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Rat Zapper Patent Held to Be Obvious Despite Objective Evidence of Nonobviousness

March 28, 2008

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Last Month at the Federal Circuit - April 2008

Judges: Bryson, Moore (author), Wolle (Senior District Judge sitting by designation)

[Appealed from: E.D. Pa., Senior Judge Kelly]

In Agrizap, Inc. v. Woodstream Corp., Nos. 07-1415, -1421 (Fed. Cir. Mar. 28, 2008), the Federal Circuit affirmed the jury’s verdict that Woodstream Corporation (“Woodstream”) was liable for fraudulent misrepresentation, and reversed the jury’s verdict that U.S. Patent No. 5,949,636 (“the ’636 patent”) was not invalid for obviousness. In finding the ’636 patent obvious, the Federal Circuit held that Agrizap, Inc.’s (“Agrizap”) objective evidence of nonobviousness was insufficient to overcome the overwhelming strength of Woodstream’s prima facie case of obviousness.

Agrizap is the assignee of the ’636 patent, directed to a method and apparatus for electrocuting pests, such as gophers and rats. The invention operates by sensing the presence of a pest with a resistive switch, which triggers a generator that electrocutes the pest. Agrizap sued Woodstream, alleging fraudulent misrepresentation and infringement of the ’636 patent. A jury returned a verdict in favor of Agrizap and awarded damages of $1,275,000 for fraudulent misrepresentation and $1,425,000 for infringement. The district court denied Woodstream’s motions for JMOL on fraudulent misrepresentation and the affirmative defenses, but granted the JMOL for noninfringement.

The Federal Circuit first reviewed the fraudulent misrepresentation verdict, holding that Agrizap offered sufficient evidence for a jury to find Woodstream liable for fraudulent misrepresentation under Pennsylvania law. The Court also upheld the jury’s damages award for fraudulent misrepresentation. Although “Agrizap never propounded a specific dollar amount for its fraud damages and instead left it up to the jury to extrapolate an amount from the various pieces of evidence submitted at trial,” the Court nonetheless held that “Agrizap introduced sufficient facts for the jury to fairly estimate an amount of damages, . . . .” Slip op. at 7. The Court noted that “[a]n award of damages is not precluded simply because of some uncertainty as to the precise amount of damages occurred.” Id.

In addressing the patent issues, the Federal Circuit found the claims invalid as obvious, and because the obviousness issue was dispositive, declined to address the other issues raised on appeal. The Court noted that during prosecution, the PTO had initially rejected the claims of the ’636 patent under obviousness-type double patenting based on U.S. Patent No. 5,269,091 (“the ’091 patent”) to the same inventors as the ’636 patent, and in view of two other patents. The ’091 patent disclosed all of the limitations of the ’636 patent claims except for the use of a mechanical switch instead of a resistive switch. The two other patents described the use of a resistive switch having separate contact points, set off by animals upon touching the two contact points. In response to the filing of a terminal disclaimer, however, the rejections were removed, and the ’636 patent issued.

The Court then noted that at two separate trade shows prior to the filing date of the ’636 patent, Agrizap demonstrated a “Gopher Zapper” product that embodied the ’091 patent. The PTO was not aware of the trade shows during prosecution of the ’636 patent. As a result, the Court relied on the Gopher Zapper product, as well as the two additional patents the PTO previously relied on in finding obviousness.

The Court cited KSR International Co. v. Teleflex Inc., 127 S. Ct. 1727, 1739 (2007), stating that “[t]his is a textbook case of when the asserted claims involve a combination of familiar elements according to known methods that does no more than yield predictable results.” Slip op. at 11. The Court held that (1) the asserted claims merely substitute a resistive electrical switch for a mechanical pressure switch employed by the Gopher Zapper, (2) the use of a resistive switch to complete a circuit for the generation of an electric charge was already known in the prior art, and (3) both of the cited resistive switch patents were directed to solving the same problem as the ’636 patent—the malfunction of mechanical switches in environments prone to dirt and dampness.

The Court considered objective evidence of nonobviousness, such as commercial success of the Rat Zapper, copying by Woodstream, and a long-felt need for electronic rat traps, all considered by the jury. However, despite this evidence, and citing to Leapfrog Enterprises, Inc. v. Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007), the Court held that the evidence was “insufficient to overcome the overwhelming strength” of Woodstream’s prima facie case of obviousness. Slip op. at 11. The Court thus held that in some situations, objective considerations of nonobviousness are “inadequate to overcome astrong showing of primary considerations that rendered the claims at issue invalid.” Id. at 12. Consequently, the Court reversed the jury’s verdict regarding invalidity, finding all of the claims of the ’636 patent invalid for obviousness.