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.

70 thoughts on “The mechanical diode

  1. 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. ;)

  2. 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.


  3. …………
    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!!

  4. 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

    you would get schlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlupschlup

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