Crannequin (Rack and Pinion)

This winch-like device was used to wind back the powerful string of a crossbow.  The strings on earlier crossbows were pulled back with the aid of a hook on the crossbowman's belt, he would catch the string in it while bent over then straighten up using the muscles in his back to do the work.  This is most likely from a hunting or sporting crossbow and was probably reloaded by an assistant standing behind the sportsman.