PTAB

IPR2019-00379

Bowtech Inc v. MCP IP LLC

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1. Case Identification

2. Patent Overview

  • Title: DUAL FEED-OUT ARCHERY CAM
  • Brief Description: The ’791 patent discloses a cam assembly for a compound archery bow. The assembly features a primary string feed-out that lets out a portion of the bowstring during the draw, and a secondary string feed-out that initially takes up and then lets out another portion of the bowstring, intended to optimize the force-draw profile and improve performance.

3. Grounds for Unpatentability

Ground 1: Obviousness over McPherson in view of James - Claims 1, 12, and 13 are obvious over McPherson in view of James.

  • Prior Art Relied Upon: McPherson (Patent 6,247,466) and James (M. R. James et al., Bowhunting Equipment & Skills (1997)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that McPherson teaches a cam assembly for an archery bow with all the key features of claim 1. Specifically, McPherson discloses a primary string feed-out and a secondary string feed-out arm that is "capable of momentarily shortening the string and subsequently lengthening the string" during the draw cycle. This independent rotational mounting of the secondary arm allows it to first take up a portion of the string and then let it out. James, a general archery reference, was cited to teach the well-known "one-cam" bow design, which uses a single eccentric cam on the bottom limb and a round idler wheel on the top limb. This design was popular for avoiding the need to synchronize two cams, a common problem that could lead to erratic arrow flight.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine the McPherson cam assembly with the one-cam bow configuration described in James. The motivation would be to gain the improved force-draw profile and energy storage from McPherson’s secondary feed-out mechanism while simultaneously benefiting from the stable, level nock travel and simplified tuning of the one-cam system taught by James. Implementing McPherson’s advanced cam on a standard and advantageous bow platform like the one-cam system would have been a predictable design choice.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination, as it involved applying a known cam design to a conventional and popular bow architecture to achieve the known benefits of each component.

Ground 2: Obviousness over McPherson in view of McPherson ’582 - Claims 1, 12, and 13 are obvious over McPherson in view of McPherson ’582.

  • Prior Art Relied Upon: McPherson (Patent 6,247,466) and McPherson ’582 (Patent 6,237,582).
  • Core Argument for this Ground:
    • Prior Art Mapping: The primary reference, McPherson, is the same as in Ground 1, teaching the core cam assembly with a secondary feed-out that takes up and then lets out the string. The secondary reference, McPherson ’582, was filed on the same day by the same inventor and discloses a complete archery bow with a bottom cam assembly and a top idler pulley. Critically, McPherson ’582 explicitly states that "other features which may be combined with the inventive bow are described in" the application that became the primary McPherson patent. Likewise, the primary McPherson patent notes that its invention may be utilized with the invention disclosed in the application that became McPherson ’582.
    • Motivation to Combine: Petitioner argued there was an explicit and exceptionally strong motivation to combine these references. The inventor of both patents expressly contemplated their combination within the specifications. A POSITA would have been directly motivated by this cross-referencing to combine McPherson’s cam assembly with the bow design of McPherson ’582. The combination would achieve the benefits of the advanced cam (improved draw profile) while also realizing the advantages of the ’582 bow, such as reduced setup/tuning problems and increased accuracy due to the coplanar arrangement of the idler and cam.
    • Expectation of Success: The expectation of success was particularly high given the explicit suggestion to combine from the inventor himself, demonstrating that the combination was not only possible but specifically envisioned.

4. Key Claim Construction Positions

  • Petitioner argued for a construction of the terms "a length of a string," "said length of said string," and "a portion of the length of said string" as recited in independent claim 1.
  • Petitioner contended that the plain language and antecedent basis in the claim require these terms to refer to different portions of a single, continuous string. The primary feed-out acts on a first portion ("a length of a string"), while the secondary feed-out acts on a second, different portion ("a portion of the length of said string"). This construction was central to Petitioner's argument that the prior art, which often shows a single string wrapped around a cam and idler wheel, teaches all limitations of the claims.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1, 12, and 13 of the ’791 patent as unpatentable.