RIDGE CORP. v. KIRK NATIONALEASE CO.

Authored by: Jeremy J. Gustrowsky

The Federal Circuit reversed a preliminary injunction that had blocked a group of trailer parts companies from selling a roll-up truck door accused of infringing an insulated overhead door patent. The court found that the accused product raised substantial questions of noninfringement under three separate claim limitations, making injunctive relief inappropriate at this early stage.

The case centered on U.S. Patent No. 9,151,084, owned by Cold Chain, LLC and exclusively licensed to Ridge Corporation. The patent covers a single-panel insulated overhead door designed to roll open and closed along curved tracks, useful for refrigerated delivery trucks. Ridge sued Kirk NationaLease Co., Truck & Trailer Parts Solutions, Inc. (TTPS), and Altum LLC, alleging that a competing roll-up door infringed the patent. The accused product uses a “sandwich” panel manufactured by Altum, consisting of a foam core between two thermoplastic membranes, which TTPS then modifies by routing horizontal grooves (compression gaps) into the panel so it can bend around curved tracks. This was the second time the case reached the Federal Circuit. An earlier preliminary injunction was vacated in 2024 because Ridge lacked standing as an exclusive licensee. After Cold Chain was added as a co-plaintiff, the district court granted a second preliminary injunction, which prompted this appeal.

The Federal Circuit focused first on the requirement that the panel be “flexible along the entire length of the panel.” The court rejected Ridge’s argument that this language only required the door to be capable of approximating curved tracks, explaining that the claim contains two separate requirements: flexibility along the entire length, and the resulting ability to bend around curves. The prosecution history supported this reading, as Cold Chain had told the examiner that the entire panel is made from flexible material rather than relying on rigid hinged sections. Because the accused door has rigid sections between the routed compression gaps, there was a substantial question whether it met this limitation.

The court also identified problems with the “outermost surface” limitation, which requires that foam insulating material form the second outermost surface of the door. The accused door places foam in the middle, sandwiched between two thermoplastic layers, so neither outermost surface consists of foam. As one brief colorfully put it, the foam is “the ice cream, so to speak, in an ice cream sandwich.” Ridge tried to salvage its position by pointing to unasserted dependent claim 9, which mentions an additional membrane, but the panel reminded readers that dependent claim language cannot expand the scope of an independent claim whose meaning is clear. During prosecution, Cold Chain had also distinguished its invention from a prior art sandwich structure (U.S. Patent No. 5,915,445) on precisely this ground.

Turning to the term “insulated overhead door,” the Federal Circuit concluded that the specification and industry evidence pointed to a door suitable for cold storage applications, rather than any door with some minimal insulating property. The specification repeatedly tied the invention to the cold storage distribution industry, and an expert witness explained that the industry distinguishes between dry-freight doors and insulated doors used for frozen or refrigerated goods. While the court declined to impose a specific R-value requirement, it found a substantial question whether the accused door, with its thin foam layer and grooves that could act as heat sinks, qualified as an insulated door under this construction.

Beyond claim construction, the court also found the irreparable harm analysis lacking. Ridge’s claim of price erosion was speculative and lacked any causal connection to the defendants’ sales, particularly since Ridge had not sold any single-panel roll-up doors before the first injunction and had the market to itself for a year afterward. The court further rejected the district court’s reliance on the tortious interference and false marking claims, noting that preliminary injunctions must address a substantial risk of future injury, and Ridge presented no credible evidence that the challenged conduct (a letter to Whiting Door and TTPS’s marketing statements) was likely to recur.

This case offers a reminder that at the preliminary injunction stage, an accused infringer need only raise a substantial question of noninfringement to defeat the motion, and careful attention to claim language, prosecution history disclaimers, and specification context can be decisive. Broad readings that render claim limitations superfluous, or that contradict positions taken during prosecution, are unlikely to provide a sound basis for a winning argument.