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Securing Light to Grid


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#1 craig bass

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Posted 09 March 2015 - 12:02 AM

Hi All,

 

I know this is an extremely basic question, but I was hoping someone could shed some light on utilizing rope and knots to secure lights to a grid. For instance, say I was attaching a 4 X 4 Kino to a grid with a Cardellini clamp, and did not have a safety chain. Say I was to then utilize a length of rope to tie the light off to the grid as a backup measure. What knot would I use to tie the light to the grid, and at what point on the Kino. What knot would I use to tie off on the grid?

 

Any insight would be greatly appreciated.

 

Thanks!

 

Craig


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#2 robert duke

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Posted 10 March 2015 - 09:13 AM

There will be some debate as there are a million and one ways to do this.

 

The knot on the grid could be a bowline, figure 8 on a bight, or a clove with a backup.  These three knots are effective as a safety tie ion place of a cable safety.  

 

The Kino body usually has two yellow wires where the backing platte is attached to the body.  These are the safety tie places.  If the kino doesn't have them, you can run the tie between the metal stiffener wire along the edge of the body and the body of the kino.  It can be a tight fit in the open spots of the bends in the kino doors, but that will also work.  IF that fails you can always Choke the body of the kino in line with the lamps.

 

The knot attaching to the kino should be a bowline or figure 8 on a bight.  There should be enough extra rope to allow focusing and some ability to move the fixture.  take into account the total fall distance and where an average person's height would be in the fall zone.  The object safetied shouldn't reach  the average person should it fall.  There are instances this cannot apply so use your best judgement.

 

When using a safety rope/sash/cord, the breaking strength of the rope should be roughly 5-10 times the weight of the object safetied.  That is the kinetic force/load (object falling) can be roughly 5-10 times the static load(object standing still).


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#3 craig bass

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Posted 16 March 2015 - 11:57 AM

Robert, thanks so much for the insight! Greatly appreciated, and makes total sense. If I was in a similar situation with a Fresnel, would it be the same story? Perhaps tying the bowline around the yoke?

 

Thanks again!


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