Ruian Xinshuo Trading Co Ltd v. RB Distribution Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Ruian Xinshuo Trading Co., Ltd. (People's Republic of China)
  • Defendant: RB Distribution, Inc. (Pennsylvania)
  • Plaintiff's Counsel: THE LAW OFFICE OF X. LYU, PLLC
• Case Identification: 2:26-cv-01412, W.D. Pa., 06/30/2026
• Venue Allegations: Venue is alleged to be proper in the Western District of Pennsylvania because Defendant RB Distribution, Inc. resides in the district (it is incorporated and has its principal place of business in Pennsylvania) and because a substantial part of the events giving rise to the action, including the decision to assert the patent, allegedly occurred in or were directed from the district.
• Core Dispute: Plaintiff seeks a declaratory judgment that its automotive replacement part does not infringe Defendant's patent for an oil filter adaptor and that the patent's claims are invalid as obvious.
• Technical Context: The lawsuit concerns aftermarket automotive engine components, specifically integrated oil filter and cooler adaptors for certain passenger vehicles.
• Key Procedural History: This declaratory judgment action was precipitated by Defendant's use of Amazon's Patent Evaluation Express (APEX) program to accuse Plaintiff's product of infringement. This accusation resulted in the removal of Plaintiff's product listing from Amazon's marketplace, prompting Plaintiff to file suit to resolve the infringement and validity dispute.

Case Timeline

Date	Event
2020-08-21	U.S. Patent No. 12,234,755 Priority Date
2025-02-25	U.S. Patent No. 12,234,755 Issue Date
2026-06-30	Complaint Filing Date

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

U.S. Patent No. 12,234,755 - "Method and Process for Manufacturing a Unitary Oil Filter Adaptor"

• Patent Identification: U.S. Patent No. 12,234,755, "Method and Process for Manufacturing a Unitary Oil Filter Adaptor," issued on February 25, 2025 ('755 Patent).

The Invention Explained

• Problem Addressed: The patent's background describes issues with prior art oil filter adaptors made from plastic or hybrid plastic-and-metal constructions. These designs are allegedly prone to failure at connection points, such as where metal inserts are molded into plastic, and require sealing plugs for holes left by the molding process, creating potential leak points. '755 Patent, col. 1:35-51 '755 Patent, col. 1:56-62
• The Patented Solution: The invention is a "casted unitary metallic oil filter adaptor" that is formed as a single metal piece, preferably aluminum '755 Patent, col. 3:5-8 This single-cast design purports to solve the prior art's problems by eliminating the need for failure-prone inserts and sealing plugs, as associated components can be threaded directly into the cast body '755 Patent, col. 2:1-3 The design also features a lubricant flow path that is entirely contained within the casting, which is described as being linear and symmetric about a longitudinal axis '755 Patent, col. 2:5-8 '755 Patent, col. 3:22-28 '755 Patent, Fig. 5
• Technical Importance: This approach aims to create a more robust and reliable oil filter adaptor by replacing complex, multi-material assemblies with a simplified, single-piece cast metal component, thereby improving durability and reducing potential points of failure '755 Patent, col. 2:3-8

Key Claims at a Glance

• The complaint challenges all claims (1-18) and specifically references independent claims 1, 8, 12, and 18 Compl. ¶10 Compl. ¶70
• Independent Claim 1 (Method):
  • casting an elongated unitary metallic body comprising: a filter housing, a lower surface for the engine, an upper surface for a cooler, an internal lubrication flow path, and a plurality of casted apertures; and
  • threading at least one of the plurality of casted apertures.
• Independent Claim 8 (Method):
  • casting a unitary metallic body comprising: a filter housing, lower and upper surfaces, a lubrication flow path, and a casted aperture; and
  • internally threading the casted aperture.
• Independent Claim 12 (Apparatus):
  • a single-cast metallic body comprising: a filter housing, a lower surface for an engine, an upper surface for a cooler, an internal lubrication flow path, and an internally-threaded casted aperture.
• Independent Claim 18 (Apparatus):
  • a single-cast metallic body comprising: a filter housing, a first surface for an engine, a second surface for a cooler, an internal lubrication flow path, and an internally threaded casted aperture.
• The complaint challenges all claims from 1-18, thereby placing all dependent claims at issue as well (Compl. ¶¶10; Compl. ¶120).

III. The Accused Instrumentality

Product Identification

The Accused Product is an "aluminum engine oil-filter-housing and oil-cooler replacement assembly" identified by Amazon Standard Identification Number (ASIN) B0CT8P77SZ Compl. ¶2 Compl. ¶27

Functionality and Market Context

• The product is a multi-component assembly intended to replace the original-equipment oil-filter and oil-cooler assembly on specific Chrysler, Dodge, Jeep, and Ram vehicles with 3.6-liter engines Compl. ¶2 Compl. ¶30 The assembly includes a housing body, a separate oil cooler, filter-related components, sensors, seals, and fasteners Compl. ¶29
• The complaint alleges that Amazon is a material sales channel for the product and that its removal from the marketplace has caused commercial injury Compl. ¶31 Compl. ¶45 The complaint includes a photograph showing the complete Accused Product assembly Compl. p. 2, figure

IV. Analysis of Infringement Allegations

The complaint does not provide a claim chart mapping the patent claims to the Accused Product. Instead, it presents narrative arguments for a declaration of non-infringement.

