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Patent Searching Tips

Conducting a Patent Search in Reference Services

  1. Index to the U.S. Patent Classification (paper or Patents ASSIST CD-ROM or USPTO Website)
    Begin with this alphabetical subject index to the Manual of Classification. Look up common terms describing the invention and its function, effect, end-product, structure, and use. Note class and subclass numbers.
  2. Manual of Classification (paper or CASSIS/Patents ASSIST CD-ROM or USPTO Website)
    Locate class and subclass numbers in the Manual. Note where the terms fall within the U.S. Patent Classification System. Scan the entire class schedule, paying attention to the dot indent. Revise search strategy as needed.
  3. Classification Definitions (microfiche or Patents ASSIST CD-ROM or USPTO Website)
    Read the definitions to establish the scope of class(es) and subclass(es) relevant to the search. The definitions include important search notes and suggestions for further search.
  4. Patents Bib (CASSIS/Patents CD-ROM)
    Find out if you are on the right path: retrieve and browse through titles of patents issued in given a class and subclass. Or redirect the search: retrieve lists of patents containing applicable keywords; note their class and subclass numbers and go back to step 2.
  5. Subclass Listing (CASSIS/Patents CLASS CD-ROM)
    Once relevant class(es)/subclass(es) are identified, obtain a list of all patent numbers granted for every class and subclass to be searched.
  6. Official Gazette - Patent Section (paper or microfilm)
    Go to the Gazette and look up summaries and a representative drawing for all patents on the list(s) to eliminate patents unrelated to the invention.
  7. Complete Patent Document (microfilm or by searching the USPTO website)
    Search the complete text and drawing(s) of closely related patents to find out how different they are from the invention.