US D1,109,423 Wireless Straightening Brush: Analysis of Recent TRO and Avoidance Strategies

I. Case Overview

On 2026/9/14, the U.S. District Court for the Northern District of Illinois accepted a design patent infringement lawsuit (Case No. 1:26-cv-11163). The plaintiff, Wenzhou Chuyin Electronics Co., Ltd., represented by attorney Qin Zhuang, filed suit against e-commerce sellers listed on Schedule A; the plaintiff has simultaneously moved to file the defendant list under seal. The case was assigned to Judge Jeremy C. Daniel.

The involved patent is a U.S. design patent, US D1,109,423 S, titled "Cordless Hair Straightening Comb," filed on 7/28/2026, and granted on 1/13/15. The patent term is 15 years, and the inventor is Shangjing Xie. The product in question is a cordless hair straightening comb/portable styling comb. In accordance with standard procedures for Schedule A cases of this type, plaintiffs typically file an ex parte Temporary Restraining Order (TRO) immediately after filing the lawsuit to freeze the defendant's store funds. Sellers in the relevant category should pay close attention.

II. Scope of Patent Protection: Solid and Dashed Lines

In U.S. design patent drawings, solid lines denote the claimed design features, while dashed lines indicate elements that are not claimed but serve to illustrate the environment. D1, 109,423 patent specification explicitly states: "The broken lines … form no part of the claimed design."

After a line-by-line review of all 10 drawing pages in this patent: The overall capsule-shaped outline is rendered in dashed lines and is not covered by the protection scope. The design features claimed for protection with solid lines include: (1) comb-tooth pattern on the comb panel (interlaced array of long capsule-shaped teeth, large oval teeth, and small dot teeth; see FIG. 9 zoomed view); (2) handle button area shape (long oval recesses, multiple concentric rings, small oval buttons, and a central small rectangle; see FIG. 10 zoomed view); (3) S-shaped waistline transition curve between the head and handle; (4) longitudinal ridges and parting line layout on the handle surface.

This practice of claiming rights only over a specific design element is known as "partial design claiming." Its legal effect is that even if the overall appearance of an accused product differs significantly from the patented product, it may still be deemed infringing if the partial design shown with solid lines is substantially similar. In U.S. design patent infringement cases, the "Ordinary Observer Test" is applied, which assesses whether an ordinary purchaser would have a confusing overall visual impression.

III. Feasible Workarounds and Improvement Directions

• 1. Distinct comb pattern: Modify tooth shape (cylindrical, square, or teardrop heads), tooth count, number of rows, row spacing, and staggered arrangement to create a clearly distinct overall visual effect.

• 2. Button area redesign: Replace the elongated oval recess and multi-layer concentric ring design with flat, circular, or square button zones. Alternatively, use sliders or touch-sensitive buttons, and reposition controls to the side or back if necessary.

• 3. Head-to-body transition update: Replace the S-shaped waist curve with a straight-step, large-radius continuous transition, or decorative ring structure.

• 4. Surface Split Adjustment: Modify the position and count of vertical split lines on the handle, or switch to a horizontal decorative texture.

• 5. Add striking visual elements: Use color blocking, texture differentiation, brand logo areas, and digital displays to create a distinct overall visual impression for casual observers.

• 6. Proactive Patent Strategy: File U.S. design patents for differentiated features promptly (leveraging partial protection strategies) to establish defensive and counter-offensive capabilities.

Disclaimer: The above analysis is preliminary and based on patent drawings; it does not constitute legal advice. Determination of design patent infringement relies on the overall visual impression of an ordinary observer. Risk assessment and feasibility of avoidance for specific products require itemized comparison by a professional agency.

IV. Risk Notice for Relevant Sellers

• Hair care appliance sellers (e.g., straightening brushes, hot air brushes, portable styling combs) should immediately compare the comb tooth patterns and button area designs of their active listings against inventory.

• The defendant list in this case has been filed under seal and is not publicly accessible; self-audit remains the only reliable method to verify if your store is included.

• Upon receiving a platform notice or court document, respond formally within the 21-day rebuttal period; failure to appear may result in funds being deducted from your account.

• For frozen stores, consult a qualified attorney promptly to evaluate litigation or settlement options.

V. Services We Offer

[Company Name] has long been dedicated to the field of cross-border e-commerce intellectual property. Our services include:

• Infringement Comparison Analysis: Item-by-item comparison of design patent solid-line features and claim analysis for invention patents, with a professional opinion issued.

• Design Avoidance Guidance: Differentiated design proposals and implementation recommendations based on patent scope.

• TRO Response and Settlement: Collaborate with U.S. licensed attorneys to handle injunction defense, settlement negotiations, and fund unfreezing.

• U.S. IP Portfolio Strategy: End-to-end services for design patents, utility patents, and trademarks—from application to enforcement.

For a case-specific assessment of this matter or your product, please contact us via [Contact: 13305000901 (WeChat ID)] or leave a message on our official website.

Disclaimer: This content is compiled from publicly available judicial documents and patent literature for reference only and does not constitute legal advice. For the latest case developments, refer to the court's public records.