(No really, thank you! This is great)
"This movement is designed to double the speed by gears of equal diameters and numbers of teeth—a result once generally supposed to be impossible. Six bevel-gears are employed..."
Mechanical analog computers, especially gun predictors, had lots of setups like that.
Educational videos today tend to go to one of two extremes. Either they're a talking head with PowerPoint, like most of the "massively online" courses. Or they have way too many jump cuts, like theatrical movies which want your attention, not your understanding.
There's also an annoying tendency to have distracting music and irrelevant graphics during narration.
Here's an old Jam Handy film, "Spinning Levers", on how a transmission works. There's a whole series of these Chevrolet films on the Internet Archive, covering major vehicle systems. Things to note:
- There's a narrator and a demonstrator. We never see the narrator, and the demonstrator never talks. So the viewer can focus.
- The demo models of parts are really good. They start with a simple version and add features until a full transmission has been built up.
- There's some simple animation. Animation is used to point out how power flows through the gears. This is much clearer than someone using a pointer.
- The editing and narration are very well synchronized.
- There's an entertaining part at the beginning and end, so you don't feel like they're beating you over the head with the boring stuff.
So I guess I should extend my original statement to the 1930s-1970s range.
Note that Shaft F and shaft D are made to rotate in opposite directions.
Then another gear is made to pit those motions against each other, by means of that wacky rotating frame A.
To see why let’s unwrap it from a polar coordinate to something more linear.
Imagine a wheel with gears resting on a rail with teeth. The wheel has an axle going through it. If you drag the wheel’s axle forward horizontally that’s like what Frame A does to impart 1x rotation. But then the rail is also moving backwards, giving you 2x rotation.
The two shafts are coaxial to each other and drive their corresponding gears in opposite directions. The frame is fixed relative to one shaft but mobile relative to the other, which is where the extra 1/2 of relative motion comes from.
The traditional way to do this was with a crossed belt. This is the higher-friction lower-slippage version of that.
But then the gear LeftC is making D rotate around the circumference of E i.e. changing the teeth of E and teeth of D which are in contact. Since this is in the same direction as above, you get 2x speed.
Essentially imaging you sitting on the edge of a plate. E is making the whole plate spin. And leftC is making you run around the circumference of the plate in the same direction as the direction of rotation. So your angular speed becomes twice as much as the speed of the plate.
Thanks for sharing!
The modern way to achieve any kind of complex mechanical motion is to attach a servo to the thing and use a computer to set a motion profile.
A bit of a shame really.
For example, I predict the increasingly suffocating digital zeitgeist will give rise to a form of competition which would be the mechanist's version of a demo scene.
People will compete to "hack" non-digital mechanics as far as they can go, from analog sensors to mobile, programmable, multi-function automatons such as Theo Jansen's Strandbeests .
Resources like this, even if their maintainers have long gone, will become coveted gold mines.
I expect the same thing to happen to ICE automobiles. To become luxury/jewellery pieces.
So-called "Tourbillon" escapements, for instance:
Fantastic (and expensive) works of mechanical movement art, but it goes well beyond this.
Some "watches" (the fanciest ones aren't really wearable, but could be considered "portable") contain an amazing number of various mechanical functions and movements (called "complications"), of utter insane complexity:
Similar such works are done in the clock space as well.
I wish I had the wealth to be able to afford such a piece (then again, if I did, I'd probably have a 3rd iteration of the Difference Engine commissioned first - sigh).
I think it's not just that. The internet allows niche hobbies to thrive where previously they would die out, because it makes it easier for people to find peers who are into the same thing. Hence it's easier to maintain the minimum required "population" for a subculture to "survive". The people involved are just dispersed across the planet.
Possibly. He was a "robotics engineer" of sorts:
He quite possibly invented a mechanical calculator:
So I could see him continue explorations of that nature.
> And would his contributions have the same impact?
Aside from his art, and possibly the various engineering commissions or consultations he was involved in - what was in his notebooks didn't see the light of day until long, long after his death. They were essentially "lost" until rediscovered much later. While he was alive, they were probably only seen by himself, and/or maybe a few students (speculating).
