Drill Press Vise

This item was kept in my grandfather's workshop.
According to an image search, it is called a drill press vise, but I do not know how to use it, so I am offering it to someone who can.
The handle turns, but it does not seem to close completely. (It might be correct as is.)
As I do not know the complete or original condition of this tool, some parts or accessories may be missing.
Please only purchase if you understand this point.