Simple mechanisms explained

Below you’ll find animated diagrams and explanations of how various mechanisms work. Some of these have been crucial to major evolutions in mechanisms and technology, and allow us to do anything from fire weaponry to make cars move with the press of a pedal.

Maltese Cross mechanism powers second hand movement in the clock:


Radial engines are used in aircraft. Today, however, most aircraft use turbine engines:

radial engine

Reciprocating movements power steam engines in locomotives:


Sewing machine:


Manual transmission mechanism, also known as “stick shift” is used to change gears in vehicles:

Manual transmission mechanism

This mechanism is called constant-velocity joint and is used in front-wheel drive vehicles:

constant-velocity joint

Torpedo-boat destroyer system is used to destroy fleet in naval military operations:

Torpedo-boat destroyer system

The Wankel engine is a type of internal combustion engine which uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons:

1. 2.

+ Bonus – mechanism you can watch forever

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{ 7 trackbacks }


1 fetus June 14, 2009 at 9:20 pm

surprise butsecks

2 aircraft June 18, 2009 at 6:50 pm

The plural of aircraft is aircraft. There is no such word as aircrafts. You might want to correct that

3 bef June 20, 2009 at 5:31 am

I just reread that, thought about it for a minute, and realized that I’d apparently confused myself. The bobbin case slides into a cavity in the base of the machine. There is no axle. The axle is a lie.

4 bef June 20, 2009 at 5:33 am

The ball in the center of the graphic represents the bobbin reel, which is a small spindle filled with thread.

Sorry for the three post set. Not firing on all cylinders here.

5 bef June 20, 2009 at 5:27 am

The bobbin (the rotating part in the bottom) is a free floating case and does not so much slide onto an axle as fit into a cavity. There is an unaffixed axle on the back side that the bobbin case floats on. If you have the chance to look at a sewing machine, the bobbin (a small spool of thread) is set into a bobbin case and threaded through the case, which is an odd little stubby, cylindrical cap of sorts, with a hinged flap that controls the tension of the case on the bobbin reel. The bobbin thread is wound through grooves in the case and then upward over the throat plate of the machine. The case is inserted into the base of the machine and slid onto a one sided axle. The loop of top thread dropped down by the needle is dragged through the bobbin case by the bobbin thread, and flipped around the bobbin case and the axle. This threads the bobbin in a straight line along the base of the fabric by threading it through loops of the top thread.

I loved these. I stared at the sewing machine one for about five minutes. I've sewn a bit, but seeing the illustration really clarified the motion. Nice!

6 TJ June 24, 2009 at 11:58 pm

looooool bef


7 owen July 20, 2009 at 3:01 am

hehe i almost liked bef's bevy of comments better than the superb animations. kudos to both.

8 name? July 20, 2009 at 3:32 am

That two-slider mechanism, number 3, is a classic "I can't believe this works" novelty, but I don't think I've ever seen it in a steam engine.

9 normd July 21, 2009 at 6:44 pm

the mechanism in number 3 is also a fine way to draw an ellipse.

10 Robbie July 21, 2009 at 7:10 pm

These are awesome. (how many words do I need in this thing??)

11 scarabeetle101 August 9, 2009 at 7:08 pm

Thankyou so much!!! I have been looking for the Maltese cross for about a year now because I forgot its name and I have been wanting to make one, and I wanted to find a way of working out the proportions. THANKYOU!!!

12 suprises August 17, 2009 at 4:53 am

they don't always come gift wrapped

13 name? September 2, 2009 at 9:46 pm

dont you have anything better to do then pick up on peoples tiny mistakes?

14 admin September 3, 2009 at 12:07 pm

corrected 😉

15 fetus2.0 September 3, 2009 at 4:39 pm

suprise, more kinky butsecks!

16 bef September 11, 2009 at 7:03 am

all i have to say is poop and the french suck

17 some dude September 11, 2009 at 7:04 am

I agree with bef the french do indeed suck, they suck bobbin

18 Graham R. Knotsi September 12, 2009 at 7:35 am

I think you meant "Don't", "than", and "people's". You're welcome.

19 F September 12, 2009 at 5:18 pm


20 mazhur September 20, 2009 at 11:36 am

very interesting!

21 Steve December 30, 2009 at 3:56 pm

That "Maltese cross" is often called the Geneva mechanism. It used to be seen in automobile odometers and digital clocks, before electronic displays took over both functions.

22 vernon marsh January 3, 2010 at 3:29 am

Good stuff. I love the maltese cross and the sewing machine. The mysterious has been made plain. Thanks. Some of these commentators seem to be on the wrong page–need to get their heads out of their asses.

23 FAISAM February 25, 2010 at 1:06 pm

really useful… bcoz we never know whts behind…


24 simon March 24, 2010 at 3:40 pm

absolutely brilliant! more, more, more! please?

25 Peter Scargill April 5, 2010 at 10:30 am

That's a REALLY useful set of animations… I always wondered how the Wankel engine worked… now I know. Thanks!

26 korpsaw April 8, 2010 at 11:34 am

Thanks for this, there is a lot of interesting things to think about with these designs. The sewing machine is the hardest to understand. Imagine, this guy (..or girl)falling asleep with this idea that popped in their heads, awesome! Yay to thinkers!

27 Sean April 12, 2010 at 1:49 pm

Why do so many people have such unreasonable expectations when it comes to writing? If it gets the point across, who cares? FYI, comma's go before the closing quotation marks. So that's "“Don’t,” “than,” and “people’s.”" The article is cool though. (:

28 natale April 12, 2010 at 6:08 pm

great article but i'm going on a tangent here. we always need to have correct grammar! it is not ok to misspell a word or make a habit of bad writing. hao destracting is dis?