On the art side alone, though - would his works have the same impact? That's difficult to say. If they were collected, preserved, and viewed by their owners properly.
I don't know this for certain, but my guess is that most of the artwork of people like LDV of that era, their art were all private commissions, for the most part, outside of a very few pieces that were "publically viewable" - for various terms of "public". Those private commissions would have only been viewed by their owners, family, and maybe a few friends or acquaintances. Outside of those, the works would not have been public, until far later, as they were sold or otherwise "moved around" in the marketplace. Their value would increase or decrease almost at a whim, but also depending on how known the artist was, and other works by the artist. What we see today of these artists is probably mostly survivor bias. There's a good chance that there were others out there of a similar note who just didn't make it because of various reasons (along with a whole host of others who weren't as good, and their art - mediocre or whatnot as it may have been - became "trash" and didn't get passed down to us, but was thrown away over time).
So - if such digital works were created - in 500 years or so, if the work was preserved (migrated from media to media, from machine to "machine", platform to platform) - it's quite possible they would have the same impact - after enough time passed (and everything else being the same).
Pure speculation, of course...
It's a signal / noise ratio.
Back then there was less noise. Today there is such a high ratio of noise that you have to wonder if the geniuses like Newton, Da Vinci, Einstein, etc. would have found a platform and similar level of exposure today, through modern means of communication like YouTube and podcasts.
You have to wonder what disciplines they would have chosen, what their acute insight would have to offer to the modern frontiers of physics, medicine, biology, computer engineering, etc.
Two identical gears start moving at the same speed. Suddenly, one gear slows down, then lurches forward at a much faster speed, and then returns to its starting speed.
While the other, identically shaped gear, spins at a constant speed the whole time.
This behavior can be seen a bit more clearly with nautilus gears that have constantly changing radii.
The blue one is being entirely driven by the red. It slows down because moving 2 notches at a greater diameter requires less rotation than moving 2 notches at a lesser diameter. It then speeds up because moving 3 notches at a lesser diameter requires more rotation than moving 3 at a greater diameter.
I'd love to get into watch building which likely utilizes a lot of these tricky movements.
By adjusting the distance from the center the ratio can be changed. Closer to the center on the driving cog (the left red one) will reduce rotation ratio and further away, will increase the rotation.
In this animation, the author decided that the left gear is driving the right one (while itself, presumably, being driven by a motor at constant speed or something similar).
Came up with a few tantalizing geometries but would always find a problem after thinking it through.
Makes me wonder how many if these were deveoped under similarly mindless activities. Also makes me wonder what a genetic algorithm or ML-based optimization/search algorithm could find.
I’m no expert, but I understand that there is no closed method for determining viable overconstrained sets past 4. So the research has a large amount of analytical/exploratory research. Very active field:
I believe the term is "positive engagement". And yeah, it's such a shame that all practical CVT's are friction based!
There is some information about ratcheting CVTs (and CVTs in general) here , although the page looks a bit sketchy. From what I've seen, they are not very practical or widely used. Maybe there is a niche where their capabilities and drawbacks are a good fit but I have not come across it.
One thing to keep in mind is that these days it's not hard to beat (both on price and power/torque capabilities) sophisticated transmission mechanism (meaning - expensive and containing many fragile mechanical parts) by simply using a larger electric motor with variable speed control and fixed gearing. Torque output at low speeds (which would be the advantage of CVT) is going to be limited by mechanical design and weight constraints of the transmission mechanism.
 - https://en.wikipedia.org/wiki/Continuously_variable_transmis...
This is basically how the pantarouter by Matthias Wandel  works:
Or take a look at this weird engine:
I am a bit nostalgic/sad about the fact that many young people who would've wanted to learn this craft a century ago are today choosing software engineering.
Like this video about number 049, a crank that only turns clockwise: https://youtu.be/y44_xMFsPQQ
> The piston and crank connections are such that the steam acts on each piston during about two-thirds of the revolution of the crank, and hence there are no dead points.
Quite a clever solution to allow startup in any position!
