endorphin Posted October 17, 2005 Share Posted October 17, 2005 I have just bought aa pair of telehoist stands to use maily with a tbar but on the odd ocasion with a 6m trilite 200 bridge (4 multipars and 6 selcom acclaims evenly spaced). Troublel is they are clearly marked not suitable for truss. I had checked the manufactures sit beforehand powerdrive :- telehoist but nowere dose it state the they canot be used for truss. I am awaiting a response to an email sent to powerdrive but was wondering if they are not suitable what stands are. Also does anyone else heer use winhc stands to lift truss? Cheers nb. I WILL not be lifting any truss unless the manufactures deem the use to be suitable. Link to comment Share on other sites More sharing options...
hadyn Posted October 17, 2005 Share Posted October 17, 2005 Also does anyone else heer use winhc stands to lift truss? Cheers nb. I WILL not be lifting any truss unless the manufactures deem the use to be suitable. Yes we quite often use a wind up type stand to support truss, but they're quite a bit heavier duty than the stands you linked to. Mostly zeniths or supertowers, with the odd gigtower thrown in. I would say just looking at them that they wouldn't be capable of supporting truss, but maybe that's just me. Hadyn. Link to comment Share on other sites More sharing options...
Simon Lewis Posted October 17, 2005 Share Posted October 17, 2005 ...but nowere dose it state the they canot be used for truss. There are several reasons why it isn't a good idea to use standard push up or wind up stands for truss (small base area, lack of kentledge, truss is usually suspended at end points etc.), and even if they were OK for truss, I'd be somewhat wary of putting up a 6m length. However, if I were a "reasonable person" looking to do the "right thing" I would download the manufacturer's data to see if my intended purchase was fit for my own intended purpose. When one looks at this page, the stand is shown with a truss adaptor plate and a length of truss. Now, granted, it doesn't show another stand 6m away, but it gives the impression that this is an acceptable use. I have used Genie Industries SuperLifts with medium duty truss, but those stands are expensive, heavy and difficult to transport. It will be interesting to see Powerdrive's rationale. Do let us know how you get on.... Simon Link to comment Share on other sites More sharing options...
damian666 Posted October 17, 2005 Share Posted October 17, 2005 It does sound to me that what you are thinking of putting on them is a little too much. As perviously said, windup stands of this sort of size are restricted by their relativley small footprint. Also they tend to be as light as the manufacturer can manage which makes them even less stable. http://www.doughty-engineering.co.uk/theatre/products.htm have a look at the Strata 515 (T55567)good kit, uk based manufacturer so sales service is good. form experience, there stands in that range are reliable and long lasting, and do what it says on the box, ie lift trusses!get the flightcased too and they become just another pair of boxes! Link to comment Share on other sites More sharing options...
endorphin Posted October 17, 2005 Author Share Posted October 17, 2005 Cheers for the comments so far. I did a load calculation and beleve it to be way withing the rated capacity of the stands although if people belive that this is to much I will look at my calculations. In regard to lifting truss with this kind of stand powerdrive make the midihoist spec :- Maximum Evenly Distributed Load 85kg / 187.43lbs Minimum Height 1950mm / 76.83" Maximum Height 3600mm / 141.84" Minimum Base Diameter 1720mm / 67.77" Maximum Base Diameter 1720mm / 67.77" Folded Length of Stand 2135mm / 84.12" Stand Leg Diameter 29mm / 1.14" Weight 27kg / 59.54lbs where as the telehoist is Maximum Evenly Distributed Load 65kg / 143.33lbs Minimum Height 1825mm / 71.91" Maximum Height 4600mm / 181.24" Maximum Base Diameter 1720mm / 67.77" Minimum Base Diameter 1720mm / 67.77" Folded Length of Stand 1780mm / 70.08" Stand Leg Diameter 29mm / 1.14" Weight 32kg / 70.55lbs The telehoist is heavier though it is taller as it is a 3 piece. however the footprint is the same. from the midihoist info A two section truss lifting tripod stand incorporating a twin safety screw locking system which, when used with REF 68 and REF 69 hinged truss adaptptors, allows an 8m span of trussing to be lifted. Also looking at other stands in the range such as the easy hoist powerdrive easyhoist they list ref 68a and 69a as optional accesories. (truss adaptors for either ladder or triangular truss) If it cant be used to lift truss ill accept that and have to by some more its just that at the moment I am abit annoyed that the manufacture has deemed them unsuitable for use and have not stated that. Whereas some of the cheaper stands can apparently be used ok. Link to comment Share on other sites More sharing options...
