Federal Circuit Finds No Prosecution Disclaimer and Affirms Claim Construction From Preliminary Injunction Hearing
SEB S.A. v. Montgomery Ward & Co. (Fed. Cir. Feb. 5, 2010)
In this case, the district court, after holding a claim construction hearing, granted a motion for preliminary injunction in 1999. The Federal Circuit affirmed the preliminary injunction order without opinion. After the defendant redesigned the accused product, the plaintiff successfully sought to supplement the preliminary injunction to include the redesigned product. After a jury trial, the defendant's accused products were found to infringe the patent. Plaintiff appealed, and the Federal Circuit ultimately affirmed. While there were many issues discussed on appeal, this post will focus on the claim construction issue.
The patent at issue claimed a deep fryer with an inexpensive plastic outer shell, or skirt. The patent disclosed that, besides a heat-insulating and heat-resistive ring, the skirt and the pan of the fryer were separated by "an air space of sufficient width to limit the temperature of the skirt." Because of the insulation provided by the air space, the skirt could be constructed from more inexpensive plastics. The district court, as part of its 1999 preliminary injunction order, construed the claim term "completely free with respect to the pan" as "there are no thermal bridges between the skirt and the pan." Defendant argued on appeal that this construction was incorrect and the term should instead be construed as "no solid material between the pan and the skirt."
The Federal Circuit noted that its "prior affirmance of the district court's preliminary injunction order does not make the district court's claim construction in its 1999 opinion the law of the case." Ultimately while the Court pointed out a "minor inconsistency" with the district court's construction, it still found that the district court's construction "rings true." The Federal Circuit disagreed with defendant's proposed construction, relying on the prosecution history, the doctrine of claim differentiation, the fact that defendant's proposed construction would read out the preferred embodiment, and the fact that "the patent stresses that eliminating thermal bridges is not the same as eliminating any solid material."
Defendant had argued that the patentee narrowed the meaning of the claim term "completely free" during prosecution by making the statement "in the case of the present invention, the outer plastic skirt 3 is completely free with respect to the pan with the exception of ring 5. This means that the space comprised between the skirt 3 and the pan 1 is entirely occupied by air and that there is no solid material therebetween" in distinguishing a prior art reference. The Federal Circuit found that defendant's "attempt to create a disclaimer simply stretches this prosecution history to far" as "read in context, the applicant's reference to 'no solid material' refers only to the volume between the sides of the pan and the skirt." Therefore, "[a]t most, the prosecution statement requires 'completely free' to mean 'no solid materials between the sides of the pan and the sides of the skirt and no thermal bridges between the base of the skirt and the base of the pan.'"
The Federal Circuit found no reversible error in the district court's claim construction and affirmed.