DMX operated motors/hoists/winches

[dkw]

Hi all,

I am involved in a school production of The Wizard of Oz and have been asked to make some scenery fly away.

We don't have much height above the lighting rig and this would only be some very small, lightweight hardboard flats.

I don't really want to involve children pulling on lots of ropes and string to make it work and have been looking at hoists or something similar to use instead.

Could anyone point me in the right direction of a mains powered hoist which I could plug directly into my DMX controlled switch pack?

This isn't the exact thing I need but I basically want a hoist without the remote control - screwfix

Thank you!

** Edit **

Ah, thanks. I understand the safety concerns of DMX but loading limits won’t be a problem - it’s simply a 2ft square board that needs to be lowered and then disappear. If I keep the line short it won’t be able to drop below the maximum length which will still be 8-10ft above the stage floor. I was hoping to just have a dedicated 6 channel controller on the stage as well so someone can operate it within eyesight. The hoists as linked above only have a very short remote control so won’t be good enough.

 

Edited December 1, 2019 by dkw

[andy™]

doubt youll find any. from a safety point, DMX cant be used to operate machinery

[dosxuk]

DMX has no error-correction or reliability-of-signal features. It should never be used for safety-critical controls, flying objects above small children would be a clear example of this.

 

While there are products out there that use extra "safety channels" (where an extra channel needs to be a specific value in order to allow the main channel to be used) and such to try and improve the safety, this wouldn't work with a switchpack driving and off the shelf hoist.

[ontoprigger]

There are going to be a number of regulatory issues with this as well, aside from DMX not being suitable for machinery control, you will need to comply with Loler and PUWER, if this is not your field of expertise, I strongly advise contacting someone who is up on all of the latest regulations.

[Cheeseweasel]

Why not hire a small, conventional (Lodestar etc) hoist with a pickle? It will be cheaper than buying something unsuitable from Screwfix and bodging it. If you don't know what this is, how to rig it, or have never used one before, then you should seriously stop thinking about motors and come up with another way of moving this set piece. I don't mean to sound harsh, but rigging and operating motors are hazardous activities.

[Jivemaster]

Those hoists are SLOW, and fixed speed, their rated load only happens when the cable is looped hence the lift is even slower . They probably have instructions not to lift things over people. In a school in my limited experience money is tight regulatory compliance is tight but child labour is free and easy to come by.

 

-I'd avoid a machine and look for a person every time.

[James Remo]

The Wahlberg DMX Winch range might present a possible solution. Easily hired from the usual suspects.

[alistermorton]

Thinking laterally - you'll see what I did here - could you use heavy duty curtain track to fly the scenery out rather than up? We have no fly space at all, so we often move scenic flats in and out of the wings on Hall curtain track with small wheels attached at the bottom of the flat to help guide it.

 

This avoids having to lift stuff at all, once it's rigged.

[J Pearce]

Small hardboard signs can also hinge up to horizontal, avoiding any lifting and needing much less strength than hauling it out.

[alistermorton]

Not just signs - we've used that technique with ceiling light fittings, chandeliers etc, swinging them out of sight behind a border.

[ninjadingle]

Another reason not to use a hoist such as this is the noise. Motors are far from silent!

[dkw]

Hi everyone,

Thank you so much for all your help - the curtain track idea is brilliant and definitely something I’d be able to rig a lot easier than flying up.

I hadn’t really thought about ‘hinging’ out of the way and is worth me looking at space to try it out.

Again, thank you all for your words of wisdom :)

[Stuart91]

We had one of those Screwfix winches for a while, it was used for lifting flight cases up onto the first floor of a building. The wire has a nasty habit of snagging and tangling, especially when there isn't much load on it. After the second one broke we decided to buy something more professional (albeit 10x more expensive). I don't think I'd recommend them for anything, never mind lifting scenery above a live stage.

[paulears]

Two feet square? I’d have thought exactly the ideal way would be cord and pulleys. A Screwfix winch can sever an arm easily! Why complicate something so simple. Risk assess both processes and string works for me! Winches are also crazily slow.

[Junior8]

Paul's right again - keep it simple. The more complex the more chance there is for something to go wrong. If it didn't have to be wood but could be cloth instead there are probably even better ways to do this.