8 ms·
Fist-sized 11M-to-1 gearbox
- yiyus 11y ago> We live in a world where an idea that does something that has never been done before can be built at home and shared without cost [...], all without it having any use or any place in the market. Outside of art, that is something we did not have a few years ago. I do not agree with this idea. Many inventions have been driven by curiosity. People playing with magnets or 8 bits computers were not trying to solve any market problem. Even physics were developed by simple people sharing curious "unuseful" experiments for centuries.
- weego 11y agoIf anything, individuals seem to have stopped inventing/investigating. It used to be that persons of means would use their means in the pursuit of some expansion of their knowledge. Now it's in pursuit of more means.
- sophacles 11y agoI don't know about this - one of the things I like to do when I travel is visit the local hackerspace. I've been to quite a few of them around the country, and they all seem to be full of wonderful people exploring and inventing for the fun of it.
- knodi123 11y agoThis is a common historical fallacy. Like "It used to be that Greeks would sit around inventing geometry, philosophy, and democracy. Now they just ruin banks." There were always both kinds of people, and the inventors who are driven by the love of science and learning have always been a minority. It's just that the people who only care about personal wealth rarely make it into history books, whereas the iconoclastic scientists frequently do. And the same is true today.
- edanm 11y ago"It's just that the people who only care about personal wealth rarely make it into history books, whereas the iconoclastic scientists frequently do." Arguably even this isn't true - Many people know the name of, say, Archimedes and Newton, but I doubt it's more than the people who know Julius Caesar and Genghis Khan. Might be close though.
- knodi123 11y agoWhat I'm trying to say is, what percentage of people can name a couple of great thinkers from the classical era? Now compare that to the percentage of people who can name a wealthy merchant or banker from the same period.
- Semiapies 11y agoEvery generation thinks it invented sex, rebellion, and curiosity.
- ethbro 11y agoThat's because these things seem to have an inverse relationship with age. (Not a flame! I feel like statistically speaking, probably true for the majority. Thankfully, there's a minority that shines even brighter with age)
- oldmanjay 11y agoYou aren't wrong about the sentiment, but parsimoniously the cause is that youth is callow
- struppi 11y agoGune: [holding up a small device] Does this look familiar? Do you know what it is? Neither do I. I made it last night in my sleep. Apparently I used Gindrogac. Highly unstable. Preed: Gune... Gune: I put at button on it. Yes. I wish to press it, but I'm not sure what will happen if I do. http://www.imdb.com/title/tt0120913/ http://www.imdb.com/title/tt0120913/ Seriously, this is a cool device. And I have no idea what I could use it for...
- LoSboccacc 11y agoI wonder what's the highest torque it can sustain without breaking. That will in turn severely limit applications because with that demultiplocation little torque will be huge at the other end.
- mjlangiii 11y agoThe article points out issues with this exact implementation at an 11M:1 gear ratio but begs the question whether a less extreme ratio using "grinder" gears has any application or not. Regardless, the conclusion about new innovations at the end of the article was exciting/encouraging to read.
- urschrei 11y agoThe application is obvious: DIY "Machine with Concrete" (http://makezine.com/2012/04/25/arthur-gansons-machine-with-concrete/ http://makezine.com/2012/04/25/arthur-gansons-machine-with-c...) kits. I'm sure Arthur Ganson won't mind.
- jacquesm 11y agoReally neat, thank you!
- deleted 11y ago[deleted]
- kokey 11y agoWill this also work as a 1 to 11M gearbox? If so it might allow a strong force (e.g. the weight of a large body of water) to spin a small electric generator. That will allow small scale hydroelectric storage for renewable sources. If not it can probably still find some applications for turning something like weak wind power into something that can create great pressure.
- furyg3 11y agoI know nothing about this, but I would imagine that this gearbox would need to be made out of some other-worldly material in order to cope with the force necessary to drive it in reverse
- nraynaud 11y agoI'm pretty sure it's already potentially self destructive if there is any snag in the output.
- nraynaud 11y agonope, cycloidal drives can't be backdriven because of the eccentric part, the friction is higher than the driving force for geometry reasons.
