Finding that a district court properly limited the claim scope to the patentee’s preferred embodiment because the specification repeatedly referred to this embodiment as "the invention," the U.S. Court of Appeals for the Federal Circuit affirmed the grant of summary judgment of non-infringement. Honeywell Int’l, Inc. v. ITT Industries, Inc., Case No. 05-1407 (Fed. Cir. June 22, 2006) (Lourie, J.).

Honeywell’s U.S. Patent No. 5,164,879 (the ’879 patent) discloses an electronic fuel injection system for motor vehicles. To prevent charge buildup, the invention provides that the polymer includes a conductive filler material to create a pathway to dissipate charge out of the system. The ’879 claims recite, inter alia, a "fuel injection system component" comprising "electrically conductive fibers."

The accused ITT "quick connect" products are nut-like structures that join components of a fuel injection system together and are composed of a polymer-carbon fiber housing. In construing the ’879 claims, the district court accorded the term "electrically conductive fibers" its ordinary meaning, which includes both metal and carbon fibers. Further, the district court construed "fuel injection system component" to mean only a fuel filter. As a result, the court granted summary judgment of non-infringement because ITT’s products were not fuel filters.

On appeal, Honeywell argued that the ordinary meaning of "fuel injection system component" is broader than just fuel filters and pointed to statements during prosecution to support the broader construction. The Federal Circuit rejected these arguments and instead focused on the specification as "the single best guide" in construing a claim. Here, the Court pointed to several instances where the specification of the ’879 patent referred to the fuel filter as "this invention" or "the present invention" and further noted the lack of reference to the fuel filter as merely a preferred embodiment. Also, the fuel filter was the only embodiment disclosed in the specification as having a polymer housing with electrically conductive fibers and, consequently, could not merely be a preferred embodiment. Finding that Honeywell’s representations during prosecution cannot enlarge the content of the specification, the Court concluded that the scope of "fuel injection system component" was properly limited in view of the specification. The Federal Circuit again relied on the specification to modify the district court’s construction of "electrically conductive fibers" to the extent it included carbon fibers because patentee repeatedly elaborated in the specification why carbon fibers were not suitable in the invention. Since the specification demeaned the properties of carbon fibers, the Court concluded that the patentee intended to disavow carbon fibers from the scope of the claims. Thus, ITT’s products, which only contain carbon fibers, also did not meet the claim limitation of "electrically conducive fibers."

Practice Note: Practitioners must be mindful that it is risky business to forgo written description of multiple embodiments, refer to a preferred embodiment as "the invention," or talk about non-preferred embodiments in a discouraging manner.

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