Winner of the Pattywac Makerbot United Challenge for collaborative design: http://www.makerbot.com/blog/2011/05/16/pattywac-makerbot-united-challenge-winner/
Thank you team! :-)
Video of the first ticking powered escapement mechanism:
Several bugs have been fixed since this release, and the current tip-of-the-spear for development is a simplified 2-gear clock with only minutes and seconds.
Current development version to be found on git hub here:
Current version of the 8-Gear Clock (revision D):
Current bleeding edge development version of the test jig:
Current repository for the latest version of the clockwork library:
Thanks to RustedRobot for his continued assistance debugging the clock!
This is both a derivative of the printable clock PoC, and of my escapement library: http://www.thingiverse.com/thing:7822 . The involute gear profiles are from the MCAD library.
(EDIT: The clock got a mention by Cory Doctorow on boing boing!
I cleaned up the code so it would render faster, moved all the gear work into the library, and created a laidOutToPrint() module to facilitate creating the STLs of the individual parts. I included an optional print volume visualizer, so you can check every part doesn't exceed the printer's capabilities.
The assembled() module is still fully animate-able, and I've added colors to help see if everything meshes properly.
The clock itself now has clip-on hands, front & back frames, and most importantly, I switched to a different set of gear ratios (3.2, 3, 2.5 & 2.5) which allows for bigger shafts by keeping the ratios small.
Assuming an 80x80x80mm printing volume, you now have a bit more than 12mm (almost half an inch!) available for the overall diameter of the shaft, the two sleeves that slide over it and the necessary clearances.
I think this configuration is close to final, except for the escapement, which will need fine-tuning... but without re-printing the rest of the clock.
Print one of each STL file, or fiddle with the script, check your work with assembled(), and then generate a new STL for each part with laidOutToPrint(), and print those.
The current configuration requires four shafts to slip the sleeved gears over, outer diameter 2mm with a clearance of half a millimeter either side. I suspect it might be possible to simply screw an M3 bolt into each end of the longest sleeves and to widen the holes in the frames a tad.
I'm unfortunately rather sure the escapement won't work properly as is, but it would be nice to know if the rest of the clock does, i.e. if you can turn the escapement wheel, and have the gear train run smoothly and the three hands spin around.
I'll be working on the escapement next, but whatever I come up with in that regard should be backwards compatible with this design, with only the need to print a new escapement wheel, escapement and pendulum.