well the first thing you need to do is a patent search, if there isn't one then you will need to fill out the proper paper work and get a patent lawyer and file you idea, then once you have that,You can either market or sell your idea be sure to have built a proto type and blue prints then in a nut shell you are good to go. there are a few more steps lots to list thats just the basics.

goto this web site it will give you more info http://www.uspto.gov/

Hope this helps good luck
john