Dbest Products Inc v. Dongguan Laiyang Trading Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Dbest Products, Inc. (California)
  • Defendant: DONGGUAN LAIYANG TRADING CO., LTD (China)
  • Plaintiff’s Counsel: Orbit IP, LLP
• Case Identification: 2:25-cv-04586, C.D. Cal., 05/21/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant is subject to personal jurisdiction in the district. This is based on allegations that Defendant conducts substantial business in the district and has previously consented to jurisdiction by suing the Plaintiff in the same court.
• Core Dispute: Plaintiff alleges that Defendant’s portable carts infringe patents related to high load capacity collapsible carts featuring specific locking and folding mechanisms.
• Technical Context: The technology concerns mechanical improvements to collapsible utility carts, seeking to enhance their structural rigidity and load-bearing capacity without sacrificing their ability to be compactly stored.
• Key Procedural History: The complaint alleges that Defendant previously filed a lawsuit against Plaintiff in the same judicial district, a fact Plaintiff cites to support personal jurisdiction. The complaint also notes that Plaintiff maintains a policy of marking its patented products to provide notice to the public.

Case Timeline

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

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

The Invention Explained

• Problem Addressed: The patent identifies a shortcoming 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 discloses a collapsible cart with sidewalls constructed from multiple panels that are rotatably coupled. To enhance rigidity in the open position, the design incorporates a "first slideable member" that moves along a "first track" spanning the adjacent panels, thereby locking them together to form a sturdy, flat sidewall. When the member is moved to an open position, the panels can fold inwardly for storage ('446 Patent, Abstract; col. 2:31-44). The overall structure is depicted in Figure 1, with the multi-panel sidewall and locking mechanism detailed in Figure 2 ('446 Patent, FIGS. 1-2).
• Technical Importance: This design aims to resolve the inherent conflict between a cart’s collapsibility for storage and its structural strength for use, providing a mechanical solution to improve load capacity ('446 Patent, col. 1:13-18).

Key Claims at a Glance

The complaint asserts infringement of at least one claim of the '446 Patent (Compl. ¶15). The first independent claim, Claim 1, is representative and includes the following essential elements:

• A collapsible cart configured to transition from a closed condition to an open condition.
• A rigid frame with a front wall, rear wall, right sidewall, left sidewall, and bottom wall.
• The right sidewall comprises a first right panel rotatably coupled to a second right panel.
• A first track formed along the first and second right panels, extending between a first position on the first panel and a second position on the second panel.
• A first slideable member engaged with the track, movable between an open position (allowing folding) and a closed position (locking the panels).

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 prior art collapsible carts "may not be sufficiently sturdy to allow for transporting heavy objects" ('546 Patent, col. 2:26-29).
• The Patented Solution: The invention describes a collapsible cart with a frame of at least five walls, where opposing walls feature panels with corresponding "latch parts." These parts are configured to mate and hold the panels in a common, rigid plane when the cart is open, but can be unlatched to allow the walls to fold inwardly. The patent also discloses features for stacking multiple carts, such as a top cover with an indentation pattern designed to receive the wheel assembly of an identical cart ('546 Patent, Abstract; col. 12:35-40, col. 13:21-48).
• Technical Importance: This invention provides an alternative mechanism for ensuring structural integrity in a collapsible design and introduces a feature for efficient, stable vertical stacking, which is relevant for storage and transport of multiple units ('546 Patent, col. 12:35-40).

Key Claims at a Glance

The complaint asserts infringement of at least one claim of the '546 Patent (Compl. ¶20). The first independent claim, Claim 1, is representative and includes the following essential elements:

• 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 disposed on an edge of the first panel.
• A second latch part disposed on an edge of the second panel.
• The first and second latch parts are configured to mate to hold the panels in a common plane.

III. The Accused Instrumentality

Product Identification

The complaint identifies the accused instrumentalities as the "Accused Products," which are portable carts sold by Defendant on Amazon.com (Compl. ¶¶11, 13). A specific list of products by Amazon Standard Identification Number (ASIN) is referenced as Exhibit C, which was not publicly filed with the complaint (Compl. ¶13).

