I had an idea about the above comment of Bessler's while considering something unrelated to it. My current build has one mechanism and I was considering how, in a future build, I would fit five mechanisms onto the face of the wheel and realised that it would be easier use the other side or face of the wheel as well. Then I fell to wondering if that's how Bessler did it.
I have always assumed that his wheel consisted of two discs firmly connected together with all the mechanisms installed between them, but in fact it would be much easier to build the whole thing on a single disc, using each side. This would explain the need to cover the two faces of the wheel with oil cloth. I thought it strange how the reports described the look of the wheel and could not see why he needed oilcloth to cover the sides, if two discs were underneath and therefore covering the insides. But in fact a simple frame attached to the single central disc would suffice to support the oilcloth, or the thin deals described in another report.
Then we come to the above quote; the word used for 'rims' is 'Felgen'. There is no other possible translation, however 'rims', these days, in relation to wheels are the outer edges of a wheel, holding the tire (tyre). They make up the outer circular design of the wheel on which the inside edge of the tire/tyre is mounted. Before rubber was invented, the first versions of tires were simply bands of iron that fitted around wooden wheels to prevent wear and tear. In the 1st millennium BC an iron rim was introduced around the wooden wheels of chariots.
So when Bessler says it looks like a wheel but it has no rim, he means that it can be described as a wheel but it wouldn't be any use as one because it has no rim or tire/tyre.
Note - Apparently the word 'rim' relates to Old Norse, 'rime, rimi, a raised strip of land, ridge'.
And from the online etymylogical dictionary - 'tire (n.) late 15c., "iron rim of a carriage wheel," probably from tire "equipment, dress, covering" (c.1300), a shortened form of attire. The notion is of the tire as the dressing of the wheel. The original spelling was tyre, which had shifted to tire in 17c.-18c., but since early 19c. tyre has been revived in Great Britain and become standard there. Rubber ones, for bicycles (later automobiles) are from 1870s.
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Yes, use both sides like the idea I put on bessler wheel.com two weeks ago.
ReplyDeleteAxel
John,
ReplyDeletedid Bessler do the wheel drawings himself ?
They look like they're built like medieval seige engines to me.
Yes he definitely did his own drawings, and they do look kind of robust!
ReplyDeleteJC
I've also played with this, my first builds used a plastic turntable off an cheap old record player, and, if you're using a wheel as a base then this is a good use of space.
ReplyDeleteI believe Bessler however was building from the axle outwards, and so would handle depth by lengthening the axle and offsetting the spoke holes in a spiraling pattern around its surface (as per the adjoining figure in MT66).
However it's handled though, the wheel obviously has/had a depth element. The bigger question i think is was it incidental, or functional (ie. did the mechanism depend upon motions in the axial plane)? MT41 would seem to strongly suggest so..
Another possibility i saw in this cryptic statement was that perhaps the underlying shape of the rim wasn't 'normal' - perhaps not square in the axial plane, or perhaps undulated or even actively undulating (say, if surrounded by a belt or tyre of some kind, that flexes radially). Or perhaps the natural underlying shape of the rim wasn't strictly circular, but elliptical or some form of polygon..
Evidently though the outer, visible rim WAS circular, axially square (ie. equal diameter on either face), and ostensibly normal in every respect, by all accounts (or lack thereof of any independent observation to the contrary).
It's just one of the many paradoxes involved. Another that bugs me is the apparent discrepancy between "on one side it is empty and light, the other heavy and full, just as it should be" vs "as one weight gives an upwards impetus (itself an intriguing description), another, at the same time, is giving an equal downwards one"... these two description can only be reconciled if both the upwards and downwards-acting weights are positioned on the same, 'heavy', side of the wheel at the same time..
Usually, resolving paradoxes is a great way to make headway on a problem. Such solutions can provide a tractable 'edge' to an otherwise intractable jigsaw. Here however the overall image just gets more ambiguous...
My best guess ATM for what this jigsaw depicts is that the shifter-weights are attached around and close to the axle, and the OB weights are out by the rim. They're possibly connected inversely, ie. left shifter weight to right OB weight, via chords running through the axle. At least, the numerous holes the axle is said to be 'punctured all over' with either accommodate chords, or fixed or slide-thru spokes. As for its additional 'many compartments', i've toyed with stowing weights in the axle, thus temporarily 'removing' them from the mechanism (ingenious eh?), only to hit the same old wall of being unable to reset and complete a cycle. So no easy exploit to be had there, apparently.
Still, these hints seem to convey that the axle forms the backbone of the mechanism..
@Vibrator,
Deletejust in case you missed it, try some M5 bolts in your Meccano scissor jack, I don't know about the newer sets, but they used to be 2BA size, metric is a bit bigger.
Take a piece with you to the pound shop (dollar store ? ), and try some from the cheap selection boxes.
Another idea is to wrap a strand of copper wire around the last couple of threads to pad it out a bit, it should stay in place long enough for a few tests.
A piece from a foil tray may work as well, or even a strip from a beer/soda can.
Excellent suggestions, thank you. However there's diminishing returns between tightening the tolerances and so increasing friction, at least with dry (non-roller bearing) pivots.
DeleteThis is why i think a WM2D model would be superior in this case, since it can entirely circumvent friction, and also the jack's own mass, to boot (obviating the need to counterbalance that aspect). This really cleans up the problem and gives an accurate comparison of input-to-output forces and distances.
Still, i'll take your advice and take a small piece of Meccano to work tomorrow, and pop into a few HW stores when i get the chance... good thinking!
Things seem to have become quiet here...
ReplyDeleteI have been working mostly with simulations lately - some work, some don't - I am still trying to nail down the conditions needed for reliably forecasting what will work (in sims and in real life), and finding that somewhat trying at times.
Recently I came across a nice simple simulation on youtube, it also has a link to download the WM2D simulation.
http://www.youtube.com/watch?v=XhH4QPqTNe8
It's quiet Mimi, true, and yet the viewing figures are holding up. I think we've lost so many of the anons since I introduced signing in, that the number of comments has dropped a lot - and yet it seems as if people are still interested in reading what is written here.
DeleteJC
Thanks John! Glad to hear that viewing is still holding up.
DeleteAfter I found the link to the simulation yesterday a found other ones, some of them are really beautiful, real works of art.
See here: http://www.youtube.com/channel/UCl87npOKeL8s9D1aJ3qJ7eA
Yes John, Mimi,
Deletequality, not quantity!
I'm still here John,..busy building and very optimistic as usual.
ReplyDeleteI definitely think Bessler built his wheel in layers.
The most I can squeeze into one layer is four weights(two sets).
The mechanism is so symetrical that the same mechanism will work both ways.
Should not be long now! LOL.
Good Trevor, never back down.
DeleteSame here.