Bubbleback Oyster models are the first thing that comes to mind, and I'm pretty sure that they were made in 1946, but they may not go back to 1940. There were also the "Air" models, Air-King, Air-Giant, Air-Tiger. Again, they may not go back to 1940, you'll have to check. For 1940, you may be looking at a generic Oyster model.
As @many mentioned, the rectangular Prince models are also interesting, but not to everyone's taste.