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Chain hoist for an LX bar?


james3mc
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Backstage we have a scaff bar which is used for storing unused luminaries. It is short, at only 4.8m. It rests across and is secured to, 4 RSJs ("I" bars).

 

This bar therefore has no lowering capabilities.

 

Want I want is to have an LX bar that can be lowered by a chain hoist. But is this possible and is it safe?

 

I'm opting for chain because I'm assuming that that is a cheaper option than either a manual winch or an electric hoist. Am I wrong?

 

We are a small community venue and therefore don't have deep pockets.

 

Advice? Suggestions?

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It's quite an expensive thing if you go for powered hoists, but on Ebay at the moment are some 1 ton manual chain hoists for quite sensible money, with a 6m drop. With some proper clamps, that would seem a a good way to do it? Of course, if it's not going to be loaded that heavily, a couple of pulleys hanging from the I-beams and some rope and nice big chunky cleats, fitted properly might be doable?
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The Stables theatre in Hastings (126 seats) uses some electric winches for lighting and raising cloths. Instead of going down the Stage Electric type route, which would allow the winches to be used for flying, they were more interested in lifting heavy things so they could be rigged at ground level.

 

The solution they came up with cost about £100 per winch (at 100kg) so £200-£300 per bar depending on how many mounting points (I believe they have only two per bar and put up with a lot of bend). They use commercial scaffolder’s electric winches (the one I looked closely at was a Parkside PSZ 250 B2 which was for 250kg). They can’t be used for flying as multiple winches won’t go at exactly the same speed but with a control for each one it is common sense to raise them roughly together then adjust (just like when using hemp). The controllers of each bar are gaffered together.

 

The electric winches are fixed onto hemp-flown bars which then raise and lower a separate wired bar – and hold the wired bar once in position. I suspect the reason for this is that if a motor fails, they can lower the LX bar with the remaining ones then drop the hemp bar, change the motor, then reverse the process. They don’t use them FOH possibly because the two FOH bars appear to have a standard rig.

 

It would be worth the travelling time to visit them if you are thinking along the same lines. I don't have a contact but they are on the internet http://stablestheatre.co.uk/ if you are interested.

 

 

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The solution they came up with cost about £100 per winch (at 100kg) so £200-£300 per bar depending on how many mounting points (I believe they have only two per bar and put up with a lot of bend). They use commercial scaffolder’s electric winches (the one I looked closely at was a Parkside PSZ 250 B2 which was for 250kg). They can’t be used for flying as multiple winches won’t go at exactly the same speed but with a control for each one it is common sense to raise them roughly together then adjust (just like when using hemp). The controllers of each bar are gaffered together.

 

 

Then they should stop using those winches immediately and check their rigger/flyman in for a refresher on rigging.

 

There is no braking arrangement on that type of scaffolders winch - the one you referenced, on Page 15 of the manual explicitly states the following:

 

Do not leave suspended loads unattended without taking the appropriate safety precautions.

 

Those safety precautions are essentially "Remove the load from the winch or apply some form of secondary suspension/load arrester" - because if the winch fails, the problem is probably not going to be the bar being stuck up there... it is more likely that it will just let the load go.

 

They they also "Put up with a lot bend" is pretty atrocious as well.

 

There is a reason electric hoists for suspending loads above people cost significant money. Hoists should be double braked at a minimum, ideally should have upper and lower limits as well as absolute upper and lower limits, should be maintained and installed by a competent person. Because when you screw up a hoisting arrangement, the results can be catastrophic.

Edited by mac.calder
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So can I lift with a chain hoist, and should I?

 

The main thing I'd consider with manual chain blocks is that you usually need two people and some coordination to fly a bar in and out successfully and although the flying distance isn't far, it does take a little while. The process is also fairly noisy. If the bar is only flying in once a month to swap out inventory and the clattering isn't going to cause problems, then this is probably fine.

 

You are also going to have to consider what you do with the control chain when not in use. Probably swag them out of the way and tie them off to a wall cleat or whatever, but it needs thinking about. Another consideration with any chain lifting device is the safe collection and storage of the lifting chain. Again, a short lift doesn't create much chain but it still needs to go into the bag/bucket safely and stay there every time so it doesn't 'run' I.e fall on someone either during the lift or at other times.

 

The bigger consideration to all this is if you and the venue really want to get into LOLER, as this all brings stuff to your door that your current setup doesn't, however much safer it may be to not have to store and access inventory using ladders or whatever.

 

I know some places that use single phase motors such as https://www.safetyliftingear.com/products/electric-hoist-250kg--240-volt-c-w-bag-/duke-du825-240v for duties such as storage or prep of equipment. (To add, that doesn't make them the correct category regarding guidelines for entertainment rigging. Often, there is not enough detail relating to the hoist itself, even in the usual manual. The linked one is stated as being 'dual-braked' though.) Basic info on standards https://www.hoistuk.com/rigging-hoist-standards-explained/

 

To be honest, in your position I would just ring up one of the many lifting gear suppliers and take their advice on production selection. There is no need to spec this yourself. Also avoid buying random stuff of the 'net.

 

PS I since found this, which is fairly helpful for a simple explanation of manual devices. https://www.hoistuk.com/everything-you-need-to-know-before-choosing-a-manual-chain-hoist/

Edited by indyld
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Yes*

 

The common standards for hoists in the entertainment industry are the German BGV-D8, D8+ and C1 - that have basically been codified into other countries standards since then. Despite what other countries have codified as (UK IIRC has "Category A" and "Category B", Australia has "designed for special lifting applications" and "not designed for special lifting applications" the D8, D8+ and C1 monikers are what you will see on an entertainment hoist.

 

D8+ is considered suitable for suspending loads above people. C1 is certified for actively moving loads above people - and is an entire system of safety, not just a motor classification.

 

If you are looking to get an off-the-shelf, non "entertainment" hoist (chain or otherwise), a minimum 5:1 safety factor and double brakes are what you are looking for.

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Parkside hoists are only rated 250KG when used with the cable doubled over a pulley, so they only lift full load to half height. If you intend to use lots of hoists you will need load monitoring so that all the pick up points share the load evenly -this will empty even the deepest pockets and certainly negate the saving using cheap hoists.

 

The raising and lowering are the easy bits! A big enough set of hoists can be made to work. It's the holding it there that's much harder to purchase cheaply

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