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Rewriting Dependent Claims into Independent Form Raises Presumption of Prosecution History Estoppel

June 02, 2004

Decision icon Decision, en banc

Last Month at the Federal Circuit - June/July 2004

Judges: En banc, Dyk (author), Newman (dissenting-in-part)

In Honeywell International, Inc. v. Hamilton Sunstrand Corp., No. 02-1005 (Fed. Cir. June 2, 2004), the Federal Circuit held that the rewriting of dependent claims into independent form coupled with the cancellation of the original independent claims creates a presumption of prosecution history estoppel.

Honeywell International, Inc.’s (“Honeywell”) patents are directed to an aircraft auxiliary power unit (“APU”), which is typically used on aircraft to generate electricity and compress air. The Honeywell APU was designed to avoid air surges by controlling a surge-bleed valve. The decision concerned three claims from two different patents. Each of the three claims originated as a dependent claim that depended from a rejected independent claim. The Examiner indicated that these three claims would be allowable if rewritten into independent form, and Honeywell responded by canceling the rejected independent claims and amending the dependent claims to expressly incorporate the limitations of the rejected independent claims. At trial, a jury found willful infringement based on the DOE and awarded over $45 million in damages.

The Federal Circuit initially answered a less controversial question, ruling that an amendment adding a new claim limitation constitutes a narrowing amendment that gives rise to an estoppel, just like an amendment that narrows a preexisting claim limitation. The Court then tackled the more controversial issue of whether rewriting a dependent claim into independent form, coupled with the cancellation of the original independent claim, constitutes a narrowing amendment. Honeywell, of course, argued that although it had surrendered the broader independent claims, there should be no presumption of surrender because the scope of the rewritten dependent claims had not been narrowed. The Federal Circuit rejected this argument, however, and concluded that in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002), the Supreme Court held that the proper focus is whether the amendment narrows the overall scope of the claimed subject matter. Accordingly, the Court reasoned, the fact that the scope of the rewritten claim has remained unchanged does not preclude the application of prosecution history if, by canceling the original independent claim and rewriting the dependent claims in independent form, the scope of subject matter claimed in the independent claim has been narrowed to secure the patent.

The Federal Circuit dug deep to find support for its ruling, even citing an old decision by Judge Learned Hand, Keith v. Charles E. Hires Co., 116 F.2d 46 (2d Cir. 1940). In Keith, Judge Hand found no difference between the situation where a claim was amended to secure allowance and one where the applicant files both a limited claim and a broader claim at the same time and then cancels the broader claim when it has been rejected.

After revealing its ruling, the Court cautioned that the presumption of surrender applies only to the amended or newly added limitation, not the whole claim. There is no surrender concerning the limitations present in the original independent claim. Equivalents are presumably not available only with respect to the limitation added from the dependent claim. Having so ruled, the Federal Circuit remanded the case for the district court to determine whether the patentee could overcome the presumption of estoppel.

Judge Newman dissented, concluding that the majority’s decision directly contradicts 35 U.S.C. § 112, ¶ 4. She concluded that this new rule will simply raise the costs and increase the difficulty of examining patents because practitioners will simply move away from using dependent claims. In her opinion, 35 U.S.C. § 112, ¶ 4 assured that claim scope is unrelated to whether the claim is in independent or dependent form, and the Supreme Court did not change that law in Festo.