Toro’s $48M Patent Win Against Briggs & Stratton Tossed

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By Peter Leung

Toro subsidiary Exmark Manufacturing Co.’s patent infringement win against competing lawnmower maker Briggs & Stratton Power Group LLC was vacated Jan. 12 because the trial court improperly deferred to the patent office.

The U.S. Court of Appeals for the Federal Circuit said the trial court should have independently considered Briggs & Stratton’s arguments that Exmark’s patent claim lacked novelty and was obvious. Instead, the trial court rejected Briggs & Stratton’s arguments in a summary judgment because the patent had already survived several reexaminations at the Patent and Trademark Office.

The Federal Circuit sent the case back to the trial court to analyze the invalidity arguments, as well the damages award.

The decision highlights the relationship between district court proceedings and reexaminations, in which a patent owner or third party asks the PTO to verify a patent’s validity. A reexam that finds a patent valid isn’t binding on courts because only the patent owner and PTO are involved, even if another party initiated the proceeding.

By contrast, other validity challenge proceedings, such as inter partes reviews, can have binding effect on other cases because IPRs involve a challenger as well as a patent owner.

The decision also applied a 2016 U.S. Supreme Court case that was supposed to make it easier for patent owners to prove willful infringement. The Federal Circuit found the trial court awarded enhanced damages using a discarded, older approach.

Grass Cutting Patent

U.S. Patent No. 5,987,863 covers a lawnmower with a unique baffle, a metal structure that directs air flow and grass clippings during operation. After Exmark sued Briggs & Stratton for infringement, the PTO reexamined the patent twice, at the request of Briggs & Stratton and another defendants. In both reexaminations, the PTO upheld the patent’s validity against the same prior inventions and research Briggs & Stratton used to attack the claim in district court.

After the reexaminations, the district court granted Exmark’s motion for summary judgment against Briggs & Stratton’s invalidity arguments, based on the results of the reexams. A jury later ruled in favor of Exmark, awarding $24.3 million in damages. The court then doubled the award, after finding that Briggs & Stratton willfully infringed the patent.

The Federal Circuit vacated the summary judgment ruling, saying the trial court must come to its own independent conclusion about the patent claim’s validity. District courts owe a level of deference to the PTO’s conclusions, but that comes in the form of a presumption that a patent is valid—a presumption that a challenger can still overcome, the court said.

There are also important differences between PTO reexams and district court proceedings, the court said. For example, the PTO examiner and the district court interpreted several terms in the patent claim differently, with the court using a broader interpretation in some instances. Even though the PTO said the patent claim was not anticipated or obvious because of prior inventions, a jury could come to a different conclusion, the court said.

Willfulness a Jury Question

The Federal Circuit also vacated the trial court’s finding that Briggs & Stratton willfully infringed the patent claim. The trial court applied an outdated test when it doubled the damages award, it said.

The trial court’s mistake was that it didn’t allow Briggs & Stratton to present its invalidity evidence to the jury because the court had already ruled that those arguments were objectively unreasonable. However, the Supreme Court’s 2016 decision in Halo Elecs., Inc. v. Pulse Elecs., Inc. required the entire question of willful infringement to go before a jury—without a trial court judge playing a gatekeeper role, the Federal Circuit said.

Judge Kara F. Stoll wrote the decision, which Judges Evan J. Wallach and Raymond T. Chen joined.

Carlson, Caspers, Vandenburgh, Lindquist & Schuman PA represented Exmark. Arnold & Porter Kaye Scholer LLP represented Briggs & Stratton.

The case is Exmark Mfg. Co. v. Briggs & Stratton Power Grp., LLC , Fed. Cir., No. 16-2197, 1/12/18 .

To contact the reporter on this story: Peter Leung in Washington at

To contact the editor responsible for this story: Mike Wilczek at

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