Mandalay Bay video wall fall

I've had arena rigging on my mind lately, will definitely be looking out for the final conclusions drawn from this.

I'll be curious what investigation takes place. With no injuries, it may be a strictly private investigation for the purposes of insurance. That could end just being a lot of photos getting taken for later review without an independent third-party surveying the damage first-hand. Could end in a settlement between the riggers and the video wall provider 2-3 years later over the property damage claims.
 
Sad, but true. We likely will never hear the exact results of this accident.
 
This is the version you tell the boss...

A former employee of one of our clients tried that line when their mothergrid got tweaked when the upstage line of motors was not engaged during an attempted re-trim. Seems it was done while our crew and most of the house crew were on lunch.

The other issue was that the grid was already loaded.

The ex-employee was terminated after review of facility surveillance video showed he was the only employee with access (keys) to the system who was in the venue in the lunch time frame.
 
This is the version you tell the boss...
I was involved with a rig years ago, at the <insert name of great big hotel chain with big beautiful ballrooms> in Downtown Portland. We installed a great big truss rig, from permanent house points, with chain motors, Hung fixtures, checked everything, ran the rig out to about 3/4's of it's play height and walked away for the night. Came back the next morning and found one corner on the ground along with it's chain motor. The point was torn out of it's spot, apparently they were really weren't rated for what they labelled, But yeah Boss shows up, " It was like this when we found it!"
 
...And what looks to be a jumbo verlock with cable at the slack end and no cable on the load side of the device.
I wasn't familiar with verlocks, so I went looking. I found one reference that specifically said "Not To Be Used For Overhead LIFTING" though it seems marketed for that. I've also seen both 425 and 500 lb WLL quoted, and have yet to find an official spec.
 
I wasn't familiar with verlocks, so I went looking. I found one reference that specifically said "Not To Be Used For Overhead LIFTING" though it seems marketed for that. I've also seen both 425 and 500 lb WLL quoted, and have yet to find an official spec.
I've had speakers (most specifically pendants) delivered from the manufacturer with Verlocks or gripples specifically to be used to hang them and I've seen them used extensively for banners and screens.
 
Generally Ver-locks are used for leveling, but you always have a safety in place. Since one of them could slip, that could put your rig out of balance and put greater weight on another pick point. If that was a Ver-lock, that is a beafier one than I have ever used.
 
It can be done safely. Just too many times it hasn't been for me. Think of all the safe MAX 737 flights.

I haven't worked on the problem, but I am sure there are safer solutions that fail less, and I'm sure they cost more, probably a lot more.

Bill,

When we sell chain hoists, we use ones rated for overhead by the manufacturers. Stagemaker is the one we use. 10 to 1 factor. Secondary brake on the load side. Everything is beefier, not working as hard and we have a manufacturer behind it for those under it.

The jerk start and stop keeps us from using it too often.

T
 
Bill,

When we sell chain hoists, we use ones rated for overhead by the manufacturers. Stagemaker is the one we use. 10 to 1 factor. Secondary brake on the load side. Everything is beefier, not working as hard and we have a manufacturer behind it for those under it.

The jerk start and stop keeps us from using it too often.

T
Isnt there a finite life to those per manufacturer?
 
Yearly inspections, parts replacement and machine replacement when appropriate. Much like the rest of rigging equipment is supposed to be in our perfect world. Although, as I said earlier, when the parts are not working hard, IE: At less than 10% of failure, they tend to last longer.
 
I just looked at Stagemaker maintanence schedule. There are a whole lot of venues where there is not a chance most or all that work will be done, like schools, churches, the vast majority of universities - and I think that's around 99% of venues in US.
 
I just looked at Stagemaker maintanence schedule. There are a whole lot of venues where there is not a chance most or all that work will be done, like schools, churches, the vast majority of universities - and I think that's around 99% of venues in US.

Using that logic, we should bag most of stage rigging. Again, we start with units that are made to a higher rating than the standard hoists. Essentially double the strength on all parts with the load limited to rating. We also rarely sell this style hoist due to the many issues with chain hoists in the situations that you and I play in. Most are utility hoists for storage not for use during shows.

We all hope the standards are followed, along with manufacturers instructions, but we cannot enforce it.
 
Stagemaker hoists are also pretty keen on chewing up their own chains if you run the chain while there's no load to keep everything taut and plumb.
 
Stagemaker hoists are also pretty keen on chewing up their own chains if you run the chain while there's no load to keep everything taut and plumb.
We have not observed this in the 20+ years of selling them. Probably because they are not used much.

BTW- Are you speaking of the 5 to 1 standard Stagemakers? Or the 10 to 1 units?
 
I heard it 2nd hand from a couple different people while soliciting feedback for an upcoming project. Consensus seemed to be, concept of reversible motor up/down = awesome, reliability of hoists = less awesome. I believe the use case was when they had them set on the ground and were feeding chain through without taking any care to ensure chain entered straight. Something about in the input gearing allowing the chain to misfeed and cause trouble.

I've used them before and not had problems, but only for flying semi-permanent PA speakers that are a very controlled, low turnover application.
 
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I use electric motor chain hoists on every arena or ltheater I work in. Also took the C-M classes and got my enterainment hoist technician card and cute diploma.

Hoists themselves fail for only a few reasons but the basic causes are lack of maintenance and overloading/severe operation. Almost any failure repair should be based on a full PM disassembly, inspection, replacement of parts as needed, and full lubrication, followed by load testing. Some things only need adjustment, like the limit switches, or obvious replacement like starting caps on single phase hoists.

On a concert tour with 120 points and almost as many hoists, it's common to see only 1 or 2 spare hoists in each size and in the last 6 or 7 shows I've rigged I can recall having to swap out a hoist only once.

I'm not sure how we got to chain hoist reliability unless there is some indication that the Mandalay Bay wall came down because a hoist lost power, control, or somehow got a jammed chain.
 

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