A patent search is performed by an inventor to determine if "prior art", that is, his or her invention already exists or has been patented in the United States or elsewhere in the world. The official database of record of United States patents resides in the USPTO website where United States patents can be researched and retrieved from the first year patents were granted in 1790 to the most recent weekly update.
3 types of U.S. patents:
1.) Utility patents granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or composition of matter.
2.) Design patents granted to anyone who invents a new, original, and ornamental design for an article of manufacture
3.) Plant patents granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant (SOURCE: USPTO website)
The USPTO has provided the below to help with searching:
It's better to search for patents using the CPC rather than keywords because patents granted between 1790 and 1975 are not keyword searchable, they are only retrievable by the patent number, the Cooperative Patent Classification (CPC) number, or the United States Patent Classification (USPC) number.
The best search strategy is to think of all terms which can be used to describe the invention. Look up these terms in the keyword search field located in the Classification Text Search box on the right side of the page to find the relevant Cooperative Patent Classification (CPC) number.
Each area of technology is identified by a CPC number. The CPC classification scheme was developed jointly by the USPTO and the European Patent Office (EPO), and it can be browsed starting with its main headings. The USPTO started classifying all granted patents and patent applications using only the CPC beginning January 1, 2015. Patents between 1790 and 2015 were classified by the United States Patent Classification (USPC) schedule. The corresponding CPC numbers have been added retrospectively to these older patents.
All newly issued patents are published weekly in the Official Gazette for Patents which is retrospectively accessible online beginning with the issue dated July 2, 2002. The preceding years beginning with volume 1 (1872) are available online via the Hathi Trust
To search in a particular index:
Searching by patent number:
Searching by inventor:
Search by Cooperative Patent Classification code: