Claim Indefiniteness After Gramm v. Deere & Company: Key Lessons from the Federal Circuit
Blog post description.
The Federal Circuit’s precedential decision in Gramm and Reaper Solutions, LLC v. Deere & Company, No. 2024-1598 (Fed. Cir. Mar. 11, 2026) provides timely and practical guidance on one of the most nuanced areas of patent law: claim indefiniteness under 35 U.S.C. § 112(f), particularly in the context of means-plus-function claiming.
For patent practitioners, inventors, and businesses alike, the case highlights a recurring tension: Functional claiming offers flexibility and breadth, but it also introduces risk if the patent specification does not adequately disclose corresponding structure. The Federal Circuit’s analysis in Gramm clarifies how much disclosure is “enough” and reinforces best practices that can determine whether a patent survives scrutiny in litigation or examination.
This decision is especially relevant for industries that rely heavily on functional language, including mechanical systems, software, and hybrid technologies. Understanding the court’s reasoning can help practitioners draft stronger patents, respond to indefiniteness challenges, and manage portfolio risk more effectively.
Understanding Means-Plus-Function Claims Under 35 U.S.C. § 112(f)
A clear understanding of the legal framework governing means-plus-function claims provides essential context for analyzing this decision.
What Is § 112(f)?
35 U.S.C. § 112(f) allows a patentee to express a claim limitation as a “means for” performing a function without reciting specific structure. In exchange for this flexibility, the claim is limited to:
The corresponding structure disclosed in the specification, and
Equivalents of that structure.
This creates a tradeoff. Broader functional language is permitted, but only if and to the extent the specification provides enough structural detail to support it.
When Do Indefiniteness Issues Arise?
A claim becomes indefinite under U.S.C. § 112(b) when it fails to inform, with reasonable certainty, those skilled in the art about the scope of the invention. In the § 112(f) context, this often occurs when:
No corresponding structure is disclosed,
The disclosed structure is too vague or generic, or
There is no clear link between the function and the structure.
The Federal Circuit has addressed these issues in prior cases, such as Williamson v. Citrix Online, LLC, 792 F.3d 1339 (Fed. Cir. 2015) and Noah Systems, Inc. v. Intuit Inc., 675 F.3d 1302 (Fed. Cir. 2012) particularly in the software context where algorithm disclosure is often required.
The Dispute in Gramm
The dispute in Gramm centered on a set of patent claims directed to a mechanical system that incorporated functional components described using means-plus-function language. These types of limitations were used to capture how certain elements of the invention operated, rather than strictly defining their physical form. As is often the case in modern patent drafting (particularly where mechanical systems intersect with control logic or automated processes) the claims relied on functional phrasing to preserve flexibility and broader coverage. Gramm sued Deere & Co. (“Deere”) for infringement of those claims.
The conflict arose when Deere, the defendant, challenged the validity of those claims, arguing that the patent specification did not provide adequate structural disclosure to support the claimed functions. According to Deere, the use of means-plus-function language required a clear identification of corresponding structures in the specification, and the absence of sufficiently detailed descriptions rendered the claims indefinite. This argument reflected a common litigation strategy: targeting functional claim language as a vulnerability under 35 U.S.C. § 112.
At the district court level, the court agreed with Deere’s position and found certain claims indefinite. The court concluded that the specification failed to disclose enough structure corresponding to the recited functions, particularly when viewed in light of the statutory requirements of § 112(f). In reaching this decision, the court appeared to take a relatively strict view of what constitutes adequate structural support, emphasizing the need for explicit and clearly identifiable disclosures tied to each claimed function. As a result, the functional language in the claims was deemed insufficiently grounded in concrete structure, leading to a finding of invalidity of the claims incorporating that functional language.
Plaintiff Gramm appealed the decision, arguing that the district court had applied an overly rigid standard and failed to properly consider how a person of ordinary skill in the art would interpret the specification. The plaintiff maintained that the patent did, in fact, disclose sufficient structural detail when read in context, including descriptions, embodiments, and illustrations that would enable a skilled artisan to understand how the claimed functions were performed. The appeal thus framed a central question that frequently arises in § 112(f) cases: how much disclosure is enough, and how should courts evaluate that disclosure in practice?
