Shenzhen Zhifu v. Core Home Fitness: Infringement Suit Dismissed Without Prejudice
Shenzhen Zhifu Network Technology Co., Ltd. filed suit against Core Home Fitness, L.L.C. in the Northern District of Illinois asserting US7614983B1 over a broad range of adjustable dumbbell products. Judge April M. Perry granted the defendant’s motion to dismiss after just 97 days, leaving the door open for refiling.
Adjustable dumbbell patent suit collapses at the pleading stage
On October 31, 2024, Shenzhen Zhifu Network Technology Co., Ltd., a Chinese technology company, filed a patent infringement action against Core Home Fitness, L.L.C. in the U.S. District Court for the Northern District of Illinois (Case No. 1:24-cv-11277). The suit asserted US7614983B1, a patent relating to adjustable fitness equipment, against a wide range of Core Home Fitness products sold under multiple brand identifiers including CORE FITNESS, LEEKEY DIRECT, Rendpas Direct, Xddias Fitness Expert, and others on e-commerce platforms.
The case ended on February 5, 2025, when Judge April M. Perry granted Core Home Fitness’s motion to dismiss (Docket 15). The complaint was dismissed without prejudice, meaning the court found deficiencies in the pleading but did not foreclose Shenzhen Zhifu from filing an amended or new complaint. A dismissal without prejudice at this stage typically reflects pleading failures — such as insufficient factual allegations of infringement — rather than a determination on the merits of the underlying patent claims.
The 97-day resolution is notably swift, suggesting the defendant moved early and aggressively on pleading deficiencies rather than allowing discovery to proceed. The public record does not disclose whether Shenzhen Zhifu intends to refile with a corrected complaint, pursue settlement, or abandon the claim entirely. The outcome leaves US7614983B1’s enforceability formally untested, and the identified accused products — including numerous Amazon-listed SKUs — remain commercially active. What drove the specific pleading deficiencies the court identified is not detailed in the available public record.
Filing to Dismissed without Prejudice in 97 days
97 days — resolved well below the typical N.D. Illinois patent case median of 2+ years
Dismissed without prejudice: what the ruling means for both parties
Motion to dismiss granted — pleading deficiency, not a merits ruling
A dismissal without prejudice on a motion to dismiss means the court found the complaint legally insufficient as drafted — most commonly due to inadequate factual allegations of infringement under the Twombly/Iqbal standard. The court did not rule on whether US7614983B1 is valid or infringed. Shenzhen Zhifu retains the right to refile a corrected complaint, subject to any applicable statute of limitations.
Procedural dismissal — no merits adjudicationRefiling option preserved, but the burden is now higher
Because the dismissal is without prejudice, Shenzhen Zhifu can attempt to cure the pleading defects and refile. However, having faced a successful motion to dismiss, any amended complaint must be materially more detailed in its infringement allegations. The public record does not indicate whether Shenzhen Zhifu has signalled intent to refile. The accused products remain on the market, and the commercial incentive to pursue the claim likely persists.
Refiling remains possibleCore Home Fitness wins this round, but exposure is not extinguished
Core Home Fitness secured a full dismissal at the pleading stage without engaging in costly discovery. However, because the dismissal is without prejudice, the litigation risk associated with US7614983B1 is not eliminated. The defendant and its multi-brand product ecosystem remain potentially exposed if a stronger complaint is filed. Early investment in claim-by-claim freedom-to-operate analysis is now commercially prudent.
Patent risk not fully resolvedAdjustable fitness equipment IP: e-commerce sellers face repeat exposure risk
This case is consistent with a broader pattern of Chinese IP holders asserting patents against U.S. e-commerce fitness equipment sellers. A without-prejudice dismissal does not deter refiling and signals that the patent remains a live threat to the market. Brands selling adjustable dumbbells through Amazon and similar platforms — particularly those operating under multiple seller identities — should treat this outcome as a prompt to audit their product designs against US7614983B1.
Live patent risk for fitness e-commerceFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Shenzhen Zhifu Network Technology Co., Ltd. | Company | Chinese fitness technology company — holder of US7614983B1 (adjustable dumbbell systems)Search in Eureka ↗ |
| Defendant | Core Home Fitness, L.L.C. | Individual | U.S. home fitness equipment company selling adjustable dumbbells under multiple brand identitiesSearch in Eureka ↗ |
| Plaintiff counsel | Weisun Rao | Attorney | Counsel for Shenzhen Zhifu Network Technology Co., Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Venture Partner, LLC | Law Firm | Representing Shenzhen Zhifu Network Technology Co., Ltd.Search in Eureka ↗ |
| Defendant counsel | Brian T. Bedinghaus | Attorney | Counsel for Core Home Fitness, L.L.C.Search in Eureka ↗ |
| Defendant law firm | Roetzel & Andress LPA | Law Firm | Representing Core Home Fitness, L.L.C.Search in Eureka ↗ |
| Presiding judge | Judge April M. Perry | Judge | Illinois Northern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s order granting Docket 15 and dismissing the complaint without prejudice indicates a finding of facial pleading insufficiency — most likely a failure to allege specific facts plausibly supporting infringement of one or more claims of US7614983B1 under the Twombly/Iqbal pleading standard. Critically, this is not a ruling on claim validity or on whether infringement actually occurred. The without-prejudice designation preserves Shenzhen Zhifu’s option to cure defects and refile, meaning Core Home Fitness’s litigation exposure is suspended rather than eliminated.
