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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. []