A small planetary gears system with a ratio of 4:1 per stage, as many stages as wanted, small, open enclosure to see the gears, and hardware free.
The gears are designed with a circular pitch of 2.5mm and they are also slightly beveled at the tips of the teeth to avoid the need of cleaning the excess of material from the firsts layers.
The OpenSCAD is not parametric, there's only parameters for clearance (set to 0.2), backslash (set to 0.1), pressure angle (set to 22.5), tolerances between nuts and bolts (set to 0.4) and length of the bolts, sometimes referred as rods. Any other change will not work.
To play with the OpenSCAD you will need the following libraries:
Public Domain Involute Parameterized Gears by LeemonBaird
thingiverse.com/thing:5505
Poor man's openscad screw library
thingiverse.com/thing:8796
Knurled surface finishing library
thingiverse.com/thing:9095
The libraries have been included in the ZIP file together with STL files for every single part, build plates for complete sets from 1 to 4 stages, just the crank and upgrade kits from 1 stage to 2, 3 or 4.
1 minute video: http://youtu.be/MUH0MGP7AGc
A shorter video (59") featuring a 10 stages set: http://www.youtube.com/watch?v=FyVZ31tLGCU&feature=plcp
More Pics: http://www.flickr.com/photos/aubenc/sets/72157629731990190/
| 145.4mm_bolts.stl | 3.0MB | |
| 1x_stage.stl | 1.7MB | |
| 1x_stages_kit.stl | 5.9MB | |
| 1_to_3_stages_kit.stl | 4.6MB | |
| 2x_stages_kit.stl | 7.8MB | |
| planet.stl | 180.4KB | |
| planetaryAssembly.zip | 5.3MB |
