It is useful to prepare different search terms for the invention in order to track down its initial U.S. Patent Classification class or subclass. The relevancy of the results can be verified using the U.S. Patent Classification Schedules. Because multiple search results are likely to arise, the U.S. Patent Classification Definitions can provide information to narrow the search and are hyperlinked from the U.S. Patent Classification Schedules. U.S. Patent documents and published applications by classification can be reviewed in the Patents Full-Text and Applications Full-Text databases.
If the correct patent is not found easily and multiple results come up from the initial search, relevant Cooperative Patent Classifications, or CPCs, can be found using the Statistical Mapping tool and are available to review. A classification search of CPC class schemes on the Espacenet website, only availabe through the patent office, can be conducted to expand a CPC search to other relevant CPCs. These databases and search criteria can provide the patent number once the exact patent is found.