Some do have "names" (most don't), but you have to go to the movement itself to see it:
This one is common, and known as the "Geneva Mechanism" or "Geneva Stop":
The actual book the animated site is based on:
...the index (table of contents) references them by name.
> In þe firſte made God of nouȝt heuene and erþe. Þe erþe forſoþe was veyn wiþ ynne and void, and derkneſſis weren vpon þe face of þe ſee; and þe ſpiryt of God was born vpon þe watrys. And God ſeide, Be maad liȝt; and maad is liȝt.
NIV Bible (20th century):
> In the beginning God created the heavens and the earth. 2 Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters. And God said, “Let there be light,” and there was light.
Also, interesting to see the old letters of Cyrillic, so thank you for the links.
> use "old", or "antique"
Yes, thanks! I knew the precise meaning of "ancient" (it is like in "Ancient Greece" or "Ancient Egypt", it is about times that were really different), it seems as an exaggeration, but thought that "old" is not specific enough and "antique" didn't came into my mind. At the same exaggeration is a valid literacy device.
Thank you, for pointing at that. I really appreciate that, because I feel that my English is not perfect, and the lack of feedback in internet conversations doesn't allow me to improve it.
Another good programmable mechanism is a spring made from sheet metal. Take a flat piece and cut a spiral with the width of the material proportional to the force you want at that part of the spring's travel. Stretch it out to form a little tower, with the base on a solid surface, and the load carried on the center of the spiral.
Arthur Ganson has used that to make kinetic artworks:
Years ago there was a website called "smallparts.com" but this was bought out and no longer exists.
And SmallParts I think is now Amazon Supply or something, but dear god would I not trust Amazon for that sort of purchase. Especially PPE like allegedly 3M respirators. Who knows how much of this is counterfeit.
Sadly they were acquired by Amazon and effectively ruined. In theory Amazon sells the same parts but Amazon's search for specialized parts is dreadful, and when you find a part it's often out of stock or available with a long lead time from a dubious supplier.
To me Small Parts is the classic example of how Amazon is systematically stamping out smaller but better suppliers. I'm not sure why Amazon even needed to acquire them. They could have sold those types of parts anyway. I wonder if they simply wanted the smallparts.com url, which now leads to Amazon.
I should clarify why I liked Small Parts vs McMaster Carr: I'm in Canada and Small Parts would ship to Canada, but McMaster Carr would not ship here unless you had a business, but my work was for a hobby.
Later I discovered that they provide CAD drawings for everything they carry. That was immensely helpful when designing things in say, Solidworks. If there were some screws that were called for it only took a visit to McMaster-Carr to get a 3D version of the real part.
Amazon Supply is pretty useless, and Small parts was never really great either.
For random stuff, surplus shed is also fun to browse.
He explains how he did those animations:
Which was rather laborious; perhaps his CAD and programming knowledge made it so that creating a physical animation engine was easier than other methods?
Regardless, I wish he'd open source it; he mentions that he might - but it's been a few years now, so...
"Power as 1 to 7". I don't think so: the cable's tension is paralleled six ways against the load, so 6 times the force.
The rope is a line along the side closest to the pulley, the other side of it // the wire pattern are made by attaching triangle(-ish?) shapes to it. Only the bend at the smallest pulley is so tight it shows.
They are contemporary with similar books on "electrical machinery" (generators and motors, mainly), "steam engineering", "home and farm improvements/implements", and many other similar subjects.
Some were aimed at the professional engineer, while others were meant or accessible to the ordinary person with such interests or needs.
I enjoy discovering and adding these books to my collection when I can find them at used and antiquarian bookstores.
Mechanisms and Mechanical Devices Sourcebook
But a lot of the more basic mechanical movements could be easily constructed; those with simple pulleys, gears, levers, etc.
So you might not be able to construct all of them, but you probably could construct a great many.
When only important shit you really wanted to encrypt was encrypted and you get a cert warning you took notice. Now one in 10 sites with an "easy/free ssl cert" that expired has normalized cert warnings on pages with cat pictures and bank sites alike.