Electromagnetic stage base?

[howartp]

Hi there,

 

We're planning a possible building scheme including new permanent stage at the moment, and looking around at ideas.

 

One thing I'm interested in on a very small scale is the ability to lock down certain items of scenery on the stage quickly.

 

A couple of years ago Starlight Express came to our nearest large theatre, the Bradford Alhambra. This was done on roller skates, and the majority of the skate ramps etc were rolled on from the wings then clamped down in seconds - I'm pretty sure this was done with electromagnets? (Either a huge metal floor, then electromagnets on the ramps, or huge electromagentic floor with metal on the clamps?)

 

Now currently we are only a church with two (semi-pro) shows a year on a temporary stage so there's no way I'm planning the whole of the stage being electomagnetised, but it is the concept I am interested in. Some of the church and stage furniture is currently bolted down with huge bolts to keep it in place when in use, and it's a 10/15 minute job to unbolt and rebolt everything. Currently it only gets moved say 15 times per year, which is not a problem. However with the new permanent stage behind the front of the church, all rehearsals and many of our events will use or expand onto the stage so the furniture will potentially be moved (in and out again) at least once a week - at that rate, we'd spend far too much time shifting the furniture for rehearsals, and the bolt threads would be worn thin within a year.

 

Having seen Starlight Express, I wondered about fastening metal feet to the furniture and having some small electromagnets (say 3-4" square) under the floor in about 8 positions which would keep the furniture fastened down in normal times, but would allow us to knock off (or turn on) the power and shift the furniture in seconds.

 

Does anyone know anything about whether Starlight Express or other shows would have used magnets, or is there something else they're likely to have used? I'm sure it wasn't simply pegged holes in the stage at key places, because the ramps weren't always in the same accurate places depending where they stopped when they rolled them on.

 

Similarly or alternatively, does anyone know of website(s) that have information about this type of fastening stage equipment/scenery/furniture down quickly - I cannot find anything on Google about electromagnets other than what they are / how they work - I expected to find something about their use in theatre if this is indeed how Starlight Express used them on their national tour?

 

Thanks,

 

Peter

[cedd]

I saw Starlight at the Alhambra too, but back then I was only a nipper and didn't pay too much attention. That said, I also had an interest in all things mechanical (still do) and vaguely remember taking note of the 2 ramps that were slid on from each wing. I think they had a lifting caster arrangement. It may even have been operated by a point lever style handle to fit in with the railway theme. The casters protruded from the base, lifting it off of the ground. When they wanted to put it in place, the casters retracted and the unit just sat on the stage. It was quite a big lump so I don't think it would have needed much more fixing than gravity.

 

Just to confirm, it's the church furniture you're looking to secure, not your show sets? I guess in that case we're talking lectern, communion rail, that sort of thing? If this needs securing for most of the time then an electromagnetic solution is just crazily over complicated not to mention wasteful of electricity - just think of how long it'll need to be on for!

 

Can you not just get wing bolts instead? If something has to be bolted down, it suggests it's secured that way for a reason - taking people's weight, being leant on, whatever. Electromagnets are a huge no-no in that case - what happens in a power cut? Plus I doubt if they'd be strong enough. Even maglocks on doors are only strong in a pulling sense. They don't work when a twisting moment is applied - like leaning on a rail maybe?

 

Chris

[paulears]

Surely, the simplest solution is best. No need for bolts - just split hinges with pins - quick, simple and foolproof.

[howartp]

I saw Starlight at the Alhambra too, but back then I was only a nipper and didn't pay too much attention. That said, I also had an interest in all things mechanical (still do) and vaguely remember taking note of the 2 ramps that were slid on from each wing. I think they had a lifting caster arrangement. It may even have been operated by a point lever style handle to fit in with the railway theme. The casters protruded from the base, lifting it off of the ground. When they wanted to put it in place, the casters retracted and the unit just sat on the stage. It was quite a big lump so I don't think it would have needed much more fixing than gravity.

 

Just to confirm, it's the church furniture you're looking to secure, not your show sets? I guess in that case we're talking lectern, communion rail, that sort of thing? If this needs securing for most of the time then an electromagnetic solution is just crazily over complicated not to mention wasteful of electricity - just think of how long it'll need to be on for!

 

Can you not just get wing bolts instead? If something has to be bolted down, it suggests it's secured that way for a reason - taking people's weight, being leant on, whatever. Electromagnets are a huge no-no in that case - what happens in a power cut? Plus I doubt if they'd be strong enough. Even maglocks on doors are only strong in a pulling sense. They don't work when a twisting moment is applied - like leaning on a rail maybe?

 

Chris

 

Hi Chris,

 

Yep, pretty much what you said sounds about right. The ramps were on some form of raised castor base, but I presumed that they locked down when in the floor position because regardless of weight there were a good number of skaters hitting those ramps at speed - if the ramps budged slightly there's potential for trouble?

 

It is mainly the communion rails which I'm referring to - everything else is big and bulky so just sits there no problem, it's the rails we have to bolt down for the 'being leant on' reason. I was wondering whether they'd hold against twisting etc, but having not found any websites of much use I couldn't find much out.

