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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Xavier Moore on January 05, 2015, 12:45:51 PM
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On the pitcures attached its showing how a spanset is wrapped around the array lift forks. on that spanset is it two spansets or one spanset and would someone be able to tell me what the lengths are because im new to vertical array lifting, and i have been doing ground stacking for a while.
i plan on investing in the sumner eventer 16 or 20 and the carvin trx3210a array speakers. the speakers weight 60 lbs ea. and the flybar is probably 20 lbs and im going to only use 4 speakers per side for now.
i was looking at the company spanset and i came across this spanet that they told me comes in different lengths.
http://www.spanset-usa.com/products-services/lifting/roundslings/stage-slingr.html
model: ss90
please help me to under stand how you wrap the spanset around the forks.
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Have you consulted a rigger?
That's probably a 6' SpanSet in use there, but as your rigger will explain to you, you're going to want to have a variety of supplies (SpanSets of varying lengths, shackles, steel, etc) in your rigging trunk.
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1) Please change your profile so that your real name is shown.
2) Hanging from a lift in that manner is not safe - the downward pull on the spanset puts sideways stress on the forks.
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On the pitcures attached its showing how a spanset is wrapped around the array lift forks. on that spanset is it two spansets or one spanset and would someone be able to tell me what the lengths are because im new to vertical array lifting, and i have been doing ground stacking for a while.
i plan on investing in the sumner eventer 16 or 20 and the carvin trx3210a array speakers. the speakers weight 60 lbs ea. and the flybar is probably 20 lbs and im going to only use 4 speakers per side for now.
i was looking at the company spanset and i came across this spanet that they told me comes in different lengths.
http://www.spanset-usa.com/products-services/lifting/roundslings/stage-slingr.html
model: ss90
please help me to under stand how you wrap the spanset around the forks.
Read the rules, fix your display name.
Thank you for your cooperation.
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2) Hanging from a lift in that manner is not safe - the downward pull on the spanset puts sideways stress on the forks.
How much?
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I was under the impression that the Sumner Eventer lifts were designed for exactly this usage in mind.
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How much?
I don't know if the Sumners are OK with side loading. I called Genie a while back and sideways loads on the ST towers are not rated. So instead you'd want something across the forks to provide a center hang point, or maybe just a spacer to keep the forks from being pulled toward each other.
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I don't know if the Sumners are OK with side loading. I called Genie a while back and sideways loads on the ST towers are not rated. So instead you'd want something across the forks to provide a center hang point, or maybe just a spacer to keep the forks from being pulled toward each other.
We use a spacer made from 2.5" square steel tubing. It's only to keep the forks from being pulled together and is not designed to suspend any load.
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How much?
That depends on the amount of friction you get by wrapping the spanset around the forks and the angle to the load beneath.
I suggest you take a piece of truss or maybe the special spreader-bar made by the manufacturer.
Another thing to be carefull about is the amount of ballast you put on the base of the lift.
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One big issue with the Sumner lifts is that the weight rating drops quite a bit as you move out on the forks with your load. The Genie does this too, but not as much as the Sumner.
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This is what I do.
Of course I had to custom make my frames to make it happen.
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Option 2
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OP: Disclaimer: I am not a professional rigger. You should consult with a professional rigger to find out how to properly do this rigging. People die from faulty rigging.
That said, if you take a loop of string and hang it over two of your your spread fingers, you will probably see how the loop can wrap around the ends of your fingers. Once you do that pull on the bottom of the loop. You will see how that tries to bring your fingers (forks of the lift) together. That should give you an idea of the forces involved, and why you need to talk to a rigger (and maybe an engineer, too).
Mark C.
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I don't know if the Sumners are OK with side loading. I called Genie a while back and sideways loads on the ST towers are not rated. So instead you'd want something across the forks to provide a center hang point, or maybe just a spacer to keep the forks from being pulled toward each other.
i could use a spacer its just that sumner does make anything like that. what i was going to attempt was to buy 2 of sumners hook blocks(pitcure below)remove the hooks and then go to a welder and have him weld the two pieces together with a piece of steel in the middle. so that i could use that as the strain so the the forks do collapse.
i wouldnt need the hooks on the hook blocks because carvins fly bar is desiged to be hung from the center.
