Trebor (Robert Knox)
just a tiny remark - or a more expanded vision if you will.
The zip brush (Kirby's) and Vorwerk's "Textilbürste" are indeed very much alike.
While I cannot make out who invented what first, it is obvious that they follow the same basic scheme. (Rotating disc having bristles, both being air flow driven).
Some Kirby guys I had here claimed that Kirby was first, some Vorwerk guys that I had here as well, they claimed Vorwerk was first. (No idea, I am not a patent attorney, nor do I think that I will ever be).
Fact is: The Vorwerk turbo hand brush has the abbreviation "TKB" (Textilkehrbürste = textiles sweeper brush or textile brush for short). It was TKB 1 for the weaker VK something stick vacs and TKB 240 for their first canister VK240. Later there were other numbers as the model numbers of main units changed. Basic thumb rule: The canister models hat somewhat "stiffer" bushings to it, to make up for a stronger suction. Also: Green middle ejector buttons mean you have a first generation model in front of you, yellow ejector buttons mean you have a later, second generation model (with some added 1000 rpm.)
The "Polsterboy" units came up, when all air-driven brush patents expired here, Vorwerk was then launching this electric motor driven unit, along with it they would issue the electric suction hoses (it was basic on the tank type units because of their remote speed control in the handle, but sold as an extra to the stick vacs which had the switch in the main handle (telescopic steel stick).
Polsterboy started up with model 410, then 411 and so on, all of them featuring an oscillating swivel brush, powered by some 50 watts internal motor. (Some models had this extra electric hand grip to it, making it possible to grind cleaning powder or sprays into the couches - prior to vacuuming of the dried powder).
Today's "Polsterboy" (upholstery boy) has 2 counter-revolving brushes, electrically powered. Whether it has a different type of rollers for rubbing in the cleaning agents, this I don't know. Also whether today's model features the extra handle with 7 m cable, I don't know either. I had withdrawn from caring about Vorwerks long ago. Nonetheless, I might give your more elaborate links to go on with.
Cheers
Joe