Did Bessler use strings and cords?

[jim_mich]

Bessler worked with pipe organs. Pipe organs required air valves to be opened and closed when each key was pressed. Some keys connected by means of rods and levers while many keys connected by means of strings and cords that pulled valves open. Springs usually closed the valves when the keys were released.

Knowing this background my question is, "How likely do you think Bessler used strings or cords in his wheel?

Why is it that many wheel designs DON'T use strings or cords?

[ovyyus]

Jim, this has to be the most difficult poll on the forum. My opinion is that strings and cords are prone to stretching (and wear) from both prolonged use and weather/humidity factors. I think that if Bessler used cords inside his wheel then it's more likely that they didn't serve a function which required critical tensions and/or lengths. I guessed that the possibility is less than 20% - but who can really know?

[Michael]

I think it's possible and probable if you take into account his statement that with pulley's he can toss wagners calculations out the window, and his statement that the machine was so well designed it could be worked on while it ran might also lend credit to this. What is easier than repairing a snapped cord, or snapping a cord and refitting it.

[jim_mich]

Bill, I see your point. But what if the lengths of the strings or cords weren't real critical. Suppose the only critical part is that all strings/cords be about the same length? In that case if they all were to stretch and wear, expand or contract equally then the wheel would continue to function.

[Michael]

Bessler goes to lengths to talk about materials being subject to wear and tear you can find this in johns third book. He also talks of the need to repair his own wheels. The question of strings and cords, as you say Bill who knows.

[ovyyus]

That's a good point Jim. After further consideration I might be tempted to change my vote to 50-50.

However, I think the principle at work inside Bessler's wheel was probably not critically reliant upon the use of string or cord - surely the principle could have many different mechanical expressions?

[jim_mich]

Whenever you have parts that move you have to contend with momentum. Sure the weights must move, but do the interconnecting components contribute anything by moving or do they hinder. The main reason to use strings and cords in an organ is to efficiently transfer movement to a distant location. The less mass that needs to be moved in between the better.

Suppose a weight at the bottom moves downward and needs move a weight on the far side of the wheel upward. A rigid connection such as a rod would need to be accelerated then decelerated during the movement. On the other hand a string or cord passing over pulleys could accomplish the same thing with very little momentum involved.

[ken_behrendt]

I voted for 90% to 100% probability that Bessler used ropes or cords inside his wheels and, as anybody who's following my ongoing research over in the Community Buzz forum will know, I've adopted the use of "catgut" lines and pulleys into my recent (last several months) designs.

When the interior space within a gravity wheel is at a premium, it only makes sense to go to some very compact method of transferring forces from one section of the drum to another. Ropes or cords moving over pulleys can easily fulfill this requirement.

However, we all seem to want to believe that actual pulleys would be used inside of his wheels. Most likely, this stems from the few actual pulleys that appear in the Bessler illustrations and textual references to them.

Why not a slightly different approach? For example, instead of using a turning pulley wheel to support a moving rope or cord, how about simple using a large radius circular guide? The guide would be stationary, but the rope or cord that wrapped around a groove or recess in its circumference would be greased so that it could slip back and forth over the guide. This method would seem to be acceptable assuming that the rope only moved back and forth a few inches during each wheel rotation. The lubrication would protect the rope from fraying during the process.

Of course, even with this approach, over time, with dissipation of the lubricating grease, the rope would begin to wear and, when it snapped, the weight whose shifting it controlled would be pulled into into its "neutral" position and taken out of action so that it would no longer contribute to the full weight array's offset CG.

How Bessler might do "repairs" on such a system while it was in motion is beyond me. Perhaps the word that is translated as "repairs" was mistranslated. Perhaps it should have been translated as "adjustments" which make more sense to me and could be possible, to some extent, for a wheel in rapid rotation.


ken

[barksalot]

IMO no cords or strings. the durability factor keeps me from considering them. I vote less than 10 percent.

[Joel Wright]

Hi Jim Do you consider the stiff wire I'm using for linkages string?If not then no.I voted as low a probability as you allow.8^D

[pstroud]

I'm doing physican wheel testing every other night. Based on my test resultes, there is a high probability that cords and strings were used. I'm observing the benefits and disadvantages of both strings and springs. They each have their place that must be respected for the results they can bring to a wheel.

Preston.

[rlortie]

I do not think any cords or pulleys were used, I believe his remark about cords and pulleys were the ones lifting the box of bricks.

To repair a machine while running that calls for threading a rope or string through a moving pulley and then attaching it seems a little improbable to me.

He said that his machine would barely turn with one lever and that the weights were in pairs. It would be a lot easier to reach into a running wheel and remove one set of levered weights and fix it then put it back in place.

I wish to meet the person who could thread a string through a pulley and tie a square not in it inside a 26 rpm 10 foot wheel without impeding its operation.

Ralph

[John Collins]

I don't think Bessler used strings or cords. The 54 day test would surely have tested such a system to destruction. Rough calculations at 26rpm gives 2,021,760 turns and I'm sure someone can come up with the amount of wear and tear such a test would do to hemp, leather, cord etc.

John Collins

[AgingYoung]

John,

Rope moving thru pulleys wouldn't have that amount of wear. Also the rope might not have had that much travel. I think there's 100% chance Bessler used rope.

Gene

[John Collins]

I agree that there would be less wear using pulleys, Gene, but shorter travel would actually be the same as longer travel in terms of wear; just a smaller area of wear, but still potentially critical. I'm unconvinced that rope was used - I don't think it was necessary as I believe other mechanical methods could achieve the same result.

It seems to me that the use of rope might be a weak point in construction with the possibility of wear leading to a break and of course stretching might also lead to malfunction.

John Collins