smash!!!

[gareth]

had a halfcoupler on a spiggot into the stand, then a 1.5m alu pipe going through it.

No wonder it broke, then - that's definitely not the way to rig a single moving light on a stand! Think about it - you've got 20-odd kilos of moving light rigged off-centre, completely outside the axis of the stand, trying its best to bend the stand's support tube. And that's before you start to factor in the dynamic loads that appear when you start swinging the head around.

 

It's a good job your falling fixture didn't damage anything or anyone, as I very much doubt your insurers would consider paying out on a claim involving such rigging practices. You can get plates that attach to the underneath of a Mac in place of the omega brackets, onto which you can fit a spigot in order to mount the unit directly over the centre of the stand.

 

Incidentally, exactly how far out from the axis of the stand did you have this fixture rigged? Right up against the tube, or at the extreme end of the 1.5m scaff bar that you mentioned?

[Ike]

These topics always concern me, not so much because accidents happen but of peoples lack of reaction when they do. I thought it would be the first reaction of anyone in the industry to want to know why an accident happened and put measures in place to prevent it, I'm sorry but you can hardly say it was a thorough investigation if all you come back with is:

I just think the manfrotto was old

OK so nobody got hurt but they could well have done, you're working practises were clearly at fault yet you "solved" the problem by throwing away the broken stand and buying two more?! Whats to stop it happening again?

 

 

EDIT: Actually I just re-read the topic and the fact the accident happened in the first place is bloody scary, who in their right mind would think that's a suitable rigging practise?

[five_pin_xlr]

Well, this happened in January, and I did a gig in December where we hired from PRG and I was told that it should be fine.

 

I made sure it was as balanced as possible when I hoisted it up, and it was fine.

 

I took this advice from a professional company so assumed it was right.

 

Although for this event we used 2 of our manfrottos and two of theirs. For the youth club event we used all our own, with 2 being new and the rest being old.

 

Because of this incident, we have invested in tank traps, so the movers can go on top. Although Truss to Manfrottos is a good idea someone told me.

[Ynot]

Well, this happened in January, and I did a gig in December where we hired from PRG and I was told that it should be fine.

Hmmmm....

Quite honestly I'm concerned that PRG might tell you that it would be fine to sit any moving head atop a stand, especially one that's extended.

I made sure it was as balanced as possible when I hoisted it up, and it was fine.

I'm still not actually clear on how you fitted the Mac - did you sit it ON TOP of the 1.5m pipe, base down, so over-hung, or did you hang it BENEATH the pipe?

Either way it's NOT something I'd do, but it just helps in assessing the situation.

I took this advice from a professional company so assumed it was right.

Like I said - surprising - and if it were me, presented with the comments in here, I'd go back to them and ask the same question.... Of more than one person.

though for this event we used 2 of our manfrottos and two of theirs. For the youth club event we used all our own, with 2 being new and the rest being old.

If you're using your kit in any public space YOU need to ensure that said kit is safe in that environment. The fact that the stand broke at all suggests that there may have been an existing stress fault that was pushed over the edge - that in itself suggests misuse during it's previous life...

Because of this incident, we have invested in tank traps, so the movers can go on top.

That's fine - it's always good to see modified practices following an incident........

Although Truss to Manfrottos is a good idea someone told me.

....but this is still a poor choice. Stringing truss betwixt two stands is (as mentioned in the other thread) a bad idea, as a) you'll need decent quality truss to hang the weight of any more than a couple of Macs (if that) and there'll be a temptation to hang as many as you can fit, and b) there are STILL going to be motion forces at work on the supports - ie the stands - and the risks of causing a collapse increases exponentially with every independently moving head you hang.

 

Don't get me wrong - not trying to stamp on you here, but what I am trying to do (as are others) is point out potentially unsafe practices in the hope that you and others won't be tempted to push the risks too far.

 

TD

[gnomatron]

Hmm, we have an annual gig where we generally hang a pair of mac 250s on each of two manfrotto stands - these ones I think. We rig them on a 4' scaff bar, about as close to the manfrotto as possible either side, and hanging down. We tend to extend the stands to no more than 2 metres. We've never had any stability problems with them, but this thread has got me wondering, especially now we've got the 250 Kryptons which move a lot faster than the old ones.

[five_pin_xlr]

http://www.manfrotto.com/Jahia/site/manfro...4|33&idx=33

 

the older ones were quite a few years older than these ones, the newer ones we purchased from AC Lighting, and they are in fantastic condition.

 

Always hang macs, never sit on top, too risky I feel

 

Should I get them all sent off for a test?

 

What is the best way for them to hang on a stand?

[zonino]

Although Truss to Manfrottos is a good idea someone told me.

