PTAB

IPR2013-00274

MotivePower Inc v. Cutsforth Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Brush Holder Apparatus, Brush Assembly, and Method
  • Brief Description: The ’018 patent discloses brush holder assemblies for electrical devices, such as generators and motors. The technology is directed to an assembly featuring a mounting block with a brush release and a corresponding removable brush holder component with a brush catch, designed to facilitate quick, safe replacement of brushes while ensuring continuous electrical contact as the brush wears down.

3. Grounds for Unpatentability

Ground 1: Obviousness over Bissett, Kartman, and Ohmstedt - Claims 1-24 are obvious over Bissett in view of Kartman and Ohmstedt.

  • Prior Art Relied Upon: Bissett (Patent 3,432,708), Kartman (Patent 5,043,619), and Ohmstedt (Patent 3,864,803).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Bissett teaches the base assembly, including a removable brush holder that slidably engages a mounting structure. To improve this design, a person of ordinary skill in the art (POSITA) would incorporate the "brush catch" taught by Ohmstedt to provide a "positive means for retaining the brush" during maintenance operations. To properly integrate Ohmstedt’s corresponding brush release mechanism, a POSITA would modify Bissett’s mounting structure using the interchangeable T-shaped cross-section design taught by Kartman, which serves the same coupling purpose as Bissett’s structure.
    • Motivation to Combine: A POSITA would combine these references because they all address the same technical problem: improving removable brush holders in dynamoelectric machines. The motivation was asserted to be explicit, as Ohmstedt discusses the technology of Bissett and purports to improve upon it, providing a strong reason to add its brush catch feature. The use of known, interchangeable T-shaped engagement structures, as taught by both Bissett and Kartman, was presented as a common and predictable design choice.
    • Expectation of Success: Petitioner contended a POSITA would have a reasonable expectation of success, as the combination merely integrated known components for their established functions to achieve the predictable result of a more secure and easily maintainable brush holder assembly.

Ground 2: Anticipation by Ohmstedt - Claims 1-3, 5-13, 15-19, and 21-24 are anticipated by Ohmstedt.

  • Prior Art Relied Upon: Ohmstedt (Patent 3,864,803).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Ohmstedt, standing alone, discloses every element of the challenged claims. The argument mapped the limitations of independent claims 1, 12, and 17 to specific components in Ohmstedt. This included its disclosure of an elongate mounting block having a stationary brush release, a removable brush holder component with a brush box and channel, and a brush catch that moves from a first, brush-gripping position to a second, released position upon engagement with the brush release. Petitioner provided detailed citations and figure analysis to show that Ohmstedt’s structure inherently meets all claim limitations.

Ground 3: Obviousness over Ohmstedt and Kartman - Claims 1-24 are obvious over Ohmstedt in view of Kartman.

  • Prior Art Relied Upon: Ohmstedt (Patent 3,864,803) and Kartman (Patent 5,043,619).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative position, Petitioner argued that Ohmstedt provides the base reference, teaching the core mounting block and removable holder with a brush catch/release system. A POSITA would then modify Ohmstedt’s assembly using the teachings of Kartman. Specifically, one would adapt the removable component of Ohmstedt to include a brush box and channel configuration like that shown in Kartman to improve the sliding engagement with the mounting block.
    • Motivation to Combine: Both Ohmstedt and Kartman teach removable brush holders for the same purpose—quick and safe mounting—in the same field of dynamoelectric machines. A POSITA would combine their features to leverage the advantages of both systems, such as incorporating Kartman’s robust channel design while retaining Ohmstedt’s effective brush retention mechanism. This combination was argued to be a simple and predictable modification.
  • Additional Grounds: Petitioner asserted additional challenges, including anticipation of claims 1-3, 6-7, 9-10, 12-13, 15-19, and 22-24 by Krulls, and obviousness challenges based on combinations of Krulls with Kartman and Krulls with Bissett.

4. Key Claim Construction Positions

  • "mounting block": Petitioner argued for the term's plain and ordinary meaning, "a structure for mounting," which is broader than the Patent Owner's proposed construction from a related litigation that required the structure to be "configured to engage the removable component."
  • "removably mounting": Petitioner proposed the construction "mounting in a manner that is not permanent." This opposes the Patent Owner's narrower proposal requiring that the component "can be safely removed while the machine is energized."

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-24 of Patent 7,990,018 as unpatentable.