Dbest Products Inc v. Wuhan ZHIDAN Network Tech Co

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: dbest products, Inc. (California)
  • Defendant: Wuhan Zhidan Network Tech. Company (China)
  • Plaintiff’s Counsel: Orbit IP, LLP
• Case Identification: 2:25-cv-04615, C.D. Cal., 05/21/2025
• Venue Allegations: Venue is alleged to be proper on the grounds that the Defendant is subject to personal jurisdiction in the district.
• Core Dispute: Plaintiff alleges that Defendant’s portable collapsible carts infringe two patents related to structural features and locking mechanisms for foldable cart sidewalls.
• Technical Context: The technology relates to mechanical improvements in portable, collapsible carts, a consumer product category focused on balancing portability, ease of use, and load-bearing capacity.
• Key Procedural History: The complaint alleges that Plaintiff has complied with its policy of marking its products with the patent numbers since the patents issued, which may be relevant to the calculation of potential damages.

Case Timeline

Date	Event
2020-01-06	Earliest Priority Date for '446 and '546 Patents
2025-04-15	Issue Date for U.S. Patent No. 12,275,446
2025-05-20	Issue Date for U.S. Patent No. 12,304,546
2025-05-21	Complaint Filing Date

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

U.S. Patent No. 12,275,446 - "High Load Capacity Collapsible Carts"

• Patent Identification: U.S. Patent No. 12,275,446, "High Load Capacity Collapsible Carts," issued April 15, 2025.

The Invention Explained

• Problem Addressed: The patent asserts that due to the collapsible nature of prior art cart designs, their sidewalls "may not be sufficiently sturdy to allow for transporting heavy objects" ('446 Patent, col. 1:13-16).
• The Patented Solution: The invention addresses this by constructing the cart's sidewalls from multiple panels that can be rigidly locked together. A sidewall is composed of a first panel rotatably coupled to a second panel along a vertical axis ('446 Patent, col. 4:49-51). To provide rigidity when the cart is open, a "slideable member" moves along a "track" that spans both panels, locking them into a co-planar alignment ('446 Patent, col. 5:16-29; Fig. 2). When the slideable member is moved back to its open position, the panels can fold inward for storage ('446 Patent, Fig. 8).
• Technical Importance: This design aims to increase the structural integrity and load capacity of a cart while retaining its ability to be collapsed into a compact form for storage or transport ('446 Patent, col. 1:20-22).

Key Claims at a Glance

• The complaint asserts at least one claim; independent claim 1 is representative.
• Claim 1 requires:
  • A collapsible cart with a rigid frame forming a compartment, the frame having front, rear, right, left, and bottom walls.
  • The right sidewall comprises a "first right panel rotatably coupled to a second right panel."
  • A "first track" is formed along both the first and second right panels.
  • A "first slideable member" engages the track and is movable between an open position (allowing folding) and a closed position to "selectively lock" the panels.
  • The closed position is defined by the slideable member being "disposed across both the first right panel and second right panel."
• The complaint implicitly reserves the right to assert other claims, including dependent claims.

U.S. Patent No. 12,304,546 - "Collapsible Carts"

• Patent Identification: U.S. Patent No. 12,304,546, "Collapsible Carts," issued May 20, 2025.

The Invention Explained

• Problem Addressed: Similar to the '446 Patent, this patent addresses the problem that "the sidewalls may not be sufficiently sturdy" in prior art collapsible carts ('546 Patent, col. 2:25-28).
• The Patented Solution: The invention describes a collapsible cart with a frame of at least five walls, where opposing walls are comprised of a first panel rotatably coupled to a second panel ('546 Patent, col. 13:30-33). Rigidity is achieved through a "first latch part" on the edge of the first panel and a "second latch part" on the edge of the second panel. These parts are "configured to mate with one another" to hold the panels in a common, rigid plane when the cart is open ('546 Patent, col. 13:34-44). When unlatched, the second panel can rotate relative to the first, allowing the cart to be collapsed.
• Technical Importance: This latching system provides a specific mechanism for reinforcing foldable cart walls, seeking to improve load-bearing capability without sacrificing the convenience of collapsibility.

Key Claims at a Glance

• The complaint asserts at least one claim; independent claims 1, 9, and 17 are included in the patent. Claim 1 is representative.
• Claim 1 requires:
  • A collapsible cart with a frame of at least five walls, where at least three walls are configured to fold inwardly.
  • One of the opposing walls consists of a "first panel and a second panel," with the second being "rotatably coupled to the first panel."
  • A "first latch part" is disposed on an edge of the first panel.
  • A "second latch part" is disposed on an edge of the second panel.
  • The latch parts are "configured to mate with one another" to hold the panels "in a common plane."
• The complaint implicitly reserves the right to assert other claims, including dependent claims.

III. The Accused Instrumentality

Product Identification

• The complaint identifies the accused instrumentalities as "numerous products" sold by the Defendant on Amazon.com, referred to collectively as the "Accused Products" (Compl. ¶13). A specific schedule of Amazon Standard Identification Numbers (ASINs) is referenced in Exhibit C, which is not included with the complaint (Compl. ¶13).

