Clutch chains

[Ike]

Following on from this thread I'm interested to know peoples experiences of clutch chains and their use in the entertainment industry.

 

Are there any really great or really poor products out there?

 

In your experiance which are the most commonly used and what's commonly stocked in the UK/wherever?

 

I might be purchasing some in the near(ish) future for my current employer however my experiance of clutch chains pretty much end at the battered old things I've used when loading/unloading HIABs so any information really is appreciated. We'll be using them mainly for setting up bridles and lugging switchgear around.

[Seano]

I don't spend a lot of time working with clutch chains, so can't really recommend any specific ones.

But, if its any help, some general comments:

 

Many clutch chains have a big O ring (masterlink) on one end, I guess because they're basically just a single-legged version of a 2 or 4 legged chain sling.

Most of the time its unnecessary but its always bulky and heavy, so best without really. (And of course if one of them is a bit heavy, you'll really notice the difference when you have a couple of dozen in a flightcase.)

 

Personally, I find the 'grab hook' style adjuster less fiddlly than the kind of clutch that kind of encloses half a link. Especially when making adjustments to the chain at height. Also there are a few 'enclosed' type clutches out there that can look ok at a glance when they're not quite properly engaged - nasty.

 

It makes sense for the minimum working length of the chain to be as short as possible, giving you the greatest possible range of adjustment. I really don't like those chains where you have an O ring on the end and then almost a foot of chain before the clutch.

 

Large hooks with conventional sprung keepers can be bad news. Its surprisingly easy to latch the hook onto other bridles, safety nets, braille lines, etc... when pulling a bridle up or lowering it in, and when it does happen it can be a bit of a nightmare to recover from to say the least.

 

So, to sum up, if I were looking to buy clutch chains, I'd ideally want to see:

• A nice neat termination at the clutch end, no bulky O ring.
  
• A grab hook rather than an enclosed clutch.
  
• The clutch as close to the end of the chain as possible.
  
• A 'latchlok' type locking hook on the other end of the chain, rather than a conventional hook with a sprung keeper.
  

 

I can certainly see why the Crosby Eliminator (ESOL) was being recommended on the other thread. I don't think I've ever met one in the flesh, but it looks really good.

 

hth

Sean

x

[MartinGreen]

We do a variety of chains, grab hook, hi grade and locking clutches.

 

You can buy them hook to hook with a clutch that moves throughout the length if you like. They really are a lot more flexible than people give them credit for.

 

We also do a clutch chain that meets BGV-C1 if required.

 

Crosby are only one of several companies who can provide a good clutch chain. We have a brand new system coming out in the next 7 days (stock arrived on Thursday).

 

Its a case of horses for courses as they say, but we are generally finding people moving more and more towards clutch chains in one form or another. As I say, its what we do for a living so we have to know what options are available.

[Seano]

We do a variety of chains, grab hook, hi grade and locking clutches.

 

Ike was asking for information on specific chains and pros/cons for one type versus another. This post can be summarised as "Clutch chains are great, buy them from me." As such I think you've crossed the line into blatant advertising, you've not even attempted to answer the questions in the OP.

 

You can buy them hook to hook with a clutch that moves throughout the length if you like. They really are a lot more flexible than people give them credit for.

Are you referring to the chain you mentioned in the other thread? This one:http://www.deepsoup.f2s.com/BR/upchain.gif

 

Did I understand you correctly, that each leg has to be within 45 degrees of vertical (or rather, within 45 degrees of the direction of the load at the apex)?

 

If so, then for the reasons I mentioned on that thread, they aren't flexible enough to be of any practical use in building bridles, sorry. If you were to use a double-legged chain for that, you'd want it to be at least capable of a 90degree included angle throughout the entire range of adjustment (ie: all the way out to one leg almost vertical and the other almost horizontal). Though even then, a maximum included angle of 120 degrees would be much more useful.

 

We also do a clutch chain that meets BGV-C1 if required.

What's the difference between one that does and one that doesn't? Is it just the 10:1 safety factor or are there other extra requirements? (ie: is a chain that meets BGV-C1 merely one that has had its SWL derated by a half?)

 

Crosby are only one of several companies who can provide a good clutch chain.

No doubt. Maybe you could address Ike's question and give us some examples of a few others?

 

Sean

x

[MartinGreen]

Apologies for the delay in answering but I have had a case of the lurgie.

 

Your right Seano, I should have explained myself better so here goes.

 

A basic Grade 8 Clutch chain is option 1. Available generally in 7mm chain dia with master link one end (O Ring) and sling hook with safety latch other. It is fitted with a grab hook clutch. Other versions can be fitted with O ring each end or sling hook each end depending on what the user requires.

 

http://www.riggingsupplies.co.uk/images/grabhook.gif

 

The advantage of a grab hook clutch is that its easy to use but the chain can fall out of it if used incorrectly. Also, some of the older grab hook clutches don't allow you to use 100% of the working load limit when you are shortening although these are now getting fewer and fewer.

 

Alternative 2 is to fit a bucket type clutch

 

http://www.riggingsupplies.co.uk/images/bucketclutch.gif

 

This is a better fit for the chain and less likely to fall out but can be a little fiddly if you only have one hand free.

