If you have a patentable invention, filing a provisional patent application can provide temporary protection of your intellectual property rights while you develop your idea further or seek funding. Provisional applications have a lower fee than non-provisional applications -- and you don't have to make formal claims or provide the same level of detail about your invention. Additionally, provisional applicants don't have to wait for the USPTO to examine the contents of the application. Your provisional application is valid 12 months from the date you file it -- and you can use the phrase "patent pending" in connection with your invention during that time.What You Can Patent
A patent provides you with the right to keep others from making and selling your invention for up to 20 years. The most common type of patent, a utility patent, protects rights in new and useful processes, machines and other things. These patents also can protect rights in non-obvious improvements made to existing things. To determine if your invention is patentable, you must first research all previous patents and other publicly disclosed inventions to ensure that no one else has already patented something similar. Because this process can be difficult and complicated, the U.S. Patent and Trademark Office recommends hiring a registered patent attorney to conduct the search for you.Don't Talk About It
If the invention has been described in a printed publication anywhere in the world, or if it has been in public use or on sale in the United States before the date that the applicant made his/her invention, a patent cannot be obtained. If the invention has been described in a printed publication anywhere, or has been in public use or on sale in this country more than one year before the date on which an application for patent is filed in this country, a patent cannot be obtained. In this connection it is immaterial when the invention was made, or whether the printed publication or public use was by the inventor himself/herself or by someone else. If the inventor describes the invention in a printed publication or uses the invention publicly, or places it on sale, he/she must apply for a patent before one year has gone by, otherwise any right to a patent will be lost.More on Prior Art
Remember, while patent searching is a big part of prior art , it is not everything. If someone has made your invention before you without patenting that still counts against your patentablity. A complete search for prior art might include for example: searching non-patent literature such as any magazine, newspaper, or trade paper article written about inventions like yours also a complete search would include international patent documents (online) and not just those found at the USPTO. Do not make the mistake of believing that just because no one else is selling your product that it does not already exist. After determining that your idea is patentable and qualifies for a patent - you now need to decide if the expense of patenting is worth it.What is reissue?
Patent law states "On taking up an application for examination or a patent in a reexamination proceeding, the examiner shall make a thorough study thereof and shall make a thorough investigation of the available prior art relating to the subject matter of the claimed invention." This means that prior art could disqualify your application for a patent.