DCT
3:25-cv-00271
Morryde Intl Inc v. Airxcel Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: MORryde International, Inc. (Indiana)
- Defendant: Airxcel, Inc., d/b/a Suburban (Delaware)
- Plaintiff’s Counsel: Irwin IP LLP
- Case Identification: 3:25-cv-00271, N.D. Ind., 10/03/2025
- Venue Allegations: Venue is alleged to be proper as Defendant maintains regular and established places of business within the Northern District of Indiana.
- Core Dispute: Plaintiff alleges that Defendant’s recreational vehicle (RV) folding staircase products infringe four patents related to the mechanical structure, deployment, and storage of such staircases.
- Technical Context: The technology concerns folding staircases for RVs, which are designed to provide a stable, ground-contacting means of entry and egress that can be stowed inside the vehicle's doorway.
- Key Procedural History: The complaint alleges an extensive pre-suit notification history beginning in November 2023, including the provision of infringement claim charts for the patents-in-suit. Plaintiff also notes that U.S. Patent No. 11,739,534 successfully underwent a supplemental examination, with the USPTO issuing a certificate in December 2024 stating that no substantial new question of patentability was raised. The complaint further alleges that Defendant was aware of the application that issued as U.S. Patent No. 12,428,850 and monitored its prosecution before it issued.
Case Timeline
| Date | Event |
|---|---|
| 2016-06-06 | Earliest Priority Date for all Patents-in-Suit |
| 2018-02-27 | U.S. Patent No. 9,903,121 Issues |
| 2019-12-31 | U.S. Patent No. 10,519,671 Issues |
| 2023-08-29 | U.S. Patent No. 11,739,534 Issues |
| 2023-11-01 | Alleged Launch of Accused "Stow Away Product" |
| 2023-11-21 | Plaintiff Notifies Defendant of Infringement Concerns |
| 2024-01-25 | Plaintiff Provides Defendant with '534 Patent Claim Chart |
| 2024-08-09 | Defendant Allegedly Confirms Intent to Continue Sales |
| 2024-10-01 | Alleged Launch of Accused "Lift Assist Product" |
| 2024-12-20 | USPTO Issues Supplemental Examination Certificate for '534 Patent |
| 2025-03-05 | Plaintiff Provides Defendant with '121 and '671 Patent Claim Charts |
| 2025-04-28 | Defendant Allegedly Aware of Application for '850 Patent |
| 2025-09-30 | U.S. Patent No. 12,428,850 Issues |
| 2025-09-30 | Plaintiff Provides Defendant with '850 Patent Claim Charts |
| 2025-10-03 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 11,739,534 - "Folding Staircase," issued August 29, 2023
The Invention Explained
- Problem Addressed: The patent's background describes previous folding staircases for RVs as "unwieldy," noting that some fail to provide a "sturdy and consistent path to the ground" and others require "great effort on the part of a user" to operate (’534 Patent, col. 1:20-33).
- The Patented Solution: The invention is a folding staircase that mounts to the floor inside the RV's door opening. It features a "threshold plate" that pivots to cover the vehicle's threshold when in use and folds inward for storage (’534 Patent, col. 1:47-54). This plate connects to the main stair assembly—comprising stringers, treads, and adjustable ground-contacting legs—via an "offsetting portion," allowing the entire assembly to pivot from a deployed position outside the vehicle to a stowed position inside the doorway (’534 Patent, Abstract; col. 4:25-54).
- Technical Importance: This configuration allows a stable, ground-contacting staircase to be stored completely within the indoor space, protecting it from road debris and weather while simplifying the mounting structure compared to under-chassis systems (’534 Patent, col. 3:52-57).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2, 4-15, and 17 (Compl. ¶¶ 56-58).
- The essential elements of independent claim 1 include:
- A mounting portion.
- A threshold plate pivotally connected to the mounting portion, which includes a ramped portion joined to a spanning portion at an oblique angle.
- An offsetting portion extending from the spanning portion.
- A pair of stringers with treads and selectively lockable adjustable legs.
- The offsetting portion, stringers, and ramped portion are connected to pivot together about a pivot axis.
- The staircase is pivotable between a first (use) position at a "relatively near angular position" and a second (stowed) position at a "relatively far angular position" from the mounting portion.
U.S. Patent No. 10,519,671 - "Folding Staircase," issued December 31, 2019
The Invention Explained
- Problem Addressed: The patent addresses the same general problem of unwieldy and effort-intensive RV staircases as the '534 Patent (’671 Patent, col. 1:12-31).
- The Patented Solution: This invention also describes a folding staircase that stows inside the vehicle but adds a specific "lifting mechanism that assists moving the staircase from its use to its stowed position" (’671 Patent, Abstract). The core of this solution is a spring assembly, disclosed as a pair of gas springs, connected between one of the stationary mounting brackets and the pivoting threshold plate. This spring exerts a rotational force to help lift the staircase, with the geometry designed to provide more assistance when the user is bearing more of the staircase's weight (’671 Patent, col. 5:25-29, col. 6:7-21).