- Kenji 11y agoNo, it cannot. As you can see in this video from the site where he explains the mechanism: https://www.youtube.com/embed/vbU1afvCRwc?version=3&rel=1&fs=1&showsearch=0&showinfo=1&iv_load_policy=1&wmode=transparent&enablejsapi=1 https://www.youtube.com/embed/vbU1afvCRwc?version=3&rel=1&fs... When he tries to move the red ring against the green ring (at 2:39), the thing doesn't budge. The gearbox concatenates two such transmissions, therefore, it cannot be operated backwards.
- melloclello 11y agoI feel like it could be used to construct mechanical calendars.
- yummybear 11y agoPrecision could be an issue according to the faq.
- new1234567 11y agoThe article mentions slippage, grinding, play, noise and vibration. These are generally undesirable in machinery. Slippage and grinding suggest significant problems with wear and durability. That would limit the lifespan of the gearbox. It's still pretty cool and could be very useful. That doesn't mean there aren't useful applications. It just means there are design tradeoffs.
- cgearhart 11y agoIt looks like a pretty rudimentary prototype. Many of those issues are addressed with better manufacturing tolerances, different materials, and tooth profiles. I'm not sure those features are inherent limitations as much as drawbacks to the prototype implementation.
- jonjenk 11y agoWhat you are describing is called "backdriving" the gearbox. Generally speaking, gear trains with high reduction ratios don't like to be backdriven. Small steel gear trains with ratios in the 1000:1 range can destroy themselves when back driven.
- kcorbitt 11y agoThe Space Needle's spinning top level is powered by a 1.5hp motor[1] at a gear ratio of 360,000:1 [2]. It makes one complete rotation every 47 minutes. [1] https://en.wikipedia.org/wiki/Space_Needle https://en.wikipedia.org/wiki/Space_Needle [2] https://books.google.co.uk/books?id=Jox4CAAAQBAJ&pg=PT262&lpg=PT262&dq=space+needle+gear+ratio&source=bl&ots=nzwsgU5HSu&sig=UTGSr7mBcaSWfjWJpXm8qjJ_Utc&hl=en&sa=X&ei=DGKeVdbGKMvn-QGZxquABQ&ved=0CC4Q6AEwAg#v=onepage&q=space%20needle%20gear%20ratio&f=false https://books.google.co.uk/books?id=Jox4CAAAQBAJ&pg=PT262&lp...
- freshyill 11y agoI stayed at the Westin Bonaventure in LA recently. An employee told us rotating bar at the top takes something like two hours to make a complete rotation. It was disorienting to have everything around you be constantly changing, yet so subtly.
- onion2k 11y agoUsing the contraption in the article hooked up to a motor at 600rpm (typical for a diesel engine), it'd take about 12 and a half days to rotate something.
- chrisBob 11y agoThe point of this gearbox is the small size. The space needle gets to use a gear that is the size of the top level, and drive it with a gear that is a few inches in diameter. That has always been easy to do and is the sort of thing this compact gearbox avoids. [edited for mistake: motor -> gearbox]
- TylerE 11y agoI seriously doubt they use a gear the size of the base. I doubt the facilities to manufacturer a gear that big exist anywhere. Gear machining is a very specialized operation.+ More likely it's a train of gears of much more moderate ratio...a series of 5:1 or 10:1 reductions, say.
- jpfr 11y agoLooks like a bunch of harmonic drive gears in a row. Every industrial robot contains a couple of these.
- chrisBob 11y agoI am most concerned about the efficiency of a design like this. People usually look for a gear reduction to increase torque, but an inefficient gearbox can make the output both slower and lower torque which is rarely desirable. The wobbling input shaft would also be tough to work around.
- kukx 11y agoIt's not completely something new https://www.youtube.com/watch?v=MBWkibie_5I https://www.youtube.com/watch?v=MBWkibie_5I
- po 11y agoI highly recommend going through Oskar's other puzzles and contraptions which includes tons of very very strange cubes, puzzle rings and other oddities: https://www.youtube.com/user/OskarPuzzle https://www.youtube.com/user/OskarPuzzle http://oskarvandeventer.nl/hanayama.html http://oskarvandeventer.nl/hanayama.html He also has done a ton of collaborations with Bram Cohen of Bittorent fame like this one: https://www.youtube.com/watch?v=RTcGCqz4ajs https://www.youtube.com/watch?v=RTcGCqz4ajs He's definitely one of those guys who just can't stop creating puzzles and new ways of thinking about problems.