29 Helenka April 12, 2010 at 6:45 pm

I always was interested how aircraft engines work. It appeared very simple 🙂

30 Gunny April 13, 2010 at 1:36 pm

It’d actually be ” persons’ ” instead of “people’s.” “People” literally means a specific civilization or culturally homogeneous group of persons. lololollolz

31 Troll April 17, 2010 at 3:59 pm

The plural of comma is commas, you're just adding more work for yourself. Is this your daily workout?

32 Troll April 17, 2010 at 4:05 pm

Just to clarify, you'll only see radial engines in older airplanes, and saying most aircraft use turbine engines is a gross generalization; piston engines still power most small aircraft, but they aren't radial.

33 Jen Brown April 25, 2010 at 2:18 am

These are absolutely amazing!

I am mechanically & scientifically uneducated, but extremely literate, & speak English French & Spanish, with a university degree from the UK.

It means a great deal to me in my 60's to actually see these mechanisms working & to imagine the ingenious minds that configured them.

The sewing machine is particularly amazing – I just stared & stared at it until I could understand it

Some people here have tried to explain in words – it doesn't work .You have to grasp it visually.

By the way, those who criticize your English are way off track. Your presentation of all this is brilliant .I can pick out spelling & grammatical errors in 3 languages, but I could NEVER explain these machines as you've done.

I thank you for educating me.

Are there any other posts like this that you do ?

34 Lee April 26, 2010 at 10:47 pm

That's not true according to AP style. "Persons" should really only be used if they're missing.

35 K.A. Coldwell April 28, 2010 at 2:32 am

Not to mention the fact that Graham R. Knotsi might be from somewhere outside of the United States, where commas go OUTSIDE of the quotation marks. Furthermore, correct writing on the Internet is very important these days; such easy publishing methods, like blogging, lower grammatical standards significantly since nit-picking editors are no longer breathing down authors' necks. It's our job as critical readers to hold writers to high standards. Incorrect grammar can lead to incorrect stories.

36 zulu April 28, 2010 at 3:24 am

yes, yes, i was thinking the very same thing

37 The Padrino May 14, 2010 at 12:00 pm

Very simple lol

38 EdM May 15, 2010 at 4:53 pm

Just as these are elements of instruments intended to deliver precision, power and reliability, so language is an equally critical implement that requires equal standards of excellence. It's interesting and fitting that both should come to be addressed on the same page. We don't tolerate shoddy engineering and manufacturing in the products we use and we shouldn't tolerate shoddy grammar, spelling and syntax either (but we should extend grace and leeway to people for whom a particular language is not their primary one).

No criticism of the web site author here, but I do deplore the commentators who are satisfied with the "just good enough to get by" attitude and of those who criticise faithful upholding of linguistic standards. They're just too lazy to make the effort and can't be bothered to keep growing and excelling in the most powerful human instrument of all — language!! These are the ones who couldn't seem to get a grasp of the blindingly obvious purpose of their education while in school and somehow missed the fact that their school years are not the sum of education, but the process of becoming equipped for it!

Did I make any grammatical or spelling errors in this comment? Could be, but I heartily welcome (and implore) corrections, as we all should. How else am I going to grow and improve in my use of the most powerful implement ever devised?

39 Tyler Burdett May 24, 2010 at 5:00 am

The manual transmission animation is flawed. The gear highlighted as first is actually fourth, and the gear highlighted as first is fourth, and so on. First hear turns the smallest crankshaft gear which turns the largest driveshaft gear, allowing low speeds and high torque using the property of leverage. Also the gear to the right should only be highlighten when it is engaged, not at all times, otherwise the gear ratios would bind the transmission.

40 Stephen June 19, 2010 at 6:13 am

@Troll: Actually, the plural of comma is NOT commas, it's commata.

41 Sean June 19, 2010 at 11:00 am

@ Coldwell – I'm from Ireland, living in England (i.e. somewhere outside the United States). Commata (cheers, Stephen) go inside the quotation marks.

42 IsisDax June 20, 2010 at 1:04 pm

I enjoyed the posting, despite poor punctuation / grammar, until the "Bonus" diagram. Maybe straight women enjoy simple engineering too. While you're addressing your ignorance about language, try working on your stereotypes about humans as well.

43 Kurtis June 28, 2010 at 4:19 am

This is a great resource for thinking over mechanics when you are stuck on a design.

44 Greenmagnate July 9, 2010 at 5:26 pm

comprehensive 3D explanation, great work.

45 khan July 27, 2010 at 8:58 pm

Boss your bonus is bes in all 😉

46 ollie July 30, 2010 at 4:17 pm

did you know mothers Wankel Rotary engine has the highest wear and tear, but the highest torque. fuckin yeaaa m8888888!!!!

47 solartronenergy August 28, 2010 at 7:09 am

awesome…the sewing machine was one I've always been curious about, but the stick tranny was an epiphany

48 name September 3, 2010 at 5:43 pm

PEOPLE'S, DON'T ask my name!

name? don't you know your name?

49 lolz September 3, 2010 at 5:47 pm

I knew a French maid that sucked, oh boy oh boy DID SHE SUCK!

50 siddhant October 4, 2010 at 12:10 pm

can anyone tell me more sites to know more things like these

its really amazing and told in a simple way……

51 Stacey Reid February 7, 2011 at 2:37 am

Years and years have gone by and I have always wondered how a sewing machine worked. Thanks for solving this long time childhood mystery.

52 Basm March 27, 2011 at 9:35 pm

Sewing machine is kinda weird – central part is hovering and isn’t connected to anything – thread goes around this thing. something isn’t right there

53 aly June 3, 2011 at 12:24 pm

These are really cool, you just want to stare at them for a wile.

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