How to Search for Patents
Are you interested in the history of a certain invention or inventor? Do you want to get rich with an idea for a new product? If so, you should be interested in patent research. The Business, Science, and Technology Department (BST) can help you search for patents.
This guide discusses five key topics:
As David Pressman explains in Patent It Yourself, 9th ed (Berkeley, CA: Nolo, 2002. T339.P74 2002Q), “A patent gives its owner—the inventor or the person or business to whom the inventor legally transfers the patent—the right to exclude others from making, using, or selling the invention ‘claimed’ in the patent deed.”
In the United States, inventors apply for patents through the U.S. Patent and Trademark Office (USPTO), which examines patent application claims and grants patents.
A great deal of information can be found in a patent, including:
- Name of the invention
- Name and contact information of the patent holder/inventor
- Patent filing (application) date and issue (grant) date
- Drawings/illustrations
- Abstracts and summaries, as well as details of the inventor
- Previous, related inventions
- Claims (the legal boundaries of the patent)
Most patents are “utility” patents, protecting a new, useful device. However, there are also “design” patents (protecting the shape or ornamental design of a product) and other types of patents.
Patents differ from trademarks and copyrights.
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Trademarks often relate to the “look” of a business, brand, or product: consistent and distinctive logos, names, symbols, and other stylistic elements that would help a customer recognize the business, product, or brand. The characteristic script of Coca-ColaÒ is one example of a trademark.
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Copyright protects original creative work such as art, books, music lyrics, and Web pages.
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For more information about different types of intellectual property, see the various Nolo publications, the Nolo.com online “Law Centers”, or the USPTO’s page, “What are Patents, Trademarks, Servicemarks, and Copyrights?”.
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There are basically two ways of searching for U.S. patents:
The USPTO Web Site
Print Resources
The USPTO Web Site
Because of backlogs in publishing printed patent indexes, the USPTO’s Web site is the best way for finding recent patents. The site is also handy if you don’t have a lot of time to page through print indexes, or you aren’t able to get to a library.
If you are searching for a particular patent, the U.S. Patent and Trademark Office provides two databases, one for issued (granted) patents and another for patent applications. You can access them for free on the USPTO’s site.
- For patents 1976-present:
- You can search and read the full text (beginning to end) without any special viewer.
- You can also see images of the front page, drawings, specifications, and claims if you download and use a browser plug-in.
- For earlier patents (back to 1790):
- You can search only by patent number or current US patent classification.
- You will only be able to access digitized images of the patent’s first page, drawings, specifications, and claims.
- To view these earlier patent images, you need to download and use a browser plug-in that can read TIFF files using ITU T.6 or CCITT Group 4 (G4) compression.
If you want to find patents that have been issued over the past few weeks, you can use the online version of the USPTO’s Official Gazette.
Print Resources
The Pratt Library’s print resources are an important back-up if you are having difficulty using the USPTO Web site. At the Library, you can use indexes to identify patents. You can also use the Official Gazette of the U.S. Patent and Trademark Office to get a summary of the patent and a diagram.
Indexes
To find a summary and diagram of a patent in the Official Gazette, you need to know the patent number or the date the patent was granted. BST has several indexes that can help:
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Annual Report of the Commissioner of Patents. Washington: Government Printing Office, Annual. (XT223.H3)
The Pratt Library owns each volume of the Annual Report for 1845-1925. This is especially important as a “bridge” between the Index of Patents (1921-1995) and earlier print indexes (covering up to the 1870s). Within each year’s Annual Report, you can find lists of patents by the name of inventor.
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Index to the U.S. Patent Classification System. Washington: U.S. Patent and Trademark Office, Annual (XT223.F44Q).
If you are looking for “all” patents of a certain type of device or design, it’s helpful to know the patent class and subclass.
- The class and subclass are numbers that the USPTO uses to designate inventions by type. For instance, the patent class and subclass for Electric Can Openers is 30 401.
- You can use the class and subclass numbers to search the USPTO’s patent databases and browse recent issues of the online Official Gazette.
