I wanted to design Lego compatible geneva drive gears and here is result. Works good with manual and motorized, but i have tested onlu the proof of concept so i have no idea how much load it can take. This prototype is printed with silk-PLA  which is very weak. I imagine with PETG or carbonfiber infused filaments should handle reasonble amount of torque. If his is not enough, one can always replace the printed driver pin with small furniture nail, just heat the nail and push it through the plastic. Enjoy and let me know if this useful or waste of time ;)https://www.thingiverse.com/thing:6706380/files

 

Edited August 14, 2024Aug 14 by Jude

That's pretty cool! It definitely would be useful for Lego gearboxes, like you demonstrate there, though I'd be more likely to aim for an all-Lego solution for most models with gearboxes

Very cool concept, compatible with Lego world! I am just thinking if we don't have actually Technic solutions that would cover that, but I might be wrong and didn't understand the whole picture of that. :D

5 hours ago, Krxlion said:

Very cool concept, compatible with Lego world! I am just thinking if we don't have actually Technic solutions that would cover that, but I might be wrong and didn't understand the whole picture of that. :D

No, there's not really any realistic way to model a full Geneva mechanism with Lego. For one thing, not only does a Geneva mechanism advance the output by a specific number of degrees each rotation, but it also holds the output in a fixed position whenever it's not moving, so it works for a gearbox like this much more nicely than a stepper would

Very cool! Definitely one of the more important simple mechanisms that Lego lacks. Extremely useful not only for a gearbox, but all sorts of other things too.

This, a proper snail cam and a 32t gear are my three biggest Technic wishes.

Edited August 15, 2024Aug 15 by Davidz90

On 8/14/2024 at 12:33 PM, Jude said:

I wanted to design Lego compatible geneva drive gears and here is result. 

This would be a huge improvement over the new yellow stepper gear for the reasons you've stated: smaller and holds the gear in position!

Never heard about geneva gears before. Thank you for sharing!

That's very nice! There are several good ways to make a working Geneva drive out of pure Lego, but of course they are nowhere near as compact as this.

Edited August 15, 2024Aug 15 by aeh5040

Thank you all for these comments!