Larger companies are typically very patent savvy and will have their attorneys review new products for patentable ideas. Generally, when you work for a company, either as an employee or a contractor, they own the ideas you come up with, so the patents list you as an inventor but list the company as the owner.
Patents are expensive - like $10,000 - $50,000 to get a patent. The U.S. used to give you a year after you publish something to file a patent on it, but I think they're moving to follow international law and say that the first person to file a patent gets it. So you're really best off filing something before you make any part of it known publicly.
If you produce the designs and contract with a manufacturing company to build it, you usually get them to sign something that says that you own all rights to it. It would be good to have a lawyer on retainer to advise you before you disclose anything and to review any legal agreements.