Case Explained: RIDGE CORP v. KIRK NATIONALEASE CO

Court: United States Court of Appeals for the Federal Circuit

Filed: 2026-07-13

The Federal Circuit reversed the district court’s grant of a preliminary injunction against the defendants, holding that the plaintiffs failed to establish a likelihood of success on the merits of their patent infringement claims and failed to demonstrate irreparable harm. The court applied the standard for preliminary injunctions under Sixth Circuit law, which requires de novo review of the likelihood of success on the merits and abuse of discretion review for the ultimate balancing of equitable factors. The court determined that the defendants raised substantial questions regarding three specific claim limitations of U.S. Patent No. 9,151,084. First, regarding the requirement that the panel be “flexible along [its] entire length,” the court found that the accused door’s panel was rigid and only made flexible through routed compression gaps, which did not satisfy the plain meaning of the claim language supported by the prosecution history. Second, concerning the limitation that “foam insulating material form[] the second outermost surface,” the court agreed with the defendants that the accused “sandwich” construction, where foam is sandwiched between two thermoplastic membranes, does not meet the requirement that the foam itself form an outermost surface. Third, regarding the term “insulated overhead door,” the court concluded that the specification and industry evidence indicate the term refers to doors suitable for cold storage applications; consequently, there was a substantial question as to whether the accused door met this functional requirement. Additionally, the court ruled that the district court erred in finding irreparable harm. The plaintiffs’ claim of price erosion lacked a causal nexus between their reduced prices and the defendants’ sales, particularly given that the plaintiffs had not sold any doors prior to the first injunction and faced no competition for a year afterward. Furthermore, the court found insufficient evidence that past allegations of false marking or tortious interference indicated a substantial risk of future injury necessary to justify forward-looking injunctive relief. The practical consequence is that the preliminary injunction is vacated, and the case is remanded to the United States District Court for the Southern District of Ohio for further proceedings consistent with this opinion. The defendants are awarded their costs on appeal.

Do It For The Case Law is a news reporting service. Nothing in this episode constitutes legal advice.