Ident Excello mill table handles?

[vecair]

Does anyone know the manufacturer or details on these table handles on my Excello mill? They can be disengaged from turning with the table feed by loosening the center knob and pulling them outward which pulls the pin out of the inside collar. They are then able to freewheel so that if bumped it will not effect the milling process. The inside collar is hardened and has plenty of holes for engagement with the pin. I have searched but have never seen anything like these.