spinmaster1 Posted February 13, 2011 Share Posted February 13, 2011 Hello, I hope this doesn't result in a 'if you have to ask ..' answer but for an upcoming school concert, I have had the idea of suspending a couple of 2m alloy bars vertically from the stage lighting rig. I plan to use two 90 degree coupler clamps on each vertical bar clamped to two horizontal static bars (one above the other) to eliminate any pivoting points. Each vertical bar would be used to suspend three 5kg lanterns using doughty boom arms. I noticed that the 90 degree coupler clamps do not state a SWL so I wasn't sure if they were suitable to use as suspension clamps. Can anyone see any problems in this setup? I hope I haven't confused anyone with my description. Any advise and guidance would be greatly appreciated. Thanks,Rob Link to comment Share on other sites More sharing options...
dbuckley Posted February 13, 2011 Share Posted February 13, 2011 I regularly do this, and can say with certainty that under the load of a few lamps the 90 degree clamps dont pivot or wiggle; you dont need double horizontal bars. Also, you dont need specialst clamps; I use another 90 clamp and a 400mm bit of scaff to hang each lamp off. All my safety lines go to the horizontal bar, so if something ugly does happen (after all, the clamps are a single point of failure) then the wires will catch the lot before it tonks someone. Not to mention that the short horizontal bars would not be a good place to wrap a safety round; if the unthinable happens the safety could just slide along the bar, and then fall off the end of the pipe... Really like the look of lights hung this way; like pipe ends but more so. As to how provably safe this is; I have no idea, but nothing untoward has ever happened on my watch doing this. Link to comment Share on other sites More sharing options...
AndyJones Posted February 13, 2011 Share Posted February 13, 2011 If the bar is hung from steels, then I would alternate the sides of the bar that you hang from to to try and keep the weight distribution even. More as a matter of paranoia, If I use half coupler clamps then I tend to drill through the bar above the clamp and put a nut and bolt through (to stop the bar sliding through the coupler) If it's only short term then I occasionally just use another clamp above the half coupler to save having to do any drilling. HTH Andy Jones Link to comment Share on other sites More sharing options...
boatman Posted February 13, 2011 Share Posted February 13, 2011 You say that your lighting rig is two horizontal bars one above the other. That sound suspiciously like some sort of truss. If it is, you must use proper truss clamps as the tube diameter will be 51mm and not the 48mm of normal scaff bar. Normal scaff clamps do not fit truss. Link to comment Share on other sites More sharing options...
spinmaster1 Posted February 13, 2011 Author Share Posted February 13, 2011 Thanks for the advice. The reason for using 2 horizontal bars is basically because they are already there, one is an IWB and the other a plain bar linked with pipe to pipe clamps. I was thinking of adding a hannging clamp to each vertical bar to safety the whole thing from, then safety each lantern from the boom's safety points. Link to comment Share on other sites More sharing options...
TomHoward Posted February 14, 2011 Share Posted February 14, 2011 We do very similar to as just described, although also add a clamp or coupler to the bottom of the bar to stop a loose boom arm being able to slip off the bar completely. Link to comment Share on other sites More sharing options...
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