The mechanical diode

A diode allows current to travel in only one direction. With that in mind, [Alex] built a mechanical diode that will only allow gear rotation in one direction to be transmitted through the system. But wait, by connecting two of these devices together he’s built something of a mechanical rectifier. An electrical rectifier converts alternating current to direct current and this mechanical version outputs clockwise rotation no matter what direction of rotation is coming into the device.

There’s video which we’ve embedded after the break as well as many pictures on his site but not much explanation. Here’s what we’ve deduced. The two large gears are inputs. Mounted on top of them is a smaller ratcheting gear that will only turn in one direction. This ratcheting gear selects whether the smallest gear on the left or right will rotate, which then feeds the output gear at the top of this image.

Comments

  1. Agent420 says:

    @XSdb:

    A proportional valve is akin to a ‘water amplifier’…

    http://en.wikipedia.org/wiki/Proportioning_valve

  2. Skyler says:

    Oh and, an inductor would be like a flywheel/waterwheel–it takes some pressure to get up to speed, but once at speed doesn’t impede the water very much. Then, keeps spinning when the water pressure slacks off. ;)

  3. Pouncer says:

    “A more comprehensive hack would be building a mechanical 8088.”

    That would truly be a sight to behold! :D

  4. Alex says:

    The ‘water amplifier’ might be more kin to a multiplier

    http://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator

  5. pookey says:

    For those of you who think that a “diode” mechanism has no application consider this:

    For years, certain manufacturers of dot-matrix and daisywheel printers used a similar contrivance to convert the back-and-forth motion of the carriage to advance the spindles that drove the ribbon cartridge. This saved the cost (and weight)of an additional motor.

    I could also envision a bicycle that dispensed with your typical crank in lieu of two pedals, reciprocating in a linear fashion. Their motion could be changed via a “diode-like mechanism to continuous rotary motion.

    BTW, if you have *any* interest in machinery, you have to get your hands on a vintage copy of “507 Mechanical Movements.” My copy was reprinted by Lindsay Books in more recent times, but a quick glance at Google suggests that several other book publishers have also reproduced it.

    pookey

  6. Alex says:

    Here are some Lego logic gates:

    http://goldfish.ikaruga.co.uk/logic.html

  7. annon says:

    You’ve got to give him credit for build quality. I would love to see an adding machine made of out these like the one in Makers.http://craphound.com/makers/download/

  8. nono says:

    Books already exist with pages and pages of thousands of these “mechanisms”… this has been done before… and probably a long long time ago.

    Very cool though…

  9. zapa47 says:

    so a planetary gearbox would be a transitor and a breaking system woudl be a resistor? so whoe want to be the first to build a mechanical calculator based off of this?

  10. chris says:

    meh.

  11. Paine says:

    It’s a great proof of concept and everything but I don’t understand how it took him 2 years to make it…….maybe it’s just me.

  12. Frogz says:

    …………
    its cool….
    its noisy…
    its useless.
    and somone said the clock hand is made of washers? wrong, its made of GEARS(do they spin too?)
    but…. i kinda fail to see what it actually does
    reminds me of a kludge i made a while back, a dc motor running on ac via a little flap of wire attached to 1 side of the shaft, it spins, the flap hits a screw in the back of the motor, it keeps spinning(and puts out a nice ammount of sparks i might add) if i can find it i’ll post a video to youtube/HaD or hell, i’ll just make a new 1
    hm, if whoever made this reads….
    put another few hands, current 1 can be used for seconds and 1 for minutes and 1 for hours
    just set up a gear ratio of 1:60:60 to keep them in synch

    better yet, leave the big gear instead of 1 rpm, make it go alot faster(and thus higher accuracy)
    1000 rotations per second for primary gear, 1000:1:60:60!!

  13. Slipster says:

    Two years of your life on that project. Ok. You need to get out more.

  14. Frogz says:

    oh…
    it has nothing to do with electricity
    haha im a idiot
    there is a few ways of acheiving unidirectional output from omnidirectional input but this is probably 1 of the more robust/reliable methods(with less slip as well)
    but anyway, when i get around to it i will post my electromechanical diode when i get around to it

  15. tim says:

    don’t use them for analog project,
    to much noise ;)

  16. Matt says:

    Very Cool.. I would like to see a version that ditches the ratchets and uses one way bearings instead… silence is golden! And would be more efficient…

  17. Jason says:
  18. markii says:

    I get the idea, but I didn’t see it blocking rotation in the backwards direction…?
    Anyway, use some Vaseline to grease it up before using it :)

  19. Frogz says:

    so instead of clack clack clack clack clack CLACK CLACK CLACK CLACK CLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACKCLACK
    you would get schlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlup

  20. thebigwhat says:

    I just can’t understand why everyone has to have a comment. yes It’s a nice model….yes its an old design…….yes it can be applied to many different things…..

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