Pulley System brain melt

[dtglasgow]

Hi everyone,

 

Trying to rig a pulley system for an Edinburgh Fringe show. We need a length of string (specifically string, not a stage rope) to hang taut at head height across the stage from SR to SL. Halfway thorugh the performance, the string needs to be wiped. I'm trying to create a pulley system to bring the rope up into the rig at the stage left side, but the problem is that there's no wall on the SL side, it's only a curtain. So I'm having trouble getting the string to stay really taught as I can't fix it to anything in the side wall.

 

Any suggestions?! Already tried just pulling the rope super tight and it doesn't seem to work. Also can't wipe to SR as there are set pieces in the way.

 

Thanks all!

 

D taylor

[Seano]

When you say 'wipe' do you mean at head height (with flags or something on the string), or are you just talking about detaching the string from its fixing on one side and striking it off to the other (ie: dragging it across the floor)?

Is there room there for a post? eg: a 2m length of ally scaff in a tank-trap base? Can you fix/screw to the floor? Is there a grid above? Do you have a stock of stageweights?

 

Questions, questions, I know, soz. But I don't think anyone can really make any useful suggestions for you without a bit more to go on.

[revbobuk]

Don't be too complicated. Double run of the string, and cut it when it needs to come off. And a vertical from tensioned SWR (to a stage weight or two, or to a screw eye in the floor)?

[RumbleO]

What do you mean by "wipe?" Do you mean that someone in the action has to wipe it with a rag, as you do with a clothes line before hanging the washing out?

 

"Wipe" in theatre usually refers to drawing a single curtain across the width of the stage.

Is this what you mean; Halfway through, the string is pulled to draw something (e.g. a banner) across the stage?

 

I would screw a french brace to the floor, or use a lighting boom with sufficient weights to get the string at head height SL, but if possible, I'd favour running the string down to the deck at an angle rather than up in to the grid from the supporting brace/boom, so the tension is pulling down in to the support rather than up and away. (Possible trip hazard, so will need to consider the safety of it in the dark.)

 

Is the "wipe" just to remove the string? Can an asm or crew do that from SL? Why do you need it to the grid?

[kerry davies]

If I see this right why "up"? Why not just drop it to the floor?

Did a similar thing for a "bed" which was a clothes line across the stage with a blanket on it for an outdoor show. Drop to floor, actors kick off stage, de-rig at break. Simples.

[AndyJones]

Something cleaver with a long retractable dog lead?

[dtglasgow]

Hi all,

 

Thanks very much for your fast replies. Here's some points to clarify...

 

 

- from preset, the string will be in place crossing the stage from SR to SL at head height. Stuff will be hung, pegged etc on it and then taken off.

 

- halfway through, the string should disappear (ideally going up since there's a lot of action/puppetry on the floor)

 

- towards the end, the string needs to re-appear, crossing the stage at head height. (so we can't just cut it).

 

Seano: We've got seriously limited space for additional scenery so no chance of getting a post in, or any more scaff. There is a grid above, and we do have stageweights.

 

There's always the chance that we could cut it and just use a different one later, but that seems a bit messy, and still doesn't solve what we're going to attach it to on SL to make sure it's pulled taut.

 

Thanks all!

 

D

[Seano]

And a vertical from tensioned SWR (to a stage weight or two, or to a screw eye in the floor)?

 

A minor point perhaps, but worth a mention..

 

A rope (steel or whatever) from grid to floor won't quite be vertical unless the tension is infinitely higher than the tension in the string - its a similar situation to a bridle, but turned on its side. It will have a >--< sort of a shape. How close it can be to vertical depends on the amount of tension that can be sustained (limited by the strength of the fixings/weight of stageweights and in any case shouldn't exceed the bodyweight of a smallish ASM), and the tension on the string. (Hopefully a floaty light string with a post card or two on it, rather than a week's washing.)

 

Seano: We've got seriously limited space for additional scenery so no chance of getting a post in, or any more scaff. There is a grid above, and we do have stageweights.

 

Ok. So on stage left that gives you only the grid and the floor to work with.

 

A suggestion.. Have a look at this rubbish little sketch:

 

http://www.deepsoup.f2s.com/BR/string1.jpg

 

It shows two lines dropped from the pulleys in the grid - pulled from the floor, diverted to flies, whatever.

