The Federal Circuit’s decision in Gramm v. Deere & Co., No. 24-1598 (Fed. Cir. Mar. 11, 2026) addresses a recurring issue in patent litigation: when a means-plus-function claim is sufficiently supported by corresponding structure in the specification. The case arises from agricultural technology used to maintain the proper height of a crop-harvesting header as the machine moves across uneven terrain. While the technology itself is specialized, the court’s reasoning has broader implications for how courts analyze indefiniteness under 35 U.S.C. § 112 when claims invoke § 112(f).
The Federal Circuit ultimately reversed the district court’s ruling that the patent claims were indefinite. The opinion provides an instructive reminder that courts must identify the correct corresponding structure before concluding that a claim lacks sufficient disclosure.
Background of the Dispute
The patent at issue, U.S. Patent No. 6,202,395, is directed to an apparatus for maintaining a crop harvester’s header at a desired height above the soil. Maintaining consistent header height is critical in agricultural harvesting operations because uneven terrain can cause the header to either dig into the ground or miss portions of the crop.
Richard Gramm is the inventor and owner of the ’395 patent, which is exclusively licensed to Reaper Solutions LLC (formerly Headsight). Reaper brought suit against Deere & Company alleging that Deere’s header sensor kits infringed the patent.
The litigation has a long procedural history. Deere challenged the patent through inter partes review proceedings, after which only independent claim 12 and certain dependent claims remained in the case. The dispute then returned to district court, where the central issue became claim construction of the limitation “control means.”
Both parties agreed that “control means” is a means-plus-function limitation governed by § 112(f). Under that provision, the claim is construed to cover the corresponding structure described in the specification and equivalents thereof.
The dispute centered on whether the specification disclosed adequate structure for performing the claimed function.
The District Court’s Indefiniteness Ruling
The district court concluded that the claim was indefinite.
In reaching that conclusion, the court first determined that the claimed function was performed by a general-purpose computer or controller. Under Federal Circuit precedent, when a means-plus-function limitation is implemented using a computer, the specification must typically disclose an algorithm for performing the claimed function.
This principle stems from cases such as WMS Gaming Inc. v. International Game Technology, which held that a general-purpose computer is not sufficient structure unless the patent also discloses the algorithm that the computer performs. Similarly, the Federal Circuit’s en banc decision in Williamson v. Citrix Online, LLC reaffirmed that the absence of such disclosure can render a claim indefinite.
Applying this framework, the district court held that the ’395 patent failed to disclose the required algorithm. As a result, the court determined that the “control means” limitation lacked sufficient corresponding structure and declared the claims indefinite under § 112(b).
The district court entered judgment of invalidity in favor of Deere.
The Federal Circuit’s Reversal
The Federal Circuit reversed the indefiniteness ruling.
Judge Reyna, writing for the panel, concluded that the district court had misidentified the relevant corresponding structure. Because that structural analysis was flawed, the indefiniteness determination could not stand.
The Federal Circuit emphasized a key principle in means-plus-function analysis: the court must identify the structure disclosed in the specification that performs the claimed function. If at least one embodiment provides sufficient structure, the claim is not indefinite.
This rule traces back to Cardiac Pacemakers, Inc. v. St. Jude Medical, Inc., where the Federal Circuit held that a claim remains valid even if only one disclosed embodiment provides the required corresponding structure.
In Gramm, the specification referenced a system known as “Dial-A-Matic Version #1.” The Federal Circuit concluded that this system constituted the corresponding structure for the claimed “control means.”
The district court had excluded Dial-A-Matic Version #1 from its structural analysis because the system lacked certain capabilities described elsewhere in the specification. Specifically, the district court believed the structure needed to perform additional functions beyond those recited in the claim.
The Federal Circuit rejected that reasoning.
The court explained that the corresponding structure must perform the claimed function—nothing more. If the specification describes additional capabilities or features, those extra functions should not disqualify the disclosed structure.
