You can go to the us Patent Office and do a search first to see if it has been done previously and, is still covered under a patent.
PatFT » Page 1 of 1 If it hasnt you can then file a Disclosure Document with the Patent Office. When filling out the document it is best to briefly describe the idea getting the point of what it does and, how it works. You dont want to get too detailed on the construction of it, general thumbnail sketches are best. What disclosure allows is further developement to the final product without the danger of the idea being stolen. When selling your idea to a company it is best to not get it under a full patent but, still have it in disclosure. The reason being is that they can modify the design slightly and, manufacture without paying you. That is why you see alot of products on the market with the Pat.Pending and, a series of numbers on them. It gives them full protection of their product and, if someone does a design change to it they can sue for infringement, saying we were going to do that.