That is a "flax wheel" or flax winding wheel. The end of the spun flax thread is affixed to 1 of the 4 cross-bars on top of the spokes of the wheel and the flax is wound "round n' round" the 4 cross-bars to make a skien of flax.
The "toothed" gear wheel usually has a "clicker" for counting the number of "loops" in the skien of flax ....... but I can't see if yours has one from the picture.
Some are made with an inclosed "gear mechanism" (in a box) with an "indicator" dial on the outside of the box. Like spinning wheels, they were all handmade.
I think I once posted a picture of a "skien of flax" and a linen (flax) dishtowel that were produced by the wife's grandmother. The dishtowel was woven on a loom or more commonly called a "barn loom".
