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Preamble Is Not a Claim Limitation

03-1394
May 10, 2004

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Last Month at the Federal Circuit - June/July 2004

Judges: Linn (author), Lourie, and Schall

In Intirtool, Ltd. v. Texar Corp., No. 03-1394 (Fed. Cir. May 10, 2004), the Federal Circuit reversed and remanded the district court’s finding (1) that Intirtool, Ltd.’s (“Intirtool”) U.S. Patent No. 5,022,253 (“the ‘253 patent”) is invalid for failing to satisfy the written description requirement under 35 U.S.C. § 112, first paragraph; (2) that Intirtool’s patent is unenforceable because Intirtool committed inequitable conduct during the patent’s prosecution; and (3) that damages that had accrued prior to Intirtool’s filing of the infringement action are barred by the equitable doctrine of laches. The Federal Circuit held that the district court had either clearly erred or abused its discretion in reaching each of these findings.

Intirtool owns the ‘253 patent, which claims hand-held punch pliers for simultaneously punching and connecting overlapping sheet metal, such as the corners of overlapping ceiling-tile grids. Intirtool sold patented tools to Texar Corporation (“Texar”) in 1992 and 1993, and Texar resold the tools to retailers. In July 1993, during a telephone conversation, Texar informed Intirtool that a very similar tool was available from other suppliers for a lower price and asked Intirtool to meet the other suppliers’ lower price. Intirtool refused to lower its price, and Texar stopped buying the tools from Intirtool. In April 2000, Intirtool filed a patentinfringement suit, accusing Texar of infringing its ’253 patent.

In a bench trial, the district court held that the ’253 patent was invalid for failure to satisfy the written description requirement, finding that the specification did not describe hand-held pliers for simultaneously punching and connecting overlapping sheet metal. The district court also held that the ’253 patent was unenforceable, finding that Intirtool had engaged in inequitable conduct because it had represented to the PTO that the described tool simultaneously punched holes and connected ceiling grids, knowing this representation was false. Finally, the district court held that Intirtool’s infringement action was barred by laches because Intirtool should have known that Texar was reselling the competing tools within the six-year period before the action was filed, and Intirtool had not shown that the delay in filing the action was reasonable.

The preamble of claim 1 in the ’253 patent recites “a hand-held punch pliers for simultaneously punching and connecting overlapping sheet metal.” The district court concluded that the preamble of claim 1 was a claim limitation because it found that Intirtool had represented to the PTO that the tool was capable of simultaneously punching and connecting ceiling grids, but further concluded that the punch pliers described in the ’253 patent do punch holes in overlapped sheets of metal but do not connect the sheets. As a result, the district court found the ’253 patent invalid for failure to comply with the written description requirement.

Reviewing the district court’s findings, the Federal Circuit concluded that the claim 1 preamble does not recite any additional structure or steps underscored as important by the specification. The Court also found no clear reliance in the prosecution history by Intirtool on the preamble rather than on the structural limitations set forth in the body of claim 1. As a result, the Federal Circuit ruled that the ’253 patent preamble is not a limitation of claim 1. Finding that the district court appeared to have based its inadequate description conclusion on its erroneous finding that the “simultaneously punching and connecting” language of the preamble was a limitation of claim 1, the Federal Circuit held that the district court’s conclusion was clearly erroneous.

The district court had based its conclusion that Intirtool had engaged in inequitable conduct on its finding that during prosecution of the ’253 patent, Intirtool had repeatedly stated and stressed that the described tool simultaneously punched holes and connected ceiling grids, knowing that this assertion was false. The Federal Circuit held, however, that Intirtool’s representations merely referred preamble features of the invention. In addition, the Federal Circuit held that those representations were not clearly incorrect, and that Intirtool’s representations during prosecution did not rise to the required level of materiality. The Federal Circuit thereafter concluded that the district court had clearly erred in its finding that Intirtool’s statements were material misrepresentations and held that the district court had abused its discretion in ruling that Intirtool had committed inequitable conduct.

The district court had found that Intirtool should have known in July 1993 that Texar was going to continue to sell punch pliers but would acquire them from another vendor because the price was cheaper based on the July 1993 telephone conversation between the Intirtool and Texar representatives.

The Federal Circuit found, however, that the July 1993 telephone discussion between the Intirtool and Texar representatives was insufficient to provide Intirtool with constructive knowledge of any act that might give rise to an infringement claim against Texar. Accordingly, the Federal Circuit held that the district court had clearly erred in finding that Intirtool should have known that it had an infringement claim more than six years prior to filing its infringement action in April 2000.