US7614983B1 — adjustable dumbbell fitness equipment system
US7614983B1 is a granted U.S. patent (application number US11/983213) covering technology in the adjustable dumbbell and home fitness equipment space. The patent’s claims are directed to the mechanical or structural innovations that enable users to selectively adjust the weight of a dumbbell unit — a category that has seen substantial commercial growth driven by home fitness demand. The specific claim scope, including independent and dependent claims, defines the boundaries of Shenzhen Zhifu’s enforcement rights in the U.S. market.
Adjustable dumbbell patents have become commercially significant as the home fitness equipment market expanded sharply. US7614983B1, held by a Chinese technology company and asserted against U.S. e-commerce sellers, is consistent with a pattern of cross-border IP enforcement in this sector. Competitors designing or distributing adjustable weight systems — particularly those sold through Amazon marketplace channels — should assess their product architectures against the claims of this patent. The case’s without-prejudice dismissal means the patent’s enforceability remains legally intact and a renewed assertion is structurally possible.
Should your product team run an FTO against US7614983B1?
Any company designing, manufacturing, importing, or selling adjustable dumbbell or variable-weight fitness equipment in the U.S. market should treat US7614983B1 as a live risk. The patent survived this litigation without any adverse validity or non-infringement ruling. E-commerce sellers listing adjustable dumbbell products on Amazon or similar platforms — especially those operating multiple seller accounts or brand identities — face the specific exposure profile illustrated by this case. A freedom-to-operate analysis should map your product’s weight-adjustment mechanism against the patent’s independent claims.
PatSnap Eureka’s FTO Search Agent can rapidly identify the claim landscape of US7614983B1, surface related family members and continuation applications, and flag design-around opportunities. For fitness equipment product teams, Eureka can cross-reference your product specifications against the patent’s technical scope and generate a preliminary risk map — enabling faster, more cost-effective clearance decisions ahead of product launch or marketplace listing.
Run a freedom-to-operate analysis on US7614983B1 to assess your product’s exposure
Run FTO in Eureka →Similar patent cases: adjustable fitness equipment in N.D. Illinois
Explore related patent infringement actions involving fitness equipment technology and adjustable dumbbell patents filed in the Northern District of Illinois.
What this case signals for the fitness equipment IP landscape
A swift pleading-stage dismissal leaves the underlying patent unresolved and the market on notice.
Pleading deficiencies are an early exit — not a patent clearance
Core Home Fitness’s victory is procedural, not substantive. US7614983B1 has not been invalidated or found non-infringed. Any competitor or retailer treating this dismissal as a green light on the patent does so at their own risk. The patent remains enforceable and the plaintiff retains the right to refile a stronger complaint.
Multi-brand Amazon sellers are high-visibility targets for patent assertion
The complaint named over a dozen product SKUs and brand identities tied to a single defendant. This pattern — broad product sweeps against e-commerce sellers — is increasingly common in the fitness equipment space. Sellers operating under multiple storefronts face compounded exposure and should proactively map their SKUs against asserted patents before suits are filed.
Shenzhen v Core — key questions answered
Shenzhen Zhifu Network Technology Co., Ltd. filed a patent infringement suit against Core Home Fitness, L.L.C. in the N.D. Illinois asserting US7614983B1 over adjustable dumbbell products. On February 5, 2025, Judge April M. Perry granted Core Home Fitness’s motion to dismiss, and the complaint was dismissed without prejudice after 97 days.
A without-prejudice dismissal means the court found the complaint legally deficient — likely insufficient infringement allegations — but did not rule on patent validity or infringement. Shenzhen Zhifu retains the right to file a corrected complaint. The patent itself remains valid and enforceable, meaning the dismissal does not provide a clearance for competitors or retailers.
The complaint named a broad range of adjustable fitness equipment products associated with Core Home Fitness, including items sold under CORE FITNESS, LEEKEY DIRECT, Rendpas Direct, Xddias Fitness Expert, ZYZHI, Pooboostore, and lnowfitness brand identifiers, with multiple Amazon ASIN product codes identified across the product line.
The case resolved in just 97 days, suggesting Core Home Fitness filed its motion to dismiss promptly after being served and the court acted without requiring full briefing cycles or oral argument. The public record does not specify the exact pleading deficiencies identified, but dismissal at this stage in N.D. Illinois typically reflects failure to meet the Twombly/Iqbal standard for plausible infringement allegations.
Yes. The dismissal without prejudice leaves US7614983B1 legally intact and Shenzhen Zhifu free to refile. Companies selling adjustable dumbbell or variable-weight fitness products — particularly through e-commerce platforms — should conduct freedom-to-operate analysis against the patent’s claims. The case demonstrates that this patent is being actively asserted and the multi-brand e-commerce model is a specific enforcement target.
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