Or if someone could direct me to a company that already has a spacer the would fit the sumner lift
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We use a spacer made from 2.5" square steel tubing. It's only to keep the forks from being pulled together and is not designed to suspend any load.
did you have those spacers made or did you buy them from a company.
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i could use a spacer its just that sumner does make anything like that. what i was going to attempt was to buy 2 of sumners hook blocks(pitcure below)remove the hooks and then go to a welder and have him weld the two pieces together with a piece of steel in the middle. so that i could use that as the strain so the the forks do collapse.
i wouldnt need the hooks on the hook blocks because carvins fly bar is desiged to be hung from the center.
Or if someone could direct me to a company that already has a spacer the would fit the sumner lift
Or you can use a spreader bar like this (just invert it for your application): http://www.globalindustrial.com/p/material-handling/hoists-cranes/lifting-spreader-beams/12-48-economy-lift-beam-adjustable-length-1000-lb-capacity
(Be aware that this particular spreader may not meet your load and fork spacing requirements. Shop carefully.)
Hang it from Sumner's hook blocks, rig your array from the center point, and not only is it safer but you've also gained slightly over a foot in array height.
Note: If you're having something custom built it could sit on top of the forks with some method to secure it. You gain even more safety and height that way.
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I have a set of Sumner 20's and this is what I do. I use a pair of the Light Source fork adaptors and a half clamp and use a piece of sch 40 pipe between. Then hang the line array with a 3' steel spanset down to the shackle on the bumper. All of the weight is on top of the forks. The fork adaptors allow adjustment to keep the weight back as far as I can based on array bumper depth and there is a set screw to tighten the fork adaptors down. I also keep the forks "flipped" in so the space between the fork is minimal. I had the pipe threaded on both ends and installed couplers on each end so there is no chance the pipe could slide through the half clamp, not sure that it ever would but it makes me feel better!
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I just ordered another set of these frames. The tubing is 2.5" steel, the cross section required to fit over the forks of our older Genies. This is drawn upside down as the long bar actually sits on top of the forks. They have half inch forged eyebolts in the center and near the ends for lifting up to 500 lbs. Holes in the short sections match holes in the forks to accept quick release pins. I strongly suggest consulting an experienced rigger BEFORE you buy and implement anything that you hang over peoples' heads.
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Polar Focus used to make the GK kits for Genie Lifts. They still show some model numbers on their site but no images. The kits might fit the Sumner lifts, I don't know.
http://www.polarfocus.com/catalog/species/84/#species-header
I sell VMB lifts and the Cosmic Truss CT-5 which is very similar, possibly oem'ed by VMB. They offer welded cross bars to fit the forks on their models, which I believe someone posted images of earlier in the thread.
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I have a set of Sumner 20's and this is what I do. I use a pair of the Light Source fork adaptors and a half clamp and use a piece of sch 40 pipe between. Then hang the line array with a 3' steel spanset down to the shackle on the bumper. All of the weight is on top of the forks. The fork adaptors allow adjustment to keep the weight back as far as I can based on array bumper depth and there is a set screw to tighten the fork adaptors down. I also keep the forks "flipped" in so the space between the fork is minimal. I had the pipe threaded on both ends and installed couplers on each end so there is no chance the pipe could slide through the half clamp, not sure that it ever would but it makes me feel better!
how are you able to determine the ammount of weight you can put on the schedule 40 pipe
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I just ordered another set of these frames. The tubing is 2.5" steel, the cross section required to fit over the forks of our older Genies. This is drawn upside down as the long bar actually sits on top of the forks. They have half inch forged eyebolts in the center and near the ends for lifting up to 500 lbs. Holes in the short sections match holes in the forks to accept quick release pins. I strongly suggest consulting an experienced rigger BEFORE you buy and implement anything that you hang over peoples' heads.
did you have to get this welded together or did you buy it from somewhere, im talking with the company multi image group
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I sell VMB lifts and the Cosmic Truss CT-5 which is very similar, possibly oem'ed by VMB. They offer welded cross bars to fit the forks on their models, which I believe someone posted images of earlier in the thread.
I use the VMB FAS-01 fork adaptor on the HDT-8 lifts.
Should work on Sumners if the fork spacing is adjustable.
JR
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does anyone know the dimensions of the forks on the sumner eventer 16. the drawing i have tells me rounded off dims, i need the exact dims. and the thickness of the forks.
i found a steel fabrication company to make me 2 spacers to slide on to the forks to keep them from colapsing together.