PTAB

IPR2026-00102

Liftwerx USA Inc v. Liftra IP ApS

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1. Case Identification

2. Patent Overview

  • Title: Main Shaft Fixture
  • Brief Description: The ’578 patent relates to a main shaft fixture used to secure the main shaft of a wind turbine during installation and repair. The fixture is designed to mount on structural parts within the nacelle and comprises adjustable pressure mandrels and facilities for mounting cranes.

3. Grounds for Unpatentability

Ground 1: Claims 1, 3-4, 6-8, 10, and 13-14 are obvious over Signore and Weaver in view of Power Climber, Holloway, and/or Stegemann.

  • Prior Art Relied Upon: Signore (Application # 2012/0141292), Weaver (European Patent No. 1,748,182), Power Climber (a 2014 press release), Holloway (Patent 9,651,020), and Stegemann (Application # 2010/0021278).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of Signore and Weaver teaches all elements of the base main shaft fixture claimed in claim 1, including a fixture divided into sections with adjustable pressure mandrels. The secondary references—Power Climber, Holloway, and Stegemann—were asserted to teach the remaining key limitation: "mounting facilities adapted for anchoring a crane on/in a nacelle." Power Climber was shown to disclose a lightweight nacelle davit (crane) mounted to a main shaft fixture. Holloway and Stegemann were argued to teach various portable cranes and mounting methods within a wind turbine nacelle, including attaching to structural components.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine the main shaft fixture of Signore/Weaver with the nacelle-mounted cranes of the secondary references to perform uptower repairs without requiring large, expensive ground-based cranes. The main shaft fixture would provide a strong, stable, and standardized location for mounting such a crane, which is an obvious design choice to improve the efficiency and safety of maintenance operations.
    • Expectation of Success: A POSITA would have had a high likelihood of success, as the combination involves integrating known mechanical components for their intended purposes. The fixture taught by Signore and Weaver is a robust structure suitable for bearing the load of a lightweight crane.

Ground 2: Claims 2, 5, and 15 are obvious over the combination of Signore and Weaver in view of Power Climber, Holloway, and/or Stegemann, further in view of Hanxing and/or Schulz.

  • Prior Art Relied Upon: All references from Ground 1, plus Hanxing (China Patent Application No. 201483408) and Schulz (Patent 4,177,701).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds on Ground 1 to address limitations in dependent claims. For claim 2, which requires "at least three radially displaceable pressure mandrels," Petitioner argued Hanxing discloses a clamp with four symmetrically arranged, radially displaceable mandrels. For claim 5, which requires the mandrels consist of "threaded bolts," Petitioner asserted Hanxing teaches adjustable bolts to press a sleeve against the main shaft, and Schulz teaches a brake screw and threaded nut assembly to actuate a brake pad.
    • Motivation to Combine: A POSITA would be motivated to use three or more mandrels, as taught by Hanxing, to better distribute forces on the main shaft, prevent bending moments, and provide a more secure attachment for shafts of varying geometries. Incorporating threaded bolts from Hanxing or a screw mechanism from Schulz was argued to be an obvious, simple, and reliable mechanical solution for actuating the pressure mandrels.
    • Expectation of Success: The combination was asserted to be predictable, as it involves substituting or adding well-understood mechanical elements (multiple mandrels, threaded actuators) into the base fixture to achieve known benefits like improved stability and adjustability.

Ground 4: Claims 1 and 3-17 are anticipated by the ’518 Patent.

  • Prior Art Relied Upon: The ’518 Patent (Patent 10,378,518).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground is based on a loss of priority date. Petitioner argued that the challenged ’578 patent is not entitled to the 2014 priority date of its parent applications (including the application that issued as the ’518 patent). During prosecution of the ’578 patent, the applicant amended the specification and claims to remove the requirement of "at least three" pressure mandrels, thereby broadening the scope to include fixtures with only two mandrels. Petitioner contended the parent applications exclusively taught and required "at least three" mandrels and provide no written description support for an embodiment with only two.
    • Anticipation Argument: Because this broadening amendment was made in 2024, Petitioner argued the effective filing date for claims 1 and 3-17 is January 24, 2024. The ’518 patent, which is one of the parent applications, was published in 2019. Therefore, the ’518 patent qualifies as prior art under 35 U.S.C. §102. Since the ’518 patent discloses a main shaft fixture with at least three mandrels (which falls within the scope of the challenged claims covering two or more mandrels) and teaches all other limitations, it was argued to anticipate claims 1 and 3-17.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 3) for claims 9, 11-12, and 16-17 based on the Ground 1 combination further in view of Cooper, Schaeffler, and Guerenbourg to teach features related to multi-part bearings and shaft-lifting actuators for bearing replacement.

4. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-17 of the ’578 patent as unpatentable.