EIK Engineering Sdn Bhd v. WILCo Marsh Buggies DragLines Inc

1. Case Identification

• Patent #: 6,918,801
• Filed: December 23, 2019
• Petitioner(s): EIK Engineering Sdn. Bhd.
• Patent Owner(s): Wilco Marsh Buggies & Draglines, Inc.
• Challenged Claims: 1-18

2. Patent Overview

• Title: Amphibious Spud Barge
• Brief Description: The ’801 patent discloses an amphibious excavation vehicle combining features of a marsh buggy and a spud barge. The vehicle uses pontoons for floatation and a track system for propulsion on land and in water, and it is equipped with retractable spuds (anchoring piles) to provide stability for excavation operations when the vehicle is floating.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 and 9-15 are obvious over Harada in view of Soehnlen.

• Prior Art Relied Upon: Harada (Japanese Application # H6-54018) and Soehnlen (Patent 3,470,633).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Harada taught the core invention: a self-propelled amphibious vehicle with pontoons, a track system, an excavator, and spuds for anchoring while afloat. However, Harada did not explicitly teach that the tracks propel the vehicle through water or that the spuds retract entirely above the bottom of the pontoons for land travel. Soehnlen, an amphibious dredge, was asserted to supply these missing elements, as it explicitly disclosed using its tracks for water propulsion and retracting its spuds into a storage position above the pontoons to allow for land travel.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine the teachings to improve Harada's vehicle. Specifically, a POSITA would be motivated by Soehnlen's teachings to ensure the spuds of Harada fully cleared the ground, a known requirement for amphibious vehicles to travel on land. Modifying Harada's tracks for water propulsion was argued to be an obvious improvement to enhance navigation.
  • Expectation of Success: Success was expected because both references concern amphibious excavation vehicles, and the proposed modifications involved applying known, common features (track propulsion, spud clearance for land travel) to a similar device to achieve a predictable result.

Ground 2: Claims 1-5 and 9-15 are obvious over Prestenbach in view of Soehnlen, Fujita, or Zong.

• Prior Art Relied Upon: Prestenbach (Patent 4,817,554) in view of one of Soehnlen (Patent 3,470,633), Fujita (Japanese Application # 2003-105797), or Zong (Chinese Publication # CN 2031016 U).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Prestenbach disclosed a conventional marsh buggy with all the claimed features (chassis, pontoons, track system for land/water propulsion, excavator) except for the spuds and the ability to perform floating excavation. The petition contended that the primary inventive concept of the ’801 patent was simply adding spuds to a known marsh buggy. The secondary references (Soehnlen, Fujita, and Zong) each taught exactly that: amphibious, tracked vehicles equipped with spuds for anchoring during floating excavation.
  • Motivation to Combine: A POSITA would have been motivated to add spuds from Soehnlen, Fujita, or Zong to the Prestenbach vehicle to solve a known problem: the instability of marsh buggies during floating excavation. The combination represented applying a known solution (spuds for stability) to a known problem on a known device (Prestenbach's marsh buggy).
  • Expectation of Success: There was a reasonable expectation of success because adding spuds to floating platforms was a well-known, common, and predictable technique for providing stability. Implementing a known spud assembly onto Prestenbach’s existing amphibious platform was argued to be a routine design choice for a POSITA.

Ground 3: Claims 8 and 18 are obvious over the Base Grounds in view of Sturdivant.

• Prior Art Relied Upon: The combinations from Grounds 1-4, in further view of Sturdivant (Patent 5,311,682).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground targeted dependent claims 8 and 18, which added limitations for a specific spud assembly comprising a hydraulic cylinder, a link, and a releasable pin connecting the link to the spud. Petitioner argued that while the primary combinations taught spud assemblies generally, Sturdivant taught the exact, specific assembly recited in these claims.
  • Motivation to Combine: A POSITA would combine Sturdivant’s assembly with the vehicles of the Base Grounds as a simple substitution of one known spud deployment mechanism for another. Sturdivant was argued to provide explicit motivation, teaching that its adjustable cylinder system was desirable because it offered advantages like using smaller, less expensive cylinders and avoiding problems associated with winch systems.
  • Expectation of Success: Success was predictable because spud assemblies were known to be generally interchangeable. Substituting Sturdivant’s well-understood mechanical assembly into the base vehicles would have been routine for a POSITA, with the resulting operation being the sum of its known parts.

• Additional Grounds: Petitioner asserted further obviousness challenges, including "Winch Grounds" (adding Soehnlen for its winch system), "Gravity Grounds" (adding Kissick for its gravity-deployed winch), and "Method Grounds" (arguing the method steps were inherent or obvious from the Base Grounds and general knowledge).

4. Key Claim Construction Positions

• "said winch has a released position where said winch cable is spooled out...under the influence of gravity" (claims 7, 17): Petitioner argued this term should be construed to mean a position where the winch is released to allow the spud to free-fall by gravity, unspooling the cable. This is narrower than the Patent Owner’s alleged litigation position that motorized unspooling satisfies the limitation. This construction was critical to Petitioner's "Gravity Grounds" based on the Kissick reference.
• "chassis" (claims 1-2, etc.) and "pontoon" (claims 1, 12): Petitioner contended these terms should be given their plain and ordinary meaning ("base frame of a vehicle" and "a sealed compartment that provides floatation," respectively). However, constructions were proposed out of caution because the Patent Owner had allegedly adopted "unreasonably narrow" interpretations during litigation, such as arguing that Soehnlen has "no chassis."

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §325(d), asserting that the petition raised new issues. It was argued that the core prior art (Harada, Soehnlen, Fujita, Zong) was not before the examiner, and that the proposed combinations specifically addressed the feature (spuds retracting entirely) that was the apparent basis for allowance.
• Petitioner also argued against denial under §314(a) (e.g., Fintiv), explaining that although 20 grounds were presented, they are grouped into five simple, logical categories. The alternative references were included for valid reasons, such as addressing potential arguments from the Patent Owner regarding prior art dates or specific spud implementations, and did not make the petition inefficient.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-18 of the ’801 patent as unpatentable.