DCT
2:25-cv-02311
Wuhan ZHIDAN Network Technology Co Ltd v. Dbest Products Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Wuhan ZHIDAN Network Technology Co. Ltd. and Wuhan LANZHI Network Technology Co. Ltd. (People's Republic of China)
- Defendant: Dbest Products, Inc. (California)
- Plaintiff’s Counsel: Mei & Mark LLP; Ni, Wang & Massand, PLLC
- Case Identification: 2:25-cv-02311, C.D. Cal., 03/14/2025
- Venue Allegations: Venue is asserted as proper because the Defendant is a California corporation with its principal place of business within the judicial district.
- Core Dispute: Plaintiffs, e-commerce sellers, seek a declaratory judgment that their stackable storage bin products do not infringe Defendant’s patent on "Stackable Collapsible Carts," and that the patent is invalid, following Defendant's infringement reports against them on the Amazon marketplace.
- Technical Context: The technology concerns collapsible containers, focusing on the mechanical structures that allow the containers to be folded for storage and securely locked into a rigid, open configuration for use.
- Key Procedural History: The complaint states that the lawsuit was precipitated by infringement complaints lodged by the Defendant with Amazon in December 2024, which resulted in the potential or actual delisting of the Plaintiffs’ products. This declaratory judgment action appears to be a direct response, seeking to resolve the infringement and validity disputes in federal court rather than through Amazon's internal processes.
Case Timeline
| Date | Event |
|---|---|
| 2020-01-06 | Earliest Priority Date for U.S. Patent No. 12,103,576 |
| 2024-10-01 | U.S. Patent No. 12,103,576 Issues |
| 2024-12-01 | Defendant Lodges Amazon Infringement Complaints (approx.) |
| 2025-03-14 | Complaint for Declaratory Judgment Filed |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 12,103,576, "Stackable Collapsible Carts," issued October 1, 2024.
The Invention Explained
- Problem Addressed: The patent’s background section notes that in prior art collapsible carts, the "sidewalls may not be sufficiently sturdy to allow for transporting heavy objects." (’576 Patent, col. 2:21-23).
- The Patented Solution: The invention is a collapsible cart with multi-panel sidewalls that fold inwardly for storage. To enhance sturdiness when open, the solution provides a specific locking mechanism where a "first track" extends across adjacent panels and a "first slideable member" moves along this track to "selectively lock the first right panel to the second right panel." (’576 Patent, col. 12:41-67; Abstract). This mechanical interlock, depicted in figures such as FIG. 42A and 42B, is designed to create a more rigid and stable structure.
- Technical Importance: The described approach seeks to combine the storage convenience of a collapsible container with the structural integrity of a rigid one, making it suitable for heavier loads. (’576 Patent, col. 8:19-24).
Key Claims at a Glance
- The complaint addresses the patent’s three independent claims (1, 11, and 15) (Compl. ¶26, 39).
- The essential elements of asserted independent claim 1 include:
- A collapsible cart configured to transition from a closed condition to an open condition.
- A rigid frame with a front wall, a rear wall, a right sidewall, a left sidewall, and a bottom wall.
- The right sidewall comprising a first right panel rotatably coupled to a second right panel, where the second panel is proportioned to fit within an opening in the first panel.
- A first track formed along the first and second right panels.
- A first slideable member cooperatively engaged to the first track, which is movable to selectively lock the first right panel to the second right panel.
- The complaint argues that its products do not meet limitations in any of the three independent claims, and therefore do not infringe any dependent claims. (Compl. ¶39).
III. The Accused Instrumentality
Product Identification
- The "Wise Oannes and MapleGrace Four Tier Stackable Plastic Storage Bins," identified by ASIN Nos. B0CGZ9ZK4Z, B0CZ12CYJB, B0CZ11331V, and B0DCGGNRSQ. (Compl. ¶17).
Functionality and Market Context
- The accused products are described as stackable plastic storage bins, sold in multi-unit sets, with wheels affixed only to the bottom-most unit. (Compl. ¶¶15, 38).
- The complaint alleges that the products utilize a "simple magnet" to secure the panels, rather than a mechanical track and slider. (Compl. ¶35). An image provided in the complaint shows a product feature labeled "Magnetic Door," supporting this allegation. (Compl. p. 11, top).
- Plaintiffs allege the products are commercially significant, having received strong customer reviews and the "Amazon Choice" badge, and that the Amazon marketplace is their primary sales channel into the United States. (Compl. ¶¶16-18).