On appeal, the Federal Circuit was tasked with determining whether the specification, read from the perspective of a person of ordinary skill in the art, disclosed enough structure to satisfy § 112(f). This inquiry required the court to balance two competing considerations: 1) ensuring that claims are not so vague as to be indefinite, while 2) also recognizing that patent specifications are written for technically skilled readers who can draw reasonable inferences from the disclosed material. The outcome would ultimately clarify the level of detail required to support means-plus-function limitations and provide further guidance for both patent drafters and litigants.
Reversing the Indefiniteness Finding
The Federal Circuit reversed the district court’s ruling, holding that the claims were not indefinite. The court’s reasoning provides several important clarifications for practitioners.
1. Structural Disclosure Must Be Viewed Through the Lens of Skilled Artisans
The court emphasized that structural sufficiency is not evaluated in a vacuum. Instead, the analysis must consider what a person of ordinary skill in the art would understand from the specification.
This means that:
Detailed blueprints are not always required.
Industry-standard components or configurations may suffice.
Context matters, particularly in established technical fields.
For mechanical inventions, relatively straightforward descriptions of components and their relationships may be enough.
2. Functional Language Is Not Inherently Problematic
The Federal Circuit reaffirmed that means-plus-function claiming is expressly permitted by statute. The use of functional language does not automatically render a claim indefinite.
Indefiniteness arises only when the specification fails to provide any meaningful structural support. In Gramm, the court found that the patent included:
Descriptions of relevant components
Illustrative embodiments
Sufficient contextual detail linking function to structure.
3. The Function-to-Structure Link Is Critical
A key aspect of the decision was the requirement that the specification clearly associate the disclosed structure with the claimed function.
The court looked for:
Explicit or implicit mapping between function and structure
Logical connections that a skilled artisan could follow
Enough detail to avoid guesswork or undue experimentation.
Notably, the court signaled that the standard is not perfection, but reasonable clarity.
Turning Federal Circuit Guidance into Stronger Patent Claims
The Federal Circuit’s decision in Gramm does more than restate existing law. It provides a practical framework for how courts evaluate (or at least should evaluate) means-plus-function claims and how practitioners should approach drafting, in response. The decision reinforces that indefiniteness under 35 U.S.C. § 112(f) is not triggered by an imperfect disclosure, but by a failure to provide enough structural context for a person of ordinary skill in the art to understand how the claimed function is performed. This distinction shifts the focus away from rigid formalism and toward real-world technical understanding.
One of the most important clarifications from the case is that structural sufficiency is inherently contextual. The Federal Circuit emphasized that disclosures must be evaluated through the lens of a skilled artisan, not a lay reader or an overly technical parsing of the specification. In practice, this means patent drafters do not need to describe every component in exhaustive detail, particularly in predictable fields like mechanical engineering. Instead, the specification should provide enough information (through written descriptions, figures, or embodiments) to allow a knowledgeable reader to connect the claimed function with the corresponding structure.
At the same time, this flexibility has limits. Functional language must still be anchored to identifiable structure, and the connection between the two must be reasonably clear. Vague references to generic components or high-level descriptions of functionality will not suffice if they leave uncertainty about how the function is carried out. The court’s reasoning makes clear that clarity is a major principle.
From a drafting perspective, this guidance translates into a more deliberate and strategic approach to specification development. Practitioners should think in terms of mapping each functional limitation to corresponding structure within the specification. This does not require rigid formulas, but it does require intentionality. Visual aids such as diagrams or flowcharts can strengthen this relationship, particularly where text alone may leave room for interpretation.
In practical terms, strong § 112(f) support often includes:
Clear identification of components or structures that perform each claimed function.
Descriptions that explain how those components operate, not just what they are called.
Supporting figures or embodiments that reinforce the connection between function and structure.
The decision also highlights the importance of anticipating how claims will be interpreted in litigation. A specification that appears clear during drafting may be scrutinized aggressively later, with opposing parties searching for ambiguity. Ensuring that structural support is both present and easy to identify can significantly reduce the risk of an indefiniteness-based challenge. This is especially important for patents expected to play a central role in enforcement or licensing.
