Endless rope drive ideas

[howardm]

Hi men,
This is a good one, I am trying to make an endless wire rope drive.
The rope is 4mm diameter. I have a ATV winch. If I do 5 turns of the drum, it works fine, BUT, as the rope creeps to the end it "spools" over itself and jams, there doesn't seem to be any way of stopping this "waking" action, even by guiding the wire. With just one turn of wire there isn't enough friction to drive the mechanism. So, has anybody done something like this, the mechanism has to work in both directions.
Thx
Howard

 

[MattF]

What's it driving/powering?

 

[normspanners]

Put runs of weld or rods longitudinally along the drum n like a capstan winch has, then it would work with less turns

How are you going to join the wire ?
because there will be a lump ?

 

[normspanners]

or you will need an in and out guide roller running very close to the drum and at either end of the drum so the wire cant spool and every thing needs to be at 90* to the shaft.

 

[dannyp]

corkscrew shaped guide on the drum itself ?

 

[Robotstar5]

You need a drum that tapers in towards the middle to stop the wire "walking" to the ends.

 

[normspanners]

If it tapers in it might reduce the tension and slip

 

[Robotstar5]

If it tapers in it might reduce the tension and slip

I was thinking of the shape of a capstan winch bollard.

 

[MattF]

If it tapers in it might reduce the tension and slip

If I'm understanding Robotstart correctly, it's literally two cones, tips centre, so the setup would always be trying to stay central. If it did creep slightly one way or the other, what it lost on one side by the decreasing diameter taper would be compensated for by the increasing diameter on the other side, as long as both sides of the pulley have the same degree of taper.

 

[awemawson]

Drive belts move to the crown of crowned pullies so you might get the opposite effect to what you want.

 

[howardm]

OK men,

Time for a re-design methinks, idea looked good in theory.!.

thanks
Howard

 

[normspanners]

Howard tell me what you are doing with it and how you joined the rope PLEAAAAASE
the suspense is killing me !!

 

[blenkie1]

or you will need an in and out guide roller running very close to the drum and at either end of the drum so the wire cant spool and every thing needs to be at 90* to the shaft.

I would think you would need something like this but if its pulling central, with good rope, and has tension it should go along the drum itself and back again by itself. Proper sized rope and not too much?

An endless rope is endless you usually need a return pully anchored somewhere so you can haul outbye and inbye. We had loads of these type of winches/haulers for transporting along the level in mines. Gravity haulers used to have one roller bolted down central to the drum winch and it would wind itself on with no problems along as you had no loose coils when starting off.

 

[normspanners]

The guide rollers would be also better being sprung loaded as automatic poly vee belt tensioner's are on cars to keep constant tension on the wire rope but their 'fleet angle' is critical to how well the rope sheaves on a flat drum.

 

[MattF]

Robotstar5: Apologies for my earlier typo in your username.

Drive belts move to the crown of crowned pullies so you might get the opposite effect to what you want.

Was wondering about that myself. Never used a looped belt/cable though, so I've no idea how they behave in use. It'd be handy to know what this drive system is for. There are possibly better choices on the drive setup.

 

[normspanners]

Drive belts move to the crown of crowned pullies so you might get the opposite effect to what you want.

IMO crowned pulleys only self centre with flat belts because as the flat belt moves off centre the drive is then transfered to the higher side of the belt this makes it track back towards the centre, because of the pulling effect on the tight side, makes it steer up the gradient until the tracking effect is neutralized ie central of the crown as long as the driven pulley (if flat) is square to the drive pulley. IMO wire ropes will want to go off the crown because their contact point is central through the wires centre , no matter what.

 

[awemawson]

You may be right, but the contact point between the rope and the pulley will be actually a small flat on the wire, albeit a very small one, where the wire deforms elastically. So in effect you WILL have a flat belt, just a very narrow one