....but this is still a poor choice. Stringing truss betwixt two stands is (as mentioned in the other thread) a bad idea, as a) you'll need decent quality truss to hang the weight of any more than a couple of Macs (if that)

 

surely that's the case for any mobile rig??

 

and there'll be a temptation to hang as many as you can fit,

 

how is this different to a fly-bar or a truss-only structure??

 

 

I'm also trying to find when in the other thread it says it is bad practice to hang mac's on a piece of truss between two stands?

[ImAlrightSpider]

An amateur group that used my space last summer had a problem with a Source Four used as a follow-spot. Evidently the bolt on the clamp allowing for panning was tightened, so that the panning resulted in a loosening of the bolt connecting the clamp to the yoke.

 

Midway through a performance, the bolt fell out, landing on the shoulder of an audience member some 30 ft. below (who was amazingly generous enough to say that there was no problem). The very warm illuminated fixture landed in the lap of the 17 year old girl who was operating it. Thanks to the safety, it went no further.

[Ynot]

Although Truss to Manfrottos is a good idea someone told me.

....but this is still a poor choice. Stringing truss betwixt two stands is (as mentioned in the other thread) a bad idea, as a) you'll need decent quality truss to hang the weight of any more than a couple of Macs (if that)

surely that's the case for any mobile rig??

Certainly is!

and there'll be a temptation to hang as many as you can fit,

how is this different to a fly-bar or a truss-only structure??

Again, no difference at all.

I'm also trying to find when in the other thread it says it is bad practice to hang mac's on a piece of truss between two stands?

Ah, well, err, humm, OK - maybe I remembered something that wasn't there! :P Apologies for mis-speaking there.

However, it's still something I wouldn't be willing to do personally.... Not without some SERIOUS assessments and safeties in place.

 

 

Always hang macs, never sit on top, too risky I feel

Hmmm.... again.

So basically you're over-loading one side of the pipe, thus placing the whole centre of gravity in jeopardy?

I have no further surprise that the thing fell, though I still wonder about the breakage - that has to go back to suspected continued misuse, however.

Should I get them all sent off for a test?

What? the stands? Might be an idea, though not sure whether stands can be tested at all....

What is the best way for them to hang on a stand?

If you put ANY lanterns etc on any sort of stand, you must ensure that a) you're not exceeding the basic design weight limit, b) that the stand can cope with any kinetic movement which may place further weight stresses (and that would be rather difficult to calculate with a moving head) and c) that the kit on the stand is properly distributed on whatever fixings you use.

If you'd put 2 or 3 Source 4 profiles, for example, on one side of a 4 foot pipe with nought else to balance out the other side, you get the same effect.

By putting your 22kG Mac offset on your pipe, you're altering the centre of gravity quite significantly. The CoG for the fixture will be around 12 to 18 inches away from the stand. There will be math to work that out - I'm long past that, but it doesn't take a genius to see where the potential problems will be....!

[gnomatron]

I think it's clear that it's the same as for any hanging sytem, but that stands are more prone to misuse. You can buy sh***y stands in Maplin for 25 quid and overload them with disco lights, it's not as easy to do that with flybars or truss structures, as they're not as likely to be used by someone with little experience, or in a venue where nobody knows any better.

[MarkPAman]

..............has anyone ever actually seen a lamp fall from a rig?

Not a lamp, but I dropped a mirror ball once while rigging it. Probably only about 5m but it seemed to take ages to hit the floor! :P

[Dmills]

I once saw a bare X1600 bubble kicked off a follow spot tower by accident (it was the one that had just been replaced), the diving for cover by all concerned was impressive, and yes they do seem to spend a LONG time in the air (1.6Kw SBA xenon, about 6 bar internal pressure when cold).

 

The bang when the thing hit the concrete was even more impressive, as was the damage to a mates motorcycle leathers (bloody lucky he was wearing them - bit to close to get out the way).

 

Other then that, I have had a few things end up hanging on safety chains due to passing scenery and the like (starlette barndoors are favourite for this, grumble), but so far nothing worse.

 

Regards, Dan.

[johnlinford]

I've heard a tale of a student who, while followspotting in the theatre at Eton College managed to end up holding the weight of the light having managed to work the yolk loose. The Queen was sitting underneath at the time...

 

This may be apocryful though...

[El Presidente]

Out of curiosity, I'm sure everyone tightens their clamps and puts safety steels on every fixture, but, has anyone ever actually seen a lamp fall from a rig?

 

Thank my lucky stars I haven't yet, I have seen someone drop barn doors twice in the succession of two shows from the bridges at a height of 40ft narrowly missing my tutor on both occasions ;)

 

Needless to say the young lady involved is no longer trusted to be in the roof anymore....

 

I hope I never get to see a light fall from a rig.

[zonino]

tbh, if your working on a bridge nobody should be underneath anyway...