Gordon Sales Inc v. Mull It Over Products LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: GORDON SALES, INC. d/b/a GORDON INC. (Louisiana)
  • Defendant: MULL-IT-OVER PRODUCTS, LLC (Michigan)
  • Plaintiff’s Counsel: Howard & Howard Attorneys PLLC; Jones Walker LLP
• Case Identification: 1:26-cv-00766, W.D. Mich., 03/09/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Western District of Michigan because Defendant resides in the district, has committed alleged acts of infringement there, and maintains a regular and established place of business in the district.
• Core Dispute: Plaintiff alleges that Defendant’s ExpandaMull™ expandable gap filler assembly infringes a patent related to telescoping assemblies for filling gaps between walls in building structures.
• Technical Context: The technology at issue addresses the construction challenge of sealing gaps between interior partition walls and exterior window mullions, providing an adjustable, sound-blocking, and aesthetically finished joint.
• Key Procedural History: The asserted patent is a continuation of a prior non-provisional application and claims priority to two provisional applications filed in 2021.

Case Timeline

Date	Event
2021-01-20	Earliest Priority Date Claimed by ’181 Patent
2025-10-14	U.S. Patent No. 12,442,181 Issues
2026-03-09	Complaint Filed

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

U.S. Patent No. 12,442,181 - "Telescoping Wall Gap Filler Assembly"

• Patent Identification: U.S. Patent No. 12,442,181 ("the ’181 Patent"), titled "Telescoping Wall Gap Filler Assembly," issued on October 14, 2025.

The Invention Explained

• Problem Addressed: The patent addresses the need for a resilient and aesthetically pleasing gap filler for use in modern commercial buildings, specifically to close the space between an interior partition wall and an exterior window frame or mullion (ʼ181 Patent, col. 1:24-40). Such fillers must accommodate relative motion between the structures (e.g., due to wind forces on the window) and block sound transmission between rooms (ʼ181 Patent, col. 1:46-52).
• The Patented Solution: The invention is a pre-fabricated assembly comprising at least two frame members that slidingly engage one another, creating an interior cavity with a variable volume (ʼ181 Patent, col. 2:3-6). A "biasing member," such as a compression spring or expandable foam insulation, is placed inside this cavity (ʼ181 Patent, col. 2:6-9; ʼ181 Patent, col. 2:18-22). This internal member exerts an outward force, pushing the frame members apart to press them securely against the partition wall and the window mullion, thereby sealing the gap (ʼ181 Patent, col. 2:36-39).
• Technical Importance: This approach provides an adjustable, off-the-shelf solution that can fit a range of gap sizes, in contrast to custom-made rigid elements or simple foam wedges that may not provide a consistent seal or accommodate structural movement (ʼ181 Patent, col. 1:52-56).

Key Claims at a Glance

The complaint asserts independent Claims 1 and 7 (Compl. ¶10).

• Independent Claim 1:

  • A gap filler assembly for filling a gap between an interior partition wall and an exterior wall.
  • A first frame member "slidingly engaging" a second frame member.
  • An "interior cavity" defined by the frame members, having a "variable volume."
  • A "biasing member" comprising "expandable foam sound insulation material" disposed within the cavity.
  • The foam material has ends engaging the interior surfaces of the respective frame members and is configured to "exert a force" to compress the assembly between the partition and exterior walls.

• Independent Claim 7:

  • A gap filler assembly for filling a gap between an interior partition wall and an exterior wall.
  • A first "u-shaped frame member."
  • A second "u-shaped frame member" that "slidingly engages" the first to define an interior cavity with a "variable volume."
  • "Expandable foam sound insulation" disposed within the cavity.
  • The foam has first and second portions engaging the interior surfaces of the respective u-shaped frame members and "exerts a force" on the second frame member away from the first.

The complaint notes that Plaintiff may identify additional infringed claims after discovery (Compl. ¶19).

III. The Accused Instrumentality

Product Identification

• The accused product is the "ExpandaMull™" expandable gap filler assembly (Compl. ¶1).

