DCT
1:25-cv-07170
Aiming Tang v. Shanghai Yanzhou Group Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Aiming Tang (China)
- Defendant: Shanghai Yanzhou Group Ltd (China)
- Plaintiff’s Counsel: Glacier Law LLP
- Case Identification: 1:25-cv-07170, N.D. Ill., 06/26/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendant targets U.S. consumers, including those in Illinois, through interactive e-commerce stores, ships products to Illinois, and accepts payment in U.S. dollars, causing substantial injury to the Plaintiff in the state.
- Core Dispute: Plaintiff alleges that Defendant’s e-commerce sales of certain towing hitch products infringe a patent related to a mechanical damping function for towing devices.
- Technical Context: The technology concerns mechanical hitches used for towing vehicles, specifically designs that aim to reduce noise, swaying, and instability caused by gaps in the connection between the vehicle and the towed trailer.
- Key Procedural History: The complaint does not mention any prior litigation, licensing history, or other significant procedural events related to the patent-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2022-03-08 | ’973 Patent Priority Date |
| 2022-09-20 | ’973 Patent Issue Date |
| 2025-06-26 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 11,446,973, "TOWING DEVICE WITH DAMPING FUNCTION," issued September 20, 2022.
The Invention Explained
- Problem Addressed: The patent background describes a problem with conventional towing devices where an "inevitable gap" exists between connecting pins and their corresponding holes, which leads to swaying, collision, noise, and abrasion during use (’973 Patent, col. 1:23-31).
- The Patented Solution: The invention introduces a "cushion" (27) that is sleeved onto the towing cantilever (the part inserted into the vehicle's hitch receiver). A "tightening bolt" (28) is then used to actively push this cushion forward until it is pressed firmly against the vehicle's "fixed seat," thereby filling any gaps, preventing axial movement, and absorbing shock (’973 Patent, Abstract; col. 4:1-17). This is intended to create a steadier, quieter, and safer towing connection.
- Technical Importance: This design provides a mechanical solution to eliminate play and slack in a standard hitch connection, which can improve towing stability and reduce wear on components (’973 Patent, col. 4:48-62).
Key Claims at a Glance
- The complaint asserts infringement of independent Claim 1 (’973 Patent, col. 7:59-8:11; Compl. ¶26).
- The essential elements of Claim 1 are:
- A towing device with a damping function, comprising a towing main body and a towing assembly mounted on it.
- The main body includes a towing cantilever and a vertical adjustment arm.
- The towing cantilever is fixed to a vehicle's pre-arranged fixed seat via fixing pins.
- A "cushion" is sleeved on the towing cantilever, located between the fixing holes and the vertical adjustment arm.
- A "tightening bolt" is provided on one side of the cushion.
- The tightening bolt can be rotated to "push the cushion" so that its end surface "is abutted against the fixed seat" of the towing vehicle.
- The complaint notes that Plaintiff reserves the right to modify its infringement theory as the case proceeds (Compl. ¶26).
III. The Accused Instrumentality
Product Identification
- The accused products are identified as "Towing Device Products" and "Infringing Products" sold by Defendant under the name AC-DK on the e-commerce marketplace Amazon.com (Compl. ¶1, ¶7, ¶16).
Functionality and Market Context
- The complaint alleges the accused products incorporate the patented invention, featuring an "integrated damping function designed to reduce axial movement and enhance towing stability" (Compl. ¶14). The complaint references screenshot printouts from Defendant's Amazon store listings, attached as Exhibit 2, which allegedly depict the accused products for sale to consumers in the United States (Compl. ¶16, ¶17). This screenshot, showing a towing hitch assembly, is the primary visual evidence referenced in the complaint (Compl. ¶16).
- The complaint alleges that Defendant's sales of these products online have hampered Plaintiff's ability to enter and expand its market share (Compl. ¶1, ¶15).
IV. Analysis of Infringement Allegations
The complaint alleges that the Defendant's "Infringing Products" infringe at least Claim 1 of the ’973 Patent (Compl. ¶26). The complaint references a claim chart in an external exhibit (Exhibit 3) to support this allegation, but the narrative allegations form the basis for the following summary.
