Delta T LLC v. MacroAir Technologies Inc

1. Case Identification

• Case #: IPR2021-01214
• Patent #: 8,579,588
• Filed: July 2, 2021
• Petitioner(s): Delta T, LLC
• Patent Owner(s): MacroAir Technologies, Inc.
• Challenged Claims: 15

2. Patent Overview

• Title: Hub Assembly for a Large Cooling Fan
• Brief Description: The ’588 patent discloses a hub assembly for a large cooling fan where fan blades are mounted onto arm members that are detachably secured to the hub. This design intends to simplify the replacement of broken or damaged arm members without requiring disassembly of the entire hub.

3. Grounds for Unpatentability

Ground 1: Obviousness over Madsen - Claim 15 is obvious over Madsen.

• Prior Art Relied Upon: Madsen (Application # 2009/0123284), in view of the knowledge of a person of ordinary skill in the art (POSA).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Madsen, which discloses a high-volume, low-speed (HVLS) fan, teaches every element of claim 15. Madsen’s fan includes a hub assembly (24) with a motor (68), a hub member (comprising top and bottom plates 56, 58 and bearing housings 54) that defines openings, and a plurality of blades (16). Petitioner contended that Madsen’s fan blade mounting shafts (48) are the claimed "arm members," which are mounted to the fan blades and positioned within the openings of the hub member.
  • Petitioner asserted two key limitations were met either directly or through obvious modifications. First, for the "detachably secured" limitation, Petitioner argued that Madsen implicitly discloses removable fasteners (screws or bolts) securing the bearing housings (54), which capture the mounting shafts (48). Removing these fasteners would allow the shafts to be removed without damaging the hub. Alternatively, Petitioner argued a POSA would be motivated to use such detachable fasteners to facilitate routine maintenance, repair of wear-prone parts like bearings, and allow for interchangeability of components, a well-known and predictable modification.
  • Second, for the "constant cross section" limitation, Petitioner contended that Madsen’s mounting shafts (48) must be cylindrical to rotate within their bearings (50), and the blade socket they fit into is also round, implying a constant cross-section. Alternatively, Petitioner argued it would have been obvious to a POSA to design the shafts with a constant cross-section, as this is the simplest, cheapest, and most common method of manufacturing shafts, especially for a rotational application.
  • Motivation to Combine (for §103 grounds): The primary motivation was to modify Madsen based on common knowledge and predictable design principles. A POSA would modify Madsen to use detachable fasteners to improve serviceability, extend the life of the fan, and reduce repair costs. Similarly, a POSA would be motivated by manufacturing simplicity and cost-effectiveness to form the mounting shafts with a constant cross-section.
  • Expectation of Success: Petitioner argued that using removable fasteners to connect fan components and manufacturing shafts with a constant cross-section were routine, well-understood practices in the mechanical arts. A POSA would have had a high expectation of success in implementing these modifications, as they would have yielded predictable results.

4. Key Claim Construction Positions

• "hub assembly": Petitioner proposed this term be construed as "a hub with multiple parts that are assembled together." This construction was argued to be critical because it requires a multi-component structure, consistent with the patent’s figures and the plain meaning of "assembly."
• "openings": Petitioner proposed the construction "one or more locations where the arm members may be detachably secured." This construction focused on the function of the openings as mounting points for the arm members.
• "detachably secured": Petitioner proposed this term be construed as "arm members are removable from the hub without damage to the hub." This construction was central to the patent’s stated purpose of allowing for easy replacement of parts and was intended to exclude destructive removal methods.

5. Arguments Regarding Discretionary Denial

• §325(d) - Same Art or Arguments: Petitioner argued that discretionary denial under §325(d) was inappropriate because the primary reference, Madsen, was never presented to or considered by the USPTO examiner during the original prosecution of the ’588 patent. Therefore, the art and arguments in the petition were new.
• §314(a) - Fintiv Factors: Petitioner argued against discretionary denial under Fintiv, asserting that the co-pending district court litigation would almost certainly be stayed if the IPR was instituted, as only the challenged claim was asserted. Petitioner also emphasized the strong merits of the petition and noted that the presiding judge in the litigation had a high rate of granting stays pending IPR.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claim 15 of the ’588 patent as unpatentable.