djw1981 Posted September 28, 2006 Share Posted September 28, 2006 Many thanks, that confirmed some of my thinking and gave me new things to consider, especially as the truss is the in-house one. Link to comment Share on other sites More sharing options...
herb Posted September 28, 2006 Share Posted September 28, 2006 Hi Folks,Regardless of the current status of gripples which I believed to be not recommended for lifting loads I think the real issue is rigging in a marquee.I have not come across many that have the ability to suspend significant loads if they are of the clearspan variety used for many corp events.Without a rated suspension point surely the rest is academic.Just a thoughtcheersherb Link to comment Share on other sites More sharing options...
dave singleton Posted September 28, 2006 Share Posted September 28, 2006 See now having worked for a marquee company in the past theres many things to consider. Firstly asking a member of the marquee crew: Dont ask anyone, because they are unlikely to no. See if theres a boss on site, if not ask the office. Someone in a marquee company no's they're tents limitations. Secondally, the gauge of the frame on clearspan is the factor which makes the difference for flying. Our 12m and 15m was a much heavier gauge and I believe could handle 400kg point load in wind conditions of up to 30mph. There is also a much lighter gauge version which is pritty much usless for any form load. One thing to look out for in the future, any tents from Owen Brown/GL Events will come with all the nessicary info, and most of their range 20m + can take huge weights. Link to comment Share on other sites More sharing options...
Pete Posted September 28, 2006 Share Posted September 28, 2006 You should of been there the day I tipped a bin full,due to an argument with a "rigger" who wanted to use them to make up some steels!I'm still uncertain whether this is kosher or not, having never seriously contemplated using Gripples this way. Using any type of rope grip rather than swaged ends to make up fixed-length steels doesn't seem like doesn't seem like best practice to me, but looking at the spec on Gripple's website I can't see why they'd be less suitable than any other proprietary rope grip for the purpose.You were obviously sufficiently certain of yourself to get into a fist fight over it that day, so care to post a definitive answer? Reason being,They were stamped not suitable for overhead lifting and infact had no SWL on them. Also I had no documentation from where they came from. More than my Jobs worth.Also same said "rigger" refused to take my generous offering of clutch chain. Said it had to be STAC. Have used gripples from time to time myself,but only for light stuff. Link to comment Share on other sites More sharing options...
ianl Posted September 28, 2006 Share Posted September 28, 2006 My gut feeling on the second point is that if Gripples aren't good enough for something, bullets (aka "Quick Term" connectors) wouldn't be a suitable alternative. Both devices work on the same principle with a similar mechanism, and for a given size of rope a Gripple is a slightly stronger device. Again, don't know. I may very well be wrong about that. Sx all from memory without checking my facts or going to look at one : bullet instructions require using a dog to clamp the wire to the metal U once adjusted, gripples don't have that facilaty bullits come with all the relevant paperwork, gripples certainly used not to Unusual rigging would not sell me griples as they are not suitable for rigging but instead sold me bullets Link to comment Share on other sites More sharing options...
Dan Appleby Posted September 29, 2006 Author Share Posted September 29, 2006 Hello folks... Seems I've opened up a right can of worms here! A few more details I've got for you on the whole rigging with gripple debate... The gripples used (I have one in front of me) have a SWL of 350kg, and DON'T say on them that they shouldn't be used for overhead lifting. The steel used was 4mm, which I'm informed has a SWL of 192kg. The steel used to attach the hoists to the marquee roof truss was looped round 3 times, which effectively gives it 3 times the wight loading capability - I.e 576kg - so no worries there - enough to clear both the hoists and the gripples. There were 3 steels from the hoist to the truss itself - one at each corner (directly under the motors) and two others stretching out to roughly the centre point of the truss (remember it was a square truss) in each direction. In a nutshell, each hoist had 3 points of connection to both the roof structure and to the truss. The marquee was a HUGE De Boer marquee (40m x 80m!), so it was pretty substantial. I can't vouch for the SWL of the structure itself, but I would guess you could hang a dam site more than we did without any problems, so I don't think this would have been an issue. The other thing I forgot to mention on the first post was the hurricaine (no, seriously). The 2nd night we were there, the marquee was battered by 70mph winds - the tail end of some hurricaine from america. We dropped the main truss over night, but other smaller truss sections that were dotted around (also hung using gripples) stayed up. Obviously, the truss (and the marquee!) was moving about a fiar bit, but it all stayed up (thankfully). Link to comment Share on other sites More sharing options...
Roderick Posted September 29, 2006 Share Posted September 29, 2006 I sincerely hope there was some substantial padding between the 4mm steels and the roof / truss!4mm steels would cut through alloy like a hot knife through butter. Link to comment Share on other sites More sharing options...
