Dbest Products Inc v. Huzhou Shunji E Commerce Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: dbest products, Inc. (California)
  • Defendant: HUZHOU SHUNJI E-COMMERCE COMPANY, LTD. (China)
  • Plaintiff’s Counsel: Orbit IP, LLP
• Case Identification: 2:25-cv-04603, C.D. Cal., 05/21/2025
• Venue Allegations: Plaintiff alleges venue is proper in the Central District of California because Defendant is subject to personal jurisdiction in the district.
• Core Dispute: Plaintiff alleges that Defendant’s collapsible carts, sold through Amazon.com, infringe two patents related to structural reinforcement and locking mechanisms for such carts.
• Technical Context: The technology concerns collapsible utility carts, a consumer product where innovations in structural integrity, load capacity, and ease of collapse are key competitive features.
• Key Procedural History: The complaint alleges that Plaintiff dbest products complies with its patent marking policy, providing notice to the public that its products are protected by the patents-in-suit. Both asserted patents claim priority from the same provisional applications filed in 2020 and are part of a larger patent family directed to collapsible cart technology.

Case Timeline

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’s background section notes that prior art collapsible carts often have sidewalls that "may not be sufficiently sturdy to allow for transporting heavy objects" ('446 Patent, col. 1:13-16).
• The Patented Solution: The invention addresses this structural weakness through a locking mechanism for the hinged side panels. It discloses a "slideable member" that moves along a track spanning the vertical seam between two foldable panels of a sidewall. By moving this member from an "open" to a "closed" position, the two panels are locked together, creating a more rigid and stable wall structure ('446 Patent, Abstract; col. 5:9-38). Figure 2 illustrates this concept, showing the slideable member (58) securing two hinged panels (26, 28) along a track (46).
• Technical Importance: This design aims to improve the load-bearing capacity and durability of a cart that can still be conveniently collapsed for storage.

Key Claims at a Glance

• The complaint asserts at least one claim; independent claim 1 is representative.
• The essential elements of Claim 1 include:
  • A collapsible cart with a rigid frame, including a right sidewall comprising a first right panel rotatably coupled to a second right panel.
  • A first track formed along both the first and second right panels.
  • A first slideable member engaged with the track, which is movable between an open position and a closed position.
  • In the closed position, the slideable member selectively locks the first right panel to the second right panel.
• The complaint 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 identifies the problem that prior art collapsible carts are not sturdy enough for "transporting heavy objects" ('546 Patent, col. 2:25-28).
• The Patented Solution: This invention focuses on the fundamental construction and latching of the cart's panels. It describes a cart with opposing walls that are themselves comprised of rotatably coupled panels. The key feature is a mating "first latch part" and "second latch part" located on the edges of these panels. When the cart is unfolded, these latch parts mate to hold the panels securely in a "common plane," preventing them from buckling inward or outward under load ('546 Patent, col. 13:32-45).
• Technical Importance: This latching system provides a method for ensuring that the unfolded cart forms a rigid, stable container capable of bearing weight.

Key Claims at a Glance

• The complaint asserts at least one claim; independent claim 1 is representative.
• The essential elements of Claim 1 include:
  • A collapsible cart with a frame of at least five walls, where one of the opposing walls consists of a first panel rotatably coupled to a second panel.
  • 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 with each other to hold the panels together in a "common plane" when the cart is in its open condition.
• The complaint reserves the right to assert other claims, including dependent claims.

III. The Accused Instrumentality

Product Identification

• The "Accused Products" are identified as collapsible carts sold by Defendant HUZHOU SHUNJI E-COMMERCE COMPANY, LTD. on Amazon.com (Compl. ¶¶ 11, 13). The complaint states that a schedule of specific Amazon Standard Identification Numbers (ASINs) is provided in an exhibit not included with the pleading (Compl. ¶13, Exhibit C).