Pete McCrea Posted October 18, 2005 Share Posted October 18, 2005 It might well come down to the fact you'd be applying an ecentric load to the stand- i.e. 200kg to the left hand side of the stand, not a purely vertical loading. This could cause the mast to bend and get jammed. Ultimately this would depend on the type of truss connector used. The whole issue may well be one of CYA- Cover Your Ass. Link to comment Share on other sites More sharing options...
damian666 Posted October 18, 2005 Share Posted October 18, 2005 Re load centres, the load is not eccentric, it should be directly centred on the stand and providing the stands are erected properly, then the loads should act directly down upon the telescoping section. Have a look at the posted picture link.Ultimatley Edwin, the first thing is manufacturer's paperwork. If you are unsure then try sending someone a drawing of what you want to do. Once you haev a written approval that the relevant stands are ok for truss-type usage then you can produce your own RA/MS etc based on your needs, and consult others if neccessary. Link to comment Share on other sites More sharing options...
Pete McCrea Posted October 18, 2005 Share Posted October 18, 2005 To clarify my thoughts, if the Powerdrives were mounted at the ends of the truss, then there is the possibility that the loads are no acting truly vetically on the stand, by virtue of the fact there is no load to one side of the stand. However if the stands were 1.5m from each end, and the fixtures evenly placed over the length of the truss, then the load may well be purely vertical. At the end of the day, and as posted above, get the manufacturer to approve the system you propose, and then make sure that you have undertaken a RA and that the method of use is stated. Link to comment Share on other sites More sharing options...
endorphin Posted October 19, 2005 Author Share Posted October 19, 2005 Just to update. Just recieved conformation from Powerdrive (very helpfull people) that the stands will be suitable for lifting truss in the situation outlined in my previous post. (assuming that the weight of the truss ect do not exceed the swl). The main reason for having the warning on the stands is to stop people using them as there apparently have been some accidents due to missuse. All that remains is to work through the load calculations then do a RA. Cheers for the advice. I will be contacting the relevent manufactures again with the finalised plan to make sure I have their approval. Edd Link to comment Share on other sites More sharing options...
p.k.roberts Posted October 19, 2005 Share Posted October 19, 2005 Just to update... :** laughs out loud **: {snip} I have also been in contact regarding this warning on Telehoists; they told me that the effects of a stand failure when supporting truss were so much more serious (i.e. if one stand fails or is not secured properly the whole truss would probably collapse) that you would in effect need a 'tertiary' method of supporting the column in the 'locked' position. In other words, something like a safety pin through the column (although you would need to discuss the potential weakening effect of this with Powerdrive). Perhaps the answer would be an extra locking collar on the top round section and a hole/pin arrangment on the middle square section? I'd be interested in any reply you get from Powerdive about this. :huh: Quote of entire previous post edited. Link to comment Share on other sites More sharing options...
endorphin Posted October 19, 2005 Author Share Posted October 19, 2005 In other words, something like a safety pin through the column (although you would need to discuss the potential weakening effect of this with Powerdrive). Perhaps the answer would be an extra locking collar on the top round section and a hole/pin arrangment on the middle square section? I'd be interested in any reply you get from Powerdive about this. Powerdrive have stated that a safty pin through the coloum would be a good idea (although without being giving the full details were unable at the present time to certify its use) The idea of a locking collar is interseting and I shall approach them and see if this is an accetable saftey. :** laughs out loud **: Cheers Edd Link to comment Share on other sites More sharing options...
Chris Higgs Posted October 25, 2005 Share Posted October 25, 2005 It's not just the strength of the stand but what supports the stand - is the supporting floor surface strong enough for three point loads, one big point load, or whatever?The stability of the whole thing is also critical - what would happen if one end gets moved accidently (vehicles, crowd, etc)Is it likely some bright spark will ask you to add 'secondaries' to overhead supports? (If so, why isn't it hanging anyway?) If it falls over, will the rigging used and the structure above sustain the loads thus created?I am supposing that this is indoors....... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.