blueboxoffroad Posted April 11, 2013 Share Posted April 11, 2013 Hi there, I've just seen some plasma (or LCD/LED) screens flown from truss with PA speakers either side with a few generic lamps. Everything except the screens had a safety on it. Given the choice, I'd rather be hit by a Parcan than a 50" display, so... How would anyone safety a plasma - I don't know what model these were, but domestic style screens seem to be short of hanging points... I don't intend doing this myself at present, but would like to know the perceived wisdom on the safest way of doing it if ever I am asked to! Link to comment Share on other sites More sharing options...
Shez Posted April 11, 2013 Share Posted April 11, 2013 I don't think I've ever encountered a screen with a safety attachment point built in. I've always safetied to the bit of the bracket that attaches to the screen - there's always something you can attach to there. There are always at least four bolts that attach the bracket to the screen whereas there's usually only one (although sometimes two) clamp(s) to attach the bracket to the truss. Neither is likely to spontaneously fail but given the choice, putting the safety around a single potential point of failure rather than one that already has redundancy built in would seem sensible. Of course you can always compare this with the long running discussion about safeties and lanterns... Link to comment Share on other sites More sharing options...
sleah Posted April 11, 2013 Share Posted April 11, 2013 Given that flat screens are commonly 'flown' on walls the world over without safeties, I think it's safe to assume the screen itself doesn't require additional attachement, it already has four points as mentioned by Shez. Similarly I've installed several dozen LCD projectors above childrens' heads with no safety. As Shez suggests, any extra safety needs to be concerning the bracket that's bolted to the screen, rather than the screen itself. Link to comment Share on other sites More sharing options...
paulears Posted April 11, 2013 Share Posted April 11, 2013 I've always thought it a bit pointless to safety the bracket. The size of the bolts holding the bracket to the support system are usually much bigger than the bolts attaching the bracket to the monitor, so isn't that a bit like putting a safety onto a G-clamp, and not the light? In the absence of any rated points, I really don't know? Link to comment Share on other sites More sharing options...
lite_lad Posted April 11, 2013 Share Posted April 11, 2013 One of the most popular brackets for this kind of thing (unicol) is made as mentioned above with the standard 4 screws into the screen and then the pole which is connecting the bracket to the clamp has a safety bolt which goes all the way through it at both ends to ensure that there is no possible way for it to come out. And this is on top of the screws which are already there to hold it in. Although interestingly while touring some plasmas as part of a show to switzerland they did insist on a SWR from the bracket to the hanging point. (and as an interesting thing were insistent that things over the audience needed double the safety ratio compared to things over stage, off the top of my head I think it was 6:1 and 12:1? which I still dont understand.... why look after the audience ant more than yourself and your cast?) Link to comment Share on other sites More sharing options...
Pete McCrea Posted April 11, 2013 Share Posted April 11, 2013 Agreed with the fact that there is nowhere to safely attach a secondary attachment. We use Unicol products, because I know they are designed with FOS included, and are ruddy robust. The point of failure I see would the be bracket being ripped out of the casing - at which point I think things will have got pretty bad. Panasonics have handles on the pro panels - however, if you safetied to that, then the panel took a knock, leaving the handle to absorb the shock loading, I'd be confident that the handle would be snapped off instantly... Link to comment Share on other sites More sharing options...
Roderick Posted April 11, 2013 Share Posted April 11, 2013 I would question if the screens used are 'fit for purpose'.If we hear of a speaker rigged off its' handles the forum is flooded with posts how wrong that is.But hanging an obviously domestic screen without a safety or even a rated bracket is fine? The average bracket for domestic screens is designed to attach the screen to a wall, once and not moving.Using the same bracket to rig a screen off a truss can create all sorts of problems. The jerky movement of a truss being raised and levelled transfers a dynamic load on a bracket designed for a static load. That can lead to fatigue at the connection points which in time can cause it to fail. Unless it is supported by the manufacturer, I wouldn't use domestic screens in a professional, temporary workplace. Link to comment Share on other sites More sharing options...
