Fortress Iron, LP v. Digger Specialties, Inc.

No. 24-2313 (Fed. Cir. Apr. 2, 2026) · United States Court of Appeals for the Federal Circuit · April 2, 2026 · No. 24-2313

Summary

The United States Court of Appeals for the Federal Circuit affirmed summary judgment that Fortress Iron’s patents were invalid because they omitted an agreed-upon coinventor. The court held that the omitted coinventor was a “party concerned” under 35 U.S.C. § 256(b), requiring notice and an opportunity to be heard before correction, and that the patents could not be corrected because Fortress could not provide those protections. The court further held that a patent incorrectly listing inventors is invalid when the error cannot be corrected under § 256.

Court
United States Court of Appeals for the Federal Circuit
Writing for the Court
Lourie, Circuit Judge; Hughes, Circuit Judge; Kleeh, Chief District Judge, sitting by designation
Jurisdiction
United States Court of Appeals for the Federal Circuit
Decision date
April 2, 2026
Docket number
24-2313
Procedural posture
Fortress appealed the Northern District of Indiana's grant of summary judgment holding that two patents were invalid for omission of a coinventor and its denial of Fortress's partial summary judgment motion seeking correction of inventorship under 35 U.S.C. § 256(b).
Standard of review
Summary judgment is reviewed de novo under the law of the regional circuit, here the Seventh Circuit. The court must draw necessary factual inferences in favor of the nonmovant and affirm only if the movant is entitled to prevail as a matter of law on the stipulated facts.
Precedential value
Published and precedential
Parties
Fortress Iron, LP v. Digger Specialties, Inc.
Disposition
affirmed

Topics

patent lawpatent prosecutionsummary judgmentstatutory interpretationappellate procedure

Practice areas

patent lawpatent prosecutioncivil procedureappellate procedure

Questions Presented

  1. Whether an agreed-upon omitted coinventor is a 'party concerned' under 35 U.S.C. § 256(b) who must receive notice and an opportunity to be heard before a court orders correction of inventorship.
  2. Whether inability to provide the omitted coinventor with the notice and hearing required by § 256(b) prevents correction of the patents under that provision.
  3. Whether patents that omit an actual coinventor and cannot be corrected under § 256 are invalid for incorrect inventorship.
  4. Whether 35 U.S.C. §§ 101 and 100(f), or the repeal of former § 102(f), permit a patent involving joint invention to remain valid when fewer than all actual inventors are listed.

Holdings

  1. An agreed-upon omitted coinventor is a 'party concerned' under § 256(b) and must receive notice and an opportunity for a hearing before the court may order correction of inventorship.
  2. The notice-and-hearing requirement of § 256(b) is a prerequisite to correction, not a procedural formality that may be disregarded when the omitted inventor cannot be located.
  3. A patent that incorrectly lists its inventor or inventors and cannot be corrected according to § 256 is invalid for incorrect inventorship.
  4. When an invention has multiple inventors, all actual inventors must be listed on the patent; naming only one actual inventor does not avoid invalidity for omission of another inventor.

Key quotations

Huang, similarly, as an agreed-upon omitted coinventor, is thus a “party concerned” such that he must be given notice and opportunity for hearing prior to any correction of inventorship under § 256(b). (7)
But § 256(b) makes those procedural protections a prerequisite to relief, not a mere formality; because Fortress cannot satisfy the notice and hearing prerequisite of § 256(b), it cannot utilize that section to correct the patents. (7)
Accordingly, we hold that a patent which incorrectly lists its inventor(s) and cannot be corrected according to law is invalid. (11)

Factual background

Fortress developed vertical cable railing panels using an initial concept and designs from Fortress personnel, with manufacturing and design assistance from Chinese companies. Employees Hua-Ping Huang and Alfonso Lin suggested changes addressing cable rotation during tensioning, and those changes were incorporated into the final patented design. The patents initially named only Matthew Sherstad and Kevin Burt as inventors; Lin was later added, but Fortress could not locate Huang to provide the notice and hearing required for correction under 35 U.S.C. § 256(b).

Procedural history

Fortress sued Digger Specialties for infringement of U.S. Patents 9,790,707 and 10,883,290. During litigation, Fortress acknowledged that Hua-Ping Huang and Alfonso Lin were coinventors; Fortress successfully added Lin but could not locate Huang. The parties filed cross-motions for summary judgment. The district court denied Fortress's motion to correct inventorship, granted Digger's motion for invalidity based on incorrect inventorship, and the Federal Circuit affirmed.

Court Document

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