Opinions — Monday, July 13, 2026

The Federal Circuit reversed the Southern District of Ohio's grant of a preliminary injunction against Kirk Nationalease Co., Truck & Trailer Parts Solutions, Inc., and Altum LLC in a patent infringement action brought by Ridge Corp. and Cold Chain, LLC asserting claims 1, 12, and 17 of U.S. Patent No. 9,151,084, directed to an insulated overhead door. The court held that defendants raised substantial questions of noninfringement with respect to three claim limitations: (1) whether the accused door's panel—which becomes flexible only through routed compression gaps in an otherwise rigid structure—satisfies the requirement that the panel be "flexible along the entire length of the panel"; (2) whether a sandwich panel construction with thermoplastic membranes on both outermost surfaces satisfies the requirement that "foam insulating material form[] the second outermost surface of the door"; and (3) whether the accused door qualifies as an "insulated overhead door" suitable for cold storage applications. The court applied Federal Circuit law to the likelihood-of-success determination while reviewing the district court's ultimate preliminary injunction decision under Sixth Circuit abuse-of-discretion standards.

The decision reinforces that prosecution history statements disclaiming scope cannot be overcome at the preliminary injunction stage through post-hoc claim construction arguments. Cold Chain's representation during prosecution that the claimed panel achieves flexibility through "flexible material" comprising the "entire panel" rather than "multiple rigid hinged sections" forecloses infringement theories premised on panels with alternating flexible and rigid sections. The court's application of claim differentiation principles clarifies that dependent claims adding optional elements cannot expand independent claim scope when the independent claim language is unambiguous—here, rejecting plaintiffs' attempt to invoke unasserted dependent claim 9's "additional membrane" language to broaden claim 1's express requirement that foam form an outermost surface. The court's reliance on the specification's focus on cold storage applications to inform the meaning of "insulated" demonstrates how context-specific functional terms will be construed, even absent explicit definitions, where the specification consistently identifies a particular field of use.

In Tramec Sloan LLC v. Surti, the Federal Circuit dismissed the appeal for lack of jurisdiction under 28 U.S.C. §§ 1291 and 1295(a)(1) because the district court's denial of defendant-appellant Surti's motion to dismiss or transfer venue was an interlocutory order, not a final judgment, and did not qualify for immediate appeal under § 1292(b), the collateral order doctrine, or mandamus relief. The court ordered no costs.

The Federal Circuit vacated and remanded the Patent Trial and Appeal Board's decision upholding claims 1 and 2 of Parus Holdings' U.S. Patent No. 6,721,705, which describes a voice-operated Internet browsing system. Google had petitioned for inter partes review asserting obviousness over two prior art combinations—Kovatch in view of Burrows and Wise in view of Burrows—presenting similar theories across three related IPRs, two of which resulted in unpatentability findings that were summarily affirmed. The Board rejected Google's challenges to the '705 patent claims, finding that Google failed to prove certain polling and ranking limitations obvious.

The court held that the Board committed legal error by analyzing the Burrows reference in isolation rather than considering how a skilled artisan would have combined it with Kovatch or Wise as Google's petition specified, emphasizing that references "must be read together, not in isolation" when the petitioner's theory calls for such combined reading. The court also found an APA violation where the Board construed "unexpected response" to categorically exclude webpage content changes—relying on the patent's specification and extrinsic evidence to restrict claim scope—without affording Google notice or opportunity to address that construction, even though the parties had not disputed the term's meaning and Google had no apparent reason to anticipate the Board's interpretation.