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List of Patents and Designs Issued by the United States from 1790 to 1847… Washington: J. and G.S. Gideon, 1847 (XT223.C 1847).
If you only know the name of an inventor, you can use the name index at the end of this List of Patents. The index will refer you to a page giving the name of the invention and the date the patent was issued.
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Subject-Matter Index of Patents for Inventions Issued by the United States Patent Office from 1790 to 1873… 3 vols. Washington: Government Printing Office, 1874 (XT223.D25Q).
If you know the name or function of an invention, you can use the Subject-Matter Index to find out the inventor’s name, patent date, and patent number.
Summaries and diagrams
Once you know the patent number or date,
- Use the Official Gazette of the United States Patent and Trademark Office (Washington: U.S. Department of Commerce, weekly. XT223.A3Q) to find a shortened version of the patent.
- The Gazette publishes information about patents granted for the week, in order by patent number.
- For each patent, the Gazette gives the name of the invention and inventor, one diagram, and the patent’s legal claims.
- The Pratt Library has most issues of the Gazette, going back to 1872.
The U.S. Government does not distribute full copies of patents to every library. For a complete copy of a U.S. patent, you need to find it on the USPTO’s Web site, or visit a Patent and Trademark Depository Library.
Maryland’s Patent Depository Library is the Engineering and Physical Sciences Library at the University of Maryland, College Park. College Park’s patents collection includes microfilm copies of utility patents (1790-present), design patents (1842-present), and other patent-related literature and indexes.
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If you are patenting an invention, you need to consider patents held in other countries. Though the Pratt Library does not currently subscribe to sources for searching patents internationally, there are some resources that can help:
- If you are looking for “all” inventions of a certain type, you can use an online version of the US to IPC Concordance, 7th ed to find out which International Patent Class corresponds to a particular U.S. class.
- With a paid subscription, Delphion (formerly IBM’s intellectual property network) allows you to search
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Derwent World Patents Index (1963-present)
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European Patent Applications (1979-present) and Grants (1980-present)
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INPADOC (1968-present), Patent Abstracts of Japan (1976-present)
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WIPO PCT Publications (1978-present)
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BST owns a handmade card index called “Inventions by Blacks,” which we will search on request. “Inventions by Blacks” consists of approximately 500 cards, focusing on 19th century inventions. Cards are in alphabetical order by name of invention and give the name of the inventor, the U.S. patent number, and the patent grant date.
The Library also has other sources, including:
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African American Firsts in Science and Technology. Raymond B. Webster. Detroit: Gale Group, 1999 (Q141.W43 1999).
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Black Inventors of America. McKinley Burt. Portland, OR: National Book Company, 1989 (XT39.B87 1989Q).
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Creativity and Inventions: The Genius of Afro-Americans and Women in the United States and Their Patents. Patricia Carter Ives. Arlington, VA: Research Unlimited, 1987 (T21.I84 1987Q).
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If you are planning to patent an invention, you should seriously consider hiring a patent attorney. Martindale-Hubble offers a Lawyer Locator, which you can search by specialty (“Intellectual Property”), location (Maryland), and other criteria. The USPTO also offers a database of registered patent attorneys and agents.
Also, Nolo Press publishes three very helpful books, which BST owns:
- Stephen Elias’ Patent, Copyright and Trademark, 4th ed. (Berkeley, CA: Nolo, 2001. T223 .E45 2001)
- David Hitchcock’s Patent Searching Made Easy, 2nd ed. (Berkeley, CA: Nolo, 2000. T210.H58 2000Q)
- David Pressman’s Patent It Yourself, 9th ed. (Berkeley, CA: Nolo, 2002. T339.P74 2002Q)
If you have no library access, or you’ve tried these sources and still can’t find what you’re looking for, please e-mail us, call (410) 396-5317, or contact us by snail-mail:
Business, Science, and Technology Department
Enoch Pratt Free Library
State Library Resource Center
400 Cathedral Street
Baltimore, MD 21201
