DCT

2:24-cv-00547

Electricprotect Corp v. Zhongshan Kaper Electrical Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:24-cv-00547, E.D. Tex., 10/03/2025
  • Venue Allegations: Venue is alleged to be proper because the defendants are not residents of the United States and are subject to personal jurisdiction in the district, allowing them to be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that power cords featuring Leakage Current Detector and Interrupter (LCDI) technology, manufactured by certain defendants and incorporated into air conditioners sold by others, infringe four U.S. patents related to electrical safety and leakage current detection circuits.
  • Technical Context: The technology concerns safety devices for electrical power cords, known as LCDIs, which are designed to detect dangerous current leakages caused by cord damage and interrupt power to prevent fires.
  • Key Procedural History: The operative pleading is a First Amended Complaint. The complaint does not mention any prior litigation, inter partes review proceedings, or licensing history concerning the asserted patents.

Case Timeline

Date Event
2017-09-22 Priority Date for ’883, ’265, and ’628 Patents
2019-05-05 Priority Date for ’724 Patent
2020-02-11 ’883 Patent Issued
2021-01-05 ’724 Patent Issued
2022-02-08 ’265 Patent Issued
2022-10-25 ’628 Patent Issued
2025-10-03 First Amended Complaint Filed

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

U.S. Patent No. 10,557,883 - “Leakage Current Detection and Protection Device for Power Cord”

The Invention Explained

  • Problem Addressed: The patent’s background section notes that conventional LCDI safety devices include a test button that can verify the internal trip mechanism is working but cannot detect whether the external leakage detection line (the "shield line") running the length of the cord is intact. (’883 Patent, col. 4:5-24). An undetected break in this shield line could render the safety device useless against a real-world current leak, creating a significant fire hazard. (’883 Patent, col. 4:20-24).
  • The Patented Solution: The invention introduces an "open circuit detection unit" that automatically monitors the integrity of the leakage detection line. (’883 Patent, col. 2:4-6). If this unit detects a break in the line, it is configured to cause the device’s switch drive module to disconnect the electrical connection, thereby cutting off power and ensuring the system fails in a safe state. (’883 Patent, col. 2:55-59; Fig. 5).
  • Technical Importance: This approach adds an automated safety check that continuously verifies the integrity of a critical safety component, moving beyond reliance on periodic manual tests which may not reveal external cord damage. (’883 Patent, col. 3:42-49).

Key Claims at a Glance

  • The complaint asserts independent claim 6 (Compl. ¶61).
  • The essential elements of claim 6 include:
    • A switch unit to control electrical connection.
    • A leakage current protection unit with a switch drive module and a leakage current detection module.
    • The leakage current detection module includes a leakage current detection line and an open circuit detection unit.
    • The open circuit detection unit includes a first and second detection module.
    • At least the first detection module and the leakage current protection unit form a "test current loop" configured to cause the switch drive module to disconnect power when the detection line or first detection module has an open circuit. (’883 Patent, col. 8:62-9:21).

U.S. Patent No. 10,886,724 - “Leakage Current Detection and Interruption Device for Power Cord”

The Invention Explained

  • Problem Addressed: The patent identifies the same problem as the ’883 Patent: conventional LCDI test circuits cannot determine whether the external shield layer is functioning properly, creating a hidden safety threat if the shield is broken. (’724 Patent, col. 1:29-42).
  • The Patented Solution: The invention proposes a power cord with a leakage detection module that includes a "first leakage current detection line and a second leakage current detection line coupled in series to form a current path." (’724 Patent, col. 2:54-57). By creating a complete, two-part loop for the detection signal, the integrity of the entire external shield system is required for the test circuit to function. If either line is broken, a manual press of the test button will fail to complete the circuit and trip the device, thereby alerting the user to the fault. (’724 Patent, col. 5:1-26; Fig. 5).
  • Technical Importance: This design directly links the functionality of the manual test button to the physical integrity of the external leakage detection lines, providing a more reliable method for users to verify the safety system is operational. (’724 Patent, col. 2:48-51).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶78).
  • The essential elements of claim 1 include:
    • A first and second power supply line.
    • A switch unit to control the electrical connection.
    • A leakage current protection unit with a switch drive and leakage current detection module.
    • The leakage current detection module includes a first leakage current detection line and a second leakage current detection line coupled in series to form a current path running from the input end to the output end and back.
    • The switch drive module is configured to disconnect the electrical connection based on a signal from the leakage current detection module. (’724 Patent, col. 5:44-6:11).

