Free Inactive Patent Search — 100% Free Inactive Patent Information

"To find patents that have merely expired you can simply set your search terms to look for patents that are 20 years old or older. However, finding a list of inactive patents is far more challenging. This website overcomes that challenge as it allows you to search through all inactive patents in the U.S. that are less than 20 years old. We created this database to help drive open source hardware (OSH) development. Our previous work has found that patents should be significantly weakened as they are actively retarding innovation and technical progress. By properly valuing open hardware development it is clear that the return on investment for OSH development is enormous. In addition, proactive measures to defend the public domain can also provide more safe space for innovators to operate. Our hope is that this database accelerates your open hardware development.

For more information please see the article published in Inventions (2016): Open Source Database and Website to Provide Free and Open Access to Inactive U.S. Patents in the Public Domain. doi: 10.3390/inventions1040024 ..."