The USPTO Patent Search Strategy: Step 4— Classification Search
How’s it going? You’re halfway through the USPTO Search Strategy at this point.
You’ve got a full list of terms describing your invention, you’ve learned your way around the Patent Public Search environment, and you’ve unearthed some patent documentation that has given you a good idea as to what other similar inventions may or may not exist compared to you own.
It’s a lot of work, I know. I’ve done this for over a decade!
Just keep in mind your time spent on a prior art search will help save you time and money in the future in determining if applying for a patent for your idea is the best next step.
Ok. Step 4:
Expand the search with relevant CPC classifications.
Go to the Classification Resources page and select the CPC classification system. Find a relevant classification and use it in a classification search in Patent Public Search’s Advanced Search with the .CPC. field code.
USPTO Classification Resource search interface
CPC Classification. Great. What is this and why is it important?
In short, CPC classification is effectively an internationally agreed upon index of all the various types of inventive technologies, from medical devices to construction tools, software to biological structures, and everything in between.
(In long … well … you can read about CPC classification here.)
What is important about it is that it a further tool in assisting you, the invention, to cover all of your patent research bases when doing a prior art search.
All patents and patent applications are assigned to various classification numbers based on the content of the invention. You want to review those areas which are most pertinent to yours.
Keywords alone are not good enough because inventions can be described using many different terms, some that you may not think about or come across, some that may not appear to describe at all what your invention encompasses. But that may be found in CPC classifications.
Suppose for example you invented a new type of hammer. Some common keywords may be “handle, metal, tool, hand-held”. However, there may be a patent out there that describes a hammer without using any of these terms at all. When words fail, turn to classification searching.
Example of classification groups and subgroups pertinent to hammer devices
For example, would you have used the term “percussive” in your description of a hammer? Well, one of the relevant CPC classifications is titled just that “Percussive Tools”. Another is “Hand-held nailing tool”.
You will also want to take into account aspects of your invention which may be described in classifications specific to components of your idea, such as just the handle of your hammer. Would you have thought of the term “implement” in your keyword search?
Once you have scoured the CPC Classification for relevant symbols, you’re going to want to go back to the Patent Search interface and search specifically for documents within these CPC areas.
Ideally you will want to scroll through all categorized patent documents, concentrating mainly on the front pages at this point to recognize anything similar.
In the case of the hammer you will want to include something similar to:
B25D1/00.cpc. OR B25C1/02.cpc. OR B25G1/02.cpc.
Secondarily, you can incorporate keyword searching restricted to CPC classification areas to narrow down your search.
B25D1/00.cpc. AND (metal WITH head) AND (rubber WITH handle)
And this almost wraps up searching with the USPTO Public Patent Search tool.
The next step also includes a very important element of published patent literature easily utilized by the public search tool: forward and backward citations.
