If It Walks Like a Duck

When you've just figured out how to do something , and you're pretty sure you're the first to do it, your instinct may tell you to file for a patent . Sometimes, however, you may find that the equipment you are using is very similar to what's already "out there," but that existent equipment was used for a totally different purpose. Basically, you've come up with a new application for existing technology. Can you get a patent to keep the market for your application from being swallowed up by the existing equipment manufacturers?

As lawyers like to say, "It depends", but a good rule of thumb is if you can use existing technology (with only minor parameter tweaks) to execute your application then you probably can't (or at least shouldn't be able to) get a patent . Unfortunately, as the lawyerly response suggests, none of this is clear cut.

In a recent infringement suit Toro was trying to assert its patent for an apparatus for loosening up subsurface soil by shooting high pressure jets of water through the turf at regular intervals against Deere & Company.

Deere defended itself by claiming the patent was invalid because it was anticipated by an earlier patent for a liquid fertilizer injector. Deere did not argue that the prior patent expressly disclosed all of Toro's limitations; instead Deere contended that the patent explicitly disclosed most of the Toro invention and inherently disclosed the remaining limitation . That is, Deere contended that if you build a fertilizer injection system following the teachings of the earlier patent, it would inherently have all the limitations of the Toro patent. And this inherent anticipation applies even if the earlier inventor did not recognize what was going on. (Indeed, in this case the earlier patent touted not disturbing the soil as a benefit of the fertilizer injector.)

Simply put, the Court of Appeals said, the fact that a characteristic is a necessary feature or result of a prior-art embodiment is enough for inherent anticipation , even if that fact was unknown at the time of the prior invention. ("[T]he discovery of a previously unappreciated property of a prior art composition, or of a scientific explanation for the prior art's functioning, does not render the old composition patentably new to the discoverer.").

The case is still being determined, but the lesson is clear ; if your invention walks like a duck and quacks like a duck you probably can't patent it, even if you think it's a swan.