IP Law Daily, PATENT—Fed. Cir.: Evenflo’s infringement of two Wonderland Switzerland child car seats patents affirmed, (Dec 17, 2025)

By Robert Margolis, J.D.

Court affirms district court’s claim construction and finding of infringement under doctrine of equivalents, while reversing one infringement finding and the grant of permanent injunctive relief, and ordering a new trial on whether an infringement was willful.

On appeal of a final judgment after a jury verdict that Evenflo Company’s child car seats infringe claims of two Wonderland Switzerland AG patents, the U.S. Court of Appeals for the Federal Circuit has affirmed the verdict that both patents were infringed. In doing so, the appellate court upheld the district court’s claim construction of several terms, and found the doctrine of equivalents supported infringement. The appellate court, however, reversed the district court’s grant of a permanent injunction against Evenflo as to the infringement of both patents, because (1) Wonderland did not ask for injunctive relief as to one of the patents, and (2) its evidence that monetary relief could not make it whole was too speculative. Finally, the appellate court found reversible error in a district court’s decision to exclude from evidence an email that the appellate court deemed probative of Wonderland’s claim that Evenflo’s infringement was willful, and ordered a new trial on the issue of willfulness (Wonderland Switzerland AG v. Evenflo Company, Inc., No. 23- 2043 (Fed. Cir. Dec. 17, 2025)).

Wonderland sued on two patents directed to child car seats—U.S. Patent Nos. 7,625,043 (the ’043 patent) and 8,141,951 (the ’951 patent). It alleged infringement of claims 1 of each patent and claim 5 of the ’951 patent. Wonderland alleged that five of Evenflo’s car seat models (its 4-in-1 and 3-in-1 models) infringe those claims. After trial, a jury rendered a verdict that: (1) Evenflo’s 3-in-1 and 4-in-1 seats infringe claim 1 of the ’043 patent under the doctrine of equivalents (“DOE”), (2) the infringement of the ’043 patent was not willful, (3) the 4-in-1 seats infringe claims 1 and 5 of the ’951 patent (literally and under DOE), and (4) the 3-in-1 seats infringe claim 1 of the ’951 patent (literally and under DOE). Wonderland then sought a permanent injunction as to the ’043 patent but not the ’951 patent, but the district court enjoined Evenflo’s activities as to both patents (though it stayed enforcement as to the ’951 patent). Evenflo appealed those determinations, and Wonderland appealed the district court’s denial of a new trial on the issue of willful infringement.

’043 patent. While affirming that the ’043 patent was infringed, the appellate court first agreed with Evenflo that its accused 4-in-1 seats do not include a “locking mechanism for selectively detachably connecting” its seat back to the seat assembly, which is recited in claim 1 of the ’043 patent. While the 4-in-1 seat backs include a stationary metal bar, the components for selectively attaching and detaching the lock rod are located on the seat assembly itself rather than the seat backs. The court rejected Wonderland’s argument that the verdict could be saved by application of the DOE, based on its expert explaining there were no practical differences in having the locking mechanism on the seat backs or seat assembly. It is insufficient under the DOE to argue the overall mechanism is equivalent, as the DOE must be applied to individual elements of the claim, the appellate court noted.

The court nonetheless affirmed the verdict of infringement of the ’043 patent, rejecting Evenflo’s argument asserting error in claim construction. Evenflo challenged the district court’s construction of “pair of receptacles” recited in claim 1 of the ’043 patent. The district court had adopted a claim construction to which the parties had stipulated, and which did not include the limiting interpretation of “pair of receptacles” that Evenflo was now urging and that would support the argument its product does not have a “pair of receptacles.” Given the stipulation, it was not error for the district court to find Evenflo was judicially estopped from arguing the more limited construction. Based on the construction the district court adopted, it also was not error to find that its accused products have a “pair of receptacles,” thus supporting the jury’s infringement finding.

The appellate court also affirmed the district court’s construction of “attachment arms … for engagement” by applying the “plain and ordinary meaning” of “engagement” rather than Evenflo’s proffered meaning “to interlock with or fit into and move together with.” The appellate court noted that the patent’s distinct use of terms such as “locking” in the written description, and “locking mechanism” and “latching apparatus” in a dependent claim, indicates that “engagement” is different and broader than something that locks. Therefore, there was no error in the jury finding infringement based on Evenflo’s accused products having “attachment arms … for engagement.”

’951 patent. Evenflo’s challenge to the infringement finding as to the ’951 patent concerned construction of the term “connected to” in claim 1 of that patent. The district court construed that term to include not only separate components “connected to” each other, but discrete parts of “a continuous base material,” i.e., parts within a single component. The appellate court found no error in that construction. Evenflo was not correct in asserting that case law provides a presumption that components “connected to” each other are physically distinct, and the appellate court distinguished the cases on which Evenflo relied. Under that correct construction, there was sufficient evidence to support the verdict of infringement, the appellate court held, because Evenflo’s base itself included components connected to each other.

Similarly, the court rejected Evenflo’s argument that no reasonable jury could have found its accused products have a “backrest movably disposed on the engaging board” as recited in the ’951 patent’s claim 1. Evenflo argued its seats have only a movable headrest, rather than a movable backrest, but the evidence showed that the term “backrest,” as used in the ’951 patent, was met by Evenflo’s headrests because a child can lean back against them. The court noted that it is the ’951 patent’s use of the term “backrest” that controls rather than the meaning Evenflo would prefer it to have.

Injunction. The court reversed the permanent injunction as to Evenflo’s activities related to both patents. Wonderland never asked for injunctive relief as to the ’951 patent, so granting such relief is an abuse of discretion. As to the ’043 patent, the appellate court held that Wonderland’s evidence of non-monetary harm, for example that by purchasing an Evenflo car seat a consumer was more likely to purchase other Evenflo products over Wonderland products, was purely speculative and insufficient to support such drastic relief.

Willfulness. The appellate court reversed the district court’s denial of Wonderland’s motion for a new trial on whether Evenflo’s infringement of the ’043 patent was willful. The district court had excluded under Federal Rule of Evidence 403 as overly prejudicial an email chain that included a message from an employee of an affiliate of Evenflo to several Evenflo employees. That message included a screenshot of claim 1 of the ’043 patent and asked how to “avoid the claims of the patent ingeniously.” As willfulness involves showing the infringement was knowing and deliberate, this evidence was probative and it was an abuse of discretion to exclude it, the appellate court held. The appellate court did not consider the error to be harmless, because it was not highly probable the exclusion had no effect on the case’s outcome.

Dissenting in part opinion. Circuit Judge Jimmie Reyna filed a separate opinion dissenting from the majority’s determination that the district judge abused its discretion in excluding the email chain, finding the district court’s analysis of the Rule 403 factors to be “careful and comprehensive.” Third Circuit law requires “substantial deference” to a trial judge’s new trial determination based on a Rule 403 ruling, meaning the decision must be “arbitrary and irrational.” Judge Reyna noted that the email chain referred to different car seats than the accused products, and thus it was reasonable for the district judge to deem it more prejudicial than probative, certainly not “arbitrary and irrational.” Judge Reyna would affirm the district court’s decision to deny Wonderland a new trial on willful infringement.

The Case is Nos. 23-2043, 23- 2233, 23-2326.

Judge: Moore, K.

Attorneys: Shamita Etienne-Cummings (Paul Hastings LLP) for Wonderland Switzerland AG. Aaron E. Handel (Shook, Hardy & Bacon, LLP) for Evenflo Co., Inc.

Companies: Wonderland Switzerland AG; Evenflo Co., Inc.

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