I came across today what i thought was a old kirby model 50 turned out to be a royal was kirby affiliated with royal or was there no patent on the design
Most vacuums looked like that in the early 20th century, but as the vacuum industry evolved Royal and Kirby ended up being the only two major brands left to still use that design.
Companies are much like people - as their not an Island unto themselves, and as there is nothing new under the sun they utilized each others ideas often, but this is something I'm sure they would not freely admit to and nor would we given the same circumstance.