PTAB

IPR2015-01247

Meyer Products LLC v. Douglas Dynamics LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Snowplow Assembly
  • Brief Description: The ’757 patent discloses a snowplow assembly for mounting on a vehicle. The assembly includes a lift frame, an A-frame holding the plow blade, and a trunnion connecting them, which allows for two distinct pivoting motions: (1) about a transverse horizontal axis to lift and lower the plow, and (2) about a longitudinal horizontal axis to allow the plow to follow uneven ground contours.

3. Grounds for Unpatentability

Ground 1: Anticipation by Pruss - Claims 1, 4-7, and 18 are anticipated by Pruss under 35 U.S.C. §102.

  • Prior Art Relied Upon: Pruss (Patent 2,139,625).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Pruss, which was not considered during the original prosecution, discloses every element of the challenged claims. Specifically, Pruss teaches a snowplow assembly with a lift frame (tower 20), an A-frame (struts 26, 26'), a plow blade, and a motion generating device. Crucially, Petitioner contended that Pruss’s "bolster" (element 18 or 55 in different embodiments) is structurally and functionally identical to the claimed "trunnion." This bolster is a transverse bar pivotally connected to the lift frame for movement about a transverse axis, and the A-frame is pivotally connected to the bolster (via bolt 16 or 59) for movement about a longitudinal axis, thus teaching the claimed dual-pivot functionality. Pruss also discloses that the entire frame can be rapidly attached and detached from a vehicle as a single assembly.

Ground 2: Obviousness over Pruss in view of Kost - Claims 1, 4-7, and 18 are obvious over Pruss in view of Kost under 35 U.S.C. §103.

  • Prior Art Relied Upon: Pruss (Patent 2,139,625) and Kost (Patent 6,354,024).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative to its anticipation argument, Petitioner argued that if Pruss were found to not explicitly teach a "driven onto" attachment method or an A-frame shaped precisely like the letter "A," these features were well-known in the art and taught by Kost. Kost, which was a reference of record during prosecution, discloses a modern snowplow with a precisely A-shaped frame (A-frame 750) and a "driven onto" mounting system where the vehicle drives up to the assembly for quick connection.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Kost’s well-known, efficient "driven onto" mounting system and its structurally simple A-frame with the dual-axis pivoting mechanism of Pruss. The motivation would be to simplify and expedite the attachment and detachment process, which Pruss itself identified as an important goal, thereby making the snowplow assembly more efficient and user-friendly.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves applying a known mounting solution (from Kost) to a known plow frame design (from Pruss), both within the same field of art.

Ground 3: Obviousness over Coates in view of Hetrick - Claims 1, 4-7, and 18 are obvious over Coates in view of Hetrick under 35 U.S.C. §103.

  • Prior Art Relied Upon: Coates (Patent 3,605,906) and Hetrick (Patent 4,236,329).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Coates, a reference cited in the background of the ’757 patent, discloses nearly every element of the challenged claims, including a lift frame, a trunnion (rotatable cross beam 60), an A-frame (frame 96), and the claimed dual-axis pivoting functionality. However, in Coates, the A-frame and plow blade are detached from the vehicle separately from the lift frame, arguably failing to meet the "single assembly" attachment limitation. Hetrick remedies this deficiency by teaching a mounting system where the entire snowplow assembly (lift frame, A-frame, and blade) is attached and detached from the vehicle as a single, complete unit using a "driven onto" method.
    • Motivation to Combine: A POSITA would have been motivated to modify the Coates design by incorporating the more efficient single-unit mounting system from Hetrick. This modification would simplify the mounting process, eliminating the need for the operator to handle separate components or manually connect chains (as required in Coates), thereby saving time and effort.
    • Expectation of Success: The combination would have been a predictable application of a known mounting technology (Hetrick) to an existing snowplow architecture (Coates) to achieve the known benefit of simplified installation.

  • Additional Grounds: Petitioner asserted anticipation of claims 6 and 18 by Keeler (Patent 2,242,472) and further obviousness combinations including Pruss in view of Watson (Patent 5,125,174), and Coates in view of Kost or Watson, all based on similar theories of combining known mounting systems with prior art plow frames.

4. Key Claim Construction Positions

  • "Trunnion": Petitioner argued for a construction based on prosecution history estoppel. During prosecution of the ’757 patent, the applicant distinguished prior art references (Watson and Kost) by arguing that their simple "pivot pins" did not meet the "trunnion" limitation. Therefore, Petitioner contended the term "trunnion" must be construed as a "transversely extending bar" that is structurally distinct from a simple pivot pin. This construction is critical to Petitioner's argument that Pruss (disclosing a bolster/bar) anticipates while other references using simple pivot pins do not.
  • "A-frame": Petitioner noted that while the ’757 patent specification illustrates a triangular or "A" configuration, it also explicitly states that "other configurations of frames other than 'A's' may be substituted." Accordingly, Petitioner argued the broadest reasonable interpretation of "A-frame" is any frame structure of any shape that performs the same function.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 4-7, and 18 of the ’757 patent as unpatentable.