1. Brainstorm keywords related to the purpose, use and composition of the invention.
2. Use Ei Patents to search your keywords; gather preliminary U.S. Classifications by reviewing the abstracts and classification definitions from the Ei Patents’ records; examine the claims and drawings from the full-text of patents; examine patents under the links, “Patent Refs” and “Cited by”, for relevancy.
3. Use the U.S. Classifications you gathered to search Ei Patents by classification number. Review the abstracts, claims and drawings for relevancy. Check all references and note the U.S. Classifications and “Field of Search” areas for additional class/subclasses to search.
Seven Step Strategy (USPTO)
How to Conduct a Preliminary U.S. Patent Search (USPTO, Video)
Prior Art Searching
Prior art searching includes more than searching patent databases, but requires checking the journal literature, dissertations, conference papers, eprints, the Web and advertising sources for any previous description of the invention. Examples include Summon for a published literature search and ThomasNet for product advertising.