DCT

1:25-cv-05420

Zipstring LLC v. Nxtgen Toys LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-05420, N.D. Ga., 09/22/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants regularly conduct business in and have committed infringing acts in the Northern District of Georgia.
  • Core Dispute: Plaintiff alleges that Defendant’s "Loop Lasso" toy infringes a patent related to a handheld string shooting device.
  • Technical Context: The technology involves toys that propel a continuous loop of string, creating the illusion that the string is floating or defying gravity through aerodynamic principles.
  • Key Procedural History: The complaint notes prior litigation between the parties involving a related patent, U.S. Patent No. 11,674,774. That case was stayed pending an Inter Partes Review (IPR) of the ’774 Patent. The current lawsuit asserts a continuation patent with a different set of claims, which the complaint states is not subject to that IPR.

Case Timeline

Date Event
2021-08-12 Plaintiff’s ZipString® device allegedly goes viral on social media
2021-11-18 Priority Date for U.S. Patent No. 12,241,715
2021-12-11 Alleged first offer for sale of accused product by Defendant
2025-03-04 U.S. Patent No. 12,241,715 Issues
2025-09-22 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

  • Patent Identification: U.S. Patent No. 12,241,715, "String Shooting Device," issued March 4, 2025 (the "’715 Patent").

U.S. Patent No. 12,241,715 - "String Shooting Device"

The Invention Explained

  • Problem Addressed: The patent’s background section describes the challenge of propelling a flexible member, like a string, over a distance, as its inherent flexibility causes it to succumb to gravity and drop quickly (’715 Patent, col. 1:26-32).
  • The Patented Solution: The invention addresses this problem by using a specific type of string with a textured or "fuzzy" surface, comprising radiating fibers, propelled at high speed by a pair of wheels. This surface texture is designed to increase air friction, creating an expanded "turbulent air boundary layer" around the moving string. This boundary layer generates aerodynamic lift that counteracts gravity, giving the looped string the appearance of floating or hovering in the air (’715 Patent, Abstract; col. 4:21-38). Figure 5 of the patent illustrates this aerodynamic effect (’715 Patent, Fig. 5).
  • Technical Importance: This approach transforms the behavior of a propelled string from a simple ballistic arc into a sustained, seemingly gravity-defying shape, creating a novel visual effect for a handheld toy (’715 Patent, col. 4:47-52).

Key Claims at a Glance

  • The complaint asserts infringement of claims 1-7 and 10-20 of the ’715 Patent (Compl. ¶21). Independent claim 1 is central to the dispute.
  • Independent Claim 1 requires:
    • A body extending in a longitudinal direction.
    • A first wheel and a second wheel, parallel to each other, with at least one being a driven wheel.
    • A housing supported by the body that covers at least a portion of the wheels.
    • A gap between the wheels through which a string is propelled.
    • One or more string guides arranged to maintain the string's position relative to the driven wheel and within the gap.
    • A specific function wherein the string guides "urge the string toward an operational position" within the gap and in contact with the driven wheel when a user moves the body in a direction parallel to the first wheel's axis.
  • The complaint does not explicitly reserve the right to assert other dependent claims, but asserts a range that includes them (Compl. ¶21).

III. The Accused Instrumentality

Product Identification

The "Loop Lasso" string shooter, specifically the "NANO Glow-in-the-Dark String Shooter Toy" (Compl. ¶18; p. 5).

Functionality and Market Context

The complaint describes the accused product as a handheld "string shooting device" sold by Defendants on platforms including Amazon (Compl. ¶11, ¶18). The complaint includes several images of the accused product, its packaging, and its online sales listing (Compl. p. 5). One image displays the product, branded "LOOPLASSO," alongside its box, which advertises its "Glow-In-The-Dark" feature with "Dual UV Blacklights" (Compl. p. 5). The complaint alleges the product is deceptively marketed, including advertising it as "The Original Zip String" (Compl. ¶18).