BlueShift Posted September 29, 2006 Share Posted September 29, 2006 If it is one of the DeBoer clearspan jobbies - I thought the support frame actually had slots down each large crossmember which allow specialist steel clamps to be attached and moved along the length of the frames - these then allow shackles to be attached accomodating spansets/ropes etc... alleviating the problem of ropes sawing through weaker alloy... Link to comment Share on other sites More sharing options...
dave singleton Posted September 29, 2006 Share Posted September 29, 2006 Yep, compleatly correct. You can buy something called a Cader clamp (the slots are called cader). I dont understand why they arnt very popular though, they dont exactly cost a great deal. Link to comment Share on other sites More sharing options...
johnhuson Posted September 30, 2006 Share Posted September 30, 2006 If it is one of the DeBoer clearspan jobbies - I thought the support frame actually had slots down each large crossmember which allow specialist steel clamps to be attached and moved along the length of the frames - these then allow shackles to be attached accomodating spansets/ropes etc... alleviating the problem of ropes sawing through weaker alloy... Pretty much every clear span marquee structure has Cader slots on both sides of the beam (top has the roof sheets slotted into it) and can be used with Cader clamps to provide a rigging point. However the question is, is the structure designed to take this additional loading. The majority of clear span structures have some capacity in varying degrees, but you can only find this information out by contacting the supplier/manufacturer in advance of the event. For an example of how much it is possible to hang off a marquee roof, please see picture below. http://www.pearcehire.co.uk/portfolio/images/ms_day.jpg Although it's a bit difficult to see all the rig there is over 2 tonnes of lighting equipment hanging off the roof of this marquee, and this doesn't include the PA delays! Granted that this is quite a large structure as far as marquees go, and rigging points in these larger tents is a pin through the beam rather than Cader clamps. But it goes to prove that it is possible to safely hang reasonable weights off some marquee structures. The thing which scares me when I've seen it done (not by me or the company I work for!) is people hanging by slinging over the purlings which run between the main roof beams. These purlings are often only supported by pop rivets into the main beam and are not suitable for taking downwards load in any way. The thing that concerns me about this thread is that there has been discussion about steels over beams, well these are pretty much the only beams in a marquee that you could sling a point over as the main roof beams have the sheets slotted into them, these being the beams which actually have potential to take load. Sorry if this is straying OT. Link to comment Share on other sites More sharing options...
swenk Posted September 13, 2018 Share Posted September 13, 2018 Hi all sorry to open a 12 year old thread. I did a search and couldn't find an newer posts and didn't really want to start a fresh one, given the sound discussion included above. SoI have an amount of truss to hang, do it all the time in this venue on chain hoists, happy with that arrangement, but on this occasion I have a serious amount of truss to hang and don't really want loads of 12m hoist's worth of chain up in the roof, weight and tidiness are both factors. I have a reasonable amount of fit up time, and plan to dead hang the truss and rig it from a scissor once hung, unlike normal. I am planning to use these for the PA truss (which will be well under the SWL of the hangers) and the No. 3 variant for the LX truss which will be ladder truss and again well under the SWL (including the self weight of the truss)they are 5:1 safety factor and I see no difference between a 300KG HVAC unit suspended for 20 years in a shop, or a piece of truss with a calculated and static load. I will be using half coupler to roping eyes on the ladder truss and slings to bow shackles on the tri and box trusses. At the top I will be using appropriate PVC steels around the RSJs (padded) or beam clamps depending on location. Discuss... thanks in advance swen Link to comment Share on other sites More sharing options...
Simon Lewis Posted September 13, 2018 Share Posted September 13, 2018 Swen, Even though the thread is pretty old, I'm not sure if the suspicion and uncertainty around using Gripples has disappeared. There's one rigging accessories website stating, "(they).... are not manufactured to any standard and cannot be used for lifting or in a situation where a shock load can occur as they cannot be fully inspected. They are suitable for hanging signs etc or for tensioning catenary wires"... Although probably more expensive, would the Reutlinger cable grippers be a better choice (for example, the ones here)? They appear more versatile and designed for rigging? Link to comment Share on other sites More sharing options...
ImagineerTom Posted September 13, 2018 Share Posted September 13, 2018 Gripples are not generally accepted as appropriate tools for rigging anything other than decor. You are also wrong to assume that PA is a static load - the vibrations in fairly modest used definitely apply forces to your rigging equipment far outside the normal parameters of a “static” load and I can find no data on how gripples survive under vibrated load. Is there any good reason why you can’t just have proper steels made to the correct sizes (they are surprisingly cheap to get properly made, certified ropes from a “brand name” rigging supplies company) and use those for your primary dead hang? Link to comment Share on other sites More sharing options...
trussmonkey Posted September 14, 2018 Share Posted September 14, 2018 Im with Tom. Pre made steels and rigging screws/turnbuckles . I wouldnt trust gripples with anything more than banners etc. Link to comment Share on other sites More sharing options...
sunray Posted September 14, 2018 Share Posted September 14, 2018 I discovered Gripples when I spent a year installing nightclub sound and light in 1995. I've seen large motorised rigs suspended on 4 of them and refused to hang products on them. It got to the point the company I was working for threatened to sack me until a rig started slipping on opening night. AFAIC they are very useful devices but not suitable for the substantial jobs that some seem to use them for. Link to comment Share on other sites More sharing options...
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