InMoov bicep rotGear/rotWorm replacement (lower ratio) *experimental*

thingiverse

I was hesitant about using continuous-rotation servos in my InMoov project, but I wasn't satisfied with the ratio of the standard rotGear/rotWorm setup. To fix this, I created a replacement worm gear set. You can find more information here: http://mhespenh.ninja/replacement-worm-gearset/ What is it? This is a 2.5:1 drop-in replacement for the stock InMoov rotGear and rotWorm (plus a spacer). This setup will rotate the large gear once every two and a half rotations of the servo, resulting in about 72 degrees of movement from a standard 180-degree servo that travels its entire range. The original ratio of the stock gears is unknown to me, but it seems to be around 15:1. gearSpacer sits between rotGear and rotTit. Its tabs face towards rotGear, with the flat side facing rotTit. If you like, you can glue gearSpacer directly to rotGear. See the second photo for this setup. This gear set will only fit into the bicep; I'll release a shoulder version later. Some disclaimers: * Very little testing has been done on these gears, so please use them at your own risk! * Provide feedback if you decide to use them! Keep in mind that you'll sacrifice quite a bit of stall torque with this setup due to the gear ratios. It's a deliberate trade-off between speed and power: while it's much easier to turn the servo end by turning the large gear, it is far harder (nearly impossible) with the stock configuration. This gear train is much more sensitive to friction and sloppy printing than the stock setup. In order for this to run smoothly, you need your printer working flawlessly. Update history: * 06 June 2015: First upload * 07 June 2015: Corrected STLs uploaded (the originals were misaligned, but otherwise unchanged) * 07 June 2015: gearSpacer was added as a shim to help ensure proper alignment of the gears when under tension from an arm hanging off.