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Patent Classification Schemes

Patent examiners typically classify an inventor’s application for a grant of patent into a number of classes, depending on that invention’s components and functions. To conduct a thorough and comprehensive patent search you should query the database by class.
• Classification brings together similar devices and concepts, even when different terms have been used to describe the inventions;
• When an invention or device is truly new there is no established or agreed terminology to describe it;
• Classification systems provide a language independent search tool, one that embraces all domains of technology;
• Patent classes are well-defined;
• Patent classes are arranged in an ordered and logical fashion;
• Patent classes are hierarchical. Classes are deconstructed into detailed sub-classes.

There are three main classification schemes in common use. These are:
1. United States Patent Classification (USPC)
2. International Patent Classification (IPC) ~ with the European Classification System (ECLA) scheme being both a variant and an extension of the IPC
3. A new (and developing) cooperative (CPC) scheme is an ongoing and evolving meld of the US and International schemes. The Cooperative Patent Classification is being developed by a partnership between the United States Patent and Trademark Office (USPTO) and the European Patent Office (EPO). The CPC is designed to replace their existing systems with a common classification scheme.