- Technical Importance: The inclusion of a lift-assist mechanism directly addresses the "great effort" required to operate heavy, ground-contacting stair systems, improving user convenience and accessibility (’671 Patent, col. 1:28-31).
Key Claims at a Glance
- The complaint asserts independent claims 1 and 6, and dependent claims 2-5 and 7-10 (Compl. ¶¶ 79-80).
- The essential elements of independent claim 1 include:
- A folding staircase with stringers, a threshold plate, and a hinge comprising first and second mounting brackets.
- Each mounting bracket has a "wall mount flange" and a "hinge flange."
- A "spring" is pivotally affixed at one end to the second mounting bracket's hinge flange and at the other end to the threshold plate's hinge flange.
- The spring is located so that it leaves the door opening "unobstructed" when the mounting brackets are installed.
- The spring exerts a force to urge the threshold plate toward its stowed position.
Multi-Patent Capsule: U.S. Patent No. 9,903,121 - "Folding Staircase," issued February 27, 2018
- Technology Synopsis: As the parent patent in this family, the '121 Patent appears to disclose the foundational concepts of a folding RV staircase with an indoor-mounted hinge and a lift-assist mechanism to aid in stowing the assembly (Compl. ¶13). It provides an earlier-claimed version of the technology further developed in the '671 Patent.
- Asserted Claims: 1-5 (Compl. ¶¶ 68-69).
- Accused Features: The complaint accuses the "Lift Assist Product," focusing on its overall structure as a folding staircase with a lift-assist spring mechanism (Compl. ¶68).
Multi-Patent Capsule: U.S. Patent No. 12,428,850 - "Folding Staircase," issued September 30, 2025
- Technology Synopsis: As a continuation of the application that led to the '534 Patent, the '850 Patent appears to claim further refinements of the core folding staircase design. The complaint specifically highlights its coverage of features like adjustable legs and a "stop bracket used when the staircase is stowed to prevent the staircase from falling inward" (Compl. ¶13).
- Asserted Claims: 1-2, 4-7, and 11-24 (Compl. ¶¶ 90-92).
- Accused Features: The complaint accuses both the "Stow Away Product" and the "Lift Assist Product," indicating claims of broad applicability. The allegations target the products' pivoting structure, adjustable legs, and use of a stop bracket to secure the staircase in its stowed position (Compl. ¶¶ 90-91).
III. The Accused Instrumentality
Product Identification
- The complaint names two accused product lines: the "Suburban Stow Away Steps" ("Stow Away Product") and the "Suburban Lift Assist Step" ("Lift Assist Product") (Compl. ¶¶ 15, 30).
Functionality and Market Context
- Both products are described as retractable, folding staircases designed for use with RVs (Compl. ¶¶ 16, 31). The primary distinction alleged is that the Lift Assist Product includes a spring mechanism to aid in stowing the stairs, whereas the Stow Away Product does not (Compl. ¶¶ 42-43).
- The complaint provides detailed allegations, supported by annotated photographs, that the products contain the key structural elements of the patented inventions. These include a floor-mounted hinge, a pivoting threshold plate with ramped and offsetting portions, stringers with treads, and adjustable, ground-contacting legs (Compl. ¶¶ 17-23, 32-38). The complaint alleges that the accused products "directly compete" with Plaintiff's own products and that their sale has resulted in lost sales for the Plaintiff (Compl. ¶50).
IV. Analysis of Infringement Allegations
11,739,534 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a threshold plate... pivotally connected to the mounting portion... including a ramped portion joined to a spanning portion... at an oblique angle | The product has a threshold plate that pivots on a mounting portion and includes a ramped portion joining a spanning portion at an oblique angle. The complaint provides an annotated photograph identifying these features (Compl. p. 4). | ¶17 | col. 4:25-34 |
| an offsetting portion extending from said spanning portion opposite said ramped portion | The product has an offsetting portion that extends from the spanning portion, opposite the ramped portion. An annotated image shows this component (Compl. p. 5). | ¶18 | col. 4:46-49 |
| a pair of stringers... each of said stringers including an adjustable leg... selectively lockable | The product's stringers each have an adjustable leg that can be locked in place. Annotated photographs identify these components (Compl. pp. 5-6). | ¶¶ 19-20 | col. 3:12-16 |
| said offsetting portion, said stringers, and said ramped portion pivot together about said pivot axis | The product includes an offsetting portion connected to the stringers, which allegedly causes these components to pivot together. An annotated photograph illustrates this alleged collective movement (Compl. p. 6). | ¶21 | col. 4:51-54 |
| said staircase being pivotable between a first position... and a second position... said relatively far angular position being larger than said relatively near angular position | The product is pivotable between a deployed position and a stowed position, where the angular displacement in the stowed position is greater than in the deployed position. An annotated image compares the two positions (Compl. p. 7). | ¶22 | col. 4:61-67 |
10,519,671 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a hinge having a first mounting bracket... and a second mounting bracket... each having a first wall mount flange... and a first hinge flange | The product has a hinge with first and second mounting brackets, each containing a wall mount flange and a hinge flange. An annotated photograph identifies these components (Compl. p. 11). | ¶¶ 36-38 | col. 4:38-56 |
| a spring pivotally affixed about a first pivot point on said second hinge flange of said second mounting bracket and said spring pivotally affixed to said second hinge flange of said threshold plate about a second pivot point | The product has a spring pivotally connected between the second mounting bracket and the threshold plate. An annotated photograph shows the spring and its first and second pivot points (Compl. p. 15). | ¶42 | col. 5:25-45 |
| said spring being located on the same side of said second wall mount flange as said pivot axis thereby leaving said door opening unobstructed | The spring is allegedly positioned behind the wall mounting flange, which the complaint asserts leaves the door opening unobstructed. | ¶42 | col. 5:31-34 |
| said spring exerting a force between said threshold plate and said second mounting bracket urging rotation of said threshold plate toward said stowed position | The spring is alleged to exert a force that assists in rotating the staircase toward its stowed position. | ¶42 | col. 6:48-61 |
Identified Points of Contention
- Scope Questions: The infringement theories appear factually straightforward based on the complaint's photographic evidence. Disputes may therefore center on claim construction. For the ’671 Patent, a key question may be whether the term "spring" should be limited to the "gas springs" and their specific variable-force properties, which are described extensively in the specification, or if it covers any biasing mechanism.
