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- Hacker News
- What is the purpose of using bearings to build a crank mechanism as in 39? https://507movements.com/mm_039.html
Maybe it's for bearing efficiency? Note that the spur gears are rigidly attached to, respectively, the crank and the shaft. So they don't require bearings at their centres. There is a link arm which pulls the gears together, and that rotates. But the key is that this arm is not transmitting the cranking power; it just holds the parts together. So its bushings/bearings don't have to be so hefty. (Their load is going to be proportional to the transmitted power; obviously the bigger the crank and more horsepower going through it, the more tightly you have to hold the gears together. But it's going to be some fraction compared to a bearing that is directly driven.)
The note only alludes to this mechanism being used to elude a patent claim, not mentioning any advantages. Someone had patented cranks in such a way that you can weasel your way out with this arrangement. I'm guessing that the patent's drawings and descriptions specifically indicated a rotating bushing on the crank wheel where the arm is attached, and this has no such arm attachment.
by kazinator - Slightly relevant, I built https://mechanisms.ln.gy/ a little while ago
Indexed and filterable index of over 4000 visualised mechanisms by thang010146 on YouTube
by hansihe - Plugging a yt channel that posts lots of these sort of models:by agrue
- Past discussions:
https://news.ycombinator.com/item?id=10374436, 27 comments 11 years ago.
https://news.ycombinator.com/item?id=26373539, 30 comments 5 years ago.
by mkl - Two more great books to have in the mechanical world:
"Manufacturing Processes for Design Professionals" - amazing photos, diagrams, explanations, etc. of every major manufacturing process - great coffee table book.
https://www.amazon.com/Manufacturing-Processes-Design-Profes...
"Materials Selection in Mechanical Design" - great book with "Ashby Charts" that let you compare materials against their material properties - e.g. strength vs. weight.
by nickpinkston - If you ever happened to go through Karlsruhe, Germany, there is a collection of mechanical transmission models from Redtenbacher. Some models were on display in the mechanical engineering building at the university.
I could only find this link (in German) about the collection. https://redtenbachersteyr.com/redtenbacher-in-karlsruhe/
One student from Redtenbacher was Reuleaux and there is another collection of transmission from Reuleaux at Cornell university. https://engineering.library.cornell.edu/kmoddl/
by hommelix - One of my favourite sites! and an interesting example of that class of sites which are book made into sites with animations/interaction --- the another classic and notable example is:
https://mathcs.clarku.edu/~djoyce/java/elements/elements.htm...
Really wish that the folks doing the 507 Mechanical Movements would finish the balance of the animations.
Curious if folks are aware of other similar text/website combinations which are still extant (many others such as Bembo's Zoo are no longer available, and of course at one point in time, this sort of thing was the province of CD-ROMs such as Leonardo).
by WillAdams - It's a great collection and exploring it is fun, but it misses on titles / names of the given linkage or movement. It makes sense when you are reading the book [0], but on a site like this where you see the individual item in isolation, a title or name would be helpful.by wowczarek