Authored by: Jeremy J. Gustrowsky
The Federal Circuit reversed a district court’s finding that U.S. Patent No. 6,202,395 was invalid as indefinite, holding that the lower court improperly excluded a key piece of corresponding structure from its analysis of a means-plus-function claim term. The patent, owned by inventor Richard Gramm and exclusively licensed to Reaper Solutions, LLC, covers an apparatus for keeping a crop harvester’s header at a set height above the ground as the machine moves through a field. The dispute centered on whether the patent specification adequately described the structure behind a “control means” limitation in claim 12.
Both sides agreed that “control means” was a means-plus-function limitation, meaning the patent specification had to disclose adequate structure for performing the claimed function of “raising and lowering the header a designated height above the soil.” The specification referenced a “head controller” described as being “as incorporated in a Deere combine.” The parties identified three commercially available Deere controllers from 1997 (the patent’s priority date): Dial-A-Matic Versions #1, #2, and #3. Where they disagreed was which of these controllers the specification actually disclosed.
The district court sided with Deere in excluding the Dial-A-Matic Version #1 from the pool of corresponding structures. The reason? A passage in the specification mentioned that the head controller provides signals for controlling both header height and the “lateral position” of the header, and Version #1 could only control height. Because the remaining Versions #2 and #3 both used microprocessors, the district court found that the specification needed to disclose an algorithm explaining how those microprocessors worked. Finding no such algorithm, the court declared the claim indefinite and entered judgment for Deere.
The Federal Circuit found this was error. The court emphasized that corresponding structure for a means-plus-function term need only perform the function recited in the claim. Here, the claimed function was controlling header height, not lateral positioning. The fact that the specification mentioned an additional, unclaimed capability did not disqualify a structure that otherwise performed the claimed function. The court pointed to its earlier decisions in Wenger Manufacturing and Golight for the principle that courts cannot restrict corresponding structure based on unclaimed features found in a preferred embodiment. Because Dial-A-Matic Version #1 used logic circuitry (diodes, switches, and integrated circuits) rather than a microprocessor, it did not trigger the algorithm disclosure requirement at all.
With Version #1 properly back in the picture as corresponding structure, the indefiniteness finding could not stand. The Federal Circuit reversed the invalidity judgment and sent the case back to the district court for further proceedings. The decision serves as a useful reminder that when courts analyze means-plus-function limitations, the focus must stay squarely on the function the claim actually recites, not on bonus capabilities a particular embodiment happens to include.