Federal Circuit Widens Net for Corresponding Structure under §112(f) – Three Takeaways for Patent Counselors

Key Findings

• The Federal Circuit corrected the district court’s legal test for indefiniteness and clarified under §112(f) that corresponding structure cannot be excluded simply because it does not include unclaimed functions described in the patent.
• Additional functions disclosed in the specification do not disqualify a corresponding structure. In Gramm v. Deere, a controller that performed the claimed function of raising and lowering the header still qualified as corresponding structure even though it did not perform other functions mentioned in the patent.
• Patent counselors should consider including description of example structures for each claimed element regardless of whether the structures perform functions beyond those recited in the claims.

Overview

A recent precedential decision from the Federal Circuit clarifies that “disclosure of an added function in the specification should not disqualify structure that meets the means clause’s requirements.” Gramm v. Deere & Company, No. 2024-1598 (Fed. Cir. Mar. 11, 2026). The specification of the patent at issue described two functions and referenced several example conventional controllers. Gramm argued that all referenced conventional controllers qualified as corresponding structure under 35 U.S.C. §112(f). The district court disagreed, concluding that one controller was restricted from being corresponding structure under §112(f) because it was unable to perform one of the functions mentioned in the specification, even though that function was not part of the claimed limitation. The Federal Circuit reversed, cabining the inquiry of what qualifies as corresponding structure under §112(f) to the requirements of the claim alone.

Background of Gramm v. Deere

Richard Gramm exclusively licensed U.S. patent No. 6,202,395 (the “’395 patent”) to Reaper Solutions LLC (“Reaper”). The ’395 patent is directed to an apparatus for maintaining the header of a crop harvester a desired height above the ground as the harvester traverses a field. Gramm and Reaper sued Deere & Company (“Deere”) alleging that Deere header sensor kits infringe the ’395 patent. Deere challenged the ’395 patent in inter partes review, leaving only independent claim 12 and certain of its dependent claims as asserted.

Claim 12 includes the following relevant language: “control means … for raising or lowering the header in accordance with said first signal in maintaining the header a designated height above the soil.” Both parties agreed that “control means” is a means-plus-function limitation under 35 U.S.C. §112(f). When considering corresponding structure, the parties agreed upon a portion of the specification of the ’395 patent that described a controller as “conventional” and “as incorporated in a Deere combine.” The parties agreed that three such conventional controllers existed as of the filing date.

Deere argued that two of the conventional controllers used microprocessors and that because the ’395 Patent did not describe any algorithm, claim 12 is indefinite as to that corresponding structure. HTC Corp. v. IPCom GmbH & Co., KG, 667 F.3d 1270, 1280 (Fed. Cir. 2012); c.f. Qualcomm Inc. v. Intel Corp., 6 F.4th 1256, 1267 (Fed. Cir. 2021). As to the remaining conventional controller, Deere argued that the specification of the ’395 patent required two functions, one of which was not performed by that conventional controller. As a result, Deere argued that the remaining conventional controller could not be corresponding structure under §112(f). The district court accepted Deere’s argument and entered judgement against Reaper.

Implications of the Decision

The Federal Circuit found that the district court used the incorrect legal test to decide if “control means” was indefinite. This is because the district court excluded corresponding structure that performed the claimed function of raising and lowering the header because the excluded structure lacked lateral-position capabilities discussed only in the specification.

Gramm reiterates the roadmap for identifying corresponding structure under §112(f) and gives guidance on resolving situations where the specification describes functions not performed by the described structures. Specifically, corresponding structure under §112(f) is not required to perform more than the claimed functions, and corresponding structure does not become disqualified simply because the specification discloses additional, unclaimed functions.