david.elsbury Posted April 12, 2013 Share Posted April 12, 2013 True, Roderick, but not all trusses are flown - I would suspect that most of the people talking about putting screens on truss are in fact referring to using upright trusses on baseplates. David Edit to add: I think it comes down to risk assessment. How likely is it, that the screen will be knocked and come loose? If it has 4 bolts to fix the mounting bracket to the truss, and 2 bolts or clamps from the bracket to the truss, failure is unlikely? Link to comment Share on other sites More sharing options...
trussmonkey Posted April 12, 2013 Share Posted April 12, 2013 actually David trusses are used all the time on screens. especially in the touring side of the business. they can be very useful if you dont have enough available evenly spaced points in the roof or if you have a lightweight (Stealth/MItix) screen that has numerous pick up points but you can actually get away with less due to the weight. personally one of the advantages of these modular screens is they are quick and easy to build. If they now require a separate safety per module then this will make the set up of them much much longer. the current module designs are pretty robust and I have not heard of a failure of the locking mechanism until this year in Miami (if that was the cause of the incident) as long as the video/AV company follows manufacturer guidelines of how many modules can hang from a single flying bar. unfortunately due to the recent LED screen failure in Miami I suspect that this issue will be in the fore front of peoples minds. TM ps . trusses also cut down on the amount of hoists you have to hang everyday. Truss is significantly cheaper to rent that a hoist!!! Link to comment Share on other sites More sharing options...
paulears Posted April 12, 2013 Share Posted April 12, 2013 Am I the only one who has stripped the threads on one of the four attachment bolts - thread wise they're very small? Link to comment Share on other sites More sharing options...
David Lee Posted April 12, 2013 Share Posted April 12, 2013 Truss monkey, I think the op is talking about standard plasma/lcd monitors being flown. Unicol flying brackets are engineered with this in mind. Link to comment Share on other sites More sharing options...
trussmonkey Posted April 12, 2013 Share Posted April 12, 2013 ahhhhhh I stand corrected.... apologies :) Link to comment Share on other sites More sharing options...
ianl Posted April 12, 2013 Share Posted April 12, 2013 One of the most popular brackets for this kind of thing (unicol) is made as mentioned above with the standard 4 screws into the screen and then the pole which is connecting the bracket to the clamp has a safety bolt which goes all the way through it at both ends to ensure that there is no possible way for it to come out. And this is on top of the screws which are already there to hold it in. I know unicol call it a safety bolt, but realistically it is just a bolt. The grub screws are just to stop it wobbling . If the " safety bolt" were removed would you really rely on the friction of the 2 grub screw to stop the pole sliding out? I hope not, in which case it's not a safety bolt in the way we talk about secondary or redundant safeties. That said I've always understood unicol safety factor to be in their over-engineering, however as has been pointed out the attachment of the unicol to the plasma is just standard instal grade engineering. Perhaps the problem lies in the fact that we have taken a very good commercial installation product and used it in the touring industry ( as we always have done) without considering whether a modified or different product is required. Or maybe it's just that no one has worked out how yet ( mirror balls rotated for years without secondary safety points, lights were safetied for years round the yoke) or maybe it's all safe and we are over thinking it Link to comment Share on other sites More sharing options...
Pete McCrea Posted April 12, 2013 Share Posted April 12, 2013 ...maybe it's all safe and we are over thinking it If you're talking about a Panasonic TH50PF hung from a Unicol bracket, then yes I'd agree. I'm not aware of a single plasma/LED/LED monitor designed for use specifically in the live events market, that has a suitable point to attach a redundant/secondary suspension to... Link to comment Share on other sites More sharing options...
Roderick Posted April 12, 2013 Share Posted April 12, 2013 This discussion reminds me of the discussions when video projectors started to appear on stage.All designed for the domestic and classroom markets and without proper hanging brackets.Many people designed and made OTT hanging baskets for them, to be safe.Maybe something similar is needed for 'domestic' screens used in a professional environment? Link to comment Share on other sites More sharing options...
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