KHD Group Inc v. Dbest Products Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: KHD Group Inc. (California)
  • Defendant: dbest products, Inc. (California)
  • Plaintiff's Counsel: LawMay P.C.
• Case Identification: 5:26-cv-02081, C.D. Cal., 04/23/2026
• Venue Allegations: Venue is alleged to be proper as the Defendant is a corporation residing in the judicial district.
• Core Dispute: Plaintiff seeks a declaratory judgment that its foldable storage cabinets do not infringe Defendant's patents, and that the patents are invalid and unenforceable, following Defendant's infringement complaints to Amazon that resulted in the removal of Plaintiff's product listings.
• Technical Context: The technology concerns mechanical designs for collapsible storage containers, a consumer product category where features enhancing portability, storage efficiency, and structural rigidity are key market differentiators.
• Key Procedural History: The litigation was initiated by the Plaintiff in response to intellectual property complaints filed by the Defendant with Amazon. The complaint includes significant allegations of patent invalidity due to the alleged addition of new matter during prosecution, which would break the patents' priority chain and expose them to intervening prior art. Furthermore, the complaint alleges the '546 patent is unenforceable due to inequitable conduct, asserting that the Defendant knowingly failed to disclose material prior art and misrepresented the origin of product photographs submitted to the USPTO.

Case Timeline

Date	Event
2020-01-06	Earliest Priority Date ('546 Patent; '446 Patent)
2021-01-06	Filing of U.S. Application No. 17/143,116 in patents' family tree
2021-12-03	Publication of Chinese Patent CN214987334U ("HAIXIN Patent")
2022-11-16	Alleged first public sale of HAIXIN products on Amazon
2023-03-01	(approx.) Filing of Defendant's Provisional Applications allegedly adding new matter
2023-12-15	Filing of U.S. Application No. 18/542,495 carrying forward alleged new matter
2025-01-31	Defendant's response to final office action during '446 Patent prosecution
2025-04-15	U.S. Patent No. 12,275,446 ('446 Patent) Issues
2025-05-20	U.S. Patent No. 12,304,546 ('546 Patent) Issues
2026-02-22	Amazon removes Plaintiff's product listings
2026-04-23	Complaint for Declaratory Judgment filed

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

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: The patent's background section notes that prior art collapsible carts may lack the sturdiness required for transporting heavy objects due to their collapsible design '546 Patent, col. 2:22-25
• The Patented Solution: The invention is a collapsible cart with a frame of at least five walls, some of which are configured to fold inwardly for compact storage '546 Patent, claim 1 To solve the sturdiness problem, it proposes using multi-part locking mechanisms-described in the claims as a "first latch part" and "second latch part"-that mate to hold collapsible wall panels together in a "common plane," providing rigidity when the cart is in its open, expanded state '546 Patent, claim 1
• Technical Importance: This approach seeks to combine the structural integrity of a fixed-wall container with the storage convenience of a fully collapsible one, addressing a primary trade-off in the design of such products.

Key Claims at a Glance

• The complaint asserts non-infringement of independent claims 1, 9, and 17 Compl. ¶33
• Independent Claim 1 includes these essential elements:
  • A frame defining a compartment with at least five walls, at least three of which rotatably fold inwardly.
  • One of the walls consists of a first panel and a second panel rotatably coupled together.
  • 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 and hold the panels in a "common plane" when latched.

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: Like its family member, the '446 patent addresses the problem that collapsible carts in the prior art can lack sufficient sturdiness for heavy loads '446 Patent, col. 1:12-16
• The Patented Solution: The '446 Patent discloses a collapsible cart where a sidewall is composed of two rotatably coupled panels '446 Patent, abstract To enhance rigidity, it features a "first track" that extends along both panels and a "first slideable member" that engages and moves along this track to lock the two panels together in an open position '446 Patent, col. 2:25-36
• Technical Importance: The track-and-slider mechanism represents a specific mechanical solution for reinforcing the joints of a collapsible structure to improve its load-bearing capacity.

Key Claims at a Glance

• The complaint asserts non-infringement of independent claims 1, 10, 16, and 22 Compl. ¶59
• Independent Claim 1 includes these essential elements:
  • A collapsible cart with a rigid frame, where a sidewall comprises a "first right panel rotatably coupled to a second right panel."
  • A "first track" formed along the first right panel and the second right panel.
  • A "first slideable member cooperatively engaged to the first track."
  • The slideable member is movable along the track to selectively lock the first right panel to the second right panel.

III. The Accused Instrumentality

Product Identification

The products at issue are "foldable storage cabinets" sold by Plaintiff KHD Group Inc. on Amazon.com under its "US-VECELO" storefront Compl. ¶4 Compl. ¶9 Compl. ¶20

Functionality and Market Context

The complaint describes the products as available in single and multi-tier configurations, with side panels that fold inwardly for storage Compl. ¶10 The key feature distinguished by the Plaintiff is the locking mechanism: the products use "one-piece rotating swing clips" that pivot to connect vertically adjacent panels to each other or to a top rim Compl. ¶¶11-14 Figure 1 of the complaint displays photographs of the plaintiff's product, highlighting the "one-piece rotating clips" that connect the panels Compl. p. 5 The complaint alleges that these products are central to its business on the Amazon marketplace Compl. ¶28

