PTAB

IPR2019-00846

SZ DJI Technology Co Ltd v. Autel Robotics USA LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Rotary Wing Aircraft Apparatus
  • Brief Description: The ’184 patent discloses an unmanned aerial vehicle (UAV), such as a quadcopter, featuring a specific lock mechanism for attaching rotor blades to driveshafts. The system uses distinct clockwise and counterclockwise lock mechanisms to ensure correct blade placement, preventing blades from being attached to driveshafts rotating in the wrong direction.

3. Grounds for Unpatentability

Ground 1: Claims 3 and 4 are obvious over Sasaki in view of Sokn.

  • Prior Art Relied Upon: Sasaki (JP Application # H06-17511) and Sokn (Patent 5,133,617).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that the combination of Sasaki and Sokn teaches or suggests every limitation of independent claim 1, from which challenged claims 3 and 4 depend. Sasaki disclosed the fundamental structure of a quadcopter UAV with a body, arms, and rotor assemblies, including paired clockwise and counterclockwise rotating propellers to cancel torque. Critically, Sasaki taught a “mistake-proof” connection using directionally threaded screws (e.g., a left-hand thread for a clockwise-rotating propeller) to ensure correct blade placement. However, Petitioner contended this continuous-thread design was prone to overtightening.

    Sokn, which addressed mounting a fan motor, disclosed an improved twist-lock mechanism using segmented helical threads (lugs) and corresponding notches. This design provided a secure connection with a fractional turn and included stop members to prevent the overtightening problem seen in Sasaki. Petitioner argued that replacing Sasaki’s continuous threaded mechanism with Sokn’s superior segmented thread (lug/notch) mechanism would have been an obvious modification. This combination would result in a shaft lock portion (from Sokn) with notches engaging corresponding lugs on the blade lock portion (from Sokn), thereby meeting all limitations of claim 1.

    For dependent claims 3 and 4, which recite the specific direction of rotation for attachment, Petitioner asserted the combination inherently disclosed these limitations. To attach a clockwise rotor blade using the combined mechanism (with left-oriented helical threads), a user would necessarily rotate the blade counterclockwise, as required by claim 3. Conversely, to attach a counterclockwise rotor blade (with right-oriented helical threads), a user would rotate it clockwise, as required by claim 4.

    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Sasaki and Sokn to solve the known problem of overtightening associated with Sasaki's continuous-thread design. Sokn was analogous art because it addressed the precise problem of securely coupling rotating components without overtightening. A POSITA would have been motivated to replace Sasaki’s fastener with Sokn’s improved segmented-thread mechanism to gain its benefits, which included preventing overtightening, improving ease of use (requiring only a fractional turn for attachment/detachment), increasing design flexibility, and eliminating the risk of cross-threading.

    • Expectation of Success: Petitioner asserted that a POSITA would have a reasonable expectation of success in combining the references. Adapting and scaling Sokn's mechanical coupling for use in Sasaki's UAV was presented as a matter of routine mechanical design, well within the skill of a POSITA.

4. Key Claim Construction Positions

  • "lock mechanism" / "clockwise lock mechanism" / "counterclockwise lock mechanism": Petitioner proposed construing these terms as "one or more components that enable a [clockwise / counterclockwise] rotor blade to be releasably attached." This construction relies on the open-ended transitional term "comprises" in the claims, arguing the mechanism is not limited to only the recited "shaft lock portion" and "blade lock portion" and may include other unrecited elements.
  • "lugs" & "notches": Petitioner proposed that "lugs" should be construed as "projections" and "notches" as "indentations." This construction was based on the terms' plain and ordinary meanings in a mechanical context, as supported by the patent's figures and dictionary definitions, to clarify their structure as simple projections and corresponding indentations.
  • "drive": Petitioner proposed construing "drive" as "a component that imparts motion." This construction clarifies that the term, as used in the claim "a drive rotating the driveshaft," functions as a noun referring to a component like an electric motor, rather than as a verb.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 3 and 4 of the ’184 patent as unpatentable.