Batten rigging configuration.

[tinnman357]

Hello all! New to the forum and new to the world of theater. I recently took over operations manger at the local civic center. I have had an overdue inspection done on our theatre. And one of the concerns is the way this batten and trim chains are terminated. In the report they stated that the trim chain is " side loaded". The current configuration has been this way for around 40 yrs. Any recommendations on how to configure this to where my trim chains run vertical vs. at an angle? The 2 pipe need to remain on the same electric. I did find the Batten Clew which looked like it would work inverted. But the manufacture stated they did not recommend installing inverted. Not to mention they were almost $900 each and I need 18 total. And the company that completed the inspection would certainly re-rig it for 23k. Looking to possibly do in house as we are a small venue with a small budget. Thank you for any advice.

 

[jtweigandt]

Would the most obvious solution be to bring a vertical with turnbuckle down to the connector plates drilled center to take the load, and leave the angled chains imperceptably slack to
check any rocking? (disclaimer.. I'm a Veterinarian not an engineer) Otherwise have someone plasma cut and bend/ fabricate a bunch of new connector plates that "fill the triangle" with a load hole at the top.. ie replace the chain triangle with a plate triangle. I'll bet you have some fab shop locally that would make the part economically

 

[NJLX]

I would recommend replacing the trim chain with a truss pick: https://www.thelightsource.com/products/12-mega-truss-pick-34

The Light Source makes multiple sizes, so if your pipes are spaced to match one of them, it's an easy swap. Also they're already engineered for this type of load, althought hey will be more wobbly.

Alternatively, treat it as a bridle and use a shackle at the point where the aircraft cable meets the trim chain, to remove the side loading from the top point. Maybe replace the wrap around the pipe with a batten clamp. Then all the loads are in-line, no side loading of anything.

 

[Dover]

I would ask them to clarify what exactly they think the hazard is, a chain simply being at an angle is not necessarily "side loading". Side loading refers to the axis of load through a piece of rigging equipment being different than what was designed by the manufacturer, sort of like how an egg is stronger long ways than on it's side. It has nothing at all to do with the physical orientation of the loaded the chain itself, a chain stretched horizontally instead of vertically is not side loaded. It is possible they are referring to the connection of the two chains to the lift line but the picture is a bit small to see clearly what is going on.
In this case I think getting an in person second opinion would be a good idea, preferably from someone that does not have rigging services for sale.

 

[tinnman357]

Would the most obvious solution be to bring a vertical with turnbuckle down to the connector plates drilled center to take the load, and leave the angled chains imperceptably slack to
check any rocking? (disclaimer.. I'm a Veterinarian not an engineer) Otherwise have someone plasma cut and bend/ fabricate a bunch of new connector plates that "fill the triangle" with a load hole at the top.. ie replace the chain triangle with a plate triangle. I'll bet you have some fab shop locally that would make the part economically

Thank for the response, great idea with having triangles fabricated. will definitely consider.

 

[TheaterEd]

I would ask them to clarify what exactly they think the hazard is, a chain simply being at an angle is not necessarily "side loading". Side loading refers to the axis of load through a piece of rigging equipment being different than what was designed by the manufacturer, sort of like how an egg is stronger long ways than on it's side. It has nothing at all to do with the physical orientation of the loaded the chain itself, a chain stretched horizontally instead of vertically is not side loaded. It is possible they are referring to the connection of the two chains to the lift line but the picture is a bit small to see clearly what is going on.
In this case I think getting an in person second opinion would be a good idea, preferably from someone that does not have rigging services for sale.

In my very unqualified opinion, I think the side loading comes from the chain looping around the pipe and back to itself. Where it reconnects to itself is likely the problem as it side-loads that link. From a liability stand point, I would advise looking into the megatruss pick product linked above as it is engineered for this type of load whereas a custom fabricated piece has no official load rating.

 

[RickR]

My biggest issue with what I see is the side loading of the wire rope thimble. A small shackle would fix that quickly and cheaply.

My second issue is that the chain through bolts don't seem to be secured. Through bolting is no longer as popular as it was a couple of decades ago. More shackles could clean that up, but I might prefer replacing the chain so that both ends go through the new top shackle. Or as @NJLX mentioned, batten clamps (and more shackles!)

 

[tinnman357]

Thank you all for your input. Yes I need to replace the trim chain with 30 proof coil chain and add shackle's to replace the nut & bolt configuration in place now. From what I have read in the OSHA regulations the nut and bolt fastening of chain to chain is a no no. The truss pick looks like it might be the way to go. Thanks again to all of you for your help.

 

[Footer]

Can you upload a better quality picture?

 

[tinnman357]

here is a little different angle, unfortunately I am unable to get a better picture due to having a production in there this week.

 

[Footer]

here is a little different angle, unfortunately I am unable to get a better picture due to having a production in there this week.

Honestly that one as far as chain on the thimble goes... is fine. I hate bolt termination of chain like that though.

 

[Van]

Honestly that one as far as chain on the thimble goes... is fine. I hate bolt termination of chain like that though.

It makes me rather uncomfortable. I'd much rather see a shackle in there, of course I'd rather see the entire thing replaced by truss, or at least see all the U-bolts removed, the stretchers coped and welded.

 

[Footer]

It makes me rather uncomfortable. I'd much rather see a shackle in there, of course I'd rather see the entire thing replaced by truss, or at least see all the U-bolts removed, the stretchers coped and welded.

Agreed.