How do you say.....


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How do you say saftey first. We had a lighting instrument used as a special and it was located close to our main curtain. No big deal, except that the gel slot would catch when the curtain was opened and closed. So today after sceen one and the curtain opened for the second time in sceen 2 or 3 (that part doesnt matter) it had spun the bolt out of the c-clamp and was hanging there by its aspestos whip....(i know someone is going to say something about the whip too)....someone forgot to put a saftey cable on it.....I am just greatful it didn't falls as there were people under it until we were able to run back, shift people forward and grab a ladder and take it down (10 minutes tops...i think)

I am currious if anyone else has has an incident like this and if so what method you used to resolve the issue? if you have not had this happen do you have a plan on how to procede if it does?
safety cables, locking washers, lock-tight, makign sure its clear of obsticles?
I must second propmonkey's opinion. You can never overly secure the light, nor can you overly check to be sure that every safety precaution has been taken.
Just curious as to whether the C-clamp became disconnected form the fixture, or the C-clamp and fixture was knocked free from the pipe?

If it was the first scenario - were there enough threads of the bolt on the outside of the nut? I would be concerned that the movement form a curtain moving it one direction and then back again was enough to spin off the nut. There should be at least 2 full turns required to remove the nut. By the way - did the falling bolt/nut/washers hit anyone.

If the C-clamp was knocked off of the pipe, check that the clamp is not bent. Sometimes this occurs and the bolt doesn't bite into the pipe in the correct position (which should be just below the widest point. Sometimes when they bend, they clamp above the widest point and either will not bite into the pipe (they just force the clamp off the pipe as you tighten the bolt) or they bit but will become dislodged with the slightest bump.

propmonkey is correct in saying the it should have been checked for clearance and of course, a safety should have been fitted.
SOunds like a too short of Bolt was loose.

Whhen sending a show to trim, be it 24 to 2400 fixtures, 10' trim to 40' trim, I personally walk every stick of truss, make sure every bolt is tight, and grab every fixture, make sure it's tight and has a safety....... I have used a 5' piece of Steel with a shackle before because they were no more safeties onsight
it was the instrument that came loose from the clamp. the clamp remained on the batton securely. I was not involved with the show setup besides plugging in 2 mics day before the show. In answer to the other question, no the bolt/washer/what ever else fell did not hit anyone.

there is no nut involved with the clamp. the bolt goes through the yoke into (i dont know what its called) but the part of the c-clamp that can turn after the clamp it self is secured. I did not see the bolt, but judging by what I had seen on other fixtures I worked with, the bolt was too small.

I do agree with everything that has been said. When I have done light hangs I have always used a safety cable.
Can you post a pic of the C-clamp? Can't say that I am familiar with what you describe
Never heard of a set screw attacing the clamp to the pipe coming loose before. On the other hand if the bolt attaching clamp to yoke was shorter than normal or in some cases factory only like 1" long, than that's somewhat understandable but not much given about 7 complete turns of the bolt to make it come out.

So how did this happen?

I'm thinking that part of our job is not just to see what happens, but study the why and what needs to be done to ensure it won't happen again. Be this from as someone said, going down the line to ensure the fixture is secure, to safety cables installed and used.

If nothing else, one can assume that your plug at least if stage pin had it's proper gap spacing to it in holding up the fixture. That's at least a good thing.
Wow, that sounds like some wicked bad luck. Did the light actually fall at all or was it just really close to it (I mean did it fall and catch on the whip or not). We havn't had anything quite that bad. Just finding a light that didn't have a safetly or something like that right before we close up the electrics or something. We're probably actually worse with our ladder fun than with the instruments, lol.

It was the 10th night or so of the show (including tech week). The light was hung as a special for the intro. when ever the curtain opened and closed you could hear it catch on something, not being back stage I never noticed it. I would think the people who were back stage should have noticed it. My assumption is that the curtain caused it to spin, but i would assume that by spinning one way with the open and then the other with the close it should have helped keep the fixture in place.

I'm glad we had twist lock plugs and a secured base. I do not think it would have held up had it been stage pin.
Ah - yes, I know the ones. Must say that I am not a fan of those clamps and much prefer the older style C clamps that actually hook over the pipe.

similar to this

At least with those ones, you can place a nylock nut on the bolt if you wish to and tighten it enough that it still has play in it.

Didn't the fact that the light would have been off focus alert attention to this fact?
I had something like this happen once. The side bolt that held the instrament to the clamp flew off in the middle of a show. We use caribiners and steel fiber to hook the c clamp to the bar as a safety, but that doesn't really help when the whol damn light comes OFF the clamp. Luckily, the instrament was propped up on the tree so that it didn't fall down and kill somebody.

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