(from the USPTO publication General Information Concerning Patents)
A patent for an invention is the grant of a property right to the inventor issued by the United States Patent and Trademark Office. U.S. patent grants are effective only within the United States, U.S. territories, and U.S. possessions. Under certain circumstances, patent term extensions or adjustments may be available. The right conferred by the patent grant is, in the language of the statute and of the grant itself, "the right to exclude others from making, using, offering for sale, or selling" the invention in the United States or "importing" the invention into the United States. What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention. Once a patent is issued, the patentee must enforce the patent without aid of the USPTO.
There are three types of patents:
For more information, please refer to the complete General Information concerning Patents at the USPTO website. For information about Utility Patents, see A Guide to Filing a Utility Patent Application. For more information about Design Patents, see A Guide to Filing a Design Patent Application. For more information about Plant Patents, see General Information about Plant Patents.
The Seven Steps in a Preliminary Search of U.S. Patents and Published Patent Applications
1. Brainstorm terms to describe the invention.
2. Use these terms to find initial relevant Cooperative Patent Classification using the USPTO website's Site Search box (www.uspto.gov). In the Site search box found in the top right hand corner of the home page enter "CPC Scheme [plus keywords(s) describing invention]"; for example, if you were trying to find CPC Classifications for patents related to umbrellas, you would enter "CPC Scheme umbrella". Scan the resulting classification's Class Scheme (class schedules) to determine the most relevant classification to your invention. If you get zero results in your Site Search, consider substituting the word(s) you are using to describe your invention with synonyms, such as the alternative terms you came up with in Step 1. For example, if you find searching for "CPC Scheme car mirror" is getting unsatisfactory results, try searching instead with "CPC Scheme vehicle mirror." (If you continue to be disappointed with the CPC Classification search results, look for your search word in the International Patent Classification Catchword Index http://www.uspto.gov/learning-and-resources/support-centers/patent-and-trademark-resource-centers-ptrc/resources/seven; CPC is based on International Patent Classification).
3. Verify the relevancy of CPC classification you found by reviewing the CPC Classification Definition linked to it (if there is one).
4. Retrieve U.S. patent documents with the CPC classification you selected in the PatFT (Patents Full-Text and Image) database (http://patft.uspto.gov). Review and narrow down the most relevant patent publications by initially focusing on the front page information of abstract and representative drawings.
5. Using this selected set of most relevant patent publications, review each one in-depth for similarity to your own invention, paying close attention to the additional drawings pages, the specification and especially the claims. References cited by the applicant and/or patent examiner may lead you to additional relevant patents.
6. Retrieve U.S. published patent applications with the CPC classification you selected in Step 3 in the AppFT (Applications Full-Text and Image) database (http://appft.uspto.gov). Use the same search approach used in Step 4 of first narrowing down your results to the most relevant patent applications by studying the abstract and representative drawings of each on its front page. Then examine the selected published patent applications closely, paying close attention to the additional drawings pages, the specifications and especially the claims.
7. Broaden your search to find additional U.S. patent publications using keyword searching in PatFT or AppFT databases, classification searching of non-U.S. patents on the European Patent Office's Worldwide Espacenet patent database (http://worldwide.espacenet.com) and searching non-patent literature disclosures of inventions using the free electronic and print resources of your nearest Patent and Trademark Resource Center (http://www.uspto.gov/ptrc).