Movers Centred in Box Truss

[pjmajor]

Does anyone have a suggestion on how to hang fixtures in the centre of box truss at particular intervals (which may not coincide with where the truss manufacturer has placed the cross braces)?

 

Do most people just cheeseborough a pipe horizontally across the two bottom truss chords and hang the fixture from the pipe? Or is there another solution?

 

Also, how can this be done with curved box truss - is there some form of cheeseborough or clamp that has a pivot or ball joint built in to flex to the form of the truss curve?

 

The challenge we have is in keeping the truss as level as possible while it is moving. It has a tight clearance on either side of it (set design), so hanging the fixtures off of one chord will not only reduce the amount of clearance, but will obviously roll the truss as well (and aside from power and data cable, there isn't anything to balance the other side).

 

We could go with triangular truss with the apex down, but I would need to ensure that it could handle the load weight, and there are aesthetic concerns (aren't there always? *grin*)

[Matt Riley]

Ignoring aesthetic concerns, I'd just rig them off alternate chords of the truss, but if that doesn't work, you could use custom metal plates with 2 half couplers on to which the fixture is bolted. If you want to fix them to curved sections you could get slots for the half couplers to bolt into instead of holes, so you can adjust the distance. Usual warnings apply- probably best to get one of the rigging companies to make it for you, and of course safety the whole thing direct to the truss.

 

HTH,

 

Matt

[Tomo]

Matt, that's simply nuts!

You could just do the sane thing:

 

Doublecheeseburgers, fixed and rotatable, with short lengths of suitable ally scaff tube between.

Hang the fixtures on the tube with the usual hanging hardware.

 

The cheeseburgers need to be suitably rated of course.

 

I think this is what you were originally considering.

[gareth]

To translate the American vernacular in Tomo's post into UK terminology, for those who are not familiar with the technical terminology from the other side of the Atlantic : a cheeseburger (or sometimes cheeseboro) is a scaff clamp.

[Tomo]

*sings*

I'm turning Americanese I think I'm turning Americanese I really think so...

 

 

I thought they were different beasties:

Cheeseborough - milled aluminium clamp for truss (usually 48mm dia)

Scaff Clamp - bent steel clamp for scaffolding, would probably damage thinwalled truss.

[gareth]

The ally clamps that are safe for use in thin-walled truss are still generally referred to as scaff clamps, they're just a different design of the same thing (usually by Doughty or Aliscaff).

[paulears]

This has me confused now, the chunky aluminium clamps useful for truss, I have always called 'Doughty' clamps. even when they are made by Aliscaff, and reserved the name 'scaff clamps' for the scaffolding style pressed versions. I've never heard these American terms before - and suspect that even if I do hear them, will now adopt my often seen confused face.

[peter]

http://www.sapsis-rigging.com/Merchant2/graphics/clamps/doughtyT57104.jpg

Doughty Clamp / Cheeseborough

 

http://www.generalrentals.com/scaffold/rigid.jpghttp://www.generalrentals.com/scaffold/swivel.jpg

Scaff Clamp (90/Swivel)

[timmath]

If you don't yet have a specific fixture choice then it may help to know that both the Martin 700 and new 250 ranges have mounting clamps which fit nicely onto both chords of a 12" truss.

 

"Also, how can this be done with curved box truss - is there some form of cheeseborough or clamp that has a pivot or ball joint built in to flex to the form of the truss curve?"

 

If you have a curved truss and are hanging things around the curve then the distance between the chords does not change.

 

 

Regards

 

Tim

[peternewman]

A tour that recently came to us had folding truss, which was held open by short bars with quick release type fixings on the end, similar to some marquees and Zip Up towers etc. They didn't load up these bars, but I image that you could, so that would solve your problem quickly and efficiently. This is only idle pondering, check with a qualified rigger etc.

 

On a side note I'd also agree that "Doughty" and scaff clamps are different beasts.