k budget sounds possible. 15 seconds is a bit slow (though better than not using them?), but a fast system can bring its own problems. 5 seconds might be a good compromise. Have you investigated whether the 15 seconds system could be run any faster?
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Thanks both

 

Unless infinitely thin the curtains must occupy a width at each side even when fully open. Does this not provide sufficient masking for a rope or winch system? Some years ago I installed a cinema curtain system for a c10m proscenium that cost around £1k for parts, so your £2k budget sounds possible. 15 seconds is a bit slow (though better than not using them?), but a fast system can bring its own problems. 5 seconds might be a good compromise. Have you investigated whether the 15 seconds system could be run any faster?

 

Thanks for that.

 

Indeed there is some width at each side (about 30cm, which is usually tied back) and so there'd be some masking of any mechanics - but the person operating would have to go off and come on to the stage from the back-centre of the stage. Hence the idea of motorised. I know that there are some issues with motorised, and it's not a given that we go down this path.

 

As for speed - 15s is definitely too slow. Unfortunately, that's the maximum the system that's been suggested to me will go (it's really just an electric "semi-domestic" system).

 

I certainly don't want huge speed - the domestic system is about 22cm/s, and I'm realistic (after all it's "just" a small community stage) I'd like to see maybe 35cm/s (so about 7s) - 5s would be even better. One of the schools mentioned used to pride themselves that they could winch 10m in under a second - hence the need to be re-roped (because they insisted on doing it, even when the wire rope was starting to fray)!

 

And your costing sounds good - although they seem to want an installation package. I really think we can install it between us.

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A stage near me has manually cranked tabs where the SWR goes down through the stage DSL, across diverter pulleys and re-emerges to a standard winch much further upstage. There's no reason why your winch handle has to be directly under the end of the tab track.
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I suspect the motorised winch I put in would be overkill (it involved quite a bit of mechanical & electrical work to install) & I would also be very nervous of anything designed for d0m3stic use by one careful householder, so I think hand-winch or rope-haul is the way to go. On the same stage we used just a simple rope-haul for the back-of-stage blacks. The main problem with either system is that if you don't keep the track & runners clean then the effort involved gets harder & harder until something breaks. Maybe your money could go on some masking flats or panels so your tabs-operator can sneak in & out along a side wall.
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.

 

Indeed there is some width at each side (about 30cm, which is usually tied back) and so there'd be some masking of any mechanics - but the person operating would have to go off and come on to the stage from the back-centre of the stage. Hence the idea of motorised. I know that there are some issues with motorised, and it's not a given that we go down this path.

 

I really think we can install it between us.

I've never understood why there seems to be some trepidation when it comes to roping track.

I installed some lighting and sound in a junior school and had to run conduit behind the mains on the proc wall. The mains had been 'tied back' which I needed a screwdriver to remove, then I found the tangle of 3mm steel. I spent maybe 10 minutes untangling and re-rigging it before I was able to move the mains and then unclipped the fixed end to slide it towards centre stage. One of the teachers asked how I'd managed to close the curtains, he was amazed at the repair as they'd been quoted £600 and he passed my details on to another school to look at their problem. Ended up rewiring and running the steel through the suspended ceiling and moving the winder to the control box at the back of the hall.

Thinking about it would that be a solution for you?

Edited by sunray
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I've never understood why there seems to be some trepidation when it comes to roping track.

 

Certainly no trepidation here - I've re-roped track before, although it's a fiddly job (and it took me a while to pluck up the courage!).

 

However, the physical removal of existing track, and the installation of new track is a different matter (especially for \a bunch of 60- and 70-year olds :)).

 

As for running the steel rope through a ceiling to the back of the hall, there's no ceiling as such - it's a very high vaulted roof, shared by stage and hall.

 

I'm going to put the project on hold for a while and perhaps look at a DIY motorising of the existing (single) track.

 

Thanks for all the comments - they've been very useful.

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Motorising a single, rather than overlap, track would demand a very high degree of accuracy with the limit-stops. The slightest error, slippage or stretch in the rope would end up with either the tabs not fully closing, or the motor stalling & possibly burning-out.
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Motorising a single, rather than overlap, track would demand a very high degree of accuracy with the limit-stops. The slightest error, slippage or stretch in the rope would end up with either the tabs not fully closing, or the motor stalling & possibly burning-out.

Naively, I would expect to put the limit switches (in the motor circuit) on the track itself, i.e. the other side of the rope mechanism. Thus it will run until the curtains arrive where they are wanted, which is hopefully short of them falling off the end of the physical track ...

