I thought it might be that ,But I noticed that the collar threads off but dosn't compress the two "fingers" in the center. I don't know,Maybe someone out there does
I think its missing something. something with 2 more fingers like it has that would fit the gap between the "fingers..." gotta be something similar to a tap handle.
After seeing the patent something still is not quite right with my guess. The Jaws/fingers inside look like the fingers to hold an Auger bit. Yet the patent shows this is used in the turret of a lathe/screw machine. I have used this type of holder that had collets inside to hold the shank of the tool bit. Who knows maybe its for a wood lathe of some sort I am not familiar with.