Moving the yarn hook to and fro over the width of the bobbin is going to be a real PITA even assuming you can get power to the flier. It may be worth considering a mechanical system with a solonoid on the frame that extends a pad that drives a small rubber tyred wheel connected to a threaded rod to move the yarn hook. A second wheel geared to the first (but offset axially) and another pad and solenoid could provide reverse hook movement. Detecting the hook is at its limits to reverse it could be done with a small magnet on the hook and a hall sensor at either limit on the frame.
This is an interesting idea. I don't quite understand how the 2 different pads and wheels are configured to reverse direction. There is something called an auto reversing thread, which would solve the reversing direction problem (
). If my understanding is correct with this specialized threaded rod I could totally get rid your solinoids and just have the wheel always hit the felt/rubber pad when it rotates around. That said it's a little tricky to manufacture this auto-reversing thread and I'm not sure how durable it would be if made out of plastic like I'd want to do. I'd avoid those threads if I can, but I'm also not ruling out such a custom part.
My concern with this solution is noise. I would't want there to be a tapping sound, but if I used a wheel and maybe a felt pad it might be ok. I wish I could understand your reversing proposal since I don't understand how that's supposed to work.
FYI - This video explains an early prototype of how I'm planning to move the hooks if I keep the motor on the spinning wheel (flyer). I've iterated on this system since then and have a pretty decent solution, but if I could move the whole rotation system off the flyer that would be great.
Mechatrommer, I'm having trouble following your proposal, but in a nutshell I think it is this. Use a planetary gear system to rotate the flyer and then tap off the sun gear to rotate a shaft to turn the hooks, right? I'd still need the auto reverse thread system I linked earlier. While this is interesting, I think such a solution would be much to expensive to manufacture for this project. Still I'd like to understand it if it's something other than what I said.
ebastler, there are several disadvantages to that design. The biggest is they are using the speed difference in the bobbin and the flyer. This adds tension to the yarn which means you can't spin thin yarn with it since the extra tension won't work with thin yarn. Also that product is expensive as you pointed out and even more expensive than the flyer are the bobbins which need special gearing. The patent was filed in 1982 so it has expired, but I'm sure I can come up with a better new solution.