DCT

1:25-cv-08022

Yunnan Lamujia Agricultural Technology Co Ltd v. Yu Chen

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-08022, N.D. Ill., 07/15/2025
  • Venue Allegations: Venue is asserted based on the Defendant having previously filed an infringement lawsuit concerning the same patent in the Northern District of Illinois, thereby availing himself of the forum.
  • Core Dispute: Plaintiffs, sellers of toilet safety frames, seek a declaratory judgment that their products do not infringe a design patent owned by the Defendant which is directed to the ornamental design for a walker.
  • Technical Context: The dispute concerns the ornamental design of mobility assistance devices, a market segment focused on products for the elderly and individuals with disabilities.
  • Key Procedural History: This declaratory judgment action was filed after the Defendant, Yu Chen, previously sued the Plaintiffs for infringement of the same patent in the same district. That prior case was reportedly dismissed as to these Plaintiffs due to misjoinder, prompting the Plaintiffs to file this action to resolve the continuing dispute.

Case Timeline

Date Event
2019-10-08 U.S. Patent No. D988,941 Application Filed (Priority Date)
2023-06-13 U.S. Patent No. D988,941 Issued
2024-10-19 Defendant files prior infringement suit in N.D. Illinois
2025-07-15 Complaint for Declaratory Judgment Filed

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

U.S. Patent No. D988,941 S - “WALKER,” issued June 13, 2023

The Invention Explained

  • Problem Addressed: Design patents protect ornamentation rather than function. The patent does not articulate a technical problem but instead presents a new, original, and ornamental design for a walker.
  • The Patented Solution: The patent claims the specific visual appearance of a walker as illustrated in its seven figures (D’941 Patent, FIGs. 1-7). The claimed design consists of the overall configuration and ornamentation of the device, characterized by features including the specific gentle curvature of the top handrails, the arrangement of horizontal cross-braces, and smooth, telescoping legs that show adjustment holes but lack any external knobs or locking mechanisms (D’941 Patent, FIG. 1). The claim covers the design "as shown and described" (D’941 Patent, Claim).

Key Claims at a Glance

  • The complaint asserts non-infringement of the patent’s single claim.
  • The claim is for: "The ornamental design for a walker, as shown and described." (D’941 Patent, Claim).
  • The essential ornamental features that constitute the claimed design as a whole include:
    • The overall A-frame structure with four legs.
    • The specific shape and profile of the upper hand-grip frame.
    • The particular configuration of the horizontal cross-braces.
    • The appearance of the adjustable legs, which are depicted without any protruding knobs or pins.

III. The Accused Instrumentality

Product Identification

The accused products are "FSA/HSA Eligible Toilet Safety Rails" and similar adjustable frames sold by Plaintiffs Lianjindun and Coelineao, identified by Amazon ASINs B0CBJMPYZX and B0CBJZF5V4 (Compl. ¶¶22-24).

Functionality and Market Context

The products are described as adjustable safety frames designed to be installed around a toilet to provide support and stability for the user (Compl. ¶22). The complaint states that Amazon.com is the primary sales channel for these products and that they are popular in the market for mobility accessories (Compl. ¶¶26-27). The complaint includes a photograph of one of the accused products installed around a toilet. This image, from an online product listing, shows the Coelineao product in its intended use environment (Compl. ¶43, FIG 2).

IV. Analysis of Infringement Allegations

The complaint seeks a declaratory judgment of non-infringement. The core of the design patent infringement analysis is the "ordinary observer" test, which asks whether an ordinary observer, familiar with the prior art, would be deceived into purchasing the accused product believing it to be the patented design. The complaint argues that the accused products are "obviously different" and not "confusingly similar" to the patented design (Compl. ¶¶40-41). The complaint highlights two main points of visual difference.