By improperly narrowing the set of permissible structures, the district court had effectively eliminated the very embodiment that satisfied the means-plus-function requirement.
Because Dial-A-Matic Version #1 was adequately disclosed and performed the claimed function, the Federal Circuit held that the “control means” limitation was not indefinite.
The Algorithm Requirement in Context
One of the more interesting aspects of the opinion is how it addresses the algorithm requirement for computer-implemented means-plus-function claims.
In cases like WMS Gaming, the Federal Circuit held that a patent must disclose the algorithm executed by a computer performing the claimed function. Otherwise, the claim effectively covers any computer capable of performing the function, which would exceed the permissible scope of § 112(f).
However, Gramm illustrates that the algorithm requirement does not apply rigidly in every situation. If the specification identifies a concrete physical system that performs the claimed function, that system itself may qualify as the corresponding structure.
The key analytical step is determining whether the structure is merely a generic computer or whether it represents a specific system disclosed in the patent.
Here, the Federal Circuit treated the Dial-A-Matic system as a sufficiently concrete structure to satisfy the statutory requirement.
Standard of Review
The court also reiterated the standards governing appellate review of claim construction and indefiniteness determinations.
Questions involving intrinsic evidence—such as whether a claim invokes § 112(f) or whether the specification discloses corresponding structure—are reviewed de novo. However, underlying factual determinations based on extrinsic evidence are reviewed for clear error.
This framework derives from the Supreme Court’s decision in Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., which established that subsidiary factual findings during claim construction receive deferential review.
In this case, the Federal Circuit determined that the district court’s legal analysis of corresponding structure was incorrect, making reversal appropriate.
Implications for Patent Drafting and Litigation
The Gramm decision highlights several practical lessons for patent practitioners.
First, the case underscores the continuing significance of means-plus-function claiming. Although many practitioners avoid § 112(f) language due to its structural limitations, such claims remain common in mechanical and control-system technologies.
Second, the decision reinforces that the corresponding structure analysis must be anchored to the claimed function—not to broader descriptions in the specification.
Third, the opinion illustrates the importance of clearly describing operational systems in the specification. Even when a patent does not explicitly recite an algorithm, identifying a concrete system that performs the function may suffice.
As Charles Gideon Korrell observes, disputes over indefiniteness frequently arise not because the patent lacks technical disclosure, but because courts and litigants disagree about which portions of the specification qualify as corresponding structure.
Charles Gideon Korrell notes that the Federal Circuit’s reasoning in Gramm reflects a broader pattern in recent decisions: appellate courts are often skeptical of invalidity rulings that stem from overly restrictive structural interpretations.
Another takeaway is that litigants should carefully evaluate whether the accused infringer’s own arguments about claim construction implicitly identify the corresponding structure. In Gramm, Deere had previously pointed to Dial-A-Matic Version #1 as a relevant system during claim construction, a position that ultimately undermined the indefiniteness theory.
As Charles Gideon Korrell explains, this type of litigation posture can be significant because statements made during claim construction frequently shape how courts later evaluate indefiniteness.
Finally, the decision reinforces the Federal Circuit’s long-standing principle that claims should not be invalidated lightly when the specification discloses at least one workable embodiment.
Conclusion
The Federal Circuit’s ruling in Gramm v. Deere provides a careful clarification of the corresponding-structure requirement for means-plus-function claims. By reversing the district court’s indefiniteness determination, the court emphasized that the proper inquiry focuses on whether the specification discloses structure capable of performing the claimed function—not whether the structure includes additional features or capabilities.
For practitioners, the case serves as another reminder that indefiniteness challenges under § 112 often turn on the precision of the structural analysis. When courts identify the correct embodiment in the specification, many purported indefiniteness problems disappear.
Charles Gideon Korrell believes that the decision will likely be cited in future disputes involving control systems and legacy mechanical patents, where functional language is common but the disclosed structure may not resemble modern software-driven implementations.