DCT

1:18-cv-00197

Rite Hite Holding Corp v. Prihoda SRO

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:18-cv-00197, S.D. Ala., 04/25/2018
  • Venue Allegations: Venue is alleged based on Defendants’ acts of infringement within the district and Defendant Prihoda North America having a regular and established place of business in Mobile, Alabama.
  • Core Dispute: Plaintiffs allege that Defendants’ fabric air ducts featuring an "Internal tensioning system" infringe four U.S. patents related to pliable-wall air ducts with internal support frameworks.
  • Technical Context: The technology concerns internal frames for flexible fabric HVAC ducts, designed to keep the ducts expanded and taut even when unpressurized, thereby improving structural integrity and aesthetics.
  • Key Procedural History: The complaint alleges that Plaintiffs provided Defendants with notice of the ’526 Patent and the applications for the ’864 and ’865 Patents as early as June 24, 2014. This early notice date may be significant for the allegations of willful infringement.

Case Timeline

Date Event
2010-11-19 Earliest Priority Date for ’864, ’865, and ’139 Patents
2011-11-03 Priority Date for ’526 Patent
2013-05-07 ’526 Patent Issued
2014-06-24 Alleged Notice of ’526 Patent and ’864/’865 Applications
2017-03-28 ’864 Patent Issued
2017-03-28 ’865 Patent Issued
2017-05-XX Alleged Notice of ’865 Patent
2018-03-27 ’139 Patent Issued
2018-04-25 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 8,434,526 - "Pliable-Wall Air Ducts with Suspended Frames"

  • Patent Identification: U.S. Patent No. 8,434,526, “Pliable-Wall Air Ducts with Suspended Frames,” issued May 7, 2013 (Compl. ¶9).
  • The Invention Explained:
    • Problem Addressed: The patent describes drawbacks of conventional fabric air ducts, which are typically suspended by attaching the fabric itself to an overhead support. This method can cause the fabric to distort, especially when a heavy internal framework is also being supported (’526 Patent, col. 1:55-61; col. 3:4-11).
    • The Patented Solution: The invention proposes a system where the internal framework, rather than the fabric duct, is the primary load-bearing structure. This is achieved by suspending the internal framework directly from an overhead support using hangers that pass through openings in the pliable duct wall, thereby transferring the weight of the system to the more rigid internal components and reducing stress on the fabric (’526 Patent, Abstract; col. 3:12-23).
    • Technical Importance: This design allows fabric ducts to maintain a consistent, non-distorted shape while benefiting from the even air distribution and reduced condensation characteristic of fabric systems (’526 Patent, col. 4:41-57).
  • Key Claims at a Glance:
    • The complaint asserts at least independent claim 1 and dependent claim 24 (Compl. ¶26).
    • The essential elements of independent claim 1 include:
      • An air duct with a pliable sidewall that defines a plurality of openings.
      • An internal framework comprising a shaft, a rib, and spokes connecting the rib to the shaft.
      • A plurality of hangers that pass through the openings in the sidewall to couple to the internal framework, such that most of the pliable sidewall's weight is carried by the framework.

U.S. Patent No. 9,605,864 - "Pliable-Wall Air Ducts with Internal Expanding Structures"

  • Patent Identification: U.S. Patent No. 9,605,864, “Pliable-Wall Air Ducts with Internal Expanding Structures,” issued March 28, 2017 (Compl. ¶13).
  • The Invention Explained:
    • Problem Addressed: The patent notes that when the fan supplying air to a fabric duct is turned off, the loss of pressure causes the fabric to deflate and sag, which is aesthetically unpleasing and can create a loud "popping" sound when the duct is re-inflated (’864 Patent, col. 2:1-7).
    • The Patented Solution: The invention describes an internal framework with an adjustable length that holds the pliable duct in a state of longitudinal tension, even when the duct is depressurized. This is achieved by placing the internal shaft assembly into longitudinal compression, which creates the reactive tensile force on the duct wall, keeping it taut (’864 Patent, Abstract; col. 4:16-25). The adjustability can be achieved through mechanisms like a threaded connection.
    • Technical Importance: This innovation ensures a fabric duct maintains its intended shape and appearance regardless of airflow, preventing sagging and eliminating the disruptive noise associated with re-inflation (’864 Patent, col. 5:5-9).
  • Key Claims at a Glance:
    • The complaint asserts at least claims 7, 14-21, and 23-26 (Compl. ¶31).
    • The essential elements of independent claim 7 include:
      • An air duct in a tubular shape that is held in longitudinal tension.
      • A shaft assembly disposed within the duct that is subjected to a longitudinal compressive force.
      • The shaft assembly has a continuously adjustable length and includes a first shaft segment and a second shaft segment that are threadedly interconnected.