Functionality and Market Context

• The complaint does not provide specific technical details about the operation of the Accused Products. It alleges that they are collapsible carts that possess the features recited in the asserted patents, including the claimed locking and latching mechanisms (Compl. ¶¶ 15, 20). The complaint positions the parties as direct competitors in the market for portable utility carts sold in the United States (Compl. ¶¶ 7, 11).
• No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

'446 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: The central infringement question for the '446 Patent may turn on the definition of "slideable member." The analysis will question whether the specific locking component on the accused carts functions by "sliding" along a "track" in the manner claimed, or if it achieves a locking function through a different mechanical action (e.g., snapping, rotating, or clamping) that falls outside the scope of the claim.
  • Technical Questions: A factual question will be whether the accused product's lock has distinct "open" and "closed" positions as required by the claim, and whether in the closed position it performs the specific function of "selectively lock[ing]" the panels together across the hinge.

'546 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: Infringement of the '546 Patent raises the question of what constitutes a "latch part." The case may depend on whether the mechanism connecting the panels of the accused carts falls within the legal construction of this term, or if it is merely a hinge or a different type of fastener.
  • Technical Questions: Analysis will focus on whether the accused product's panel-joining mechanism performs the specific function of holding the panels in a "common plane" to provide structural rigidity, as opposed to merely connecting them.

V. Key Claim Terms for Construction

'446 Patent: "slideable member"

• The Term: "slideable member" (Claim 1)
• Context and Importance: This term is the central inventive concept of Claim 1. The entire infringement theory for this patent rests on whether the locking component of the Accused Products is properly characterized as a "slideable member" that moves along a "track."
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The Summary section describes the element broadly as a "first slideable member cooperatively engaged to the first track" ('446 Patent, col. 2:31-33), without imposing significant structural limitations, which could support a construction covering any component that slides to lock.
  • Evidence for a Narrower Interpretation: The detailed description and figures show a specific embodiment (58) which is a distinct piece that slides over the exterior of the panels ('446 Patent, Fig. 2; col. 5:19-24). A defendant may argue that the term should be limited to a structure consistent with this disclosed embodiment.

'546 Patent: "latch part"

• The Term: "latch part" (Claim 1)
• Context and Importance: This term defines the connection mechanism between foldable panels, which is the core of Claim 1. The infringement analysis will turn on whether the connectors on the Accused Products meet the definition of mating "latch parts." Practitioners may focus on this term because the patent uses "latch part" in Claim 1 but "fastener" in Claim 9, suggesting a potential distinction in meaning that could be critical to claim scope.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent does not provide an explicit definition for "latch part," which may support giving the term its plain and ordinary meaning, potentially encompassing a wide range of interlocking components like hooks, clips, or tabs.
  • Evidence for a Narrower Interpretation: The function of the latch parts is specified: to "mate with one another and hold the first and second panels in a common plane" ('546 Patent, col. 13:39-42). A defendant may argue that this functional language requires more than a simple connection and limits the term to mechanisms that actively align and secure the panels against buckling.

VI. Other Allegations

• Indirect Infringement: The complaint alleges only direct infringement under 35 U.S.C. § 271 and does not plead facts to support claims of induced or contributory infringement (Compl. ¶¶ 1, 15, 20).
• Willful Infringement: The complaint does not include an explicit allegation of willful infringement. It does allege that Plaintiff "mark[s] its carts protected by one or more of its patents with the patent number(s)," which may be relevant to establishing notice for purposes of damages (Compl. ¶10).

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

This case appears to center on classic questions of claim scope and the application of claim language to accused product features. The key questions for the court will likely be:

1. A question of structural and functional correspondence for the '446 Patent: Do the accused carts employ a locking mechanism that operates as a "slideable member" moving along a "track" as specifically claimed, or do they use a mechanically different solution to achieve the same result of reinforcing the side panels?

2. A question of definitional scope for the '546 Patent: Can the claim term "latch part," in the context of the patent's specification and claims, be construed broadly enough to read on the specific components used to join the foldable panels of the accused carts?

3. An evidentiary question for both patents: Given the general nature of the allegations in the pleading, the case will depend on whether the evidence in the referenced claim chart exhibits (not publicly filed) is sufficient to show that the accused products sold by a third-party seller on Amazon practice each and every limitation of the asserted claims.