Planetary gear

September 20, 2009 3:14 AM

♥☐➔5▼❀?
posted by twoleftfeet (23 comments total)

Wankel!
posted by A189Nut at 3:23 AM on September 20 [2 favorites has favorites]

When I was a toddler, my dad made a hanging clock from Mecano, I recall looking at the gearwheels for hours, we did not have baby tv then. This post is great, takes me way back!
posted by kudzu at 3:39 AM on September 20

As the Mods* used to say, this post is gear!

*The English ones. In the 60s. Before there was an internet.
posted by flapjax at midnite at 3:41 AM on September 20 [3 favorites has favorites]

I wish I could visualize things in three dimensions like these guys do.
posted by BrotherCaine at 3:42 AM on September 20

This has to be the least helpful text description of a post that I've seen on metafilter. I do love gears, though.

Here's more "Gear Pr0n."

Make your own gears from junk mail, or use your desktop cutting machine.

Here's how one guy made a wooden gear clock, and here are some more tips, if you want to make your own.

Cornell's KMODDL is worth poking around to see a whole bunch of historical gears, linkages, motors, pumps, and machines in general.

Finally, if you want to know how (a differential works, or) your car goes around corners without scrubbing either the inside or the outside tire, this explanation from GM/Chevrolet in the '30s is the best explanation of the problem and the solution I've ever seen.
posted by Hello Dad, I'm in Jail at 4:30 AM on September 20 [9 favorites has favorites]

I wish I could visualize things in three dimensions like these guys do.

Use the right gear and you'll be visualizing in 30-dimensional hyperspace.
posted by PeterMcDermott at 4:32 AM on September 20 [1 favorite has favorites]

and only 1 related video away from the "❀" link is this simple Overunity Mechanical Power Transmission
posted by russm at 4:36 AM on September 20

Soooooooooooooo cool!
posted by Matthias Rascher at 4:43 AM on September 20

russm: "simple Overunity Mechanical Power Transmission"

Dude thinks he has made a perpetual motion machine and cannot even make his backing music last the whole duration of the video.

Who the hell would actually think a torque converter followed by an inverse torque converter would result in over unity power? Is he just trolling for gullible investors, or just smart enough to be facepalm stupid or what?
posted by idiopath at 5:46 AM on September 20 [5 favorites has favorites]

Dude thinks he has made a perpetual motion machine and cannot even make his backing music last the whole duration of the video.

QFT
posted by kcds at 6:10 AM on September 20

Here is my favorite kinetic sculpture, found within the window treatment of a Mexican restaurant here in Seattle. I can't be sure, but I suspect it may be a variant of Chebyshev's four bar "straight line" linkage.

Imagine that the point in the middle of the linkage which travels almost rectilinearly becomes fixed, and is rotated by a crank. Then the "legs" would reciprocate in somewhat eccentric paths, which is what I think I see in the bobbing motion of the head and legs of the horse model.
posted by Tube at 6:16 AM on September 20

They have a good breakfast there too, at Pesos. I went there once around 1 AM and afterward my legs definitely reciprocated in a somewhat eccentric path.
posted by twoleftfeet at 6:22 AM on September 20

I recognize that my previous comment is not specifically about planetary gears, but the more general subject of kinetic sculpture. Interestingly enough though, the planetary gear was developed as a response to the ordinary crank having already been patented!

A very famous epicyclic chain is the Watt sun-and-planet gear, patented in 1781 as an alternative to the crank for converting the reciprocating motion of a steam engine into rotary motion. It was invented by William Murdoch. The crank, at that time, had been patented and Watt did not want to pay royalties.
posted by Tube at 6:31 AM on September 20

I think the presentation of this all-too-wonderful post was overly cutesy. I nearly didn't bother looking at any of the videos, but then I did, and I was happy that I did. Rethink that next time, and you'll draw more viewers.

Still, how cool. I was looking at the heart video and said to myself "but there's no way those gears interface and actually work." And then he turned the crank, and holy fuck! They did!
posted by hippybear at 6:33 AM on September 20 [2 favorites has favorites]

From the youtube video about the heart I was introduced to the Penguin Bomb!
posted by cyphill at 8:11 AM on September 20 [4 favorites has favorites]

I think the presentation of this all-too-wonderful post was overly cutesy. I nearly didn't bother looking at any of the videos, but then I did, and I was happy that I did. Rethink that next time, and you'll draw more viewers. Still, how cool. I was looking at the heart video and said to myself "but there's no way those gears interface and actually work." And then he turned the crank, and holy fuck! They did!

Huh? That was word-for-word EXACTLY my experience.
posted by krilli at 10:32 AM on September 20

cyphill: From the youtube video about the heart I was introduced to the Penguin Bomb!

Holy crap, there's got to be a spring in that thing... it would be extremely impressive if someone did that out of origami.
posted by Arandia at 11:53 AM on September 20

Panetary gears in real life.
posted by TedW at 11:54 AM on September 20

Prius taks advantage of transmissions similar to these planetary systems:
Prius Simulator
posted by DesbaratsDays at 12:01 PM on September 20

Needs moar Sturmey-Archer.

And who knew that the simple banjo tuner uses epicyclic gears too?

Most wind turbines use this kind of geartrain, too.
posted by scruss at 1:46 PM on September 20

Surely this post isn't complete without a reference to Spirograph! Or spare yourself the actual gears and grab Inkscape and this extension.
posted by pwnguin at 1:57 PM on September 20

These gears are epicyclic.
posted by spiderskull at 4:32 PM on September 20

Arandia: you can see the elastic band around its neck. Quite ingenious.
posted by five fresh fish at 4:52 PM on September 20