by Dennis Crouch
The Federal Circuit’s recent decision in Wilco Marsh Buggies and Draglines, Inc. v. Weeks Marine, Inc., 23-2320 (Fed. Cir. Aug. 19, 2025) (nonprecedential), illustrates how the Federal Circuit appears to be increasingly disregarding the jury’s role in fact finding — in this case disputes about whether a competitor’s prior sales were anticipating based upon the on sale bar. Looking at it from an alternative perspective, the decision demonstrates how the Federal Circuit’s regular disregard of conclusory expert testimony can vaporize what appear to be genuine factual disputes.
The case involved U.S. Patent No. 6,918,801, directed to an amphibious vehicle with tracked pontoons and retractable spuds for stabilization during excavation operations. Weeks Marine successfully argued that a 1993 sale of the MudMaster amphibious dredge anticipated the asserted claims under the on-sale bar of 35 U.S.C. § 102(b). The Federal Circuit affirmed summary judgment of invalidity, finding that no reasonable jury could conclude the 1993 MudMaster lacked a “chassis” as required by the claims, despite what appeared to be competing expert testimony on this critical element.
To establish anticipation under 35 U.S.C. § 102, a defendant must prove by clear and convincing evidence that a single prior art reference discloses each and every element of the claimed invention. This is fundamentally a question of fact that is usually given to a jury decide based upon the Seventh Amendment right to a jury trial. But, the issue may be taken from the jury and decided by a judge on summary judgment if the record reveals “no genuine dispute of material fact.”
The clear and convincing evidence standard creates a high evidentiary bar for defendants seeking invalidity — with juries sometimes and is sometimes referred to as “highly probable.” When combined with the requirement that all reasonable inferences be drawn in favor of the non-movant, this standard theoretically makes summary judgment inappropriate whenever credible expert testimony disputes whether prior art discloses claim elements. Wilco demonstrates how courts can circumvent this protection by characterizing expert disagreements as insufficiently substantive to warrant jury consideration.
The 1993 MudMaster Sale and the “Chassis” Dispute
The Federal Circuit focused on whether the MudMaster sold in 1993 contained a “chassis,” which the district court had construed to mean “the supporting frame of a vehicle, exclusive of the body or housing.” Weeks Marine put on evidence that the machine had connector pipes that extended through a trunnion support frame and that constituted a chassis. But, Wilco’s expert argued that those elements were insufficient to be called a chassis.
This setup sounds like a disputed issue of material fact, but the Federal Circuit disagreed – finding that the patentee’s expert’s arguments were insufficiently detailed to create a genuine dispute of material fact.
Invalidity Summary Judgment Affirmed