WIP: Gears

Discussion in 'Design and Modeling' started by bartv, Mar 14, 2008.

  1. bartv
    bartv New Member
    Just experimenting a bit with some mechanical stuff here. I want to create a cube with gears on all sides that actually work! I think that with four gears (like in the screenshot), it'll work but I'm still figuring out what to add to the top and bottom (adding the same gears to the top and bottom would lock up the device, I think?)

    What do you think?



  2. Rob Maris
    Rob Maris New Member
    Hi Bart,

    Nice Gadget...!!! I have been trying to figure out your device and I think that by adding a similar gear to the top and/or bottom of the cube the device will stop working. Not if you want all gear to keep rotating that is. Or am I mistaking here...?

  3. bartv
    bartv New Member
    Hi Rob,

    yeah, that would lock everything up... I *think* that I could solve it by adding not one, but four smaller gears at the top and bottom. That might give a new problem: making the teeth of the gears fit together. I'll keep tinkering with this and turn it into an extremely useless yes complicated little machine :p

  4. pete
    pete Shapeways Employee CEO & Co-Founder
    Hi Bart,

    ahum complicated and useless. I like it? :confused

    How did you compute those gears? Did you use templates?

  5. bartv
    bartv New Member
    I used a Python script for Blender to calculate the gears. It's quite old and doesn't work very well anymore so I only got the shape of one gear tooth(?). With a bit of manual spinning and filling up some holes I got these gears.

    You can find that script here:



  6. rubicon
    rubicon New Member
    Hi Bart,

    2 hints

    1. place the gears separately from the cube, aligned flat.
    So, the layers of material form equal rims across all teeth. If your gears are placed vertical the modeled shape of the theeth at the 'äquator' are rougher than that at the poles.

    2. on top of the cube you can place a planet-gear:

    fine detail, laying flat, fun to watch.
    (in the post, the scheme for the planet gear skipped the blanks but you know what i mean: 1 big Sun-wheel in the midlle and the 4 planet wheels around)

    PS: heard anything from stefano? He left without a trace...
    Last edited: Apr 23, 2008
  7. macouno
    macouno New Member
    Yeah not possible to add gears on top...

    But perhaps you could add the same sort of thing as on the side of an old locomotive wheel... make something go up and down. Then you can do a piston as well!
  8. bartv
    bartv New Member
    @rubicon: thanks for the hints. I think you're right about aligning the gears to get comparable printing quality, although with our new 'Detail' materials this is not much of an issue anymore (see the blog post I wrote today).

    Part of the experiment was to print out a fully working mechanical design in one pass though, so I'd rather try and get it all printed at once. It should be possible - we have some working examples of that here, but my engineering skills are woefully inadequate ;)

    Stefano became a father about a year, year and a half ago. I guess he's still buried in diapers!

    @macouno: oohh, that would add some steam-punk-insanity to the thing yes! Let's see if we can make that work...

  9. svenpb
    svenpb New Member
    You should use bevel gears for that. The current tooth profile is no good for 90 degrees angles. It will work, but it is not mechanically sound.

    edit: I mean miter gears
    Last edited: Aug 2, 2008
  10. bartv
    bartv New Member
    Ah, I'd never have figured that out on my own. I'll give those a try, thanks!

  11. Whystler
    Whystler New Member
    On the bottom, or on the top ... you could add one gear, with a crank, that drives one of the side gears. Something like this:

    (note: this is just a mock up I put together .. i realize that the teeth of the cogs are not even)


  12. bartv
    bartv New Member
    Hey Whystler,

    that's a cool idea! I think I'll have to revisit my old gearbox one of these days and give it a try ;)