Chain Motor on Flyrail

[LX_]

Hi All,

I have seen a practice done quite often and I wanted to know if it were standard/acceptable.

Heavy scenery is loaded onto a batten on the ground of a single-purchase counterweight fly system. It is then hoisted up using a chain motor tied off to the fly rail, then hooked onto the empty arbor to drag the arbor in, hoisting it up. The chain motor is left there for the run of the show, holding the weight in place.

Is such practice acceptable??

Thanks.

 

[WildBill]

Hi All,

I have seen a practice done quite often and I wanted to know if it were standard/acceptable.

Heavy scenery is loaded onto a batten on the ground of a single-purchase counterweight fly system. It is then hoisted up using a chain motor tied off to the fly rail, then hooked onto the empty arbor to drag the arbor in, hoisting it up. The chain motor is left there for the run of the show, holding the weight in place.

Is such practice acceptable??

Thanks.

Short answer, no. The point of a counterweight system is to have the arbor and the scenery almost exactly the same weight and use the lock on the rail to hold the scenery. But then again, a lot things go on that I find unacceptable. I'm kind of a stickler for doing things the correct, and safe, way.

WB

 

[lwinters630]

Hi All,

I have seen a practice done quite often and I wanted to know if it were standard/acceptable.

Heavy scenery is loaded onto a batten on the ground of a single-purchase counterweight fly system. It is then hoisted up using a chain motor tied off to the fly rail, then hooked onto the empty arbor to drag the arbor in, hoisting it up. The chain motor is left there for the run of the show, holding the weight in place.

Is such practice acceptable??

Thanks.

No. Your chain hoist is probably not designed to for that and it will void any manufactures liability placing the whole liability on you (personally). There is something called a mule winch that utilizes a drum hoist, that can be designed with a structural engineers, taking into account how it attaches to the arbor. Even when using a mule winch the arbor is loaded with weights and balanced. I have used J J.R.Clancey.

 

[Footer]

I've done it. I have a weird rail though so I have a place to actually place the motor below the rail floor. I also have arbors designed to take a mule winch. It was for a piece that a drop have to come into the deck with the pipe touching the floor, the dancers then stepped over the drop, and the pipe went out. Really weird piece.

I've also been in houses that lacked a loading rail and we did this to load arbors. However, we did not leave it that way. The motor was there to get the arbor in, after that we threw weight until it was in weight and we landed the motor.

Big issue with this is not what it can do to hurt someone... but what it can do to your system in general. I've seen this done improperly and seen arbors ripped from T-tracks. I've seen T-track damaged, arbors bent... the list goes on. You really need to make sure that you are keeping everything square when doing this. Most modern rails aren't setup for this.

 

[gafftapegreenia]

We have two mule winches that we use with our rail., which was designed for such use.

I'm with Footer that under the right circumstances, with the proper equipment and knowledge, a chain hoist used to run a line set can be ok. however I would never want to leave that hoist under load for the run of a show.


Sent from my iPhone using Tapatalk

 

[LX_]

Thanks all for your input. I really appreciate it and knowing that now I will be more aware of being around such practices. We do use a mule winch sometimes to hoist without weight. Heres the picture for fun!

 

[porkchop]

I don't hate this as a solution to rig heavy elements when weight cannot be reasonably added while taking the piece out to trim. That being said, I feel like the arbor should be loaded so the piece is in weight as soon as possible so the (single brake) chain hoist isn't taking the load for the entire run.

 

[DuckJordan]

Even when that break fails on the chain motor it will slowly move its not going to crash down.

 

[Scarrgo]

Is that part of the rail built to hold that kind of weight?
It seems to me that the locking rail would not be rated for that much weight, in that direction...

I have been in houses that use a mule to assist in big heavy moves, but the rail is built with that in mind...
Sean...

 

[BillConnerFASTC]

Some non standard (for a manufacturer) lock rails are designed for these loads but few. I'd prefer a means to keep out of balance only on the arbor heavy side if this is really necessary. Load at bridge and lower to height for attaching batten load.

 

[AudJ]

I was under the assumption there was no loading bridge in this case. Aside from over-loading a batten (definitely a no), would there be a need for a hoist with a bridge?

 

[DuckJordan]

I was under the assumption there was no loading bridge in this case. Aside from over-loading a batten (definitely a no), would there be a need for a hoist with a bridge?

So for beauty and the beast. They are touring with a 2000lb plate rail. A motor on an about for this would be great because the plate rail doesn't add weight to the line set until it's 12' from the loading bridge arbor side. So for that 12' you have 2000lbs of weight in a very unsafe situation. The motor could control the arbors descent until the piece was actually on the pipe as well as assist on the out to carefully bring the piece in.

 

[BillConnerFASTC]

I was under the assumption there was no loading bridge in this case. Aside from over-loading a batten (definitely a no), would there be a need for a hoist with a bridge?

Yes, where the batten is not at low trim to load. For instance, a tall piece of scenery.

 

[tjrobb]

We are also in the "no loading rail" situation. Remodel in 1983, originally a Vaudeville house. Walls couldn't bear a bridge. We have a 1000# winch for loading. Only a very few are allowed to operate it (comm. theatre), all employees. There's also a now - famous incident where we pulled the lock rail out of the floor.

 

[Protech]

This isn't a practice we would recommend, and I'd bet that the chain motor manufacturer would not, either. I'm not entirely opposed to it for use in VERY limited circumstances, such as lifting heavy walls off he floor until they are under counterweight - however a great deal of caution must be exercised. and I believe there are better methods. As a "poor-mans automation" element as described, I think its a terrible idea.

My biggest fear with a setup like this someone using the capacity of the chain hoist IN ADDITION to the fully loaded counterweight arbor in order lift scenery that is too heavy for the system. I've actually seen something like this. Know your systems load limits and abide by them!

For venues without a loading rail/bridge, A purpose build capstan winch (also known as a bull winch) should be used. This process can be dangerous under even the best conditions, however. They should only be used by trained and qualified technicians. Most major equipment manufacturers (ourselves, JR Clancy, etc manufacture them and can provide training). Keep in mind that arbors need to be provisioned for capstan usage and your rail must have a reaction bar in order to use them correctly.

Is that part of the rail built to hold that kind of weight?
It seems to me that the locking rail would not be rated for that much weight, in that direction...

I have been in houses that use a mule to assist in big heavy moves, but the rail is built with that in mind...
Sean...

Most locking rails today are designed and engineered to withstand 500psf of UP load. Some are specified at 300psf however 500 is more common. I would be more concerned about the chain motor in this scenario if the theater is of modern construction.

 

[StradivariusBone]

I saw a load in of a touring show that used chain motors hung from the grid to assist battens at various points, my guess was to aid in scenery that exceeding the point load rating of the batten itself form the looks of how it was set up as most had a bridled point hung under (or near) where the chain motor attached. Slightly different from the what OP was going for, but similar result. It seems like they left the rail unlocked and used the motor to move the pipe after it was all buttoned up, but I didn't get a chance to see it closer, not sure if they weighted the arbor to the total scenery weight or let the chain hoist take up some of the load. Just wondering if that's more standard than hoisting the arbor?

 

[Protech]

Edit to my previous post: I mistakenly wrote PSF (pounds per sq. foot). The correct specification is PLF (pounds per linear foot). My mistake!