IV. Analysis of Infringement Allegations

The complaint alleges that the Defendants' infringement is detailed in claim charts attached as Exhibits B, C, and D (Compl. ¶21). However, these exhibits were not filed with the complaint document. In the absence of these charts, the infringement theory must be drawn from the complaint’s narrative allegations.

The complaint asserts that Defendants infringe by "making, using, selling and offering to sell a string shooting device embodying the invention protected under the claims of the '715 Patent" (Compl. ¶21). This allegation is conclusory and does not map specific features of the Loop Lasso product to the elements of the asserted claims within the body of the complaint.

  • Identified Points of Contention:
    • Factual/Evidentiary Questions: The central point of contention will be factual: does the accused Loop Lasso device contain the structures recited in the claims? Specifically, discovery will be needed to determine if the product has internal "string guides" and, if so, whether they perform the claimed function of urging the string into an operational position in response to specific user movements. The complaint's visual evidence shows the product's exterior but provides no insight into its internal mechanics (Compl. p. 5).
    • Scope Questions: A likely area of dispute will be the interpretation of the functional limitation requiring the "string guides" to "urge the string toward an operational position...as a user moves the body in a direction parallel to the first axis" (’715 Patent, cl. 1). The parties may dispute whether any guiding surfaces in the accused device perform this specific, motion-dependent corrective function, or if they serve a more general purpose.

V. Key Claim Terms for Construction

  • The Term: "one or more string guides" that "urge the string toward an operational position ... as a user moves the body in a direction parallel to the first axis" (from claim 1).

  • Context and Importance: This term is critical because it describes not just a structure ("string guides") but a specific dynamic function that structure must perform in response to user action. The infringement analysis will depend heavily on whether the accused device is found to possess structures that meet both the structural and functional requirements of this limitation. Practitioners may focus on this term because its functional language provides a potential basis for a non-infringement argument if the accused product’s guiding components operate differently.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification describes the guides’ purpose broadly as helping "maintain the string in the proper orientation relative to the drive wheel" (’715 Patent, col. 5:6-9). It also discloses a "guiding slot" that makes contact with the string when "gestures are made by a user," which could support an argument that any structure that interacts with the string during user movement is a "string guide" (’715 Patent, col. 9:30-34).
    • Evidence for a Narrower Interpretation: The patent illustrates specific embodiments of the guides, such as a "guiding slot 108" and a "guiding tab 105" (’715 Patent, Figs. 6, 10; col. 10:2). A defendant may argue that the term should be limited to these disclosed structures or their equivalents. Furthermore, the claim recites a highly specific condition for the "urging" function—in response to user movement "parallel to the first axis"—which could support a narrow construction that excludes guides that function under different conditions (’715 Patent, cl. 1).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement, stating that Defendants instruct customers on how to use the product in an infringing manner (Compl. ¶25, ¶28). It also alleges contributory infringement on the basis that the accused device is "specially made or adapted" for infringement and is not a "staple article of commerce suitable for substantial non-infringing uses" (Compl. ¶27, ¶29).
  • Willful Infringement: Willfulness is alleged in a conclusory fashion (Compl. ¶22). While the complaint does not allege pre-suit knowledge of the ’715 Patent specifically, it does establish a history of litigation between the parties over the parent ’774 Patent, which may be used to argue that Defendants were aware of Plaintiff's patent portfolio (Compl. ¶4).

VII. Analyst’s Conclusion: Key Questions for the Case

  1. A central issue will be evidentiary and factual: As the complaint relies on unattached exhibits for its infringement theory, a primary question is whether discovery will reveal that the internal mechanism of the accused Loop Lasso product contains "string guides" that perform the specific, motion-dependent function required by claim 1 of the ’715 Patent.

  2. The case is also likely to turn on a question of claim scope: How will the court construe the functional requirements of the "string guides" limitation? Whether this limitation is interpreted broadly to cover any guiding surface that interacts with the string during user movement, or narrowly to require the specific corrective action recited in the claim, will be a critical determinant of the infringement outcome.