For the method claims (1-11), the complaint argues that the Plaintiff, Ruian Xinshuo, does not perform the claimed manufacturing steps in the United States Compl. ¶50 It further alleges that the Accused Product is not manufactured using a process that meets every limitation of the method claims, specifically contending that the process does not involve casting an aperture and then threading it as required Compl. ¶¶51-52

For the apparatus claims (12 and 18), the complaint alleges that the Accused Product does not contain a "single-cast metallic body" that incorporates every recited structural and relational limitation Compl. ¶57 The central non-infringement argument is that the Accused Product does not possess an "internally-threaded casted aperture" as that term is properly construed Compl. ¶58 The plaintiff posits that "openings created by drilling and machining after formation of a casting, do not satisfy the claimed 'casted aperture' limitations" Compl. ¶53

Identified Points of Contention

• Jurisdictional Questions: For the method claims, a threshold question is whether the importation and sale of a product in the U.S. constitutes infringement under 35 U.S.C. § 271(g), which will depend on whether the product was "made by" the patented process.
• Technical Questions: A key factual dispute will concern the actual manufacturing process of the Accused Product. The evidence will need to show whether its apertures are formed during casting or created by subsequent drilling and machining from a solid casting.
• Scope Questions: The case raises a significant claim construction dispute over the term "casted aperture." The court will need to determine if the term is limited to an aperture fully formed during the casting process or if it can also cover an opening that is initiated during casting (e.g., as a boss or pilot hole) and then finalized by post-casting machining and threading.
• Scope Questions: Another question is whether the Plaintiff's "multi-component assembly" Compl. ¶29 can infringe claims directed to a "single-cast metallic body." This may depend on whether the core housing of the Accused Product itself meets all claim limitations, regardless of the other components it is sold with.

V. Key Claim Terms for Construction

"casted aperture"

• Context and Importance: This term appears in all asserted independent claims and is at the heart of the non-infringement dispute. Plaintiff contends its product's apertures, allegedly formed by drilling or machining after casting, fall outside this limitation Compl. ¶53 Practitioners may focus on this term because its construction could be dispositive for both the method and apparatus claims.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patentee (Defendant) may argue that the claims require "threading" the "casted aperture," which is inherently a post-casting step, suggesting the claim anticipates subsequent machining of a feature that originates in the casting '755 Patent, cl. 1 '755 Patent, cl. 8
  • Evidence for a Narrower Interpretation: Plaintiff may argue that the modifier "casted" requires the aperture (the hole itself) to be substantially formed by the casting process. The patent's focus on creating a "unitary" part without the need for post-molding modifications like plugs could be used to argue for a construction that limits post-casting work '755 Patent, col. 2:1-8

"single-cast metallic body"

• Context and Importance: This term, central to the apparatus claims, defines the unitary nature of the invention. Plaintiff alleges its "multi-component assembly" does not meet this limitation Compl. ¶29 Compl. ¶57 The interpretation will determine if an assembly that includes the claimed part can be considered non-infringing.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patentee may argue that as long as one component within the accused assembly is a "single-cast metallic body" that meets all the structural limitations of the claim, infringement is established, regardless of other components sold with it.
  • Evidence for a Narrower Interpretation: Plaintiff may point to the patent's title ("Unitary Oil Filter Adaptor") and repeated emphasis on a single, integrated component to argue that if any claimed function or surface (e.g., the cooler mating surface) resides on a separate component within the accused assembly, the "single-cast" limitation is not met '755 Patent, title '755 Patent, abstract

VI. Other Allegations

• Indirect Infringement: The complaint affirmatively pleads non-infringement of indirect infringement theories, alleging there is no underlying direct infringement and that Plaintiff lacks the specific intent required for inducement Compl. ¶61 It also denies contributory infringement, stating the Accused Product is a lawful replacement part with substantial noninfringing uses Compl. ¶62
• Willful Infringement: Willfulness is not alleged by the Plaintiff. However, the Plaintiff does seek a declaration that the case is "exceptional" under 35 U.S.C. § 285, which would entitle it to an award of attorneys' fees Compl., Prayer for Relief F

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

• A core issue will be one of definitional scope: can the term "casted aperture," as used in the patent, be construed to cover an aperture created by drilling and threading a solid portion of a casting, or is it limited to a hole that is substantially formed during the casting process itself?
• A second critical issue is one of invalidity: does the combination of prior art references cited by the Plaintiff-which allegedly teach cast carriers (EP '645), aluminum casting (EP '848), and threaded connections (WO '738)-render the asserted claims obvious to a person of ordinary skill in the art, thereby invalidating the patent?
• A key evidentiary question will be one of factual process: how is the Accused Product actually manufactured? The determination of whether its apertures are initiated in casting or drilled entirely post-casting will be critical evidence for the court to apply to its construction of the claims.