Stage curtain cable winder

[Hockeybod]

A couple of years ago I replaced the steel cable on our stage curtain winding mechanism, and over the holiday some idiot has taken the cable off and left the ends hanging loose. It took me ages to work out how to do it last time, and stupidly I didn't take a photo of it when complete. The attached pic shows the mechanism as it was before replacing the damaged cable, fortunately this time the cable isn't kinked. I seem to recall the the length of cable wound round the drum determines the length of travel of the curtains, and the leading track carriages have a clamp to adjust the curtain positions, but apart from that it's vague.

Can anyone offer any instructions to shorten the task?

[paulears]

No, the wrap is simply to get enough friction - if the cable is now a bit short. a few less turns will be fine. The killer is always that you must work out where the travel starts, and of course no joins at the winch end during the travel. What usually happens is you run out of good cable and discover you can only open partially. They're just fiddly.

[DrV]

Say which way you want it to rotate to open the tabs and I'll describe it step by step. I'm forever having to rewind ours because other stage users keep managing to get it off. Is it stage left or stage right?

[DrV]

Knew I'd seen this somewhere...

https://hallstage.com/wp-content/uploads/How-To-Cable-Winch-Operated-Tracks.pdf

The key to making it as easy as possible is to detach the cable that goes through the little hole at the front end of the spiral (near the handle) and leave the rear one in place. Compress any tensioners that there are on the pulleys. Then wind the rear cable on by rotating the handle. Hold the handle in place and wind one or two turns of the free end of the cable (that should be all that's left) onto the front end of the spiral so that you end up with just enough cable to thread through the other little hole and into the other clamp. Get as much tension as you can into the cable before doing up the clamp.  Run the tabs open and closed a couple of times and try to get a bit more tension into the cable. Once you've got the cable as tight as you possibly can, check your clamps are tight then release the tensioners.

[wolfie588]

I used the hallstage guide linked in DrV’s reply to renew the cable on our community hall curtains just before Christmas and the instructions worked a treat. I struggled to keep the tensioners compressed at first but found cable ties would hold them against the springs whilst feeding the cable on onto the drum.

My first post - hope it helps!

[sunray]

8 hours ago, DrV said:

Knew I'd seen this somewhere...

https://hallstage.com/wp-content/uploads/How-To-Cable-Winch-Operated-Tracks.pdf

The key to making it as easy as possible is to detach the cable that goes through the little hole at the front end of the spiral (near the handle) and leave the rear one in place. Compress any tensioners that there are on the pulleys. Then wind the rear cable on by rotating the handle. Hold the handle in place and wind one or two turns of the free end of the cable (that should be all that's left) onto the front end of the spiral so that you end up with just enough cable to thread through the other little hole and into the other clamp. Get as much tension as you can into the cable before doing up the clamp.  Run the tabs open and closed a couple of times and try to get a bit more tension into the cable. Once you've got the cable as tight as you possibly can, check your clamps are tight then release the tensioners.

First time I got involved with one of these was a damaged wire and replacement required. Not having any sort of guide to work with I threaded the wire over an end pulley, through the track and bobbins and back along the other track, over the pully and clamped into the rear hole,  filled the winder leaving 2 or3 turns empty then pulled tight and clamped the other end into the front hole.

At that point there was something like 5m left, I coiled it and secured to the handle. Then started winding and quickly realised it wasn't tight enough. Wound it back to starting point and tied the pulley springs closed, most likely with offcuts of 3/0.029" and adjusted the rope in the front clamp.

Releasing the ties the winder ran smoothly back a forth several times then making sure both curtains were fully open and the winder was at least one turn from the open position (this is not as obvious as it seems) clamped the leading bobbins to the wire.

Several full close/open sequences worked perfectly. Unbolting the handle I trapped the surplus coil between the handle and drum round one of the fixings.

Pretty much as DrV describes, I was about 14 at the time, working alone on the school stage.

Having worked on a number of them since it is easier to fit a replacement wire (with some surplus) than refit an existing wire which has been cut to length.

 

The one tip I will offer: It's more important to ensure both curtains are fully open at the same time rather than trying to get then correct when closed.

Edited January 4 by sunray
Just re-read and realise OP is trying to re-fit existing cable.

[Hockeybod]

On 1/3/2024 at 11:27 AM, DrV said:

Say which way you want it to rotate to open the tabs and I'll describe it step by step. I'm forever having to rewind ours because other stage users keep managing to get it off. Is it stage left or stage right?

Sorry, been away from PC for a day St right

[Hockeybod]

Thanks for all the replies and useful tips. I plan to do it this evening. I agree fresh cable is easier to work with, and I wouldn't even bother with one that has and kinks in it

Edited January 4 by Hockeybod

[DrV]

12 minutes ago, Hockeybod said:

Thanks for all the replies and useful tips. I plan to do it this evening. I agree fresh cable is easier to work with, and I wouldn't even bother with one that has and kinks in it

Up to you but I wouldn't worry about a few kinks, provided it runs through everything smoothly. If it were supporting something that would be a different matter. And because it's permanently under tension the kinks don't really matter if you've got them straight before you wind it on.

[sunray]

1 hour ago, DrV said:

Up to you but I wouldn't worry about a few kinks, provided it runs through everything smoothly. If it were supporting something that would be a different matter. And because it's permanently under tension the kinks don't really matter if you've got them straight before you wind it on.

Yes I generally agree with this  and will admit to replacing a badly kinked cable with a lightly kinked and using good bits of the removed cable to add safety wires to lighting bars. 

Added to that I have a complete recovered set in stock; winder, cable, pullies, bobbins (minus track) which was replaced when an expert condemned the lot after the cable came off the drum. I was asked to quote against the report and being a massive factor cheaper than the expert got the job. While there surveying I rethreaded the kinked cable so they could use it for their end of term presentation and it ran so well I asked why they wanted to replace it? 

Report showed it to be a hazard so came under H&S.

Edited January 4 by sunray

[Hockeybod]

On 1/3/2024 at 10:34 AM, paulears said:

No, the wrap is simply to get enough friction - if the cable is now a bit short. a few less turns will be fine. The killer is always that you must work out where the travel starts, and of course no joins at the winch end during the travel. What usually happens is you run out of good cable and discover you can only open partially. They're just fiddly.

Job done, following the instructions you all provided made it very straightforward. The two key tips for me were

1. compress the tensioning springs with cable ties and only release them once the cable is fairly tight and everything else is finished. Tight is good!

2. Fill the winch drum almost full apart from one or two turns to avoid crossing over. Too much cable on the drum isn't a problem, but too little WILL restrict the travel of the curtains and prevent them from opening or closing fully.

[sunray]

Having more rope on the drum than is required for the travel is no problem whatsoever as long as a whole space is left empty, indeed having an extra turn or two more will considerably help when rethreading it in the future.