U.S. Patent No. 9,605,865 - "Pliable-Wall Air Ducts with Internal Expanding Structures"

  • Patent Identification: U.S. Patent No. 9,605,865, “Pliable-Wall Air Ducts with Internal Expanding Structures,” issued March 28, 2017 (Compl. ¶17).
  • Technology Synopsis: This patent details the mechanical structure of an internal framework for a pliable air duct. The invention centers on a system comprising a ring movably coupled to a shaft, where the ring can be fixed relative to the shaft to place the duct in tension and hold it in compression, with specific claims directed to the geometric and functional relationships between the spokes, hub, and ring (’865 Patent, Abstract; Claim 1).
  • Asserted Claims: At least claims 1, 4-6, and 8-12 (Compl. ¶36).
  • Accused Features: Defendants’ “pliable air ducts with internal tensioning” are accused of infringing (’865 Patent, ¶36).

U.S. Patent No. 9,927,139 - "Pliable-Wall Air Ducts with Internal Expanding Structures"

  • Patent Identification: U.S. Patent No. 9,927,139, “Pliable-Wall Air Ducts with Internal Expanding Structures,” issued March 27, 2018 (Compl. ¶21).
  • Technology Synopsis: This patent claims a fabric duct system designed to maintain an expanded shape at both active (pressurized) and inactive (unpressurized) states. The invention describes an internal framework that holds the pliable sidewall in tension by subjecting the framework itself to a reactive compressive load, with claims focusing on the system's ability to maintain its shape regardless of internal air pressure (’139 Patent, Abstract; Claim 1).
  • Asserted Claims: At least claims 1-5 and 7-13 (Compl. ¶41).
  • Accused Features: Defendants’ “pliable air ducts with internal tensioning” are accused of infringing (’139 Patent, ¶41).

III. The Accused Instrumentality

  • Product Identification: The accused products are Defendants' "pliable air ducts with internal tensioning" (Compl. ¶26, ¶31, ¶36, ¶41).
  • Functionality and Market Context:
    • The complaint identifies the accused functionality using a visual from Defendants’ website, which describes an “Internal tensioning system” (Compl. p. 5). This system is alleged to retain the duct's round shape with or without air supply using an aluminum track, reinforcing rings, and a tensioning ring (Compl. p. 5). The image titled "Internal tensioning console with tensioning ring" depicts a ring with spokes connected to a central component, designed to be installed inside the ducting (Compl. p. 5). The complaint alleges that tension is achieved via a "threaded axial connection," which is used to adjust the system and "perfectly straighten[] the shape" of the duct (Compl. p. 5).
    • The complaint alleges these products are imported, made, sold, and used in the United States (Compl. ¶26).

IV. Analysis of Infringement Allegations

’526 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
an air duct having a pliable sidewall to extend in a longitudinal direction, the pliable sidewall defining a plurality of openings... The accused products are pliable air ducts. However, the complaint does not provide specific allegations or evidence regarding a "plurality of openings" in the sidewall for hangers. ¶26 col. 4:58-62; col. 5:4-8
a framework to be disposed within the air duct... comprising... a shaft extending in the longitudinal direction; a rib... and a plurality of spokes connecting the rib to the shaft The accused "Internal tensioning system" is disposed within the duct and includes an "aluminum track" (the alleged shaft), along with "reinforcing rings" and a "tensioning ring" (the alleged ribs) connected by spokes to a bracket on the track. ¶26; p. 5 col. 4:6-15
a plurality of hangers... coupled to the framework via access through a corresponding opening... most of the total weight... is to be carried by the framework. The complaint does not provide sufficient detail for analysis of the hanger system or how the accused product is suspended. col. 4:46-57; col. 5:21-26
  • Identified Points of Contention:
    • Evidentiary Question: A primary issue is the lack of factual allegations supporting the "plurality of openings" and "plurality of hangers" elements, which are central to claim 1 of the ’526 Patent. The complaint's evidence focuses on the tensioning mechanism, not the specific suspension method claimed.
    • Scope Question: The analysis may turn on whether the accused product's "aluminum track" and associated "bracket" fall within the scope of the claimed "shaft" and "spokes."

