Sunday, March 02, 2008
Ratcheted filament driver

I had an idea in the bath. To feed the filament, all we need are two ratcheted holes and a solenoid to drive them apart and bring them together. No gears or rotary bearings would be required, and we'd have absolute control over filament driving.
I built this working prototype from two bottle tops, one aluminium and one steel 'cos that's what I could find without having to dive into the kitchen rubbish bag. I drilled a central 2.5mm hole through in the direction I wanted the filament to go (out the top) and cut 4 radial slots out of the hole with a sharp knife about 7mm long. The aluminium one is far too soft. Move them together, filament moves forward. Move them apart or let a compression spring do it for you, filament stays put.
We can change the distance driven, change the timing, and vary the power of the solenoid to change driving pressures. A spring or split washer on top might help even things out.
A similar system might step beaded belts.
Hold on to a static filament and you can step along it...
I shall simultaneously celebrate this idea and obtain another ratcheting component.
Vik :v)
Labels: driver, fliament, ratchet, reprap