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American Patent Searching.

Steps to look up U.S. slide rule patents
by Jim Cerny in ISRG Message 22416

1. There is a list of U.S. slide rule patents on the Oughtred Society Web site at:

2. You may have a particular patent, maker, or rule in mind. For purposes of practice with the process, let's assume you are just browsing for something interesting. I decided to look at patent 2,079,464 granted to Hishasi Okura for a "Hyperbolic Slide Rule."

3. Next, go to the USPTO Web site at
The first time you need to navigate at the left to Patents->Search, which brings you to
Click on the link in the center of the page titled "How to Access Full-Page Images." Read that carefully. It explains that the USPTO's full page images of filings are scanned in a version of the TIFF format. That means you need to install a free plug-in to be able to view/print/save the page images with your browser. They include the links to where you can get these. For Windows there are two choices, AlternaTIFF and interneTIFF. Based on glancing at each site's FAQs I subjectively decided to go with interneTIFF!
Follow their directions on how to download and install it. For the first few days the product has full functionality, then some of the functions are limited unless you license it. For occasional use the free version should be sufficient.

4. OK, now you are ready to resume at the USPTO site. Assuming you are searching by patent number, go to the patent search by number page at
Copy and paste, or type, the patent number into the Query panel. It will accept it with or without commas. Click on SEARCH. (Note that some of the USPTO pages break the normal behavior of the BACK button in your browser if you get to the point of navigating back and forth among the site's pages.)

5. When it finds the match it will report that full text is not available (except for recent patents, essentially post-slide rule era), but scanned images of the pages are. Click on the Images button. The page images should display in your browser. Within the USPTO page displayed, at the top of the image, you should see a special interneTIFF tool bar. That lets you navigate back and forth through the page images, save pages, and print pages. You also end up with a utility called innoVUE installed on your system that lets you view and print pages, if you've saved them with your browser plug- in. I also found that Adobe Photoshop and Adobe Photoshop Elements could open the saved TIFF files.

Simple as all that! Except that one thing usually leads to another. In this case the patent listed Hisashi Okura as assignor of the patent to Hemmi. From the line drawing of the rule I was pretty sure it was a Hemmi 153 rule, though the model number is not given in the patent. A bit of searching with Google for Hemmi slide rule 153 brings up several matches.


- Jim Cerny


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last modified September 10, 2023