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Hoist Design - Issues with Wire ropes travelling.


Mantadive

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I am new to this forum.

Background on me, I am a retired builder, living in Thailand. As I age my knees are going to go, so I decided to build a lift in my home here. (2 storey)

I have completed this mostly, I goes up and down.

I designed a counterweight system using a wire rope around a drum, with a built in overspeed arrestor ( uses centrifical force to throw out cams) 

My problem is this.

The wire rope between the lift car and the counterweight wraps around a drum the operates the overspeed arrestor. the drum is approx 4 inches in dia. the cable wraps around once, 

The cable 'walks, along the drum as it rotates to the extent that the wire rope will cross over itself. I have tried it with 3 wraps aroung the drum, which is a bit better but doesnt solve the problem

Does anyone have any suggestions or ideas.

I have thought of running a seperate cable to the lift car only (not the counterweight, it will still operate on another cable) from the drum with a seperate elec motor to wind \the cable back up using Vbelts and pulleys. This is problematic as I have to slow the revs down to approx 14 rpm. There is not enough room to fit in the system of pulleys required. If I use a geared motor I will have to setup a system of reversing the motor for both up and down travell. 

This is doeable but complicated.  

So I am looking for ideas/advice. 

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Philip

Thanks for the suggestion.

That is a possibility, though I think the drum is probably too thin. Maybe I will get a new drum made to replace the existing one, I can also make it 150 mm diameter, I think this would help. 

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19 hours ago, Philip Lock said:

Hi, Can you get a helical grove machined in the drum to match the wire diameter? Pretty straightforward on a basic lathe.

As long as the edges were smooth this would give the rope some direction as the drum rotates

Philip

Thinking about it, I am not sure that a helcoil wrap on the drum will stop the cable walking. Wouldnt it  just follow the helicoil along ? The problem is that as it walks sideways it gets to a point where the cables start to rub and cross. I would like to try to stop them walking ( they walk in either direction depending on the rotation. )

 

Maybe flanges that limit the distance it can walk, If the flanges were tight to the cable warp with no allowance to walk, I thinhk this would stop it. What do you think? 

I would use 3 wraps instead of one as it seems to run smoother. 

Anyhow I look for to your imput.

 

Regards

Manatadive

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Ivhan Khan

Thankyou for your suggestion, however I think that I found a simpler solution.

I was researching and came across another forum that discussed much the same issue.

Their solution was to use a concave drum as used in a capstan winch for a boat winch.

This I can make simply. 

https://cr4.globalspec.com/thread/3492/Capstan-Drums-need-Help

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Hi, regarding my suggestion of a helicoil wrap, I see this doing the same task as a flange in that it would direct the wire rope to wrap around the drum without crossing over.

However the capstan winch idea sounds good so best of luck.

It would be nice to see a video of the successful solution when up and running!

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Philip

I think that the wire rope will still walk along the helicoil.

I will probably make flanges that are the exact width apart as 3 wraps of the wire. Then the wire rope has nowhere to travel. 

It will still try to travel, so there could be a bit of friction on the rope, however the lift only rises 3.6 m with a drum size of 150 mm, so not too much. 

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