Shenzhen Xiang Yun Duan v. Dynamic Manufacturing Group: Trailer Lock Patent Dismissed With Prejudice
Shenzhen Xiang Yun Duan Network Technology Co., Ltd filed suit against Dynamic Manufacturing Group LLC in the Florida Southern District Court, asserting US11427044B2 against 19 trailer lock product listings. The parties jointly stipulated to dismissal with prejudice after 164 days, with each side bearing its own legal costs unless otherwise agreed in writing.
Trailer Lock IP Dispute Ends in Prejudicial Joint Dismissal After 164 Days
On May 23, 2025, Shenzhen Xiang Yun Duan Network Technology Co., Ltd, a Chinese network technology company and holder of US11427044B2, filed an infringement action against Dynamic Manufacturing Group LLC in the United States District Court for the Southern District of Florida before Judge David S. Leibowitz. The complaint targeted 19 specific trailer lock product listings sold by the defendant under various Amazon ASINs, alleging those products infringed the asserted patent covering trailer locking technology.
The case concluded on November 3, 2025, when the parties filed a Joint Stipulation of Dismissal with Prejudice pursuant to Federal Rule of Civil Procedure 41(a)(1)(A)(ii). The court ordered the action dismissed with prejudice and directed each party to bear its own attorneys’ fees and costs, except as otherwise agreed in writing. Dismissal with prejudice is a final resolution — the plaintiff is permanently barred from reasserting the same claims against the defendant in future litigation.
The 164-day resolution timeline, achieved without a recorded merits ruling, is consistent with a negotiated settlement reached before substantive motion practice or claim construction. The mutual cost-bearing arrangement and the ‘except as otherwise agreed in writing’ carve-out suggest the parties may have reached a private commercial arrangement, though the public record does not disclose specific terms. What drove the stipulation — whether a licensing deal, design-around, or commercial concession — remains undisclosed.
Filing to Dismissed with Prejudice in 164 days
164-day case duration — resolved well within average district court trial timelines
Dismissed with prejudice: what the joint stipulation means for both parties
Rule 41(a)(1)(A)(ii): Joint Stipulation Ends the Case Permanently
A dismissal with prejudice under Fed. R. Civ. P. 41(a)(1)(A)(ii) is a consensual, court-approved termination that carries full res judicata effect. Unlike a dismissal without prejudice, the plaintiff cannot refile the same claims against the same defendant. Both parties must sign the stipulation, signalling mutual agreement to end the dispute — typically after reaching some form of commercial understanding.
Permanent bar on refilingPlaintiff Permanently Releases Claims Against This Defendant
By agreeing to dismissal with prejudice, Shenzhen Xiang Yun Duan has permanently relinquished its infringement claims against Dynamic Manufacturing Group for the 19 accused trailer lock ASINs. The patent US11427044B2 itself remains in force and enforceable against other parties. The cost-bearing carve-out suggests the plaintiff may have secured a private commercial concession, but this is not confirmed by the public record.
Patent survives; claims releasedDynamic Manufacturing Exits Without a Merits Ruling
Dynamic Manufacturing Group obtains a permanent dismissal of this specific action without any court finding of infringement or validity. The absence of a merits ruling means no adverse precedent was established. However, with prejudice dismissal does not provide a formal invalidity finding — the defendant carries no declaratory judgment shield if the patent holder pursues related claims in a different context or against different products.
No infringement finding on recordPrivate Resolution Leaves Sector-Wide Uncertainty on Trailer Lock IP
The sealed commercial terms and absence of a merits ruling mean that US11427044B2’s scope and validity remain untested in court. Other trailer lock product sellers — particularly those operating on Amazon marketplace — should note that this patent remains active and assertable. The plaintiff’s willingness to litigate against specific ASINs signals an active enforcement posture that may extend to other competitors in this product category.
Patent remains enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Shenzhen Xiang Yun Duan Network Technology Co., Ltd | Company | Chinese network technology firm — holder of US11427044B2 (trailer lock technology)Search in Eureka ↗ |
| Defendant | Dynamic Manufacturing Group LLC | Company | Dynamic Manufacturing Group LLC — seller of trailer lock security products on Amazon marketplaceSearch in Eureka ↗ |
| Plaintiff counsel | Benjamin Wayne Dowers | Attorney | Counsel for Shenzhen Xiang Yun Duan Network Technology Co., LtdSearch in Eureka ↗ |
| Plaintiff law firm | Gunther Legal | Law Firm | Representing Shenzhen Xiang Yun Duan Network Technology Co., LtdSearch in Eureka ↗ |
| Defendant counsel | Austin Robert Nowacki | Attorney | Counsel for Dynamic Manufacturing Group LLCSearch in Eureka ↗ |
| Defendant counsel | Derek Roger Fahey | Attorney | Counsel for Dynamic Manufacturing Group LLCSearch in Eureka ↗ |
| Defendant law firm | The Plus IP Firm PLLC | Law Firm | Representing Dynamic Manufacturing Group LLCSearch in Eureka ↗ |
| Defendant law firm | The Plus IP Firm, PLLC | Law Firm | Representing Dynamic Manufacturing Group LLCSearch in Eureka ↗ |
| Presiding judge | Judge David S. Leibowitz | Judge | Florida Southern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The joint stipulation language — ‘dismissed with prejudice’ with each party bearing its own costs ‘except as otherwise agreed in writing’ — is a standard settlement-adjacent formulation. The prejudice designation forecloses any refiling of these specific claims against Dynamic Manufacturing Group. The cost carve-out is notable: it does not represent a fee award but instead preserves the effect of any private financial arrangement between the parties, which the public record does not disclose. No merits findings were made.
