No, I think I've seen them inside a photo copier. From memory, the pitch and diameter of the groove the cable sits in varies, it starts as a larger diameter and decreases steadily then at the mid point it starts increasing again in a mirror image. I've not been able to find any images on google of what I'm looking for. Maybe a straight spool will do. I guess if I run a tensioner and v grooves on the spool it will get enough friction not to slip.
Thanks
Splint |