 

Or control it with a push button you have to keep your finger on ...

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The only motorised curtain winches I'm familiar with have adjustable cams in the control unit which operate micro-switches. You inch the tabs to where you want the Opened & Closed limits to be set, then move the cams until the appropriate switch closes or opens to start or stop the motor. Like roping, it's a bit fiddly, even when your limits aren't too critical. With an overlap track you have most of the length of the overlap to play with, but with a single track there's no room for error. Edited by sandall
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Having repaired many totally destroyed curtain systems including ones where the curtains had been dragged forcibly through small holes and where winches had physically ripped themselves off their mountings I would strongly suggest a dead mans handle system that does require you to keep your finger on the button.

 

Although many systems do use a geared selector on the winch there are some with switches mounted on the track. Notable for the switches dangling off the track on the end of their cable. If this sounds like a bleak picture it's because Northern Light used to get called in after all the resident experts had finished dabbling. hence why I got to fix so many tab-tastrophies.

 

First thing worthy of note. There's no such thing as an "economical" motorised curtain system. Not unless you want the curtains to open erratically and very slowly with a loud whining noise and the sound of plastic gears crunching loudly. It takes a reasonable force to open a curtain smoothly and swiftly. That can be done with a human pulling a rope or a winch with a control system. One of those things is cheap and reliable, the other is expensive and will result in curtains stuck mid-position if it fails during a show.

 

Choosing the cheap reliable option (human powered) the best approach is to use a curtain track intended for roping. I'd suggest Hall's equipment if it's still available. Not cheap, but reliable and so tough that you could hang a politician from one of the bobbins. The options for roping could include a steel wire rope going to a hand operated crank or a simple textile rope with a weight on the end so it hangs down in a decisive manner. My own choice would be the hand pulled rope. Over enthusiastic cranking of a hand winch can result in a huge knotted wire-rope mess when it skips the drum, and also poses a finger trapping risk.

 

Now for some case examples of curtain failures.

 

Example one. A horrible old wooden bobbin track which had been greased. The grease had the classic WD40 effect of providing temporary respite from the issue of wear and dirt buildup, but then gathered all the dust in the vicinity and turned into a disgusting resinous goo that made opening the curtains manually almost impossible. Fortunately a small but powerful DC winch had been added, and it used brute force to drag the curtains open against the will of the coagulated grease.

Except it had this really annoying habit of blowing fuses. Not because of the strain it was under, but because the switches at the ends of the tracks were dangling off, meaning that it stalled forcibly but silently at the end of travel and the large transformer in the panel limited the current until the fuse blew.

That was, until one of the caretakers who had been shown how to change the fuse put in a bigger and therefore better fuse. The transformer then went up in smoke.

 

No problem, a local electrician came in and changed the transformer for a new one which then went up in smoke again.

 

Then we were called in. The repair involved removal of the worst of the grease from the tracks, the re-fitting of the limit switches and the replacement of the transformer and fuse. I also removed the latching function so someone has to stand there and hold the button to open and close the curtains. That way the motor won't be left in a stalled state again.

 

Example two. An event venue is being refurbished and their curtains stop working. The resident experts have a go and then Northern Light get called.

I turned up to find what had obviously been a phase reversal issue. But to fix the fact that the curtains were going in the wrong direction they had swapped all the wiring to the buttons in local and remote control positions. What they didn't realise was that the limits at the end of the tracks were now wrong. Then they swapped some more wires and one popped out and they didn't know where it went to they stuffed it down the back of the DIN rail out of sight and called NL.

 

A little bit of information about what had actually happened other than "It just stopped working" would have been useful. No drawing so I had to trace all the panel wiring including remote button stations. It quickly becomes apparent what had happened and I effectively have to re-build the panel. Once it's going I let them know it's working and got confirmation that the phase reversal issue had happened during refurbishment of the building. Then one of them said "Did you find the wire stuffed down the back?" Yes... yes I DID find the wire stuffed down the back.

 

In both these failures the curtains were rendered unusable until repaired.

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I'd suggest Hall's equipment if it's still available. Not cheap, but reliable and so tough that you could hang a politician from one of the bobbins

Didn't Steeldeck take over manufacture of at least the most popular Hall Stage stock? Never tried with a politician, so will have to take your word for that :).

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I'd suggest Hall's equipment if it's still available. Not cheap, but reliable and so tough that you could hang a politician from one of the bobbins

Didn't Steeldeck take over manufacture of at least the most popular Hall Stage stock? Never tried with a politician, so will have to take your word for that :).

All the current crop are much too lightweight to stress anything.

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