DCT
5:23-cv-02432
Columbia Insurance Co v. Simpson Strong Tie Co Inc
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Columbia Insurance, Co. (Nebraska) and MiTek Inc. (Missouri)
- Defendant: Simpson Strong-Tie Company Inc. (California)
- Plaintiff’s Counsel: Practus, LLP; Stinson LLP
- Case Identification: 5:23-cv-02432, N.D. Cal., 06/06/2025
- Venue Allegations: Venue is based on Defendant being a California corporation with its principal place of business in the Northern District of California, where it has allegedly committed acts of infringement and maintains a regular and established place of business.
- Core Dispute: Plaintiffs allege that Defendant’s structural fire wall hangers infringe a patent related to connecting structural components to fire-rated walls while maintaining the wall's fire-resistant properties.
- Technical Context: The technology concerns structural connectors used in building construction, specifically designed to minimize discontinuities in fire-retardant sheathing when attaching floor joists or trusses to a wall.
- Key Procedural History: The complaint details a lengthy history between the parties, including prior litigation over a parent patent (U.S. Patent No. 10,316,510). Notably, Defendant previously challenged the validity of the patent-in-suit, U.S. Patent No. 11,021,867, in a Post Grant Review (PGR) proceeding before the Patent Trial and Appeal Board (PTAB). The PTAB declined to find the asserted claims unpatentable, a decision later affirmed by the U.S. Court of Appeals for the Federal Circuit. These prior proceedings may significantly influence the analysis of willfulness and could estop the Defendant from raising certain invalidity arguments.
Case Timeline
| Date | Event |
|---|---|
| 2013-12-31 | '867 Patent Priority Date |
| 2014-Spring | MiTek FWH Hangers released |
| 2017-06 | Simpson Predecessor DG Hangers released |
| 2019-04-01 | Simpson DGF Series released |
| 2021-06-01 | U.S. Patent No. 11,021,867 Issued |
| 2023-03-15 | PTAB Final Written Decision upholds asserted '867 patent claims |
| 2023-06 | Simpson DGT Series introduced |
| 2025-01-07 | Federal Circuit affirms PTAB decision |
| 2025-06-06 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 11,021,867 - "Hanger for Fire Separation Wall"
The Invention Explained
- Problem Addressed: In construction, attaching structural components like floor trusses to fire-rated walls often requires cutting large openings in the fire-retardant sheathing (e.g., gypsum board). This creates a "large discontinuity" that compromises the integrity of the fire separation wall and reduces its fire-resistant rating ( Compl. ¶15; ’867 Patent, col. 1:35-42).
- The Patented Solution: The invention is a structural hanger designed to minimize this discontinuity. It features a channel-shaped portion that holds the joist on one side of the sheathing and a separate connection portion that attaches to the wall's internal frame. These two parts are joined by an "extension portion" designed to pass through a narrow slot in the sheathing, thereby "sandwiching" the sheathing between the hanger's components and maintaining the wall's fire-retardant characteristics (’867 Patent, Abstract; col. 3:35-49).
- Technical Importance: This design allows builders to securely attach structural supports while preserving the continuous fire-rating of a wall assembly, a critical safety feature and building code requirement, particularly in multi-family residential structures (Compl. ¶11; ’867 Patent, col. 1:24-34).
Key Claims at a Glance
- The complaint asserts dependent claims 13 and 18, which incorporate independent claims 1 and 16, respectively (Compl. ¶¶31, 32).
- Independent Claim 1: A hanger comprising:
- a channel-shaped portion configured to receive the structural component, including a base lying in a base plane;
- a connection portion for attachment to the wall, including a back flange;
- an extension portion with flanges extending from the channel portion to the connection portion, configured to extend through the sheathing with its planes generally perpendicular to the base plane; and
- the back flange and channel-shaped portion defining a sheath space to receive the sheathing, locating the channel and back flange on opposite sides of the sheathing.
