Posted by Joe Courage (216.164.86.144) on December 07, 2002 at 10:40:59:
Scott, sorry for the delay in getting back to you. Thank you very much for your questions. I have not been keeping up with everything on the discussion board, but I will try to reply in a timely manner from now on. For those of you who haven't seen my previous post, you can check out "This Is How It Works - Part Two" which I sent earlier this year.
I am not sure if I understand your first question, but I will try my best. It is not always the easiest thing to successfully communicate something. It can possibly be taken two or three different ways by the readers. But, we shall overcome.
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Your first point:
"If the lever is allowed to freefall, so the weight on the end moves faster than the rim of the wheel, then it must necessarily move closer to the axis as it falls than the weight directly across from it. To me, that means that it will not be able to do any lifting at all."
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The outer end of the lever does travel quite a bit and you are absolutely right when you noticed that at certain parts of its trip its distance from the axis gets closer, although it is just a little bit. That is because it h-a-s to. There is no way it could work if it didn't.
If you visualized my previous description the way I was hoping, you would have noticed that it is supposed to do this. But no problem. My fault for not being clear enough! I will try harder.
If you will, please go back to the descriptions of the square spindle and notice how its levers are attached by their hinges. The levers do not rotate at the center of the wheel, but each lever instead rotates at each corner of the square spindle, using its own hinge.
If this is still hard to visualize, no problem - you can understand it by observing the whole wheel mechanism from one side, looking at a cross-section of the spindle (on paper). To do this, take a ruler and draw a square at the dead center of a large circle on a piece of paper, perhaps about 8 1/2 x 11, making the sides of the square the same size as the height of the ruler, or about 1 1/4 inches. You can make an instant circle real quick and easy by turning over a dinner plate on the paper and then draw the circle using the rim of the plate. Use a short ruler as an imaginary lever and hold it vertically with its lower left corner touching the little square's lower right corner. Slowly and very carefully rotate the ruler as though it was connected by a pin to the corner of the square, and you can observe it becoming noticeably closer to the rim as it goes through its 180 degree turn. Understand now? [I wonder if this has something to do with the "over-balanced wheel" expression I keep noticing once in a while?]
You will see that the lever's outer end will not be as close to the rim when it is just beginning to fall as after it completes its mission and butts up against the side of the spindle at a right angle, after it swings for about 180 degrees. (. . . This equates to the bottom of the ruler (the lever) coming flush with the bottom of the square, i.e., the spindle). Of course, the whole wheel is moving, too, so the swing may be considered by some as more than a 180, depending on how you wish to count it. The levers can be wed as being very independent from one another and the rest of the wheel as to when they stop or slow down or go fast. This is o.k. because they all take their turn in going through each phase of their journey around the spindle. They all hit the spindle one right after the other, each in their own turn, programmed according to the way the machine was built, although the offset sections "meshed" with each other. Any questions, please ask.
By the way, if you have read the expression "weights twirling around an axis" or similar words attributed to eyewitnesses, they just LOOKED that way. The weights did not actually "twirl" completely around, but about half-way. Then they were taken by the pawls o
second question:
"I also don't understand your description of the levers, with 2 horizontal, and 2 vertical (in a cross). How can they ever achieve this position if they are hinged as you describe?"
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Scott, good catch on this one! You are absolutely right - they would never achieve this postured look in real life. This description is an overly-polite juxtaposed layout of the four levers, kinda like a reference during assembly - like a wax banana. In a real-life rotating wheel, the only way they could ever be seen like this would be to stop the wheel and have them moved by hand and held in position. And of course this would serve no purpose. Normally, the levers are hinged to and constantly twirl around the axis, which we can describe as an imaginary length-wise line passing through the center of the square-sided spindle.
This means that only one lever at any one time would be in a perfectly closed butted position (the position of impact) at its inner end with one of the sides of the spindle at its assigned location along the length of the spindle; the outer ends of the other levers would be spread out along the circumference of the wheel according to the various phases of their journey around the spindle.
And even the lever in the "power" position would be lined up in the "closed" or "butted" position with the spindle only for an instant. The more levers a wheel has, the shorter the instant, but it would still have the same amount of clout for each lever.
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Bessler made his newer wheels larger by simply making the levers longer and everything else more brawny, which was a whole lot simpler and quicker for him to do than laboriously building a longer offset spindle which could accept more sets of levers. It would have been MUCH more difficult back then for one man to do all this. It should be a breeze using today's tools and procedures compared with Mr. Bessler's simple tools and bare hands.
The inner ends of the other three levers, if you unleash your imagination a little bit as to how they relate to the spindle at the point where they are attached by a strap hinge, first resemble a wide-open "mouth" cartoon (like PacMan?) during the moment in time that they start to gather speed after passing over the top of the wheel (the 360 degree or zero mark), then as they start to drop and go faster and faster, the "mouth" would appear to be about half open. Then as the wheel and each of the levers move along, each "mouth" finally completely closes in turn at the instant of impact, which is the impact of the butt end of the lever with one of the turning sides of the spindle. The inner end of the lever (the two by three) with the strap hinge bolted to it has only a few inches of "travel" while it is open, because it is attached to a corner of the spindle by a hinge. Half the hinge is bolted to the spindle; the other half is bolted to the lever. You can see how the awesome dynamics of centrifugal force play such a critical role in keeping everything twirling along in such a powerful manner.
One minor note regarding pawls is that there is a choice as to where to attach them; either on the "pickup" area of the wheel (the outer rim) or to the weight at the outer end of the lever itself, whichever seems easier; it's not a biggy. The pawl's general location remains the same since it does the same catching function.
Also, the pawl method is definitely not the only way to take care this particular function of the wheel's operation. It is relatively unimportant in the scheme of things when compared to the brilliant principal design he used to power the wheel's axis. He probably used a different way to bring the levers to the top after they had applied their power to the spindle. This was the only "quick and dirty" way that immediately came to my mind that I could figure out with the least amount of sweat and still feel comfortable with. There definitely are others.
Each lever's p
questions, just some writers like this one who is finding out how challenging it can be to transmit an understandable presentation, even when the principle is simplicity itself which you will keep finding out as we go forward. I see where I could have sent more details, so I will give it my best. I plead guilty to Murphy's Law. :-)
Joe