Functionality and Market Context

The complaint alleges that Defendant offers for sale and sells these portable carts to consumers in the United States, including within the Central District of California, through online platforms like Amazon (Compl. ¶11). The complaint does not provide sufficient detail for analysis of the specific technical functionality of the Accused Products.

IV. Analysis of Infringement Allegations

The complaint references, but does not include, representative claim chart exhibits (Exhibits D and E) that would detail its infringement theories (Compl. ¶¶15, 20). The narrative allegations state that Defendant's Accused Products directly infringe by practicing each limitation of at least one claim of each asserted patent. No probative visual evidence provided in complaint.

Identified Points of Contention

• Scope Questions: For the ’446 Patent, a likely point of dispute will be the definition of a "track" and a "slideable member." The litigation may turn on whether the accused product’s locking mechanism, whatever its form, falls within the scope of these terms as construed from the patent's specification and prosecution history. Similarly, for the ’546 Patent, the interpretation of what constitutes a "latch part" that is "configured to mate" will be critical.
• Technical Questions: A central factual question for the court will be to determine the precise mechanical operation of the Accused Products. Evidence will be required to establish whether the Defendant's carts actually possess sidewalls made of multiple, rotatably coupled panels and whether they employ a locking feature that functions as the claimed "slideable member" or "latch part."

V. Key Claim Terms for Construction

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

• The Term: "first slideable member"
• Context and Importance: This term is the active component of the claimed locking mechanism. Its construction will determine whether the accused product's locking element, which may have a different shape or method of attachment, infringes. Practitioners may focus on this term because the patent’s viability against a competitor’s product hinges on whether this term is construed broadly to cover functionally similar locks or narrowly to the specific embodiment shown.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes the element functionally as being "cooperatively engaged to the first track" and "movable along the first track" to lock the panels ('446 Patent, col. 7:26-31). This language could support a construction that encompasses any component that slides along a guide to perform the locking function.
  • Evidence for a Narrower Interpretation: The patent figures depict the slideable member (58) as a specific C-shaped bracket or clip that slides over a raised rail (46) ('446 Patent, FIG. 2). A party could argue that the term should be limited to this disclosed structure or its direct equivalents.

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

• The Term: "latch part"
• Context and Importance: This term defines the interlocking elements that provide rigidity to the cart's walls. The infringement case for the '546 Patent depends on whether the connection points on the accused carts can be characterized as "latch parts" that "mate."
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The term "latch" is a common mechanical term, and in the absence of a specific definition in the patent, it could be argued to deserve its plain and ordinary meaning, covering a wide range of interlocking fasteners.
  • Evidence for a Narrower Interpretation: Claim 9 of the same patent, which depends from a similar independent claim, specifies that the "fastener member" is "integrally disposed on an edge" of the panel ('546 Patent, col. 14:19-25). This language, along with figures in the related '446 patent showing specific clip-like structures (e.g., '446 Patent, FIG. 2, item 72), could be used to argue for a narrower definition tied to integrated, clip-style connectors rather than separate fasteners or other joining methods.

VI. Other Allegations

Willful Infringement

The complaint does not explicitly use the term "willful infringement." However, it does allege that Plaintiff complies with its patent marking policy, which serves as public notice of its patent rights (Compl. ¶10). This allegation could lay the groundwork for a future claim of willfulness, particularly for infringement occurring after the filing of the lawsuit.

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

1. A central issue will be one of definitional scope: can the claim terms "slideable member" ('446 Patent) and "latch part" ('546 Patent) be construed broadly enough to read on the specific locking mechanisms used in the Defendant's products, or will they be narrowed to the specific embodiments depicted in the patent figures, potentially allowing the accused design to fall outside the claim scope?

2. A key evidentiary question will be establishing the technical reality of the accused products. As the complaint provides no detailed diagrams or functional descriptions of the Defendant's carts, the outcome will depend heavily on evidence produced during discovery that demonstrates whether the accused products' components and their method of operation are structurally and functionally equivalent to the patent claims.