The Vertex Angle - Fall 2002

In the Fall 2002 Vertex Angle newsletter, we asked the following question.

"Approximately how many mousetrap patents have been issued in the US since 1903?"

One Internet source indicates that 4400 mousetrap patents have been issued since John Mast's patent and over 400 mousetrap patents are filed in the United States Patent and Trademark Office (USPTO) annually. However, our own USPTO patent database search yields somewhat less prolific numbers.

The USPTO offers the public a database of issued and pending published patents plus a search engine that permits patent searches of varying degrees of complexity. One simple method of searching patents is by "key word" in the title or abstract of the patent. The USPTO database contains patents issued since 1790 but only post-1975 patents can be "keyword" searched.

A search for "MOUSETRAP" in the title yields 42 issued patents, while a similar search on "MOUSE TRAP" (two words) yields an additional 46 issued patents. However, a closer inspection of these 88 issued patents indicates that "mousetrap" and "mouse trap" are terms also used to describe computer logic switches and mechanisms unrelated to trapping mice. In addition, the USPTO lists both design patents (i.e. industrial designs) and utility patents on the same database. This would suggest that the number of mousetrap utility patents issued since 1975 is 71.

Another search method relies upon patent classifications. Each patent falls into one of several hundred classifications related to functionality. For example, a snap-trap design falls into classification 43, "Fishing, trapping and vermin destroying", and sub-classification 81, with "swinging-striker". There are 479 issued patents in class 43/81, since the patent system was established in 1790, with 107 of these patents predating the 1903 Mast patent. Again, this number is somewhat misleading because some of these patents are not related to trapping mice.

Another potential sub-classification to search is 61, which applies to a "Swing or sliding enclosures". There are 548 issued patents in class 43/81 with a number of these patents related to mousetraps. While searching additional classifications and sub-classifications may identify a few additional mousetrap patents, it appears the classifications 43/81 and 43/61 have captured the vast majority of issued mousetrap patents.

So what's the answer? Well, given the limitations of the USPTO database, a reasonable estimate would be more than 300 but certainly less than 1000. So, the correct answer is (d).

By comparison, at the end of 2002 there were 119 issued patents related to transgenic mice and a further 74 patent pending and published applications. Given the growth rate of the biotechnology sector, it is apparent that the day will soon come that there will be more patents issued for mice than for mousetraps!

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