Rigging truss from a balcony

[light-man]

I have never used rigging, as it is always been there, nor have I attached it to anything, but I have a query, and that is as follows:

 

Well, I have a railing around a gantry that runts at the back of the stage, and around stage left and right, overhanging the audience a bit. Now this railing has 2 wooden pannels that make it, and I am thinking of hanging PAR56 or 64 from it, but because it is a 70s wooden thing the gap in the wooden panels isn't wide enough to simply hang fixtures, so I have come up with a plan to fit small pieces of truss or tubing from the wooden rail, but at a slight distance.

 

Now, if I have a triangle truss flat or even a single tube, how can I attach it to the wooden railing?

 

Here is a drawring to show what I'm trying to accomplish (the blue thing is the hook that would look the correct one to me!):

 

http://img259.imageshack.us/img259/6656/trussandhukku0.png

 

I can't find anything on the internet, so do you have any advice please?

[paulears]

If the timber structure is sound and secure, I suspect if the load is just a length of lightweight truss and a few PArs, I'd perhaps of used something very similar. The obvious thing is that the weight on the front chord of the truss will pull the top chord away from the vertical support - how much depends on the load, putting a sideways component onto the vertical timber rail, not just a vertical one. The engineers amongst us might be able to calculate this and be absolute on their maths based conclusion.

 

I think I'd just look at it carefully and make my own assessment in a not quite so scientific way - perhaps even hanging the truss and then testing how it responded to loading. If I was happy, I'd go with it - but this is just me - others may well disagree strongly.

[J Pearce]

I have used similar brackets to create a bar rigged off a balcony.

 

One thing I would suggest is to make the vertical bar that sits on the side of the balcony opposite to the truss as long as possible, as it is this part that takes the majority of the load, so it is wise to spread the load across the whole height of the balcony front.

[boatman]

The first item on this page might be what you're looking for.

[Maddison]

If the timber structure is sound and secure,

 

Which is of course a massive caveat to any advice that can be given here...

[Nevermore]

What holds the wooden panels up? You mentioned a railing - depending on what this is it could be simpler and safer to hang from that.

 

I'm nervous about recommending hanging truss from the top of an old bit of wood which probably hasn't been looked after very well - after all, no one will have expected it to be used as a rigging fixture! Obviously you're in a better position to assess its suitability though, so if you're confident in its strength then that may not be an issue.

 

As has been mentioned, you will want to make sure that you spread any load across a lot of the surface of the paneling. You might want to fit a back-plate where you're intending to hang clamps to accomplish this. Bear in mind that the panel will want to pivot about the bottom of the panel and there could be substantial sideways force on fixings at the top of the panels. You need to make sure that the fittings there are designed to resist this force.

 

Finally I would strongly suggest you find a fully independent secondary suspension, especially since you're rigging above the audience's heads!