Another key takeaway is that the level of required detail varies by technology, but the underlying principle remains the same. Mechanical inventions may rely on descriptions of physical components and their relationships, while software-related inventions often require more explicit explanations of processes or algorithms. The Gramm decision does not impose a rigid rule, but it reinforces the need to tailor disclosure to the expectations of the relevant field.
For prosecution, the case offers helpful support when responding to § 112(f) rejections, particularly where examiners apply overly strict standards. At the same time, it underscores that the strongest position begins with a well-drafted specification. Addressing structural support proactively is far more effective than attempting to fix deficiencies later.
Ultimately, Gramm reinforces a balanced approach to means-plus-function claiming. Functional language remains a valuable tool, but only when supported by meaningful structural context. By focusing on clarity, deliberate mapping, and the perspective of skilled artisans, practitioners can draft claims that are both broad and defensible while minimizing the risk of indefiniteness, both during prosecution as well as in litigation.
The Ripple Effects of Gramm on Intellectual Property Practice
The Federal Circuit’s decision in Gramm reflects a continued shift toward a more practical, context-driven approach to evaluating patent claims, particularly those that rely on functional language. Rather than imposing rigid requirements, the court reinforced that validity under § 112(f) depends on whether the disclosure meaningfully informs a skilled artisan. This approach has important implications for how patents are drafted, examined, and enforced.
One of the most notable impacts of the decision is the increased predictability it brings to means-plus-function analysis. Practitioners have long faced uncertainty regarding how much structural disclosure is sufficient. Gramm helps reduce that uncertainty by reaffirming that sufficiency is a contextual inquiry grounded in the perspective of skilled artisans.
At the same time, the decision makes clear that functional claim language will continue to face scrutiny, especially in high-stakes litigation. The court did not lower the bar but clarified that the standard is one of meaningful disclosure. For businesses relying on patents as strategic assets, this reinforces the importance of strong, well-supported specifications.
In practical terms, the decision highlights several key implications for patent strategy:
Functional claiming remains viable, but only when clearly tied to identifiable structure.
Courts are likely to reject overly rigid indefiniteness-based arguments or positions that ignore the perspective of skilled artisans.
The ruling is particularly relevant for industries in which functional language is common, such as advanced manufacturing, robotics, and software-enabled mechanical systems. These fields often rely on describing what a system does rather than detailing every physical component. Gramm confirms that this approach is acceptable, but only when the specification provides enough context to bridge function and structure.
From a portfolio management standpoint, the decision may prompt companies to reassess existing patents. Older assets, especially, may lack the level of structural clarity now expected in litigation. Reviewing key patents with an eye toward § 112(f) support can help identify vulnerabilities before they become disputes.
When evaluating patents in light of Gramm, practitioners and businesses should consider:
Whether each functional limitation is supported by clearly identifiable structure in the specification.
Whether a skilled artisan could implement the claimed function without undue experimentation.
Whether the connection between function and structure is easy to explain in litigation.
Ultimately, Gramm reinforces a central principle: flexibility in claim drafting must be balanced with clarity in disclosure. The decision does not discourage means-plus-function claims, but it emphasizes that their strength depends on the quality and clarity of the supporting specification. Practitioners who internalize this balance will be better positioned to secure and defend valuable patent rights.
Gramm serves as a practical and authoritative guide for navigating means-plus-function claiming. The Federal Circuit’s decision reinforces a balanced approach: functional language is permissible and valuable, but only when grounded in meaningful structural disclosure.
For patent professionals, the message is clear: careful drafting and thoughtful specification development are essential to ensuring that patents remain enforceable and resilient. Applying the lessons from this case allows practitioners to better align their strategies with Federal Circuit (and other courts’) expectations and develop stronger, more defensible patent portfolios.
If you’re interested in learning more about this topic or how the principles discussed in this article may impact your business, don’t hesitate to contact us at info@patentxl.com or at +1(610)871-2024.
