Electronic shifting servo mount (cable-actuated)

This was a failed design for an electronic shifting project I was working on. It's a mount plus other stuff for a standard servo to mount to the driveside chainstay of a bike & use it to actuate the rear derailleur using a standard shift cable.

It is used in addition to the user's current RD.

We tried this with the highest torque servo we had (about 20 kgf cm, I think), & it was far too weak for a double spring old Shimano 105 rear derailleur. I think we tried with more modern long cage Shimano Claris RD (single spring) & it still was too weak.

Incidentally, many months after I designed this, this appeared:

• https://www.kickstarter.com/projects/1598276649/xshifter-worlds-first-universal-wireless-smart-shi
• http://www.xshifter.com/

Which mounts similarly, & actuates similarly. I haven't played with them & I'm not sure how they got a strong enough servo/linear actuator, but they cost too much for me to find out.

Since it actuates over a very short cable length with no considerable bends, the reduced friction should permit pretty good quality, if it worked.

Updates

17 Dec 2016: Uploaded some PDFs & images demonstrating how the assembly comes to together.

Assembly & Materials

Uses zipties & inner tube shims to mount to the seatstay.

Need some small screws, don't know the threading or size.

You will need an additional aluminum (sheet metal) servo mount. I think a CAD of that is provided. It came with the servo we had; I never tried to buy one, so I don't know anything about availability.

Category: Sport & Outdoors