 

Just to answer your question about power cuts, AFAIK there are two types of electromagnets - some need power to lock (which you're referring to), others need power to release - in which case there would only be power present when we were moving the rails.

 

I'm trying to find some alternative to using threaded bolts of any sort, whether they are winged, screwdrivered, spannered or what, if possible. The sideways movement is easily solvable by standard slide bolts but that won't stop them tipping.

 

Surely, the simplest solution is best. No need for bolts - just split hinges with pins - quick, simple and foolproof.

Paul, I'm not sure how split hinges would work - are you thinking on the scenery side of things rather than the church furniture side? (In which case we already use split hinges for some scenery constructions)

 

Any other thoughts anyone?

 

Peter

[ImagineerTom]

It's not electromagnets on the Starlight Set

 

Electromagnets are not the solution to your problem (as others have pointed out, the power consumption alone would be phenominal) and would be completely useless on the starlight example - they have a direct pull strength but very little lateral strength (and it's lateral forces that would be generated by skaters and also in your situation) so are no good at all.

 

Do the maths - if the communion rail is 1m high and just one slightly chunky patron leans on it the point load on the fixing to the floor would be around a ton. You've got to allow for several people possibly leaning on it (this must fall under the auspices of Building Regs) which means you're looking at a fixing method that has a rated load of several tonnes - Bolts are about the simpliest (and cheapest) fixing that can take this sort of strain. Any other system is going to require more complicated cross bracing, secondary supports or radical re-engineering of the floor / rails and lots of very complicated sums.

 

 

[J Pearce]

Most communion rails slot into receivers in the floor (not unlike a tank trap I suppose) with covering plates for when it is not in use.

[howartp]

Do the maths - if the communion rail is 1m high and just one slightly chunky patron leans on it the point load on the fixing to the floor would be around a ton. You've got to allow for several people possibly leaning on it (this must fall under the auspices of Building Regs) which means you're looking at a fixing method that has a rated load of several tonnes - Bolts are about the simpliest (and cheapest) fixing that can take this sort of strain.

Fair enough.

 

Any other system is going to require more complicated cross bracing, secondary supports or radical re-engineering of the floor / rails and lots of very complicated sums.

This is always an option - we're talking a £360,000 +VAT project here, and the sanctuary area is already being extended so there's no problem putting in a structure underneath as we do so if necessary.

 

Most communion rails slot into receivers in the floor (not unlike a tank trap I suppose) with covering plates for when it is not in use.

Yes, some of our churches have them, but then when you move them elsewhere they have to sit on their 'spikes' (for want of a better word) making holes in the carpet or scratching the floor, so we purposely don't want to go down that route unless such spikes are easily removable from the rails.

 

Thanks for all the replies.

 

I guess we'll have to look at our options around some support structure under the raised sanctuary which still utilises a bolting mechanism but which doesn't take much doing.

 

Peter

[J Pearce]

Turn them upside down or hang them up.

[kerry davies]

Don't jump down my throat here but is it time to do a bit of policy thinking? Is it a church used as a theatre or a theatre used as a church?

 

I am serious, as if it is used every week as a theatre then perhaps prioritising your designs around 'theatre as church' will give you new ways to approach the difficulty. One community play in a High Anglican church meant removal of the pews, taking it back to pre-Victorian design, building a central stepped platform and tiered seating down one side of the building. This then meant that a portable altar was moved on and off the patform for services and the steps used for communion kneelers.

 

90% of an increased congregation wanted it to stay the same way but the diocese wasn't so sure. The vicar did however 'lose' half a dozen pews on restitution so they could keep the new tea bar.

[howartp]

Don't jump down my throat here but is it time to do a bit of policy thinking? Is it a church used as a theatre or a theatre used as a church?

 

I am serious, as if it is used every week as a theatre then perhaps prioritising your designs around 'theatre as church' will give you new ways to approach the difficulty. One community play in a High Anglican church meant removal of the pews, taking it back to pre-Victorian design, building a central stepped platform and tiered seating down one side of the building. This then meant that a portable altar was moved on and off the patform for services and the steps used for communion kneelers.

 

90% of an increased congregation wanted it to stay the same way but the diocese wasn't so sure. The vicar did however 'lose' half a dozen pews on restitution so they could keep the new tea bar.

Hi Kerry,

 

Don't worry, I won't jump down your throat. Someone else in our village (who chose to remain anonymous) has asked the same question, but they were asking it out of maliciousness, not as a constructive question to aid thinking.

 

Our church is primarily a church and will remain so, albeit that we are a community centre whose premises are in use all day, every day during the week plus the odd parties, fayres, coffee mornings etc on Saturdays. We as a church/community put on one pantomime per year, in February half term, at which over 1250 people attend over 8 performances. The rehearsals for this start in October and are held three times a week through to the panto week itself. Our rehearsals from October to new year are on the floor in front of the sanctuary, then the stage is installed around new year, after which we rehearse on the stage. In addition to this, we have a Kydz theatre group moved to us when their previous venue (a former middle school) closed 3 years ago. They rehearse on our premises weekly, then put on 3-4 shows per annum elsewhere as our present stage is temporary and takes two-three weeks to install including scenery framework etc.

