One of my wife's late grandfathers worked for Hoover much of his life, particularly the manufacture of a model called the "Constellation" which was basically a ball.

That was our vacuum for much of my early youth, a coppery-gold painted metal with tan rubber parts.
It was the subject of the only actual single conversation I had with him before he passed.

The thing could be made to reverse the air flow also by swapping the hose connection.

Hi Mike - that hoover ball model almost looks like some kind of diving helmet apparatus!

- Michael

It had to be a reflection of the "space-aged" thinking of that era. Like having your very own Sputnik!
My wife's grandfather talked about how the two hemispheres were were stamped from metal sheet in a large press.