DCT
9:22-cv-81679
Voltstar Tech Inc v. Walmart Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Voltstar Technologies, Inc. (Illinois)
- Defendant: Walmart Inc. (Delaware)
- Plaintiff’s Counsel: Sriplaw PLLC
- Case Identification: 9:22-cv-81679, S.D. Fla., 10/31/2022
- Venue Allegations: Plaintiff alleges venue is proper because Defendant has committed acts of infringement and maintains a regular and established place of business within the Southern District of Florida.
- Core Dispute: Plaintiff alleges that various USB wall chargers sold by Defendant infringe a patent related to the compact physical design and construction of such chargers.
- Technical Context: The technology concerns the mechanical and electrical design of AC-to-DC power converters, commonly known as USB chargers, aiming to reduce their physical size and manufacturing complexity.
- Key Procedural History: The patent-in-suit, RE48,794 E, is a reissue of U.S. Patent No. 9,024,581. The complaint notes that the reissue process amended Claim 1 to narrow the dimensional limitations, changing a length requirement from "equal to or less than 2.0 inches" to "less than 2.0 inches" and adding a new width limitation of "less than 1.75 inches." This amendment may affect the scope of infringement and potential intervening rights defenses. The complaint also states that Plaintiff ceased selling patented articles as of the original patent's issue date, which suggests that any potential damages would be based on a reasonable royalty theory rather than lost profits.
Case Timeline
| Date | Event |
|---|---|
| 2008-05-21 | Priority Date (U.S. Patent App. 12/124,515 Filed) |
| 2009-11-26 | Original Patent Application Published |
| 2015-05-05 | U.S. Patent No. 9,024,581 Issued |
| 2021-10-26 | U.S. Reissue Patent No. RE48,794 E Issued |
| 2022-10-31 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissue Patent No. RE48,794 E - "Charger Plug with Improved Package"
- Issued: October 26, 2021
The Invention Explained
- Problem Addressed: The patent describes several problems with prior art wall chargers. They were often bulky, preventing the use of adjacent outlets; they protruded excessively from the wall, making them susceptible to being struck; and their manufacturing was complex and costly, often requiring insert-molding of the electrical blades and manual soldering to connect them to the internal circuit board (RE48,794 E Patent, col. 1:42-2:41).
- The Patented Solution: The invention is a "reduced plug-size charger" with a design that purports to solve these issues. It proposes a mechanical construction where the electrical blades are separate components slidably mounted into a clamshell-style housing, rather than being insert-molded (’794 Patent, col. 4:11-17, Figs. 2A-2C). This design allegedly simplifies assembly and avoids the need for direct soldering by using spring contacts to create an electrical connection between the blades and the internal printed circuit board (PCB) (’794 Patent, col. 10:35-44). The overall package is dimensionally constrained to avoid interfering with adjacent wall outlets.
- Technical Importance: The described approach sought to reduce manufacturing costs and time while producing a charger with a smaller, more user-friendly physical footprint (’794 Patent, col. 1:15-18).
Key Claims at a Glance
- The complaint asserts at least independent Claim 1 (’794 Patent, col. 13:17-14:23; Compl. ¶62).
- The essential elements of independent Claim 1 include:
- A charger plug housing containing first and second separate blade members.
- A DC connector with an aperture to receive a power cord.
- A specific housing geometry with a defined face area, outer profile, and rear end.
- The housing must be sized with a longitudinal length of less than 2.0 inches and a width of less than 1.75 inches.
- The housing's outer profile must cause "no interference with an adjacent receptacle."
- The design must allow for convenient connection/disconnection of a power cord even when an obstacle is near the power source.
- The complaint does not explicitly reserve the right to assert other claims, but this is standard practice.
III. The Accused Instrumentality
Product Identification
- The complaint identifies six accused products: Merkury Innovations USB Wall Charger, Ttech Universal Charger Power Adapter Plug 1A Travel Charger, Wintek 20W Power Port, Cooper Direct Dual Port USB Charger, Vogek Dual Port USB Wall Charger, and Overtime 2 Port USB Adapter (Compl. ¶¶18, 25, 32, 39, 46, 53).
Functionality and Market Context
- The accused products are all USB wall chargers sold by Walmart, designed to convert AC power from a wall outlet into DC power for charging electronic devices (Compl. ¶19). The complaint alleges that these chargers feature a "reduced plug-size" design specifically so that they do not block or interfere with adjacent outlets when plugged in (Compl. ¶20). The complaint provides an image of the accused Merkury charger, showing its compact, rectangular form factor (Compl. p. 5, fig. unnumbered). Similar images are provided for the other five accused products, illustrating a common design theme (Compl. pp. 7, 8, 9, 10, 12).
IV. Analysis of Infringement Allegations
The complaint alleges that the accused products infringe at least Claim 1 of the ’794 Patent. The infringement theory focuses on the external dimensions and non-interference properties of the chargers.
