Ridge Corp. et al. v. Kirk NationaLease Co. et al., Appeal No. 2025-1254 (Fed. Cir. July 13, 2026)

In its only precedential patent opinion last week, the Federal Circuit considered an appeal of a preliminary injunction issued by the U.S. District Court for the Southern District of Ohio relating to U.S. Patent No. 9,151,084, directed to “an insulated overhead door” that is designed to roll open and closed in tracks.  Based in part on numerous material claim construction disputes raising a substantial question as to whether the patentee could show infringement, the Court found that the district court erred in granting preliminary injunctive relief, reversed, and remanded for further proceedings.

While the Federal Circuit reviews the grant or denial of a preliminary injunction under the law of the appropriate regional circuit, the Federal Circuit has itself built a body of precedent applying general preliminary injunction considerations to a variety of patent law cases.  As such, “in reviewing the grant or denial of a preliminary injunction, the estimated likelihood of success in establishing infringement is governed by Federal Circuit law.” Under that precedent, if an accused infringer raises a substantial question concerning infringement, the preliminary injunction should not issue because the plaintiff has not shown a sufficient likelihood of success. The court here concluded that the defendants had raised such a substantial question, and that the district court therefore erred in granting preliminary injunctive relief.

The court first a claim limitation requiring that the overhead door include a “panel being flexible along the entire length of the panel so as to be capable of approximating the curvature of curved tracks.” The accused door was comprised of a rigid and inflexible panel, which is then modified to traverse a curved track by the routing of horizontal grooves into the panel. The court disagreed with the plaintiffs that the claim language does not require a panel that is “innately flexible,” and determined that defendants raised a substantial question regarding whether the accused door could satisfy the “flexible along its entire length” limitation. The court concluded that, although the grooves allow the panel to move along a curved track, the plaintiffs are unlikely to succeed in establishing that the door has a panel “that is flexible along its entire length” due to the inflexible panel sections between the grooves. The court also found that defendants raised a substantial question regarding whether the accused door could meet a claim limitation requiring that “foam insulating material form the second outermost surface of the door,” because the accused door has a “sandwich” construction – consisting of two thermoplastic layers surrounding a layer of foam.  Finally, the court concluded that there is a substantial question regarding whether the accused door is an “insulated overhead door” because the patent’s specification created a strong inference that an “insulated overhead door” is a door that is suitable for use in cold storage applications, which the accused door was not.

Because the court found that there was a substantial question whether the accused door could meet these three separate claim limitations, it concluded the district court erred in determining that the plaintiffs had established a likelihood of success on the merits of their infringement action, reversed, and remanded for further proceedings.

The opinion can be found here.

This article summarizes aspects of the law and does not constitute legal advice. For legal advice with regard to your situation, you should contact an attorney.