Nice bumper WWII70,thanks for sharing.Well back then,because Rolex patented the rotor,I guess until the patent expired everybody else went with non-spinning rotor inventions.Obviously the crown trials were also popular.That was also the intention of John Harwood.Being challenged during the WW I as an active service man,he saw the problems caused by the crown ( dust-water...) and came up with that bezel function setting the hands.This way the watch was sealed and no space for dust to penetrate.
The Glycine fold lever was another interesting and chic invention in 1932,fold away lever acting as crown.
Until 1942 there was no bi-directional winding rotor,first one was Felsa 690 aka Bi-dynator.Those years watchmakers were really creative,eh?