In order to be patentable it needs to be a significant enough change so as to make your fans clearly different. My uncle is a patent or mental preperties attorney and the anology he gave me was this. There are several hundred patents for shopping cart wheels. Most of them pertain to the material the wheel is made out of or the method the rubber is attached to the hub. Very few of them have to do with how the wheel attaches to the cart itself nor to how they pivot since the number of ways that can be done are few and abvious as as such not patentable. Another example would be lawn mower blades. Very few patents exist even thought there are almost limitless shapes you could use for them...a blade is a blade so to speak. There are people that specialize in patent searches at the archival level as well as online services that will do it for a fee. I was told once that the first thing you do before you talk to anyone about it is to send yourself a certified letter detailing your idea and who you are approaching about it. When the letter arrives DO NOT open it. File it away and it serves and evidence of your idea with the US post office as a validating witness, to be opened at court in the event the idea is stolen.
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