Functionality and Market Context

• The complaint alleges the ExpandaMull™ product is an "expandable gap filler assembly" used for filling or covering gaps between building walls (Compl. ¶1). The infringement allegations suggest the product's functionality is based on a structure containing a first frame member slidingly engaging a second, creating an interior cavity with a variable volume that contains expandable foam insulation (Compl. ¶¶12-14; Compl. ¶¶16-18). The complaint does not provide further details on the product's market context or commercial importance.

IV. Analysis of Infringement Allegations

The complaint alleges that the Accused Product infringes at least Claims 1 and 7 of the ’181 Patent (Compl. ¶10). The allegations rely on an "Exhibit C," which was not included with the filed complaint (Compl. ¶12; Compl. ¶13; Compl. ¶14; Compl. ¶16; Compl. ¶17; Compl. ¶18). No probative visual evidence provided in complaint.

’181 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a first frame member slidingly engaging a second frame member	The Accused Product is alleged to include a first frame member that slidingly engages a second frame member.	¶12	col. 4:41-43
an interior cavity defined by the first and second frame members, wherein the interior cavity has a variable volume	The Accused Product is alleged to include an interior cavity defined by its frame members, with the cavity having a variable volume.	¶13	col. 4:43-45
a biasing member comprising expandable foam sound insulation material... configured to exert a force on the first frame member in a direction away from the second frame member for compressing the first and second frame members between the interior partition wall and the exterior wall	The Accused Product is alleged to include a biasing member of expandable foam sound insulation within the cavity that engages the frame members and is configured to exert an outward compressive force.	¶14	col. 6:54-63

Identified Points of Contention

• Technical Question: A central factual question will be whether the "expandable foam sound insulation material" in the Accused Product is "configured to exert a force" sufficient to perform the claimed biasing and compressing function. The analysis may distinguish between foam that passively fills a void and foam that actively generates a specified expansive force to secure the assembly, as described in the patent (ʼ181 Patent, col. 2:36-39).
• Scope Question: The term "slidingly engaging" may become a point of contention. The court may need to determine if this term covers any telescoping or overlapping arrangement, or if it is limited by the specification to the specific U-shaped channel configurations depicted in the patent's embodiments (e.g., ʼ181 Patent, Fig. 4).

V. Key Claim Terms for Construction

• The Term: "biasing member comprising expandable foam sound insulation material ... configured to exert a force"
• Context and Importance: This term is critical because it defines the mechanism that generates the expansive force to hold the assembly in place. The dispute will likely center on whether the foam in the Accused Product is merely a passive acoustic filler or an active mechanical component that meets the functional requirements of the claim.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent summary broadly describes the invention as using "internal springs or by expanding foam" to urge the frame members apart, suggesting the two are interchangeable means for achieving the same function (ʼ181 Patent, col. 2:36-37). This may support a construction where any foam that provides some outward pressure meets the limitation.
  • Evidence for a Narrower Interpretation: Claim 1 explicitly requires the foam itself to be the "biasing member" and to be "configured to exert a force" for "compressing" the assembly between walls. This functional language could support a narrower construction requiring proof that the foam has specific, engineered resilient properties sufficient to perform this mechanical task, not just fill a space. The specification also describes an alternative embodiment using distinct "compression springs" (ʼ181 Patent, col. 2:6-9), which could be used to argue that when "foam" is claimed, it must perform the same biasing function as a spring.

VI. Other Allegations

• Willful Infringement: The complaint alleges that Defendant's infringement is "willful and deliberate" (Compl. ¶23). The pleading does not, however, state a factual basis for this allegation, such as pre-suit knowledge of the patent or a prior notice letter from the Plaintiff.

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

The resolution of this dispute appears to depend on two primary questions for the court:

1. A core issue will be one of functional definition: Does the "expandable foam" within the Accused Product function as a "biasing member" that is "configured to exert a force" for compression, as required by the claims? The case may turn on evidence demonstrating the specific mechanical properties of the accused foam, rather than its mere presence as an acoustic insulator.
2. A key evidentiary question will be one of structural correspondence: Does the physical construction of the ExpandaMull™ product, particularly the way its frame members "slidingly engage" and define a "variable volume," map directly onto the elements of the asserted claims? The outcome will likely depend on a technical comparison between the accused device and the specific limitations recited in Claims 1 and 7.