’864 Patent Infringement Allegations

Claim Element (from Independent Claim 7) Alleged Infringing Functionality Complaint Citation Patent Citation
an air duct... in a tubular shape... the air duct being in longitudinal tension The accused system is advertised to "Perfectly straighten[] the shape," which Plaintiffs allege places the pliable duct in longitudinal tension. ¶31; p. 5 col. 5:8-14
a shaft assembly... disposed within the air duct... subjected to a longitudinal compressive force The internal framework, alleged to be a shaft assembly, would be subjected to a reactive compressive force as a result of placing the duct in tension. ¶31; p. 5 col. 5:15-17
...shaft assembly having a continuously adjustable length... The complaint does not provide sufficient detail for analysis of whether the adjustability is continuous. col. 17:58-61
...includes a first shaft segment and a second shaft segment... being threadedly interconnected. The accused system's description of an "adjustable... threaded axial connection" for tensioning suggests the presence of threadedly interconnected components that function as shaft segments. The "Detail of tensioning rings" image shows a threaded rod mechanism. p. 5 col. 17:65-68
  • Identified Points of Contention:
    • Technical Question: A key factual dispute will be whether the accused product's operation actually creates the "longitudinal tension" in the duct and corresponding "longitudinal compressive force" in the framework, as required by the claim.
    • Scope Question: The court may need to determine if the components of the accused "threaded axial connection" meet the claim definitions of a "first shaft segment" and a "second shaft segment."

V. Key Claim Terms for Construction

For the ’526 Patent

  • The Term: "most of the total weight of the pliable sidewall to be carried by the framework"
  • Context and Importance: This limitation defines the core functional concept of the ’526 Patent: shifting the primary structural load from the fabric to the internal frame. Proving infringement will require showing that the accused system functions in this specific manner.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification explains that the purpose is to reduce distortion and stress on the fabric, which may support an interpretation that any system where the framework carries more than 50% of the weight meets the claim (’526 Patent, col. 4:43-45).
    • Evidence for a Narrower Interpretation: The background section contrasts the invention with prior art where the fabric itself is suspended (’526 Patent, col. 1:55-61). This may support an argument that the term requires a system where the fabric is essentially non-load-bearing, a potentially higher standard than simply carrying "most" of the weight.

For the ’864 Patent

  • The Term: "longitudinal tension" and "longitudinal compressive force"
  • Context and Importance: These paired terms describe the push-pull dynamic that is central to the ’864 Patent's invention. The infringement analysis will hinge on whether these opposing forces exist in the accused product. Practitioners may focus on these terms because they define a testable physical state.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent states that the framework "exerts a tensile force 36 that tensions duct 18," which in turn subjects the shaft to a "reactive longitudinal compressive force 40" (’864 Patent, col. 5:8-17). This could suggest that the presence of any such reactive force pair meets the limitation.
    • Evidence for a Narrower Interpretation: The patent repeatedly describes the goal as achieving "tautness" and preventing sagging (’864 Patent, col. 5:11-14). A defendant could argue that these terms imply a threshold level of force sufficient to achieve this result, and that incidental or minimal forces do not infringe.

VI. Other Allegations

  • Indirect Infringement: The complaint's prayer for relief seeks to enjoin inducement of infringement, but the body of the complaint does not provide specific factual allegations to support this claim, such as referencing user manuals or other instructional materials (Compl. p. 8, ¶b).
  • Willful Infringement: Willfulness is alleged for all four asserted patents. For the ’526, ’864, and ’865 patents, the allegations are based on specific pre-suit notice allegedly provided to Defendants as early as June 24, 2014 (Compl. ¶27, ¶32, ¶37). For the ’139 Patent, the allegation is based on knowledge from the patent’s publication and issuance (Compl. ¶42).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of evidentiary proof versus claim requirements: Can Plaintiffs demonstrate that the accused products meet limitations that are not apparent from the website evidence provided, such as the "’526 Patent’s" requirement for hangers passing through openings in the fabric wall? A failure to prove this element for every asserted claim of the ’526 Patent could be fatal to that portion of the case.
  • A key technical question will be one of functional operation: Does the accused "Internal tensioning system" actually operate by placing the pliable duct in "longitudinal tension" while simultaneously subjecting the internal framework to "longitudinal compression," as required by the claims of the ’864, ’865, and ’139 patents? The case may depend on expert testimony analyzing the forces at play within the accused products.
  • A critical question for damages will be the effect of the alleged pre-suit notice: The allegation of notice for three patents dating to 2014, nearly four years before the suit was filed, raises a significant possibility of a finding of willful infringement and potential for enhanced damages if the notice is proven to be sufficient and infringement is found.