Each line has a sandbag on the end, and the ends of the string are made off a couple of meters or so from the sandbag. If the sandbags are relatively heavy compared to the string, it'll hang more or less as I've drawn it when the string is 'out'.

 

When the string comes 'in', the ends get made off to floor anchors (stage screw/weights/whatever), and tension is taken up again on the lines to give:

 

http://www.deepsoup.f2s.com/BR/string2.jpg

 

String 'in'.

 

There's a bit of jiggery pokery to be dealt with, in that the tension in the lines from the grid needs to be high enough to keep the string tight, but obviously you don't want to drag/float the stageweights. If the 'vertical' lines aren't vertical (they wont be) you also need to set the height of the string correctly. Bearing in mind that they will inevitably 'tow' in towards centre stage, it might be best if they're as far off stage as you can get them.

 

If its possible to anchor the string on the wall on SR, do so (eg: by using a carabiner so you can unclip it from the grid line and clip into the wall anchor when the string is set). It'll be well worth it to only be dealing with the inevitable wibbly-wobblyness of the 'vertical' line at one end. You could make the string off directly at the sandbag on that side, and simply swing it over to the wall and clip in.

 

There's maths you can do to work out the approximate relative tensions in strings & ropes, for a certain amount of 'sag' in the horizontal and a certain degree of towing-in-ness in the 'vertical'. The sums aren't that hard really, but I dont have time/cant be arsed to chug through that now. To be honest its prolly best left alone if you already have brain-melt anyway. Better to experiment with real string. ;)

 

Best of luck.

[Jivemaster]

Without knowing much -in particular the mass of the load to be hung from the "string" could the string be held manually (DSM each end) with a tripod to take out the otherwise inevitable wobble.

 

Please bear in mind that the string will SAG under load so the "head height" you quote could be quite variable, Things could slide to the centre.

[librarian28]

Without knowing much -in particular the mass of the load to be hung from the "string" could the string be held manually (DSM each end) with a tripod to take out the otherwise inevitable wobble.

 

Please bear in mind that the string will SAG under load so the "head height" you quote could be quite variable, Things could slide to the centre.

 

And then, at the end of the sequence, you could call us in to fly the two DSMs up to the grid - we're always looking for work.

 

But my main question (off topic, I guess) is to ask Seano how to include a sketch in a posting. 'Spect I am missing something obvious.

[Rigger]

Can the 'string' not be a solid bar or similar suspended between 2 vertical poles that can then be flown?

[Seano]

Without knowing much -in particular the mass of the load to be hung from the "string" could the string be held manually (DSM each end) with a tripod to take out the otherwise inevitable wobble.

That's a nice idea - scores highly on the KISS principle. ;)

You could probably go even more lo-tech and replace the tripod with a simple stick!

 

Depending on what action is taking place on stage, I wonder if it might even be ok just to put the string down on the floor when its struck. Even actors are fairly unlikely to trip over a piece of 2mm cordage lying on the floor.

 

Here's another idea:

 

http://www.deepsoup.f2s.com/BR/string3.gif

 

Pulleys in the grid, tab-track floor pulleys on the floor, and a 'control line' of (for example) black sash on either side. The string is tied off to the onstage side of the control line loop, as is a long-pattern maillon which encloses the return line. The reason for that is that it keeps the lines parallel rather than them forming a big triangle when the floor pulleys are moved off a bit to tension the cross-stage string. (If the control lines are nice and tight with the string on its in dead, they'll slacken off a bit as it flies out.)

 

With a few extra pulleys, it *might* be possible to divert one set of control lines over to the other so that a single operator can bring the string in & out. But then again it might be more of a faff to get that working nicely than its worth.

 

 

But my main question (off topic, I guess) is to ask Seano how to include a sketch in a posting. 'Spect I am missing something obvious.

 

Not massively obvious. You can't upload images to the BR directly, so what you need to do is get them on a website somewhere and then post a link using "img" tags or the "insert image" button (two icons to the right of the smiley face up there above the window you type your text in.) I put pictures up on a bit of free webspace that comes with my ISP account (the sketch above is hosted here: http://www.deepsoup.f2s.com/BR/string3.gif), but you could easily use Flickr, Photobucket or some other photo sharing service.

[Nicktaylor]

I was wondering how the sketches made it on to here directly!