IP Law Daily, PATENT—E.D. Mich.: Chinese auto-parts seller temporarily restrained from marketing and selling allegedly copied pipe clamps, (May 6, 2026)

By Mandavi Singh, LL.M.

The court found that a manufacturer of exhaust connection systems established a likelihood of success on the merits and that it would likely suffer continuing price erosion, lost sales, and market-share harm without immediate relief.

A federal court in Michigan has granted an ex parte temporary restraining order (TRO) barring a Chinese aftermarket auto-parts seller from importing, marketing, or selling allegedly infringing exhaust pipe clamps after finding that the plaintiff, a US-based manufacturer of exhaust connection systems, demonstrated a strong likelihood of success on its patent infringement claims and established that immediate relief was necessary to prevent irreparable competitive harm. The court concluded that the accused products appeared to be “virtual” copies of the patented clamps and that the patent owner would likely continue to suffer price erosion, lost sales, and diminished market share absent injunctive relief. The court also determined that advance notice of the motion likely would allow the defendant to continue distributing allegedly infringing inventory into the U.S. marketplace, but service remained pending (Norma U.S. Holding LLC v. Xingtai Jinwo Commercial Trading Co., Ltd., No. 2:25-cv-13619-RJW-CI (E.D. Mich. May 5, 2026)).

Background. The patentee/plaintiff, Norma U.S. Holding LLC (Norma), manufactures and sells pipe clamps and exhaust connection systems used in vehicle exhaust assemblies from its facility in Auburn Hills, Michigan. The defendant, Xingtai Jinwo Commercial Trading Co., Ltd. (Jinwo), operates an automotive parts business from Hebei Province, China, and sells pipe clamps and related products through online sales channels directed to U.S. customers.

The dispute involved U.S. Patent No. 7,520,539 (the ’539 patent) titled “Pipe Clamp with Gasketed Center Rib,” which issued on April 21, 2009, and that has sixteen claims. The patent covers pipe clamps and couplers designed to connect exhaust pipes while improving sealing against gas leakage. Norma alleged that Jinwo infringes at least independent Claims 1 and 16 of the patent. Claim 1 described a four-part assembly comprising a circumferential band with protruding ribs and flanges, a tightening mechanism, a split sleeve, and an internal gasket to create a gas-tight seal between adjoining pipes.

Norma alleged that Jinwo sold a product identified as the “Jinwo DPF Filter Clamp Kit And Gasket Kit Directly Replaceable With OE Clamps And Gaskets,” which Norma described as a copy of its commercially successful “55W” pipe clamp. According to the complaint, Jinwo marketed the accused products through its own website and through third-party online resellers serving U.S. customers. Norma filed suit alleging direct infringement under 35 U.S.C. § 271(a) and induced infringement under 35 U.S.C. § 271(b), asserting that Jinwo knowingly copied the patented design to capitalize on Norma’s marketplace success. Norma simultaneously moved ex parte for a temporary restraining order under Federal Rule of Civil Procedure 65(b), arguing that service on a Chinese defendant under the Hague Convention could take several months and that Jinwo likely would continue selling the accused products and conceal assets before a preliminary injunction hearing could occur.

Ex parte relief. The court first addressed whether ex parte relief was justified. Relying on Granny Goose Foods, Inc. v. Brotherhood of Teamsters & Auto Truck Drivers, Local No. 70, 415 U.S. 423 (1974), the court emphasized that ex parte temporary restraining orders are permissible only in limited circumstances necessary to preserve the status quo and prevent irreparable injury. The court found that the lengthy process for serving Chinese defendants supported immediate relief because Jinwo likely would continue importing and selling the accused products before service could be completed.

Likelihood of success. The court next held that Norma established a strong likelihood of success on the merits. Applying the Federal Circuit’s infringement framework from Markman v. Westview Instruments, Inc., 52 F.3d 967 (Fed. Cir. 1995), aff’d, 517 U.S. 370 (1996), the court concluded that Claim 1 required no specialized construction because its terms carried ordinary meanings understandable to a person of ordinary skill in the art. After reviewing the annotated images and claim charts submitted by Norma, the court determined that the accused clamp plausibly embodied all limitations of Claim 1, including the circumferential band, tightening mechanism, split sleeve, and gasket assembly. The court stated that the accused product appeared to be a “virtual copy” of Norma’s patented design.

Irreparable injury. Citing Robert Bosch LLC v. Pylon Manufacturing Corp., 659 F.3d 1142 (Fed. Cir. 2011), the court recognized that patent owners are not entitled to an automatic presumption of irreparable injury but may establish such harm through evidence of direct competition and loss of exclusivity. The court found that Jinwo’s allegedly infringing sales caused continuing price erosion, lost sales, and reduced market share for Norma’s patented clamp products. The court further determined that the risk that Jinwo could evade a future monetary judgment heightened the irreparable nature of the harm.

Public interest. Finally, the court concluded that the balance of hardships and public interest favored injunctive relief. Relying on Abbott Laboratories v. Andrx Pharmaceuticals, Inc., 452 F.3d 1331 (Fed. Cir. 2006), the court stated that the public generally benefits from the enforcement of patents likely to be valid and infringed. The court reasoned that Jinwo would suffer little hardship because it would remain free to sell other noninfringing products, whereas Norma would continue to lose marketplace exclusivity absent immediate relief.

Conclusion. Balancing these factors, the court entered a 14-day temporary restraining order, required Norma to post a $5,000 bond, and deferred consideration of a preliminary injunction until service on Jinwo could be completed or Jinwo voluntarily appeared in the case.

The Case is No. 2:25-cv-13619-RJW-CI.

Judge: White, R.

Attorneys: Richard W. Hoffmann (Reising, Ethington, PC) for Norma U.S. Holding LLC.

Companies: Norma U.S. Holding LLC; Xingtai Jinwo Commercial Trading Co., Ltd.

Cases: Patent MichiganNews