as I Expanded a rim rear hub and built a custom coaster,
I could not have gear .... and I missed it!
I'm inspired by old bikes (1900), and tractor mower gearbox!
I used bike gears, plexiglass and machined parts
I put two weeks to get the idea and create plans
and about 2 months to realize the gearbox!
there are three speeds and axis drive and output are the same
the selection system is brass
plexiglass box is to see the mechanism
Plans were made to the scale to facilitate manufacturing and various tests of setting up
when you change the speed which was led starts to rotate in the air and it is another that takes over
brass washers avoids usury
for machining gears supports, a special machine (mortiser) was used
I had to disassemble a lot of speed freewheel bike in order to make this arrangement
I then just solder the sprockets on their support
it slides on the shaft and causes a finger, which thanks to a spring, causes the pinion that is desired, while leaving the others free
just as a system of tractor mower!
- Bottom 4 sprockets rotate at the same time
- Right there the output gear (the piece with the red lines allows to see the rotation)
- Top left, the three sprockets rotate independently of each other (the brass Shifting used to lock the one you want)
here you can see in works