- userbinator 11y agoThis "extract the difference of speeds between two parts" method is quite common to get extremely high reduction in a small amount of space; this is a ~70:1 single-stage gearbox found in a rearview mirror positioner, and it only has 6 parts: https://en.wikipedia.org/wiki/File:Rearview_Mirror_Epicyclic_Gears.jpg https://en.wikipedia.org/wiki/File:Rearview_Mirror_Epicyclic... Put 4 of those in series and you'll get 24M:1.
- IshKebab 11y agoThis is not too different from a harmonic drive. In fact it's basically a single-planet epicyclic drive inside a harmonic drive. Kind of nice but I don't know if it counts as a new type of gearbox. https://en.wikipedia.org/wiki/Harmonic_drive https://en.wikipedia.org/wiki/Harmonic_drive
- drostie 11y agoWell, harmonic drives are cycloid drives that use elasticity rather than eccentricity to do the same task, so let's focus on cycloid drives. It's not quite the same your typical cycloid drive, but it has a strong relationship. Cycloid gears are about having an inner circle of radius A rotating within an outer circle of radius B by putting the center of A's circle on its own circle of radius C = B - A. If C is small, then a fast rotation of C produces a slow off-center rotation of B relative to A. Since it's off-center, usually a bunch of holes (theoretically also of radius C, I think?) are drilled in B and filled with "output rollers" which connect to one single shaft which is on-center relative to C. Thus C connects on-center to this asymmetric B, which connects to an on-center output shaft that otherwise rotates as B does. In his case, these holes don't exist and the rotation is never on-center. But you can use the same mechanism to convert his amateur cycloidal drive to one that has an on-center rotation of the input shaft. Now normally in a cycloidal drive, A is regarded as fixed, while C is rotating, and B is still. In this case his C is totally implicit, his B is rotating, and he is at two different A's which rotate relative to each other. There are therefore presumably two different Cs, too. It's hard to really isolate the exact mechanism in terms of connected cycloid drives. It is not as simple as fixing C and watching a single cycloidal drive's A rotate as a response to a rotating B, because that would have the reverse mechanical advantage. It's also not obviously "two cycloidal drives connected together by C", which would have a mechanical advantage near 1. So I'm not sure what it is, but I don't think you can just say "oh, it's a harmonic drive."
- birk5437 11y agoIts sometimes nice to take a break from software/digital engineering and build stuff in the real physical world. Feels like a vacation for my brain almost.
- sj4nz 11y agoPerhaps not with this ratio, but something like this with a quartz movement, with the right ratios should be able to advance a "day of year hand" around the face of a clock. If you wanted to get really fancy, advance a DoY-hand for Venus, Mars, Jupiter, as well as the Earth's.
- jglauche 11y agoJust a 3D printed gearbox. For me this is rather a promotional article than something really interesting. We've been able to print these kind of gears for years with reprap or reprap-like 3d printers.
- Keyframe 11y agoCould it be used for high precision movements? For example a stepper motor with very small and large movements? I know it's mentioned in the article.. but if it could be done then one could maybe create a CNC for DIY CMOS or something.
- Thiz 11y agoI want to see the inverse. Eleven million spins with one rotation of the shaft.
- scott_karana 11y agoCouldn't you just rotate the "output" shaft, to accomplish exactly this? Sure, the required torque would be immense, but... ;)
- cgearhart 11y agoFriction will prevent that, similar to the self-locking behavior of a worm gear. Even if you could get it started, it would take as much energy to spin the output shaft once as it takes to spin the input shaft 11 million times. If you tried to quickly spin the output shaft, the forces exerted on the gears would shred the materials almost instantly.
- Florin_Andrei 11y agoIt would be fun to calculate the power input required for that. I suspect it would be in the range of megawatts or so - instantly vaporizing the gearbox (assuming you could somehow push that power into it before you destroy it mechanically).
