Posted on August 22, 2025
District court correctly found the asserted patent anticipated by prior art.
In a nonprecedential decision, the U.S. Court of Appeals for the Federal Circuit affirmed a district court’s ruling invalidating a patent directed to amphibious excavation technology, while rejecting associated infringement claims. The plaintiff, a Louisiana-based manufacturer of marshland excavation equipment, had alleged infringement of its patented amphibious vehicle design by a national marine construction and dredging contractor. The district court granted summary judgment after finding that an earlier commercial amphibious excavator, developed and sold by a third-party equipment supplier, disclosed all limitations of the asserted claims. The Federal Circuit agreed, holding that the earlier product included the required structural components and rendered the patent anticipated under pre-AIA Section 102(b). As a result, the infringement claims failed, and the judgment of invalidity was affirmed (Wilco Marsh Buggies and Draglines, Inc. v. Weeks Marine, Inc., No. 23-2320 (Fed. Cir. Aug. 19, 2025)).
Background. The plaintiff/appellant, Wilco Marsh Buggies and Draglines, Inc., is a Louisiana-based manufacturer specializing in amphibious excavation equipment used in wetland and marine construction. The defendant/appellee, Weeks Marine, Inc., is a major marine construction and dredging firm operating throughout the United States.
In this lawsuit, Wilco Marsh asserted its U.S. Patent No. 6,918,801 (the ’801 patent), titled Amphibious Vehicle. The ’801 patent describes a self-propelled amphibious vehicle for use in excavation and dredging operations. Claim 1 recites a vehicle composed of a chassis, pontoons to ensure flotation, a track system for land and water propulsion, and multiple spuds that can be positioned above or below the pontoons. These features, as claimed, were intended to facilitate movement and operational stability across wetland terrain.
Wilco initiated the lawsuit in 2020, asserting that Weeks’ “Amphibious Excavators” infringed various claims of the ’801 patent. Weeks moved for summary judgment, arguing that the claims were invalid as anticipated by prior art, notably the MudMaster excavator publicly sold in 1993 and displayed at the 1981 ConExpo trade show. The district court, adopting Wilco’s proposed construction of “chassis” as “the supporting frame of a vehicle, exclusive of the body or housing,” ultimately granted Weeks’ motion on reconsideration. It ruled that the 1993 MudMaster embodied every claim limitation, including the chassis, thereby rendering the asserted claims invalid. Wilco appealed.
Federal Circuit’s review. The Federal Circuit reviewed the grant of summary judgment de novo, following the Fifth Circuit standard, as articulated in Click-to-Call Techs. LP v. Ingenio, Inc., 45 F.4th 1363, 1367 (Fed. Cir. 2022). Referencing Golden Bridge Tech., Inc. v. Nokia, Inc., 527 F.3d 1318, 1321 (Fed. Cir. 2008), the appellate court emphasized that while anticipation under § 102 is a factual question, it is amenable to summary judgment where the record reveals no genuine dispute of material fact.
Public use and on-sale bar. Weeks relied on the on-sale bar and public use provisions of pre-AIA 35 U.S.C. § 102(b), which render a patent invalid if the claimed invention was on sale or in public use more than one year before the patent’s filing date. Citing Scaltech Inc. v. Retec/Tetra, LLC, 178 F.3d 1378, 1383 (Fed. Cir. 1999), the court reaffirmed that a prior art product can only anticipate a patent claim if it includes every limitation. The burden was on Weeks to demonstrate that the MudMaster sold in 1993 met this standard.
Chassis limitation and expert evidence. Wilco’s principal argument on appeal was that a material fact dispute existed as to whether the 1993 MudMaster included a “chassis.” The Federal Circuit disagreed. It found that uncontroverted record evidence—specifically assembly instructions and expert testimony—demonstrated that the 1993 MudMaster included two 16-foot connector pipes functioning as the supporting frame. This satisfied the district court’s definition of “chassis.”
Although Wilco’s expert, Mr. Bennett, offered an opinion that the MudMaster lacked a chassis, the court found his testimony conclusory and unsupported by the record. Citing Regents of Univ. of Minn. v. AGA Med. Corp., 717 F.3d 929, 941 (Fed. Cir. 2013), the court held that conclusory expert declarations cannot raise a genuine dispute of material fact. Indeed, Mr. Bennett conceded that amphibious vehicles must include structural support for pontoons and acknowledged that beams could form part of a chassis.
Alternative grounds. Notably, the Federal Circuit relied on the 1993 MudMaster sale alone, avoiding the need to assess earlier MudMaster versions from 1980 and 1981. Citing King Pharms., Inc. v. Eon Labs, Inc., 616 F.3d 1267, 1278 (Fed. Cir. 2010), the court reiterated that appellate courts may affirm on any ground supported by the record, even if not expressly adopted by the district court.
Wilco also argued that Weeks had forfeited the 1993 sale argument. The appellate court rejected this, finding that Weeks had adequately raised the issue in its motion for reconsideration and that Wilco failed to object in the district court. The panel cited In re Google Tech Holdings LLC, 980 F.3d 858, 838 (Fed. Cir. 2020), to underscore that issues not timely raised below are considered forfeited absent exceptional circumstances.
Conclusion. Thus, the Federal Circuit affirmed the judgment of invalidity for the ’801 patent. Because the Federal Circuit concluded that the 1993 MudMaster anticipated all asserted claims of the ’801 patent, it declined to reach arguments about the 1980 and 1981 MudMaster versions.
The Case is No. 23-2320.
Judge: Hall, J.
Attorneys: Meredith Leigh Martin Addy (AddyHart PC) for Wilco Marsh Buggies and Draglines, Inc. Michael K. Leachman (Jones Walker LLP) for Weeks Marine, Inc.
Companies: Wilco Marsh Buggies and Draglines, Inc.; Weeks Marine, Inc.
MainStory: TopStory Patent FedCirNews LouisianaNews GCNNews
