Dbest Products Inc v. Guangzhou Linyu Trading Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Dbest Products, Inc. (California)
  • Defendant: Jieyang Juxiaonian Co., Ltd (Chinese company)
  • Plaintiff’s Counsel: Orbit IP, LLP
• Case Identification: 2:25-cv-04587, C.D. Cal., 05/21/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant is subject to personal jurisdiction in the district, having previously consented to jurisdiction by suing Plaintiff in the same district and by conducting substantial business there.
• Core Dispute: Plaintiff alleges that Defendant’s line of portable carts infringes two patents related to the structural design and locking mechanisms of collapsible carts.
• Technical Context: The technology concerns consumer-grade collapsible utility carts, where the key engineering challenge is to create a structure that is both lightweight and foldable for storage, yet strong and rigid when expanded for carrying loads.
• Key Procedural History: The complaint alleges that Plaintiff has complied with its patent marking policy for both patents-in-suit, providing notice to the public that its products are protected by the asserted patents.

Case Timeline

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

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

(“the ’446 Patent”), issued April 15, 2025.

The Invention Explained

• Problem Addressed: The patent’s background section identifies a weakness in prior art collapsible carts, stating that "the sidewalls may not be sufficiently sturdy to allow for transporting heavy objects" due to their collapsible design (’446 Patent, col. 1:13-16).
• The Patented Solution: The invention addresses this by constructing the cart’s sidewalls from two separate panels that are rotatably coupled. To enhance rigidity when the cart is open, the design incorporates a "first slideable member" that moves along a "first track" spanning both panels. By moving this member from an "open position" to a "closed position," the user can lock the two panels together, creating a more stable, load-bearing wall (’446 Patent, Abstract; col. 5:19-28). This locking mechanism is illustrated in figures such as Figure 2, which shows the slideable member (58) and track (46) on a sidewall (’446 Patent, Fig. 2).
• Technical Importance: This design aims to provide a collapsible cart that combines the convenience of compact storage with the structural integrity required for carrying heavy loads, a key trade-off in this product category (’446 Patent, col. 1:13-18).

Key Claims at a Glance

• The complaint asserts at least one claim of the ’446 Patent (Compl. ¶15). The lead independent claim is Claim 1.
• The essential elements of Claim 1 include:
  • A collapsible cart configured to transition from a closed to an open condition.
  • A rigid frame with multiple walls, including a right sidewall.
  • 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" is engaged with the track and is movable between an open position and a closed position to "selectively lock" the first right panel to the second.

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

(“the ’546 Patent”), issued May 20, 2025.

The Invention Explained

• Problem Addressed: Like the ’446 Patent, the ’546 Patent seeks to remedy the structural instability of prior art collapsible carts, noting their sidewalls "may not be sufficiently sturdy" for heavy objects (’546 Patent, col.2:25-27).
• The Patented Solution: This patent claims a collapsible cart with a frame of at least five walls, where opposing walls are comprised of a first and second panel. The innovation lies in the connection mechanism: a "first latch part" on the edge of the first panel and a "second latch part" on the edge of the second panel are configured to "mate with one another" to hold the two panels "in a common plane" when the cart is open (’546 Patent, col. 13:33-47). This creates a rigid, flat wall from two foldable sections.
• Technical Importance: The invention proposes a specific edge-based latching system as a means to achieve sidewall rigidity in a collapsible cart, distinguishing it from other reinforcement methods (’546 Patent, col. 13:33-47).

Key Claims at a Glance

• The complaint asserts at least one claim of the ’546 Patent (Compl. ¶20). The lead independent claim is Claim 1.
• The essential elements of Claim 1 include:
  • 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 panel rotatably coupled to the first.
  • 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 first and second latch parts are configured to "mate with one another" and hold the panels "in a common plane."

III. The Accused Instrumentality

Product Identification

The complaint identifies the "Accused Products" as "numerous products" sold by the Defendant on Amazon.com (Compl. ¶13). A specific schedule of Amazon Standard Identification Numbers (ASINs) is referenced as Exhibit C, which was not publicly filed with the complaint (Compl. ¶¶ 3, 13).

Functionality and Market Context

The Accused Products are described as "portable carts" (Compl. ¶7). The infringement allegations suggest they are collapsible and incorporate features corresponding to the patented technology, such as multi-panel sidewalls with locking mechanisms (Compl. ¶¶ 15, 20). The complaint positions the Plaintiff as a "leading innovator" in the U.S. market and alleges Defendant sells infringing products directly to consumers in the district via online retail platforms (Compl. ¶¶ 7, 11).

