I was one of the folks working on JD rotary combine designs around the time the IH and NH were introduced. I did an internal research report at one time that showed Deere was actually working on an interesting rotary combine design at the Tech Center in the early 1950's. That is Fifties.

The reason you will not find patents on any of the early work is that patents were not filed. Once you file a patent application it does two things:

1) Starts the clock ticking on patent life which now is 20 years from the date of filing I believe but at the time was 17 years from the date of issue....or something like that. Please don't quote those numbers.  Something that is so different may not make it from the patent filing to production for 10 years or more in a large company system at which time you would only have 7 years or so of protection left.

2) Let's every one in the industry have an advance notice of what you are working on/future products.

A common policy among R&D companies is to work on things but not make them public with patents. As long as it is still in an "active" development project, but NOT disclosed in public, you can always file for a patent later.

Richard "Dick" DePauw was the engineer at IH whose name is on the main IH rotary patent.  When IH went down the tubes financially and started moving people all over the place he came over to work at John Deere and was my boss for a time at John Deere Harvester Works engineering. He was a fine man to work for and was careful never to cross work done at IH with work done at JD. He worked on other things. JD did NOT hire him for his IH knowledge. He was an experienced combine engineer which are not all that common and worked mostly on platforms and testing as I recall.

An unrelated comment: The elephants ears/auger rotor feed section debate is not as simple as it sounds. There are advantages and disadvantages to each system. IH's patent clearly tied up the elephant ears.

One of the absolutely fascinating things about agricultural combine design is the wide range of both crops and conditions of each of those crops that a combine is expected to perform in.  From down rice to standing wheat and 35% moisture corn to green soybeans - it is an engineering balancing act. Add to that the need to be able to function as a large grain truck, a cleaning system and to be stable and safe with a light 15' cutting platform as well as a heavy 12 row corn head way out front and combines are an engineer's dream... or nightmare.

Maybe that is why folks are so interested in this subject even after 40-50 years or more?

Jim at Dawn