- sitkack 11y agoMaybe make the gearbox out of mirrors and the "shaft" out of light. Suspend the whole thing in a magnetic field.
- intrasight 11y agoWhy wouldn't one just use three nested cycloidal gears to achieve the same result?
- Semiapies 11y agoWhy they include an animated gif of someone turning another gearbox with a far lower ratio puzzles me. But I'm going to go with "yes, this is useless, unless remade with much better materials". The current version is imprecise, high-friction, snd can't even survive one rotation of the output.
- Semiapies 11y agoHuh. Was someone under the impression that the GIF was of the gearbox in question, or did they not RTFA enough to realize I was simply agreeing with the inventor for the same reasons he enumerates?
- Gravityloss 11y agoThat is the gearbox. The output shaft is the red one.
- Semiapies 11y agoYou're right, sorry. I hadn't watched the second video.
- na85 11y agoReminds me of a fun trick that was popular when I was in undergraduate mechanical engineering: A gear train that has one end spinning, powered by a small DC motor, and one end bolted/welded/glued/otherwise fixed solidly to a wall. Increase the ratio enough and you can have an output shaft that will take years to go through even a fraction of a revolution ;)
- dominicgs 11y agoThere is one by Arthur Ganson in the MIT museum[1]. It's part of a great exhibit of fun/quirky machines and there's an interesting video about it on youtube[2]. [1] https://www.youtube.com/watch?v=5q-BH-tvxEg https://www.youtube.com/watch?v=5q-BH-tvxEg [2] https://www.youtube.com/watch?v=2Rov_Lriqvk https://www.youtube.com/watch?v=2Rov_Lriqvk
- Animats 11y agoHere's a planetary drive using roughly the same concept. This is 64:1 per stage. https://www.youtube.com/watch?v=P-Obt-9tZVo https://www.youtube.com/watch?v=P-Obt-9tZVo
- kordless 11y agoWould be good for a telescope mount, maybe.
- lisper 11y agoBecause of the non-back-drivability, I would use this for making winches.
- columbo 11y agoIf it had enough torque (which seems to be a problem given the plastic nature) I could see it breaking loose rusted or stubborn bolts. Maybe? In a scenario like that you wouldn't really care about precision or sound. Though 11 million turns still seems like a lot of cranking... maybe if it had a 9v attachment it could be a portable bolt breaker. Feels like a stretch though, would be fun to play with. Though now that I think about it the holder of the bolt breaker would probably start slowly turning before the bolt does... weeeee
- chadgeidel 11y agoThe problem with rusted or stubborn bolts I've encountered is the mechanical friction on the threads usually greatly exceeds the shear force (??) that the bolt can tolerate. I've snapped a head off more than once. That's a real bummer.
- stephengillie 11y ago> Headed in a different direction, Van Deventer has a new type of gear he calls “grinder gears” that comprise an inner gear with one fewer tooth than the outer gear, causing it to wobble its way through the rotation. For the engineers, it’s a variation of a cycloidal drive. Oh, he reinvented a Gerotor. > A gerotor unit consists of an inner and outer rotor. The inner rotor has N teeth, and the outer rotor has N+1 teeth. The inner rotor is located off-center and both rotors rotate. https://en.m.wikipedia.org/wiki/Gerotor https://en.m.wikipedia.org/wiki/Gerotor
- HeyLaughingBoy 11y agoThe mechanism is reminiscent of the one in the Newbould Indexer: http://www.imperialnewbould.com/the-newbould-indexer.html http://www.imperialnewbould.com/the-newbould-indexer.html This discussion has a link to RJ Newbould describing how he invented the indexer: http://www.chiefdelphi.com/forums/archive/index.php/t-68265.html http://www.chiefdelphi.com/forums/archive/index.php/t-68265.... It's a really interesting explanation for us mechanism geeks :-)
- fredgrott 11y agoI know the answer..think Tesla..but instead of a small auto a big truck or better yet a big ship... both require a rethinking of the transmission to transfer power from the engine to the wheels or propeller in order to get bigger torque this gear device solves that particular problem