3D-Printed Geneva Drive

For this Instructable I made a 3D-Printed Geneva Drive, which is a mechanism that converts constant rotational motion into rapid, indexed motion of a certain number of degrees. This is really hard to visualize, even from pictures, but Wikipedia has a great animation here: http://en.wikipedia.org/wiki/Geneva_drive . I originally made this Geneva Drive to be a present, but I ended up not needing to give it away, so I keep it around as a cool engineering project. I designed it in SolidWorks from pictures of Geneva Drives online, and had it 3D printed by Shapeways. You can see a video of me rotating it by hand here: http://www.youtube.com/watch?v=XuHOVUXu2yE

Step 1 Why are Geneva Drives Useful?

A Geneva Drive is a mechanical system used for many unusual applications. In a movie projector, if the driving part is rotated at 30 revolutions per second, the driven part will pause on each frame for 1/30 of a second, then rapidly switch to the next frame, rather than having the film strip continuously fly through the projection mechanism, which causes flickering. The Geneva Drive was originally invented in Geneva, Switzerland as a watch component. If one of the slots is filled in, the Geneva Drive becomes a Geneva Stop. When the driving gear hits the filled slot, it is unable to continue, allowing the driving gear to rotate only a fixed number of times in each direction. This is useful in watchmaking because if a watch spring is overwound or underwound, the spring will be permanently damaged. A properly designed Geneva Stop with the driving gear connected to the watch winder will prevent this from happening.

Comments

[dscott4]

Cool,

I would love to see it added to the 3D print group I have just started

http://www.instructables.com/group/3Dprint/

Thanks

[craig3]

You should mount a motor underneath it and keep it going.

[Vlorbschnat]

I totally should, I didn't really design it with that in mind, though, so it would be a bit tricky to do now. Also, I'm not sure how resistant this 3D-printed plastic is to wear

[Kiteman]

Or you can see it here: