Odd design - Will it work?

[OldProfessorBear]

K. old  design scrapped. see this. keep in mind that the reel is attached to the platform.

Spoiler (click to show/hide)

http://www.flickr.com/photos/33330632@N07/3115134467/

The purpose of the windlass (the cylinder) is ... ?

[Alptraum]

To drive the airbrake system.

[tsjaikdus]

[edit]

<<text removed>>

I just noticed that the diameters of the windlass need to be different for each rope in order for the weight to drop.

In theory it could be made to work if the winches were geared so that several rotations of the counterweight winch produced a single rotation of the elevating winch. However, this would require that the counterweight drop through several times the distance the platform rises, and that entire distance would have to be below the lowest position of the platform. In other words, Alptraum would need a whacking deep hole in the floor.

I found that if the weight was on the larger cylinder and this cylinder was directly connected (no gearing or such) to the smaller cylinder (the smaller has the rope to the sealing), that the weight does only drop a little, while the cilinder is moving upwards fast.

*hate it when things are not as obvious as they appear to be*

[/edit]

[von Corax]

[edit]

<<text removed>>

I just noticed that the diameters of the windlass need to be different for each rope in order for the weight to drop.

...

I found that if the weight was on the larger cylinder and this cylinder was directly connected (no gearing or such) to the smaller cylinder (the smaller has the rope to the sealing), that the weight does only drop a little, while the cilinder is moving upwards fast.

*hate it when things are not as obvious as they appear to be*

[/edit]

I should have thought of that. We used to have a chainfall hoist which used a similar principle.

I am wondering if weight could be an issue here, though – how much heavier than the toilet-roll does the counterweight have to be to make it work, and how much weight must you add to the toilet-roll to make it come back down?

(I wish I weren't 250 km from my workshop right now!)

[tsjaikdus]

Quick sample during brake from work (hope it is correct)

Imagine:
Big cilinder (weight attached) has circumference 100
Small cilinder (cord to ceiling) has circumference 75

Then:
If the cilinder rotates 360 degrees, then the cilinder's center point (or platform) is pulled up 75

At the same time the big cilinder unwinds 100 and is also pulled up 75, so the weight drops a distance 100-75 = 25

As the total weight of the system must go down in order for it to work, the weight W must be at least 75/25 = 3 times the weight of the platform (in case no pullies are used that is).