- Independent Claim 16: A hanger comprising:
- a channel-shaped portion with a base and side panels to receive a structural component;
- a connection portion with a back flange to engage a vertical face of the wall's upper plate;
- first and second extension flanges interconnecting the channel and connection portions, configured to extend through an opening in the sheathing;
- the components defining a sheathing space; and
- the back flange being sized and arranged to at least partially block the opening in the sheathing to reduce exposure of the wooden top plate.
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are Defendant’s "DGF Series" (models DGF, DGHF, DGBF) and "DGT Series" (models DGT, DGHT) of Strong-Tie Fire Wall Hangers (Compl. ¶¶28-29).
Functionality and Market Context
- The DGF and DGT Series are single-piece metal connectors designed to attach structural components like joists to walls that have sheathing, such as drywall, mounted on them (Compl. ¶30). The complaint alleges these products are marketed for use with walls having two layers of 5/8-inch-thick drywall and feature a "drywall gap" that allows the sheathing to be installed after the building is framed (Compl. ¶¶37, 44, 47). The DGT Series was allegedly introduced to replace the DGF Series around June 2023 (Compl. ¶¶29, 102).
IV. Analysis of Infringement Allegations
11,021,867 Patent Infringement Allegations (based on Claim 1)
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a channel-shaped portion configured to receive the structural component...the base having an upper surface lying in a base plane | The accused DGF and DGT Series hangers include a channel-shaped portion, highlighted in complaint visuals, configured to receive a joist or truss. This portion has a base and side panels. | ¶38, ¶48 | col. 12:16-24 |
| a connection portion configured for attachment to the wall, the connection portion including a back flange...the connection portion and channel-shaped portion being in a fixed, spaced apart relation | The accused hangers have a connection portion with a top flange to overlie a wall's top plate and a back flange extending downward. As single-piece metal parts, the portions are in a fixed relation. | ¶39, ¶45, ¶49 | col. 12:25-32 |
| an extension portion including first and second extension flanges extending from the channel-shaped portion to the connection portion...configured to extend through the sheathing | The accused hangers possess first and second extension flanges that connect the channel-shaped portion to the back flange and are configured to extend through drywall when installed. | ¶40, ¶41, ¶51 | col. 12:33-38 |
| the back flange and the channel-shaped portion defining a sheath space sized and shaped to receive the sheathing therein so that the channel-shaped portion is located on one side...and the back flange is located on an opposite side | The space between the hangers' channel-shaped portion and back flange is marketed as a "drywall gap" sized to receive two layers of sheathing, which places the components on opposite sides of the sheathing. A complaint visual illustrates this gap. (Compl. p. 11, "Top View of the DGHF"). | ¶44, ¶52 | col. 12:41-50 |
11,021,867 Patent Infringement Allegations (based on Claim 16)
| Claim Element (from Independent Claim 16) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a channel-shaped portion configured to receive the structural component...and side panels extending upward from the base | The accused DGF and DGT Series hangers have a channel-shaped portion with a base and side panels, as highlighted in a complaint diagram. (Compl. p. 8, DGF, DGHF, DGBF diagrams). | ¶38, ¶48 | col. 13:40-45 |
| a connection portion configured for attachment to the frame wall, the connection portion including a back flange configured for engaging a vertical face of the upper plate | The accused hangers have a connection portion that includes a back flange configured to engage a vertical face of a frame wall's top plate. | ¶39, ¶49 | col. 13:46-51 |
| first and second extension flanges interconnecting the connection portion and the channel-shaped portion...being configured to extend through an opening in the sheathing | The accused hangers have extension flanges that connect the other portions and are designed to pass through an opening in the wall's sheathing. | ¶40, ¶41, ¶51 | col. 14:2-7 |
| the back flange being sized and arranged to at least partially block the opening in the sheathing to reduce the exposure of the wooden top plate | The back flanges of the accused hangers are alleged to at least partially block the opening created in the sheathing when installed. A complaint visual depicts this blocking function. (Compl. p. 12, "Annotated Top View of the DGHF"). | ¶46, ¶55 | col. 14:15-19 |
- Identified Points of Contention:
- Technical Question: The complaint asserts that because the accused hangers are constructed of a single piece of metal, their constituent parts are in a "fixed, spaced apart relation" as required by the claims (Compl. ¶¶45, 54). A potential point of contention could be whether the inherent flexibility of the single-piece metal structure meets the claimed "fixed" relationship, or if some degree of movement or flex exists that is inconsistent with the claim language.