US11427044B2 — Trailer Lock Mechanical Security Device Technology
US11427044B2, filed under application number US16/456189, covers trailer lock technology — specifically mechanical security devices designed to secure trailer hitches and couplers against theft or unauthorised towing. The patent is assigned to Shenzhen Xiang Yun Duan Network Technology Co., Ltd and represents a US utility patent grant. The patent’s enforceability in the Southern District of Florida against Amazon marketplace sellers signals it covers commercially deployed hardware configurations, not merely a paper filing.
The assertion of US11427044B2 against 19 Amazon ASINs reveals the competitive intensity in the trailer security hardware market. Patents in mechanical locking device categories are increasingly leveraged by Asian-origin patent holders to create licensing pressure on US distributors and Amazon sellers. For product teams and IP counsel in the vehicle security, trailer hardware, and outdoor equipment sectors, this patent represents a live enforcement risk — particularly given the lack of any validity challenge or claim construction in the public record.
Should you run an FTO against US11427044B2?
Any company developing, importing, or selling trailer hitch locks, coupler locks, or similar mechanical trailer security devices — particularly through Amazon or other e-commerce platforms — should consider a freedom-to-operate analysis against US11427044B2. The plaintiff’s enforcement action named 19 distinct ASINs across multiple product configurations, suggesting broad commercial relevance. The absence of a merits ruling means the patent’s claims have not been narrowed or invalidated by this litigation.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US11427044B2 against your product specifications, surface relevant prior art, and identify design-around opportunities before you bring trailer lock products to market. Eureka also tracks the litigation history and prosecution record of this patent, allowing your IP team to assess enforceability risk in real time without manually reviewing USPTO and court filings.
Run a freedom-to-operate analysis on US11427044B2 to assess your product’s exposure
Run FTO in Eureka →Similar Trailer Lock and Hardware Security Patent Cases in US District Courts
Explore comparable patent infringement actions involving mechanical trailer lock and vehicle security devices filed in Florida and other US district courts.
What this case signals for the trailer lock and hardware IP landscape
A fast, prejudicial dismissal in a 19-ASIN infringement action reveals key enforcement patterns in e-commerce hardware IP.
Chinese patent holders are actively enforcing US patents on Amazon product listings
This case illustrates a growing enforcement model: Chinese technology companies asserting US utility patents against Amazon marketplace sellers. With 19 specific ASINs named, the complaint was highly targeted. Sellers in the trailer lock and hardware security category should audit their product listings against active patents held by non-practising entities and overseas originators.
Dismissal with prejudice at 164 days is consistent with a licensing resolution
Cases dismissed this quickly via joint stipulation — without any substantive court ruling — typically suggest a commercial deal was reached. The ‘except as otherwise agreed in writing’ cost provision reinforces this inference. IP teams monitoring enforcement patterns should treat this outcome as a probable licensing event rather than a clear defendant win.
Shenzhen v Dynamic — key questions answered
The case was dismissed with prejudice on November 3, 2025, after 164 days, via a Joint Stipulation of Dismissal under Fed. R. Civ. P. 41(a)(1)(A)(ii). Each party bears its own attorneys’ fees and costs unless otherwise agreed in writing. No merits ruling was issued by the court.
The plaintiff asserted US11427044B2 (application number US16/456189), a US utility patent covering trailer lock technology. The patent is held by Shenzhen Xiang Yun Duan Network Technology Co., Ltd and was asserted against 19 Amazon ASIN trailer lock products sold by Dynamic Manufacturing Group LLC.
Dismissal with prejudice is a final termination of the case with full res judicata effect. The plaintiff is permanently barred from refiling the same infringement claims against the same defendant. It does not invalidate the patent — US11427044B2 remains enforceable against other parties. It also does not constitute a finding of non-infringement or invalidity.
Dynamic Manufacturing Group’s trailer lock products sold on Amazon under 19 specific ASINs were accused of infringement, including ASINs B0D9M6ZW66, B0D9M815Z9, B0DYJVNZD5, B0DYJX1B9G, B0DYK2S983, B0DZ1PS6J2, and 13 further listings. The targeted approach naming individual ASINs is consistent with e-commerce-focused IP enforcement strategy.
No formal settlement agreement appears in the public record. However, the dismissal with prejudice via joint stipulation — combined with the cost provision allowing for amounts ‘otherwise agreed in writing’ — is consistent with a private commercial resolution. The specific terms, if any financial arrangement was reached, have not been publicly disclosed.
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