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A USPTO Search

In my previous post I discussed keyword, classification and ambient knowledge searches, and promised to provide a concrete example, specifically an example of a USPTO search.

So let’s get right down to it, using as our example US patent number 7,062,800, titled “Plunger.”  US patents and patent publications are conveniently accessed at Google Patents ( or any number of other sites; my favorite is Free Patents Online (, which conveniently offers access to a good variety of non-US patent documents, and which also has a number of search features that I use quite regularly.  Although you can follow along with the html version of this patent, it’s usually more useful to obtain a .pdf, or otherwise obtain access to some form of the patent document that provides the drawings.

Once you’ve gotten US7,062,800, look on the front page until you find the application number — in this case 10/808,096.  What we’re going to do now is to use the USPTO’s  public Patent Application Information Retrieval (public PAIR) system to download all1 of the documents that have passed back and forth between the applicant for this patent and the USPTO during the course of examination of this patent — that is, during the “prosecution” of this patent application.  In order to accomplish this feat, go to and enter the appropriate words in the CAPTCHA box; assuming you’ve been lucky enough to be able to correctly read the gibberish present therein, you should then be able to search for the application number by leaving that radio button for that option selected (it’s the default option) and entering the number as an unbroken string of numbers, in this case “10808096” (but without the quotes).

Once you’ve run the search, you should get a “Bibliographic Data” page with a number of tabs across the top.  Click on the “Image File Wrapper” tab, then click the check box immediately to the left of the blue “PDF” button at the top of the rightmost column, and then click the blue “PDF” button itself to save the complete prosecution history.2

You’re almost there.  Open up the downloaded .pdf and go to page 52, where you’ll see a “Search Notes” form, and on it an indication that the Examiner in this plunger case searched for earlier patent art is US class 4, subclasses 255.01, 255.05, 255.08, 255.11 and 255.12.  This makes perfect sense since you can search for class 4 (at and find that it corresponds to “BATHS, CLOSETS, SINKS, AND SPITTOONS,” with subclass 255.1 corresponding to a subclass of class 4 titled “OBSTRUCTION REMOVER,” subclass 255.05 to a subsubclass of 255.1, directed to “With Force Cup (e.g., a plunger),” etc.

That’s an example of classification searching.  Now go to page 11 of the .pdf and you’ll see that the Examiner performed a second search later on in prosecution, in which he updated his earlier search (this time skipping 4/255.080); if you go to page 12 of the .pdf you’ll see that there are now also keyword searches, which have been run in the USPTO’s proprietary EAST search system.3  I’m not going to cover the syntaxis of these searches, but a cursory look should convince you that it basically involves proximity searching for multiple keywords, often with stemming thrown in.

That same cursory look should also convince you that there’s nothing especially spiffy4 in what the USPTO does, nor indeed is there any spiffyness manifest in the computerized search systems of any of the other worldwide patent offices.  However, despite the same basic approach, there’s a lot to be learned from looking at the search methodologies that patent offices use — and, if you have a patent application in prosecution, at the specific searches your Examiner or Examiners have been using.

Quite truthfully, I always find it very sobering to look at patent office searches, particularly keyword searches, because they remind me of the extent to which art is cited based on choice of keywords.  And keywords, to continue the “choice of nets” theme, are not nearly as easy to pick as people usually think.

But that’s a topic for another post.

  1. Apart from copyrighted articles, which are not downloadable in this public PAIR system in order to prevent copyright violation. []
  2. Again, apart from copyrighted documents.  You may also find that file history information is not available for older serial numbers.  Also, be aware that the USPTO does not certify its electronic prosecution history files; if you want a certified file wrapper you have to order it. []
  3. Public training is available for this system as well as the WEST system; see []
  4. A patent attorney term of art. []