- Scope Question: For Claim 16, the term "at least partially block the opening" introduces a question of degree. While the complaint provides visuals suggesting some blockage occurs, the dispute may focus on whether the extent of this blockage is sufficient to meet the claim limitation, especially when read in light of the patent's stated purpose of reducing the exposure of wooden components.
V. Key Claim Terms for Construction
The Term: "extension portion" (Claim 1) / "extension flanges" (Claim 16)
Context and Importance: This is the critical structural element that enables the hanger to bridge the fire-retardant sheathing, connecting the joist-holding channel to the wall-mounting flange. The construction of this term will define the required geometry for the part of the hanger that passes through the wall sheathing.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The summary of the invention describes the element functionally as an "extension portion" that "extends from the channel-shaped portion to the connection portion and interconnects" them (’867 Patent, col. 2:10-13). This language may support a construction covering any structure that performs this interconnecting function.
- Evidence for a Narrower Interpretation: The patent’s detailed description and figures consistently depict this element as "two extension flanges" (e.g., flanges 60 in Fig. 2) that are generally planar and parallel (’867 Patent, col. 5:1-17). Parties may argue that the claims, when read in light of the specification, should be limited to this two-flange embodiment.
The Term: "fixed, spaced apart relation" (Claims 1 and 16)
Context and Importance: This term defines the required structural relationship between the part of the hanger that holds the joist and the part that attaches to the wall. Its construction is key to determining whether a single-piece, potentially flexible hanger infringes. Practitioners may focus on this term because the complaint grounds its satisfaction of this element in the hangers' single-piece metal construction (Compl. ¶¶45, 54).
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent states the connection portion is "fixed in position relative to the channel-shaped portion such that that channel-shaped portion does not rotate relative to the connection portion" (’867 Patent, col. 2:15-18). This could be interpreted to mean "fixed" primarily prohibits relative rotation, potentially allowing for some degree of linear flex.
- Evidence for a Narrower Interpretation: The term "fixed" itself implies a rigid, unmoving connection. A party could argue that if the single-piece construction allows for significant flexing under load, the relationship is not truly "fixed" as a person of ordinary skill in the art would understand in the context of a load-bearing structural connector.
VI. Other Allegations
- Indirect Infringement: The complaint does not plead a separate count for indirect infringement. However, the factual allegations state that Defendant marketed its hangers for the specific purpose of connecting joists to walls with sheathing, which could form the basis for an inducement theory (Compl. ¶¶37, 47).
- Willful Infringement: The complaint makes extensive allegations to support willfulness. It alleges Defendant had knowledge of the patent and its infringement based on: (1) direct notification from Plaintiffs' counsel on June 25, 2021 (Compl. ¶90); (2) Defendant’s active monitoring of Plaintiffs' patent applications for over eight years (Compl. ¶112); (3) Defendant’s own unsuccessful Post Grant Review challenge to the ’867 Patent at the PTAB (Compl. ¶¶93, 98); (4) the Federal Circuit’s subsequent affirmance of the PTAB’s decision upholding the claims (Compl. ¶99); and (5) Defendant's continued sale of the accused DGF series and introduction of the new DGT series after these adverse rulings (Compl. ¶¶101-102).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural and functional correspondence: does the single-piece construction of the accused DGF and DGT hangers, including their specific geometry and placement of flanges, meet every structural and relational limitation of the asserted claims, particularly the requirement in Claim 16 that the back flange "at least partially block the opening in the sheathing"?
- A primary legal question will concern willfulness and intent: given the detailed history of competition, prior litigation over a parent patent, and an unsuccessful post-grant review of the patent-in-suit itself, do the facts alleged by the Plaintiffs demonstrate that Defendant acted despite an objectively high likelihood that its actions constituted infringement of a valid patent, potentially warranting enhanced damages?