Engineering Library

Class Searching: Searching for Patents Issued Before 1969

The CASSIS Bibliographic Information Files database indexes patents issued from 1969 to the present. If you are searching for an invention that could have been patented earlier than 1969, you will need to search your class and subclass numbers again, in the Classification Information Files database.

For any class and subclass number, the Classification Files database will provide the list of patent numbers issued with that class and subclass, from 1790 to the present. The Classification Information Files database provides no title, abstract, date, assignee, or inventor information.

Step 1: Starting the Classification Information Files Database

On the CASSIS Terminal:
Check the screen to see if Cassis Workstation appears at the top. If it doesn't click "HOME" if available or press the F10 key then Enter (Proceed) to reach the menu.

From the Main menu select Patents, then Patents CLASS. Then click to start the Classification Information File - By subclass. When the title screen comes up press any key to continue.

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Step 2: Enter Your Search

Once you have opened the database, use the arrow keys to highlight the classification line. Type your classification and subclassification on the line as shown here (with a slash mark between the numbers) and then press the Enter key:

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The 1 that will appear in the right-hand column is the total number of classifications in the database that match your search.

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Step 3: List Your Search Results

To find out how many patents are in this classification press F3 key at the top of the keyboard to DISPLAY the list of these patent numbers. This list will provide only the patent number -- no title information is available.

Each patent number will be followed by the designtion O or X, indicating Original Classification and Cross Reference Classification, respectively. The distinction between them is irrelevant for a patent search.

Once the first screen of the patent number list appears, you may move up and down through the list with the keyboard's arrow keys, or with the Page Up and Page Down keys.

This is the first page of the 115 patent numbers

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Pressing the Page Down key provides you with the second page.

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For more information about these patents you will need to look at the Summaries or the Full Text of the Patents.

Information about printing and downloading search results.
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Send them to the Engineering Library: englib@u.washington.edu
Last modified: Thursday September 23 2004