Functionality and Market Context

• The complaint alleges the Accused Products are portable, collapsible carts sold to consumers in the United States through Amazon's e-commerce platform (Compl. ¶¶ 7, 11). The infringement allegations imply these products possess features corresponding to the patented technology, such as collapsible frames with multi-panel sidewalls and mechanisms to lock those panels for structural rigidity (Compl. ¶¶ 15, 20). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 12,275,446 Infringement Allegations

The complaint alleges that the Accused Products directly infringe at least one claim of the ’446 Patent (Compl. ¶15). While the complaint references a detailed claim chart in Exhibit D, this exhibit was not provided with the filed document (Compl. ¶12). The infringement theory appears to center on the assertion that the Accused Products are collapsible carts embodying the limitations of independent claim 1. Specifically, Plaintiff’s theory suggests that the sidewalls of the Accused Products are composed of at least two hinged panels, which would read on the "first right panel rotatably coupled to a second right panel" limitation. The theory would further contend that these products incorporate a locking mechanism, alleged to be the claimed "first slideable member," which moves along a "track" that spans both panels to lock them into a rigid, co-planar orientation for use.

U.S. Patent No. 12,304,546 Infringement Allegations

The complaint similarly alleges direct infringement of the ’546 Patent and references a corresponding claim chart in Exhibit E, which was also not provided (Compl. ¶¶ 20, 5). The narrative infringement theory for independent claim 1 of the ’546 Patent appears to target the same features of the Accused Products but frames the infringement using the patent's distinct terminology. The theory likely posits that the locking system on the Accused Products' folding panels constitutes the claimed "first latch part" and "second latch part," and that these parts are "disposed on an edge" of their respective panels. The allegation would be that these "latch parts" are "configured to mate" to hold the panels "in a common plane" when the cart is in its open, useable state, thereby satisfying the claim limitations.

Identified Points of Contention

• Scope Questions: A central issue may be the relationship between the claim terms "slideable member" (’446 Patent) and "latch part" (’546 Patent). The court may need to determine if these terms describe mutually exclusive structures or if they could both read on a single mechanism in the Accused Products.
• Technical Questions: A factual dispute may arise over the precise operation and location of the locking mechanism on the Accused Products. Evidence will be required to determine if the accused feature functions as a "slideable member" that is "disposed across both" panels as required by the ’446 Patent, or as "latch parts" that are "disposed on an edge" of the panels as required by the ’546 Patent.

V. Key Claim Terms for Construction

The Term: "slideable member" (from '446 Patent, Claim 1)

• Context and Importance: This term is the central active component of the locking mechanism in the ’446 Patent. Its construction will define the breadth of locking designs that fall within the scope of the claims and will be a focal point of the infringement analysis.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes the element functionally as being "movable between an open position... to a closed position to selectively secure or lock the first right panel 26 to the second right panel 28" ('446 Patent, col. 5:20-24). This functional language may support an interpretation that covers any component that slides to lock the panels, regardless of its specific form.
  • Evidence for a Narrower Interpretation: The embodiments and figures consistently depict the "slideable member" as a specific C-shaped clip (58) that slides over a raised, linear "track" (46) ('446 Patent, Fig. 2, Fig. 8). A defendant may argue that the term should be limited to structures consistent with this disclosed embodiment.

The Term: "latch part" (from '546 Patent, Claim 1)

• Context and Importance: This term defines the locking mechanism in the ’546 Patent. Whether it is construed broadly to include sliding locks or narrowly to mean only interlocking fasteners will be critical to infringement. Practitioners may focus on this term because its plain meaning could differ from the "slideable member" of the companion patent, creating a potential distinction for the accused device to escape one or both patents.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim requires only that the first and second latch parts are "configured to mate with one another" to hold the panels in a common plane ('546 Patent, col. 13:41-44). This generic "mating" language could arguably encompass a wide variety of fasteners, including a slide that engages a track.
  • Evidence for a Narrower Interpretation: The patent does not provide an explicit definition for "latch part." A defendant could argue that in the context of mechanical arts, a "latch" implies a specific type of connection, such as a hook-and-catch or a snap-fit mechanism, and does not extend to a member that merely slides to bridge a seam.

VI. Other Allegations

The complaint does not provide sufficient detail for analysis of indirect or willful infringement.

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

The resolution of this dispute will likely depend on the court's answers to two central questions:

• A core issue will be one of claim construction and definitional overlap: Can the term "slideable member" from the ’446 Patent and the term "latch part" from the ’546 Patent be construed to cover the same locking mechanism? The case will explore whether the Accused Product's design falls within the scope of one, both, or neither of these key terms.
• A key evidentiary question will be one of technical and functional mapping: Assuming a claim construction is established, what is the precise mechanical operation of the locking feature on the Accused Products? The outcome will depend on whether Plaintiff can present evidence demonstrating that the accused mechanism performs the specific functions and is located in the specific positions—such as being "disposed across both" panels (’446) or having parts "on an edge" (’546)—required by the claims.