’973 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A towing device with a damping function, comprising a towing main body (1) and a towing assembly (2) mounted on the towing main body (1)... | Defendant is alleged to make, use, and sell "Towing Device Products" that have an "integrated damping function." | ¶1, ¶14 | col. 7:59-62 |
| ...a towing cantilever (3) ... fixed, through fixing pins (26), on a fixed seat pre-arranged at a rear end of a towing vehicle... | The accused products are alleged to be towing devices that mount to a vehicle in the manner described in the claim. | ¶13, ¶26 | col. 7:63-8:1 |
| ...a cushion (27) is sleeved on the towing cantilever (3)... | The accused products are alleged to incorporate the elements of Claim 1, which includes a cushion component to achieve the damping function. | ¶13, ¶14, ¶26 | col. 8:1-2 |
| ...the tightening bolt (28) can be rotated to push the cushion (27)...so that an end surface of the cushion (27) is abutted against the fixed seat pre-arranged at the rear end of the towing vehicle. | The accused products are alleged to use the patented mechanism to "reduce axial movement and enhance towing stability," which Claim 1 achieves by having a bolt push a cushion against the fixed seat. | ¶14, ¶26 | col. 8:5-11 |
- Identified Points of Contention:
- Scope Questions: A primary issue may be whether the components of the accused product meet the specific structural definitions in the claim. For instance, does the accused device have a distinct component that functions as a "cushion" that is "sleeved on the towing cantilever," or is its anti-rattle feature integrated differently?
- Technical Questions: The infringement analysis may turn on the precise mechanism of action. The claim requires a "tightening bolt" that "can be rotated to push the cushion" until it "is abutted against the fixed seat." The court may need to determine if the accused product achieves its stability enhancement through this exact pushing and abutting action, or through a technically distinct method such as a wedge, cam, or expansion mechanism.
V. Key Claim Terms for Construction
The Term: "cushion (27)"
- Context and Importance: This term defines the central component of the claimed damping mechanism. Its construction will be critical, as the infringement analysis depends on whether the accused product contains a structure that meets this definition.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification suggests the cushion can be made of "several damping pieces (35)" that "can be randomly added and subtracted or replaced," which may support a broader construction not limited to a single, solid block (’973 Patent, col. 5:29-36).
- Evidence for a Narrower Interpretation: The claim requires the cushion to be "sleeved on the towing cantilever," and the figures depict it as a distinct, collar-like object (27) positioned around the cantilever (’973 Patent, Fig. 5; col. 8:1-2). This could support a narrower definition limited to a separate component with a through-hole.
The Term: "tightening bolt (28)"
- Context and Importance: This is the active element that creates the damping force. Whether the accused product's tightening mechanism qualifies as a "tightening bolt" will be a key point of dispute.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim describes the bolt functionally, stating it "can be rotated to push the cushion" (’973 Patent, col. 8:5-7). This functional language could be argued to cover any rotatable threaded fastener that performs the specified pushing function.
- Evidence for a Narrower Interpretation: An embodiment describes the tightening screw (28) passing through a "threaded hole (32)" in a separate "adjustment plate (31)" (’973 Patent, col. 5:7-17). Parties may argue this context limits the term to a traditional screw or bolt assembly, and not other types of rotational tightening mechanisms.
VI. Other Allegations
- Indirect Infringement: The complaint does not plead specific facts to support claims of induced or contributory infringement, such as by alleging Defendant instructs its customers to assemble or use the product in an infringing manner. The prayer for relief includes a boilerplate request to enjoin aiding and abetting (Compl. ¶A.b.).
- Willful Infringement: The complaint alleges that Defendant’s infringement "has been and continues to be willful" (Compl. ¶30). The factual basis for this allegation is not specified, and the complaint does not allege that Defendant had pre-suit knowledge of the ’973 Patent (e.g., via a notice letter).
VII. Analyst’s Conclusion: Key Questions for the Case
This dispute appears to center on a straightforward, single-patent infringement allegation concerning a mechanical device. The key questions for the court will likely be:
- A core issue will be one of structural correspondence: does the accused towing device contain the specific, physically distinct components recited in Claim 1—namely a "cushion" that is "sleeved" on the cantilever and a "tightening bolt"—or does it achieve a similar result with a different physical architecture?
- A key evidentiary question will be one of mechanism of action: does the accused product’s anti-rattle feature operate by a "bolt" that "pushes" a "cushion" to "abut" the fixed vehicle seat, as strictly required by the claim language, or does it employ a different mechanical principle to reduce movement?