IV. Analysis of Infringement Allegations

'546 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Non-Infringing Functionality	Complaint Citation	Patent Citation
a first latch part disposed on an edge of the first panel... and a second latch part disposed on an edge of the second panel	The accused products utilize "one-piece rotating clips" that are unitary structures, not a combination of a "first latch part" and a "second latch part" Compl. ¶34	¶34	col. 13:34-40
wherein the first latch part and the second latch part are configured to mate with one another and hold the first and second panels in a common plane	The product's clips pivot to connect vertically adjacent panels or a panel to a top rim; they do not function to hold two laterally adjacent panels in a "common plane" Compl. ¶35	¶35	col. 14:1-5

'446 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Non-Infringing Functionality	Complaint Citation	Patent Citation
a first track formed along the first right panel and the second right panel	The complaint alleges the product's mechanism relies on rotating clips, which do not constitute or engage with a "track" that spans two panels Compl. ¶60	¶60	col. 7:21-25
a first slideable member cooperatively engaged to the first track	The product's "one-piece rotating clips" are not a "slideable member" that moves along a track; they are rotating components Compl. ¶60	¶60	col. 7:26-37

• Identified Points of Contention:
  • Structural Mismatch: The central infringement dispute appears to be a structural one. The court will need to determine if the accused "one-piece rotating clips" are the structural and functional equivalent of the patents' claimed two-part "latch parts" ('546 Patent) or track-based "slideable member" ('446 Patent).
  • Functional Mismatch: The analysis will also question whether the function of the accused clips matches the claimed function. The complaint alleges the clips connect panels vertically, whereas the '546 patent claims a mechanism to hold panels coplanar Compl. ¶35
  • Written Description Support: The complaint raises a significant validity challenge by alleging that terms like "latch part," "fastener member," and "coupler member" in the '546 Patent claims lack any antecedent basis or descriptive support in the patent's specification, which may render the claims invalid under 35 U.S.C. § 112 Compl. ¶45

V. Key Claim Terms for Construction

Term 1: "first latch part" and "second latch part" ('546 Patent)

• Context and Importance: This terminology is at the core of the non-infringement argument for the '546 patent. The Plaintiff's entire defense is that its "one-piece" clips cannot be a two-part latch. The term's construction will likely be dispositive for infringement of Claim 1.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patentee (Defendant) may argue that "latch part" should be interpreted functionally to mean any components that cooperate to perform a latching function, regardless of whether they are physically distinct before assembly.
  • Evidence for a Narrower Interpretation: The plain meaning of "a first... part" and "a second... part" suggests two distinct components. The Plaintiff will argue that since the specification provides no special definition or examples of "latch parts," the term must be given its plain and ordinary meaning Compl. ¶34 The complete absence of the term "latch part" from the '546 patent's detailed description will be a strong argument for a narrow construction and may also support the Plaintiff's invalidity argument for lack of written description Compl. ¶45

Term 2: "slideable member" ('446 Patent)

• Context and Importance: This term is critical for the '446 patent infringement analysis, as the accused product uses a "rotating clip" mechanism. Practitioners may focus on this term because the distinction between "sliding" and "rotating" is a clear mechanical difference.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patentee may argue that "slideable" should not be read so literally as to exclude all other forms of motion, and should cover any member that moves from an unlocked to a locked position along a defined path.
  • Evidence for a Narrower Interpretation: The specification repeatedly describes the member as being "movable along the first track" '446 Patent, claim 1 and shows it in figures as a component that translates linearly (e.g.,'446 Patent, FIG. 2, item 58). The plain meaning of "slideable" implies linear movement, contrasting with the rotational movement of the accused clips.

VI. Other Allegations

• Indirect Infringement: The complaint is a declaratory judgment action and does not allege indirect infringement. Rather, it preemptively denies any liability for direct, contributory, or induced infringement of the patents-in-suit Compl. ¶32 Compl. ¶58
• Willful Infringement: The complaint does not allege willful patent infringement by the Plaintiff. Instead, it alleges that the Defendant's enforcement actions-filing allegedly baseless takedown notices with Amazon-were willful and exceptional, forming the basis for a request for enhanced damages and attorney's fees against the Defendant Compl. Prayer G The complaint also contains detailed allegations that the Defendant committed inequitable conduct before the USPTO by failing to disclose known, material prior art and misrepresenting evidence, which could also support a finding of an exceptional case Compl. ¶¶47-55

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

This case appears to center on three critical questions for the court:

1. A question of mechanical definition: Do the Plaintiff's "one-piece rotating clips" fall within the scope of the patents' claims for two-part "latch parts" ('546 Patent) and track-based "slideable members" ('446 Patent)? The resolution will depend on whether the court adopts a narrow, structural interpretation of these terms or a broader, functional one.

2. A question of priority and new matter: Are the asserted claims entitled to their claimed 2020 priority date? This will require determining if the core "inward-folding storage box" design was present in the original applications or if it was improperly added as "new matter" in 2023, potentially invalidating the claims in light of the intervening HAIXIN prior art.

3. A question of enforceability and intent: Is the '546 patent unenforceable for inequitable conduct? This will hinge on evidence of what the Defendant knew about the HAIXIN prior art and prior sales, whether that information was material, and whether the Defendant's failure to disclose it to the USPTO demonstrates a specific intent to deceive the agency. The complaint's use of a screenshot showing the prior art for sale on Amazon is presented as direct evidence of this knowledge Compl. p. 8, Fig. 4