- Technical Questions: For the '534 Patent, a potential point of contention is the interpretation of relational terms like "oblique angle," "pivot together," and "relatively near/far angular position." The analysis will question whether the accused product's geometry and kinematics fall within the scope of these terms as construed in light of the patent's specification and drawings.
V. Key Claim Terms for Construction
Term 1: "spring" (from '671 Patent, Claim 1)
- Context and Importance: The definition of "spring" is central to the infringement analysis for the Lift Assist Product. Practitioners may focus on this term because the patent specification’s only disclosed embodiment is a "gas spring" with a "relatively flat force curve," which provides a specific functional benefit (’671 Patent, col. 5:46-51). The defense may argue that the accused product uses a different type of spring (e.g., a simple extension or coil spring) that lacks this characteristic and therefore does not infringe.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Independent claim 1 uses the general term "spring" without qualification. Dependent claim 5 specifies that the "spring is an extension spring," which suggests under the doctrine of claim differentiation that the broader term in claim 1 is not limited to extension springs, let alone gas springs (’671 Patent, col. 8:51-52).
- Evidence for a Narrower Interpretation: The specification exclusively describes the embodiment as a "pair of gas springs" and repeatedly emphasizes the technical advantages of their specific force curve in providing variable assistance during lifting (’671 Patent, col. 5:25, col. 6:7-21). This repeated emphasis could be used to argue that the invention is limited to springs possessing these functional attributes.
Term 2: "relatively near angular position" / "relatively far angular position" (from '534 Patent, Claim 1)
- Context and Importance: These terms define the operative movement of the staircase between its use and stowed positions. Their construction is critical because infringement depends on the accused product exhibiting movement between two states that satisfy these relational definitions. A defendant could argue the terms are indefinite for failing to provide an objective standard for measurement, or that their product's angular travel does not meet the definitions.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent does not assign numerical values to these angles, instead describing them functionally in relation to the staircase's position (use vs. stowed) (’534 Patent, col. 4:61-67). This may support a construction where any pivotal movement from a functional deployed position to a functional stowed position meets the limitation.
- Evidence for a Narrower Interpretation: The figures, particularly Figures 1 and 2, depict specific angular relationships between the mounting portion and the threshold plate in the use and stowed positions (’534 Patent, Figs. 1-2). A party could argue that the scope of these terms should be limited to the general range of angles disclosed in these embodiments.
VI. Other Allegations
Indirect Infringement
- The complaint alleges inducement of infringement, stating that Defendant provides customers with "manuals and instructions" and other materials demonstrating how to install and use the accused products in an infringing manner (Compl. ¶¶ 51, 59, 70, 81, 93).
Willful Infringement
- The willfulness allegations are based on extensive alleged pre-suit knowledge. The complaint asserts that Plaintiff first notified Defendant of its infringement concerns in November 2023 and subsequently provided detailed claim charts for all four patents-in-suit over the following two years. The complaint further alleges that Defendant was aware of the pending application for the '850 Patent during its prosecution and, after all notices, confirmed its intent to continue selling the accused products (Compl. ¶¶ 24-28, 45-48, 64, 75, 86, 98).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the term "spring" in the '671 patent, which the specification exclusively describes as a "gas spring" providing a specific variable-force function, be construed to cover the mechanism used in the accused "Lift Assist Product"?
- A second key issue will be one of claim construction and indefiniteness: will the relational terms "relatively near" and "relatively far angular position" in the '534 patent be found to provide a sufficiently clear and objective boundary to define infringement, or will they be challenged as indefinite?
- A central question for damages will be willfulness: given the detailed allegations of a nearly two-year pre-suit notification period that included the exchange of specific infringement charts, the court will have to determine whether Defendant's alleged decision to continue selling the accused products constituted willful and deliberate infringement.