RE48,794 E Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A charger plug capable of connecting with a... power source... to convert... input power... to DC output power, the charger plug being electrically connectable to a rechargeable electronic device via a power cord... | The accused chargers are advertised and sold as USB wall chargers that connect to an AC power source to provide DC power to devices like mobile phones. | ¶19 | col. 13:17-23 |
| the charger plug comprising: first and second separate blade members secured within the housing... | The complaint alleges the accused products employ a "reduced plug-size charger plug." It does not provide details on the internal construction or whether the blades are separate members. | ¶20 | col. 13:25-29 |
| the charger plug including a DC connector having an aperture adapted to removably receive a corresponding power cord plug end... | The accused products are USB wall chargers designed to connect to a power cord for charging a device. | ¶19, ¶21 | col. 13:31-35 |
| i) being sized so that the charger plug housing comprises a longitudinal length extending between the front wall and the rear end and the longitudinal length is... less than 2.0 inches, a width of the housing outer profile being less than 1.75 inches... | The complaint provides specific measurements for each accused product, alleging they fall within the claimed dimensions (e.g., the Merkury charger is alleged to have a length of ~1.902 inches and a width of ~1.529 inches). | ¶24, ¶31, ¶38, ¶45, ¶52, ¶59 | col. 13:54-14:4 |
| ii) the outer profile having no interference with an adjacent receptacle of the power source... | The complaint alleges that upon plugging the accused chargers into a wall outlet, they do not "block or interfere with the use of adjacent outlets." | ¶20, ¶27, ¶34, ¶41, ¶48, ¶55 | col. 14:5-9 |
| so that when space is limited by an obstacle... the power cord plug end may be conveniently received by the DC connector and the power cord plug end can be conveniently removed... | The complaint alleges the size and shape of the chargers allow a power cord to be "easily inserted into and removed... while the charger is plugged into the source of AC power." | ¶21, ¶28, ¶35, ¶42, ¶49, ¶56 | col. 14:10-21 |
- Identified Points of Contention:
- Scope Questions: The case may turn on the construction of the functional limitation "no interference with an adjacent receptacle." A court will have to determine the scope of this phrase—whether it means no physical overlap whatsoever, or if it allows for minimal contact that does not prevent the use of an adjacent outlet.
- Technical Questions: The complaint's infringement allegations focus entirely on the external form factor and dimensions of the accused chargers. It provides no evidence or allegations regarding their internal construction. A key question for discovery will be whether the accused products actually contain the "first and second separate blade members" and solder-less spring contacts that are central to the patent's description of the invention, or if they use a different internal architecture (e.g., conventional insert molding and soldering).
V. Key Claim Terms for Construction
- The Term: "outer profile having no interference with an adjacent receptacle" (Claim 1(ii))
- Context and Importance: This term is central to the dispute, as it defines the primary functional benefit alleged by the plaintiff. The infringement analysis for every accused product relies on the assertion that it meets this limitation (Compl. ¶¶ 20, 27, etc.). Practitioners may focus on this term because its scope is not strictly defined by the claim language and will likely require interpretation based on the patent's specification and prosecution history.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent's background describes the problem being solved as plugs that provide "little or no interference with use of an adjacent receptacle" (’794 Patent, col. 1:47-49). A party could argue this suggests the term should be interpreted functionally, meaning the accused device does not prevent a standard plug from being inserted and used in the adjacent socket.
- Evidence for a Narrower Interpretation: The patent also states that the plug is sized so as not to "impede access to or use of an adjacent outlet" (’794 Patent, col. 4:66-67). A party could argue this sets a high bar, and that any physical overlap or contact with the space of the adjacent outlet constitutes "interference." The specific dimensions recited in claim 1(i) may be argued to be the patentee's own definition of what dimensions achieve the "no interference" function.
VI. Other Allegations
- Indirect Infringement: The prayer for relief requests a judgment of induced infringement (Compl. p. 14, ¶A). However, the body of the complaint does not plead specific facts to support the knowledge and intent elements required for such a claim, such as allegations that Walmart's instructions or marketing materials guide end-users to infringe the patent.
- Willful Infringement: The complaint seeks a determination of willful infringement (Compl. p. 14, ¶C). The pleading does not allege pre-suit knowledge of the patent or patent family by the defendant. The basis for willfulness, if any, would likely rest on Defendant's conduct after being served with the complaint.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: How will the court construe the functional term "no interference with an adjacent receptacle"? The resolution of this question will be critical, as the plaintiff's non-interference allegations appear to be a primary basis for the suit across all accused products.
- A key evidentiary question will be one of internal construction: Do the accused chargers infringe the structural elements of the claims related to their internal assembly (e.g., "separate blade members," spring contacts)? The complaint is silent on the internal mechanics of the accused products, and infringement of these limitations cannot be determined from the provided external photographs and dimensional analysis alone.
- The case presents a question of infringement theory vs. patent disclosure: The complaint's infringement theory rests almost exclusively on the external size and shape of the accused chargers. This will be tested against the patent's heavy emphasis on a specific internal manufacturing and assembly method (solder-less, non-insert-molded blades) as the point of novelty. The court will have to determine if infringement can be found based on external dimensions alone if the accused products do not practice the internal structural innovations described in the patent.