It’s a Drill Stand.
Many Power Tool manufacturers back in the day manufactured Drill Press Stands that could be used with the corded drills they manufactured, to make the drills into portable drill presses, or small drill presses for shops or craftsman who didn’t have a dedicated drill press.
Companies like Duss and Festool in Germany still manufacture similar drill press stands, and Bosch does, or at least did up until recently, although the stands are usually not sold in North America.
I’m not sure what brand that might be.
Black & Decker, Thor, Miller Falls, Stanley Power Tools, etc., probably all made similar stands back in the day.
Older stands used to clamp the collar on the drill near the chuck, AND, mount to the back of the drill as well.
Newer stands just tend to hold the collar near the chuck.