Background
Schmeisser GmbH owns U.S. Patent No. 10,866,045, which concerns a housing for a firearm cartridge magazine. Schmeisser sued AC-Unity d.o.o. and RTG Parts, LLC for allegedly infringing claims covering magazine housings with specified internal regions, walls, protrusions, and distance-related limitations. RTG Parts later settled and was dismissed, while the district court entered a preliminary injunction against AC-Unity.
After claim-construction proceedings, the District of Wyoming held that the terms “first distance (A),” “second distance (B),” “third distance (C),” and “offset (V)” were indefinite. Relying on that construction, the court granted AC-Unity partial summary judgment of invalidity and noninfringement and dissolved the preliminary injunction. AC-Unity’s separate counterclaim alleging unenforceability remained unresolved.
The Court’s Holding
The Federal Circuit exercised pendent appellate jurisdiction over the otherwise nonappealable claim-construction and partial-summary-judgment orders because they were inextricably intertwined with the appealable order dissolving the preliminary injunction. The district court had expressly based the dissolution on its claim-construction and summary-judgment rulings, so the appellate court could not meaningfully review the injunction ruling without also reviewing those orders.
On the merits, the Federal Circuit held that the distance-related terms were not indefinite. The claim language, specification, figures, and prosecution history identified what each distance represented, and the distances were measurable using conventional tools. A skilled artisan could examine a magazine housing, identify and measure the claimed distances, and determine with reasonable certainty whether the housing fell within the claims.
The district court applied the wrong legal standard by focusing on whether a skilled artisan could calculate particular distance values needed to build an operable magazine without jamming. That issue concerns enablement, not indefiniteness. The Federal Circuit therefore reversed the indefiniteness portions of the claim-construction order and the resulting partial summary judgment, vacated the order dissolving the preliminary injunction, and remanded for further proceedings.
Key Takeaways
- A claim is sufficiently definite when its scope can be determined with reasonable certainty; it need not provide every design value required to build an operable embodiment.
- Whether a skilled artisan can successfully make and use the invention is an enablement question analytically distinct from indefiniteness.
- An appellate court may exercise pendent jurisdiction when nonappealable rulings are inextricably intertwined with an appealable preliminary-injunction ruling.
Why It Matters
The nonprecedential decision reinforces the doctrinal boundary between indefiniteness and enablement. Courts evaluating definiteness must ask whether skilled artisans can understand the claims’ scope with reasonable certainty, not whether the patent supplies all parameters necessary to construct a working product.
The ruling also illustrates how an erroneous claim construction can undo downstream invalidity, noninfringement, and preliminary-injunction decisions that depend on it. Those issues return to the district court for further proceedings, while AC-Unity’s unresolved unenforceability counterclaim remains pending.