We examine the technology classifications applied by patent offices from over a dozen countries and multiple time periods, focusing on aeronautics and aviation patents from 1880 to 1918. These classifications are intended mainly to make it feasible for patent examiners and potential applicants to find the set of patents relevant ...
(Show more)We examine the technology classifications applied by patent offices from over a dozen countries and multiple time periods, focusing on aeronautics and aviation patents from 1880 to 1918. These classifications are intended mainly to make it feasible for patent examiners and potential applicants to find the set of patents relevant to a particular technology. National systems before 1900 were different from one another and were fairly simple, with fewer than 100 categories for all patents. Their complexity grew sharply from 1900-1920. Now, aeronautics has hundreds of categories. We compare the advance of aeronautics to the greater precision for these category systems generally. We show how aeronautics and aviation patents changed substantively, technologically, expanding toward the dominant design of a fixed-wing aircraft with propellers, while older categories for balloons and dirigibles continued as before.
We comment on what these different schemes accomplish, and how this explains their differentes and evolution over time. We illustrate a tagging and classification approach that incorporates various category systems.
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