Patented Design Feature (from D'941 Patent) Alleged Differentiating Feature of Accused Product Complaint Citation Patent Citation
Smooth, telescoping legs with adjustment holes but no external mechanisms. Legs feature prominent, circular push-button knobs for adjusting the height. The complaint provides a close-up image of the accused Lianjindun product with green circles indicating these knobs (Compl. ¶43, FIG 1). ¶¶42-43 D’941 Patent, FIG. 1
A rear structure consisting of two horizontal cross-bars. A rear structure that includes not only two horizontal cross-bars but also two additional vertical bars connecting them. The complaint includes an image of the Lianjindun product with green circles highlighting these additional vertical bars, which are absent from the patent's drawings (Compl. ¶47, FIG 4). ¶¶45-47 D’941 Patent, FIG. 3
The overall ornamental design for a "walker." The overall ornamental design for a "toilet safety frame." The complaint repeatedly identifies the accused products as such (Compl. ¶22) and provides an image of the Coelineao product installed around a toilet, which may influence an observer's perception of its overall design in a different context from a general-purpose walker (Compl. ¶43, FIG 2). ¶¶22, 24 D’941 Patent, Title

Identified Points of Contention

  • Scope Questions: A primary issue may be whether the scope of a design patent for a "walker" can extend to a product marketed and used as a "toilet safety frame." The analysis may question whether the different product names and intended use environments create distinct overall visual impressions that would prevent an ordinary observer from being deceived.
  • Ornamental Questions: The central dispute will likely focus on the visual significance of the differences identified in the complaint. The court may need to determine whether the addition of adjustment knobs and vertical support bars constitutes a substantial departure from the patented design as a whole, or if these are minor functional details that do not alter the overall ornamental appearance in the eyes of an ordinary observer. The complaint contrasts images of the accused products' features with annotated figures from the patent to emphasize these differences (Compl. ¶¶43-44, 47-48).

V. Key Claim Terms for Construction

In design patent litigation, there are typically no claim terms to construe in the same manner as utility patents. However, the title of the patent can inform the scope of the claimed design.

  • The Term: "walker"
  • Context and Importance: The patent is explicitly titled and described as a design for a "walker" (D'941 Patent, Title, Description). The accused products are identified as "toilet safety frames" (Compl. ¶22). Practitioners may focus on whether this difference in product identity and application is legally significant under the ordinary observer test. The question is not the definition of "walker," but whether the design is tied to that article of manufacture in a way that limits its scope.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party could argue that the title is merely descriptive and that the patent protects the ornamental features of the frame itself, irrespective of its specific application. The core of the infringement test is a comparison of the drawings to the accused device, and the visual similarity of the frames' structures may support a broader application of the design.
    • Evidence for a Narrower Interpretation: The patent consistently refers to the article as a "walker" (D'941 Patent, Title, Description). A party could argue that an ordinary observer would view the patented design in the context of a walker and the accused product in the context of a toilet accessory, and that this difference in context is sufficient to create a different overall visual impression. The complaint's inclusion of a photograph showing the accused product fitted around a toilet supports this contextual distinction (Compl. ¶43, FIG 2).

VI. Other Allegations

  • Exceptional Case Allegations: The Plaintiffs seek a finding that the case is "exceptional" under 35 U.S.C. § 285, which would permit an award of attorney fees (Compl., Prayer for Relief ¶2). The complaint does not explicitly state the basis for this request, but it may be predicated on the argument that the accused products are "obviously different" from the patented design (Compl. ¶41) and on the procedural history of prior litigation initiated by the Defendant (Compl. ¶¶31-36).

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

  • A core issue will be one of product context and scope: Can the ornamental design for a "walker," as claimed in the D'941 patent, be infringed by a product sold and used as a "toilet safety frame"? The outcome may depend on whether an ordinary observer would perceive the designs in their respective commercial contexts as being substantially the same.
  • A key evidentiary question will be one of ornamental distinction: Are the specific visual differences alleged in the complaint—namely, the presence of prominent adjustment knobs and additional vertical bars on the accused products—significant enough to create a different overall ornamental impression from the patented design, or are they minor variations that an ordinary observer would disregard?