IV. Analysis of Infringement Allegations

The complaint references claim chart exhibits (Exhibits D and E) that were not included in the public filing, instead summarizing that they demonstrate how the Accused Products satisfy each limitation of at least one claim of each patent-in-suit (Compl. ¶¶ 15, 20). In the absence of the charts, the infringement theory is based on the narrative allegations.

The complaint’s theory for the ’446 Patent is that the Accused Products embody a collapsible cart with the claimed multi-panel sidewall, a track spanning the panels, and a slideable member that locks the panels into an open, rigid state (Compl. ¶15). For the ’546 Patent, the theory is that the Accused Products feature a collapsible frame with opposing walls made of two panels that are held in a common plane by mating "latch parts" located on their respective edges (Compl. ¶20).

No probative visual evidence provided in complaint.

Identified Points of Contention

• Scope Questions: The dispute may turn on the scope of key terms. For the ’446 Patent, a central question will be whether the accused locking mechanism constitutes a "track" and a "slideable member" as those terms are understood in the patent. For the ’546 Patent, the analysis will focus on whether the components on the accused carts qualify as mating "latch parts."
• Technical Questions: A factual dispute may arise over whether the accused products function as claimed. For the ’446 Patent, this involves whether the accused mechanism is "movable... between an open position to a closed position" to lock the panels. For the ’546 Patent, evidence will be required to show that the accused mechanism holds the panels "in a common plane" to provide the claimed rigidity.

V. Key Claim Terms for Construction

• The Term: "first slideable member cooperatively engaged to the first track" (’446 Patent, Claim 1)

• Context and Importance: The infringement analysis for the ’446 Patent depends entirely on whether the locking feature of the accused product falls within the definition of this phrase. Practitioners may focus on this term because its construction will determine whether the claim covers a broad category of sliding locks or is limited to the specific embodiment shown in the patent's figures.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claim describes the member's function to "selectively lock the first right panel to the second right panel," which could support a construction that includes any sliding component achieving this result (’446 Patent, col. 7:29-30).
  • Evidence for a Narrower Interpretation: The specification and figures depict a specific embodiment of the slideable member (58) as a C-shaped clip that slides over a raised track or rail (46) (’446 Patent, Fig. 2; col. 5:19-28). A party could argue the term should be limited to structures that are the same or equivalent to this disclosed embodiment.

• The Term: "latch part" (’546 Patent, Claim 1)

• Context and Importance: This term is the lynchpin of the infringement allegation for the ’546 Patent. Its definition will be critical because the patent’s specification primarily describes a "slideable member" and "track" mechanism, not a distinct "latch part." The court's decision on whether the specification provides adequate written description for "latch part," and how that term is construed, could be dispositive.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claim functionally defines the latch parts as components on panel edges that "mate with one another" to hold the panels "in a common plane" (’546 Patent, col. 13:43-45). A party might argue that any mechanism performing this edge-mating and planar-locking function meets the definition.
  • Evidence for a Narrower Interpretation: The specification of the ’546 Patent, which shares a common specification with the ’446 Patent, repeatedly describes the locking mechanism as a "slideable member" (e.g., 58) and "track" (e.g., 46) (’546 Patent, col. 7:4-24). A party may argue that "latch part" must be construed consistently with the only locking mechanism actually described in detail in the specification, or that the term lacks sufficient written description and is therefore invalid.

VI. Other Allegations

Willful Infringement

The complaint does not explicitly allege willful infringement. However, it does plead that Plaintiff marks its products with the asserted patent numbers, an allegation that could be used to establish knowledge of the patents for the purpose of enhanced damages if infringement is found (Compl. ¶10). The prayer for relief also requests attorneys' fees (Compl. ¶18).

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

• Claim Construction and Written Description: A core issue will be one of lexical scope and support: can the term "latch part," as used in the ’546 Patent claims, be validly construed to read on the accused devices when the shared patent specification predominantly describes a "slideable member" and "track" mechanism? The outcome of this claim construction and potential validity challenge under 35 U.S.C. § 112 will be fundamental.
• Evidentiary Proof of Infringement: A key question will be one of structural and functional correspondence. As the complaint provides no visual evidence of the accused products, the case will turn on discovery to establish the precise design and operation of the defendant's cart-locking mechanisms. The central factual dispute will be whether those mechanisms perform the specific functions of a "slideable member" on a "track" (’446 Patent) or mating "latch parts" that hold panels "in a common plane" (’546 Patent), as those terms are ultimately construed by the court.