May 6, 2009
Like case law has the key number system, patents have 4 topical indexing systems that you can use to retrieve patents about related technologies.
The 4 classification systems are the U.S. Classification system, the International Classification system, the European Classification System, and the Derwent Classification System. All of these subject classification systems use a different numbering system.
Most useful on Westlaw would be the U.S. Patent Classification system. When reviewing a U.S. patent on Westlaw, the U.S. Classification system number will be on the patent. If you run that number as a search term you will retrieve other patents classified to the same subject. In US-PAT the U.S. Classification number is in the CLA field; the International Classification number is in the IPC field. Try CLA(741/047 ) or IPC(B60R-022/48).
Many other databases useful to patent research also include these classification numbers. For instance, when trying to determine if a patent is or has been involved in litigation, search PAT-DOCK-SUM. If you are looking for patents regarding related technology that have been litigated, search using the patent classification number, for example try the International Classification number PIC(B60R-21/16) or the U.S. Classification search PUC(180) +1 169.
However, it is hard to use a classification system if you can’t browse it. We have the Derwent Classification system on Westlaw available to browse – go to the Patent Practitioner Tab, scroll the Tools (left) pane down to Derwent Research Tools, open the arrow then click on the letter you want to browse.
The Manual of U.S. Patent Classification database (FIP-USPATCL) has descriptive titles of the approximately 430 patent classes and 140,000 subclasses. To find a list of the various codes, access the FIP-USPATCL database and enter the search ci(contents). This will give you 2 documents. The first document is the numerical list of patent class codes. The second document is the alphabetical list