 

There are also locking clutches available where you cannot take the chain out of the clutch unless you press a button at the side of the clutch to take the chain out. Obviously this is safer as the chain cannot fall out and you can use it inverted if you require without worrying about chain slipping or the like.

 

The following picture hopefully gives you a good breakdown of what a clutch chain can look like. This one is a RUD VIP Hi-Grade 10, which gives up to a 25% higher WLL for a chain the same diameter as grade 8.

 

http://www.riggingsupplies.co.uk/images/zoom.jpg

 

I attach a loading chart for all chain sizes in VIP Hi-Grade so as to explain the safe maximum angle of use (Seano, does this explain inclusive angle?)

 

RUD VIP Load chart

 

They are available in 1, 2, 3 or 4 leg versions although by far the one we are asked for the most is just plain old single leg 2m long.

 

When I was talking about a new clutch chain that we have where the clutch moves along the chain I was talking about this one RUD e-DUR chain system catalogue PDF On page 7 at the bottom there is a picture showing a 2 leg chain with the clutches moved into different parts of the chain so you are not restricted to having the chain at the top.

 

The advantage of moving the clutch means there is a flexibility to shorten the chain wherever along the length of it you want to (you are not just left having to reach for the top of the sling).

 

If you don't know who RUD are by the way, most of your motors are probably fitted with their chain, be it Verlinde, Liftket or CM.

 

I hope this information provided is useful, its just what I know and customers report back to me.

 

Oh and most importantly (almost forgot) they MUST come with a certificate.

 

Edit number 2 : Seano, you can get them with latchlock type hooks but it costs a lot more (double) so isn't financially viable.

[Seano]

Your right Seano, I should have explained myself better so here goes.

I wasn't complaining that you didn't explain yourself I was complaining about the blatant advert, and that you ignored the OP's questions.

 

The advantage of a grab hook clutch is that its easy to use but the chain can fall out of it if used incorrectly.

The chain can also fall out of a bucket type clutch if used incorrectly, or rather, the clutch can deform and fail if used incorrectly and subsequently loaded.

See paragraph 3 here. This mode of failure isn't an issue with a grab hook, since there's no right or wrong side for the loaded chain.

 

<bucket type clutch>This is a better fit for the chain and less likely to fall out but can be a little fiddly if you only have one hand free.

Its "a little fiddly" with both hands free, its extremely fiddly with only one. Like you said, the great majority of grab-hook clutches on the market now give you 100% of the strength of the chain, so in what way are they not a 'good fit' for the chain?

 

There are also locking clutches available ... you can use it inverted if you require without worrying about chain slipping or the like.

Its news to me that conventional clutches (of either type) are significantly less stable when used 'inverted', got a source for that? I can see how a locking clutch might be advantageous in some cases, but really don't think this is one of them.

 

The following picture hopefully gives you a good breakdown of what a clutch chain can look like.

Er... right. I've got a pretty solid idea what a clutch chain looks like already ta, and I'm pretty sure Ike does too.

 

Its an interesting contrast to the Crosby Eliminator though:

http://www.deepsoup.f2s.com/BR/crosbyeliminator.jpg

No excessively large O ring, grab hook clutch, minimum adjusted length as short as possible, and a hook that wont accidentally grab hold of other bridle legs etc. whilst being pulled up or lowered in. I've never seen the Crosby Eliminator in the flesh, but if I were in the market for a general purpose clutch chain I'd definitely want to check it out. It looks like it might be the second-best bridle adjusting chain on the market.

 

I attach a loading chart for all chain sizes in VIP Hi-Grade so as to explain the safe maximum angle of use (Seano, does this explain inclusive angle?)

I understand inclusive angles quite well, thanks. I was asking whether the chain with the movable clutch you referred to was the two-legged chap you mentioned on the other thread. That chain looks great for picking up certain PA systems, but I think its pretty clear its effectively useless for adjusting bridles.

 

The load chart you've attached there actually doesn't have anything to say about safe maximum angle of use anyway - it merely gives approximate load factors for 0-45 degrees and 45-60 degrees. In the overwhelming majority of cases in our industry, you're looking for an included angle of about 60 - 90 degrees in bridles (and sometimes flatter when the required apex height demands it).

 

All of which is a bit academic really, since noone is ever likely to buy 2-legged chains for general bridle adjustment. They might be good in a handful of specific venues, but realistically they're way too specialised to take on tour.

 

When I was talking about a new clutch chain that we have where the clutch moves along the chain I was talking about this one RUD e-DUR chain system catalogue PDF On page 7 at the bottom there is a picture showing a 2 leg chain with the clutches moved into different parts of the chain so you are not restricted to having the chain at the top.

 

The advantage of moving the clutch means there is a flexibility to shorten the chain wherever along the length of it you want to (you are not just left having to reach for the top of the sling).

 

The picture shows how the clutches can be moved along the sling, but not why. I can't for the life of me think of an example of when I'd ever want to do this, and apart from "because you can" there's certainly no reason to do it in either of those pictures.

In my experience, you either want to adjust the chain from the top (the very top, ideally) or you want to adjust it from the bottom (in which case you can use the chain inverted). I just don't see how this is an advantage, particularly as it seems likely to double the chance of a poorly engaged or misused clutch (since there are effectively 2 of them).