Source: Iowa University Libraries Patents Guide guides.lib.uiowa.edu/patents
Patents CANNOT be searched by keyword alone. The U.S. and other countries have classification systems that categorize issued and pending patents into technology groups identified by a number, and these must be used in order to do a thorough search. Start with a keyword search in Google Patents to identify relevant patents, examine their classifications, and then search key classifications. Google Patents may be used on its own to identify just one or two relevant patents.
Steps to Starting a Preliminary U.S. Patent Search
4. In the blue box:
Download the PDF
See Patent citations – other patents cited by this patent
See Cited by – patents that have cited this patent
Click on the USPTO link to view the patent at USPTO
5. Classifications
Note the CPC classifications/technology areas
Review the definitions https://www.uspto.gov/web/patents/classification/
This video from the Purdue Northwest Library will walk you through the basics of searching for patents in Google Patents.