IV. Analysis of Infringement Allegations
'576 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Non-Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A collapsible cart... | The complaint alleges the Accused Products are "collapsible storage bin or box, not a collapsible cart or vehicle," citing a dictionary definition of "cart." | ¶33 | col. 12:41 |
| a first track formed along the first right panel and the second right panel... | The complaint alleges the Accused Products lack this element. An annotated patent figure shows the claimed track (46). | ¶34; p. 10 | col. 12:56-60 |
| a first slideable member cooperatively engaged to the first track... to selectively lock the first right panel to the second right panel... | The complaint alleges the Accused Products employ a "simple magnet" for closure, which is asserted to be an "entirely distinct way to secure" the panels. A product photo shows this feature labeled "Magnetic Door." | ¶34-35; p. 11 | col. 12:61-67 |
- Identified Points of Contention:
- Scope Questions: The dispute raises a fundamental question of claim scope: does the term "collapsible cart" as used in the patent, which describes a wheeled apparatus for transporting objects, read on the accused products, which Plaintiffs characterize as "storage bins"? (Compl. ¶33). A related question concerns Claim 15's requirement for a "top cover with an indentation... to receive a wheel assembly when stacked," which Plaintiffs allege is absent and unnecessary because their products have only one set of wheels at the base of the stack. (Compl. ¶¶37-38). The complaint includes a photograph of the stacked accused products showing wheels only on the bottom unit. (Compl. p. 13).
- Technical Questions: A central technical dispute is whether the accused products' magnetic closure system meets the claim limitations of a "first track" and a "first slideable member". The complaint alleges a clear structural and functional distinction, contrasting the patent’s mechanical sliding lock, shown in an annotated figure (Compl. p. 10), with its product's magnetic door (Compl. p. 11). The court may need to determine if there is a literal or equivalent correspondence between these two different mechanisms.
V. Key Claim Terms for Construction
The Term: "collapsible cart"
- Context and Importance: The construction of this term is critical because if the accused "storage bins" are determined not to be "carts," the infringement analysis may end there. Practitioners may focus on this term as it represents a threshold question of applicability.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent's abstract and summary describe a "collapsible cart" with features like a "rigid frame forming a compartment" and walls that fold, which could arguably encompass any collapsible container for carrying items. (’576 Patent, Abstract).
- Evidence for a Narrower Interpretation: The patent repeatedly refers to prior art for "Shopping Cart[s]," "Rolling Tote Bag[s]," and "Wheeled Dolly" devices, and its own embodiments consistently depict wheels and handles for transport. (’576 Patent, col. 1:39-2:20; Figs. 1, 10). This context may support a narrower construction limited to wheeled, mobile containers.
The Term: "first slideable member cooperatively engaged to the first track"
- Context and Importance: This term defines the core locking mechanism. Its construction will determine whether the accused products' magnetic closures can be seen as infringing. Plaintiffs' non-infringement argument for Claim 1 hinges on the structural and functional differences here.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A patentee might argue the term broadly covers any movable locking element that engages with a guiding structure to secure the panels.
- Evidence for a Narrower Interpretation: The specification provides detailed descriptions and figures (e.g., FIG. 2, FIG. 42A, 42B) showing a distinct physical "track" (46) and a "slideable member" (58) that physically moves along it. (’576 Patent, col. 6:46-56; col. 9:21-35). This detail could support a narrow interpretation that requires these specific structural features, potentially excluding a magnetic closure that lacks a physical track or a sliding component.
VI. Other Allegations
- Tortious Interference with Contractual Relations: The complaint includes a state law claim for tortious interference. It alleges that Plaintiffs have a contractual relationship with Amazon to sell their products; that Defendant knew of this relationship; and that Defendant intentionally and improperly interfered by lodging "baseless infringement Complaints" designed to induce Amazon to delist the products, which caused actual harm in the form of lost sales and damage to seller rankings. (Compl. ¶¶51-53).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the term "collapsible cart," which the patent repeatedly associates with wheeled mobility and transport, be construed to encompass the accused products, which Plaintiffs frame as "stackable storage bins"?
- A key technical question will be one of structural non-equivalence: does the accused products' magnetic closure system satisfy the specific claim limitations of a "track" and a "slideable member," or is there a fundamental mismatch in mechanical structure and operation that places the accused products outside the literal scope of the claims?
- The case also presents a significant validity challenge: will the patent's claims be found invalid as anticipated or obvious in light of prior art references, such as the Panosian publication, that were allegedly not before the USPTO examiner during prosecution? (Compl. ¶¶45-46).