Searching patents and published applications by classification usually results in a more comprehensive search than one done by word and phrases (keyword searching).Use this process to find a classification that matches your interest:
Find a few similar patents
Note the classifications assigned to those patents
Search the classes in a different patent search tools (Patent Lens, Espacenet, USPTO, etc)
Read the definitions of those classes
Search on the relevant classification codes
Repeat the process until you are satisfied you have found patents to suit your purpose
University of Central Florida Libraries offers this quick and helpful video explaining patent classification and how to conduct a search in Espacenet.
Using keywords to find the classifications you need:
Go to the USPTO's Classification Text Search Tool and use your keywords to search All CPC (CPC replaced USPC in 2015 and includes up-to-date utility patents).
Scan the results looking at the ones for Class Schemes (class schedules) to determine the most relevant classification to your invention.
Class Schemes are arranged hierarchically. Scan through the scheme to find the classification that is relevant to your invention. You can also use the Find function in the browser.
Click on the to review the definition and verify the relevance of the class, subclass, etc.
Once you know the classes and subclassses that work for you, you may search by those numbers in any of the patent sources.
Once you have your classification codes:
Use PatFT's Quick Search to find patents for each of your codes. Use the abstract and representative drawings to quickly assess each patent.
Next look for your codes in AppFT's Quick Search to find published patent applications. Note: These are public disclosures that are considered prior art even if the application does not result in a U.S. patent.
Google Patents covers the entire collection of granted patents and published patent applications from the USPTO, EPO, and WIPO. US patent documents date back to 1790, EPO and WIPO to 1978.
Searches patents from 95 jurisdictions, drawing from US (USPTO), European (EPO), Australian (AU), and World (WIPO) patents. The structured search allows you to create search strings and combine search concepts.
Offers free access to information about inventions and technical developments from 1782-present for European countries as well as other countries. Full-text access varies based on country.
to review the definition and verify the relevance of the class, subclass, etc.
