Our build thread, renovation and extension

Our build thread, renovation and extension

Author
Discussion

WinstonWolf

72,857 posts

238 months

Thursday 13th February 2020
quotequote all
Muncher said:
Tuna said:
One solution...


Connect the hoist ropes together, end to end... so you have one long rope with a hoist at each end. Then run the rope from the roof, down to a pulley on the left, up to a pulley, across to the other side, down and back up again....


[H]__ _________ ___[H]
0 0 0 0
| | | |
| | | |
| | | |
| | | |
| | | |
O O



Then the two hoists are sharing the load, and the pulleys should even out the draw.
Thanks, it's not about evening out the draw, it is just how the cable winds onto the reel, which is difficult to control precisely. There is also the action of the autobrake on the winch, which I suspect may mean the two would get slightly out of sync over time. With independent control of either hoist at the moment I can at least always adjust each side as necessary.

It took quite a lot of work to get them working this well, so I'm loathe to majorly redesign the setup unless it makes it perfect. A mate who is great with electronics said he could design something to electronically control the level, but I'd rather not take up a load of time and money if someone can suggest a something very simple which does the job.

I will try and get a video of it in action tonight.
This is about as simple as it gets, the six pulleys are free to rotate and I reckon it should self level. If you drop it to the bottom and there's any slack it'll take up automatically. That's assuming you're swapping two motors for a single motor and an anchor...

You could mount the lower to pulleys on turnbuckles if you want some fine adjustment.

Tuna

19,930 posts

283 months

Thursday 13th February 2020
quotequote all
singlecoil said:
Remove the cable from one winch. Place pulleys under a convenient tread so that the cable from one winch goes down to the stairs, through the first pulley, through another pulley on the other side, then up to the second previously emptied winch. As the winches are operated the cable will move through the pulleys sufficiently to allow for differences in winding speed.
Simpler version of my plan, yes.

singlecoil

33,311 posts

245 months

Thursday 13th February 2020
quotequote all
Tuna said:
singlecoil said:
Remove the cable from one winch. Place pulleys under a convenient tread so that the cable from one winch goes down to the stairs, through the first pulley, through another pulley on the other side, then up to the second previously emptied winch. As the winches are operated the cable will move through the pulleys sufficiently to allow for differences in winding speed.
Simpler version of my plan, yes.
In engineering simpler is usually better, plus my plan doesn't have a splice running through the pulleys.

Muncher

Original Poster:

12,219 posts

248 months

Thursday 13th February 2020
quotequote all
https://youtu.be/SHMAKTHjPKg
Stairs going up


https://youtu.be/5kfFIwXAtPg
Safety bar going across


Slackline

411 posts

133 months

Thursday 13th February 2020
quotequote all
singlecoil said:
Tuna said:
singlecoil said:
Remove the cable from one winch. Place pulleys under a convenient tread so that the cable from one winch goes down to the stairs, through the first pulley, through another pulley on the other side, then up to the second previously emptied winch. As the winches are operated the cable will move through the pulleys sufficiently to allow for differences in winding speed.
Simpler version of my plan, yes.
In engineering simpler is usually better, plus my plan doesn't have a splice running through the pulleys.
Tuna has more lifting power in the 2:1 config, but is slower.

With all options, a limit switch at the top to stop the motors is definitely required. Unless they are encoded?

singlecoil

33,311 posts

245 months

Thursday 13th February 2020
quotequote all
Slackline said:
Tuna has more lifting power in the 2:1 config, but is slower.
Muncher said:
It raises and lowers powered by 2x 400kg hoists

Slackline

411 posts

133 months

Friday 14th February 2020
quotequote all
singlecoil said:
Slackline said:
Tuna has more lifting power in the 2:1 config, but is slower.
Muncher said:
It raises and lowers powered by 2x 400kg hoists
Your point is?

There's many ways to skin a cat, just because people have different ways to yours doesn't make them incorrect.

There's no need for a splice in Tunas version BTW - Equally, your way will also work.

Muncher, It looks like the stairs are swinging because of the different loads due to the wire bunching, as you've noticed. Not sure what hinge assembly is at the top, but there's a good chance it will not be liking it. Running 2 motors that aren't sync'd will always do that, even in a rolling bridle type of rig they will. I would suggest using the paw plate (rigging plate) and 2 lines from one winch method I described to stop that. I can do you a sketch if you need.

singlecoil

33,311 posts

245 months

Friday 14th February 2020
quotequote all
Slackline said:
singlecoil said:
Slackline said:
Tuna has more lifting power in the 2:1 config, but is slower.
Muncher said:
It raises and lowers powered by 2x 400kg hoists
Your point is?

There's many ways to skin a cat, just because people have different ways to yours doesn't make them incorrect.
Nobody is saying any way is incorrect, but my point is, if it needs explaining, that 800kg lifting capacity doesn't need the extra leverage that Tuna's version supplied. How much lift did you think that hinged set of stairs needs?

uk66fastback

16,454 posts

270 months

Saturday 15th February 2020
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Far beyond my capabilities or brain power, this! I'd have had some kind of fixed stairs somewhere cos I wouldn't have wanted to give myself this conundrum. You'll get it sorted. That bar that goes across is like something from some '80s Bond movie far out in space!