PTAB

IPR2017-00472

Fox Factory Inc v. SRam LLC

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Petition
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1. Case Identification

2. Patent Overview

  • Title: CHAINRING
  • Brief Description: The ’027 patent relates to a bicycle chainring for a drivetrain featuring a specific tooth geometry to improve chain retention. The invention combines alternating wide and narrow teeth with an outboard offset of the tooth tips, designed to engage the corresponding outer and inner link spaces of a bicycle chain more securely.

3. Grounds for Unpatentability

Ground 1: Obviousness over Parachinni and JP-Shimano - Claims 1-2, 5-6, 13-15, 18-19 are obvious over Parachinni in view of JP-Shimano.

  • Prior Art Relied Upon: Parachinni (Patent 5,285,701) and JP-Shimano (Japanese Utility Model Kokai No. S56-42489).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Parachinni discloses the limitations of a solitary bicycle chainring with teeth that are offset toward the outboard side to improve chainline and stability for large-diameter chainrings. It argued JP-Shimano discloses the core concept of a chainring with alternating wide and narrow teeth, where the wide teeth engage the outer links and narrow teeth engage the inner links of a chain, a design explicitly intended to prevent the chain from dropping. The combination of Parachinni’s offset design with JP-Shimano’s alternating tooth profile would allegedly render the features of independent claims 1 and 13 obvious.
    • Motivation to Combine: Petitioner asserted that both references address the same fundamental problem of chain derailment. A person of ordinary skill in the art (POSITA) seeking to improve chain retention would combine the known benefits of Parachinni’s offset chainring with the known chain-retaining tooth profile of JP-Shimano. This combination was argued to be a predictable application of known technologies to achieve a known goal.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because combining these features involved applying known design principles for their intended purposes and would not require any modification beyond routine skill.

Ground 2: Obviousness over Parachinni, JP-Shimano, and Hattan - Claims 3-4 and 16-17 are obvious over Parachinni, JP-Shimano, and Hattan.

  • Prior Art Relied Upon: Parachinni (Patent 5,285,701), JP-Shimano (Japanese Utility Model Kokai No. S56-42489), and Hattan (Patent 3,375,022).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon the combination in Ground 1 by adding the teachings of Hattan to address the dependent claims requiring at least 75% "axial fill" of the chain link spaces. Petitioner contended that Hattan teaches preferred tooth thicknesses for a standard bicycle chain that result in an axial fill of 74.6% to 96%. This teaching directly addresses the limitations of claims 3, 4, 16, and 17.
    • Motivation to Combine: After combining Parachinni and JP-Shimano to improve chain retention, a POSITA would be further motivated to optimize the tooth widths for even better engagement. Hattan, which also addresses preventing chain disengagement, provides specific, desirable tooth thickness ratios. A POSITA would incorporate Hattan’s teachings as a routine design choice to optimize the combined chainring’s performance.
    • Expectation of Success: Petitioner argued that optimizing tooth width for a given chain size was a well-known practice, and applying Hattan’s preferred dimensions to the Parachinni/JP-Shimano design would be a straightforward and predictable modification.

Ground 3: Obviousness over Parachinni, JP-Shimano, and Nagano - Claims 1-2, 5-6, 13-15, 18-19 are obvious over Parachinni, JP-Shimano, and Nagano.

  • Prior Art Relied Upon: Parachinni (Patent 5,285,701), JP-Shimano (Japanese Utility Model Kokai No. S56-42489), and Nagano (Patent 4,576,587).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presents an alternative or supplemental argument to Ground 1 by incorporating Nagano, which Petitioner argued discloses asymmetrical teeth with an outboard offset. This combination is particularly relevant to Petitioner's proposed claim construction of "teeth" as being asymmetrical. Substituting Nagano’s asymmetrical, outboard-offset teeth into the Parachinni chainring, and then further modifying them to be alternatingly wide and narrow per JP-Shimano, would allegedly meet all limitations.
    • Motivation to Combine: A POSITA would incorporate Nagano’s asymmetrical tooth profile as a known design choice to better guide the chain onto the chainring, thereby improving alignment and increasing clearance between the chain and the bicycle frame. This addresses an issue noted in Parachinni regarding its enlarged chainring.
    • Expectation of Success: Modifying the tooth shape to be asymmetrical as taught by Nagano was presented as a simple substitution of one known tooth profile for another to gain a predictable advantage, a task well within the skill of a POSITA.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) for claims 3, 4, 16, and 17 based on the combination of Parachinni, JP-Shimano, Nagano, and Hattan, which relied on the same design modification theories presented in the grounds above.

4. Key Claim Construction Positions

  • "teeth": Petitioner argued this term should be construed as "asymmetrical teeth with the inboard and outboard sides of the teeth not being mirror images of each other." This position was based on prosecution history disclaimer, where the patent owner allegedly distinguished the claimed invention from prior art (Martin) by characterizing the invention's teeth as having "unique asymmetrical tooth features" in contrast to Martin’s symmetrical teeth.
  • "offset from the plane in a direction toward the outboard side of the chainring": Petitioner contended this phrase should be construed as an offset from a plane that bisects the plurality of teeth, not the entire chainring body. This argument was based on the patent's originally filed Figure 10. Petitioner alleged that a revised figure submitted during prosecution improperly introduced new matter by shifting the bisecting plane to the center of the chainring body.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-6 and 13-19 of Patent 9,182,027 as unpatentable under 35 U.S.C. §103.