Patent Searching: Tips for Inventors

Nearly any patent professional will recommend a formal patent search before filing a patent application. While a search is costly, it can actually save money. A search can reveal that someone else already invented your invention. This knowledge saves the time and expense of filing a patent application that would later be rejected.

If you're interested in saving the money involved in a formal search, you may consider doing an informal search yourself. If you find that your invention already exists, you will save the cost of the formal search.

There are several methods for searching for patents.
You can go to the USPTO in Arlington, Virginia
You can go to your local depository library - Oklahoma's can be found here, information for depository libraries in general can be found here
You can search on the USPTO website

A good place to start a website search is a keyword search.
Go to www.uspto.gov
Click on "search" under "Patents" on the left side of the screen
Click on "quick search" in the upper portion of the green box on the left
Enter search terms in one or both of the boxes (usually it's best to leave everything else the same as the default screen)
Click on "search"
Go through the resulting list to see what patents are like your invention, noting any differences between the patent and your invention

Another way to check for prior art is to use the Classification Codes. This helps reduce the difficulty associated with different patents using different terms for the same thing (ex: car, vehicle, automobile, motor-coach). It also allows you to find relevant patents that issued before 1976. There's an index and manual for classification codes, but there's an easier way. Using the patents you found using the keyword search, look at the classification codes of those patents most similar to your invention. There will be several codes following the words "Current U.S. Class." There will also be codes listed after the words "Field of Search." You can use these codes to find other similar patents.

Go to www.uspto.gov
Click on "search" under "Patents" on the left side of the screen
Click on "advanced search" in the upper portion of the green box on the left
Enter "ccl/xxx/xxx" where "xxx/xxx" is the code you found.
Change the pull-down option from "1976 to present" to "1790 to present"
Click on "search"

Go through the resulting list to see what patents are like your invention, noting any differences between the patent and your invention

If don't find any patents on your invention, the next step is consulting a patent professional, who will likely recommend a formal patent search. This search is done by a professional, who is more adept at searching and can find patents (and other prior art) unavailable on the website.