 

If we are able to go ahead with our project, the permanent stage will be behind a sliding moveable wall, which will open up in seconds. Thus all rehearsals and performances for both our panto and the Kydz shows will be able to take place on the stage, as will any choir or brass band performances we hold (which we'll usually host one or two of per annum). Whether the furniture will need removing for all of the Kydz rehearsals remains to be seen, but it definitely will for the panto (we have 40 kids in the panto, Kydz has only 15 or so) rehearsals. Thus any easier mechanism to remove/reinstall the rails on anything approaching a regular basis will be so much easier for all involved.

 

The permanent stage being further back will also allow us to get at least another 2 performances worth of audience capacity (ie another 300+ people) in without adding more performances.

 

Peter

[kerry davies]

Thanks Peter, glad you are taking it in the spirit in which it was intended. My initial thoughts have been reinforced and I think that your group should look at it from the PoV of; "OK, we have a multi-purpose space, how do we use it as a church?" The amount of secular usage would suggest that it needs to be approached as a venue with multiple use rather than a church used as other things.

 

Whether it needs a complete redesign or the sort of post-hole and cover idea that Jonathan suggests is your question. Is there a way to mount them like some in older churches where a brass rail slides out from the sides telescopically?

Can you build units with kneeling pad and rail constructed as an integral unit, like prie dieux? http://www.churchantiques.com/category/prayer-desks/ You can buy twin units for marriages so why not build some in any configuration that works for you?

 

You need to think outside the box and maybe brainstorm it with some of the craftspeople in the congregation, methodists tend to be can-do people with greater manual skills than a lot of high church attendees. We used to ply cover the whole of our "Big Seat" for nativities. Bit dangerous for some of the 'ickle angels, but it was in a good cause. :unsure: AND 10 years before HASAWA.

[howartp]

Thanks Peter, glad you are taking it in the spirit in which it was intended. My initial thoughts have been reinforced and I think that your group should look at it from the PoV of; "OK, we have a multi-purpose space, how do we use it as a church?" The amount of secular usage would suggest that it needs to be approached as a venue with multiple use rather than a church used as other things.

 

Whether it needs a complete redesign or the sort of post-hole and cover idea that Jonathan suggests is your question. Is there a way to mount them like some in older churches where a brass rail slides out from the sides telescopically?

Can you build units with kneeling pad and rail constructed as an integral unit, like prie dieux? http://www.churchant...y/prayer-desks/ You can buy twin units for marriages so why not build some in any configuration that works for you?

 

You need to think outside the box and maybe brainstorm it with some of the craftspeople in the congregation, methodists tend to be can-do people with greater manual skills than a lot of high church attendees. We used to ply cover the whole of our "Big Seat" for nativities. Bit dangerous for some of the 'ickle angels, but it was in a good cause. :unsure: AND 10 years before HASAWA.

Hi Kerry,

 

Thanks for your response, and I take on board all of your comments and gladly. The problem would be the Church Council/congregation - they were already shocked when I suggested this stage project out of the blue, although I think most of them are with me so far (meeting next week will determine that!) - so to take it further and de-sanctify the church room on a majority basis would be a step too far I think. (ie making the main church room a community room which becomes a church on a Sunday - although having said that they don't know yet that I'm proposing to do exactly this with the Vestry in order to make a larger brighter entrance porch to the church!)

 

Just a minor point in case I've mislead you, the main church room presently stays as the church room other than for special events; we have a hall and two smaller meeting rooms where the majority of our secular use takes place. If you already understood that, that's fine.

 

After your last post I did start thinking about other options such as standalone rails with some depth to them such that they don't need to be fastened down, and it is possible that this approach might be doable. I'm not sure I understand what you're referring to when you say rails which slide out, but I had considered some form of non-threaded bolt (metal shaped peg?) with two holes through it's width that sits through a hole in the raised floor - once in place a mechanism under the floor slides through those holes locking it down, and a simple door bolt within the rails does the same through the top hole:

 

 

http://www.oakworthmethodists.org/Resources/images/SancRail.png

Peter

[kerry davies]

Some churches have a communion rail in 4 parts, two brass tubes fixed at either side of the entrance to the sacristy/altar area having two internal brass tubes that slide out to form the complete barrier. Check out High Anglican and Catholic churches.

[howartp]

Some churches have a communion rail in 4 parts, two brass tubes fixed at either side of the entrance to the sacristy/altar area having two internal brass tubes that slide out to form the complete barrier. Check out High Anglican and Catholic churches.

Thanks for all your replies Kerry - I'll have a look.

 

Peter

[Tris]

Could you use a key clamp solution. They make a 'ground socket' which secures with a set screw and is flush with the surface. When not in use you could drop a filler in. Something with scaff legs wouldn't cause much damage to a floor when out compared to a spike