U.S. Patent No. 11,243,265 - “Intelligent Leakage Current Detection and Interruption Device for Power Cord”

Technology Synopsis

This patent describes a system to address undetected open circuits in an LCDI power cord's protective shield line (’265 Patent, col. 1:28-34). The invention is an "intelligent" device that includes a dedicated "detection monitoring module" coupled in series with first and second leakage current detection lines. This module is configured to automatically detect an open circuit and, in response, trigger a drive module to cut off power, providing an active, continuous safety check that is not reliant on manual testing (’265 Patent, Abstract).

Asserted Claims

The complaint asserts independent claim 1 (Compl. ¶95).

Accused Features

The complaint alleges that the power cords included with the defendants' air conditioners contain the patented intelligent leakage detection and interruption technology (Compl. ¶¶95, 53-55).

U.S. Patent No. 11,480,628 - “Power Cord for Use with a Leakage Current Detection and Interruption Device”

Technology Synopsis

This patent focuses on the physical construction of the power cord itself to improve leakage detection. The invention claims a power supply cord comprising at least two power lines, each covered by an insulating layer, and at least two leakage current detection lines disposed around those layers (’628 Patent, col. 10:35-42). A key feature is "at least one insulating structure covering at least one of the at least two leakage current detection lines to electrically insulate" them from each other, which allows for more precise detection of leakages from specific power lines (’628 Patent, col. 10:50-55).

Asserted Claims

The complaint asserts independent claim 1 (Compl. ¶112).

Accused Features

The complaint alleges that the physical structure of the power cords supplied with the defendants' air conditioners infringes the claims directed to the cord's construction (Compl. ¶¶112, 53-55).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are "Infringing Power Cords" (including models KP-LC10, KP-LC13, and KP-LC15) allegedly manufactured by Defendant Zhongshan Kaper and incorporated into "Infringing Air Conditioners" (Compl. ¶¶53-55). These air conditioners are sold by the other named defendants, including through Amazon storefronts and for brands such as Tripp Lite (Compl. ¶¶55, 62).

Functionality and Market Context

The accused power cords are alleged to be designed and certified for the U.S. market under the UL1699 standard and include LCDI safety features (Compl. ¶54). The complaint provides a product image for a Tripp Lite air conditioner that explicitly advertises a "NEMA 5-15P Plug with Leakage Current Detector and Interrupter (LCDI)" as a feature (Compl. ¶69). The complaint alleges that Defendant Zhongshan Kaper has a monthly production capacity of over 2 million leakage protection products and that the U.S. market accounts for about 50% of its sales (Compl. ¶20).

IV. Analysis of Infringement Allegations

The complaint references claim chart exhibits (Exhibits E and F) that are not included in the provided document; therefore, the infringement allegations are summarized below in prose.

’883 Patent Infringement Allegations

The complaint alleges that the accused power cords directly infringe at least claim 6 of the ’883 Patent (Compl. ¶61). The narrative infringement theory suggests that the accused products contain a complete leakage current detection and protection device that includes the claimed "open circuit detection unit." This unit is alleged to perform the claimed function of forming a "test current loop" that automatically causes the device to disconnect power if the external leakage detection line is broken (Compl. ¶¶34, 61). An image of an air conditioner advertising its LCDI plug is presented as exemplary evidence of the infringing feature (Compl. ¶69).

’724 Patent Infringement Allegations

The complaint alleges that the accused power cords directly infringe at least claim 1 of the ’724 Patent (Compl. ¶78). The infringement theory posits that the accused cords are constructed with the claimed leakage detection module containing a "first leakage current detection line and a second leakage current detection line coupled in series to form a current path" (’724 Patent, col. 5:53-57; Compl. ¶78). This structure is alleged to be present in the power cords used with the accused air conditioners, such as those advertised with an LCDI plug (Compl. ¶¶86, 89).

Identified Points of Contention

  • Scope Questions: For the ’883 Patent, a central question may be whether the term "open circuit detection unit" requires a specific, dedicated circuit for active monitoring, or if it can be construed more broadly to cover any circuit configuration that functionally results in a trip when the detection line is broken. For the ’724 Patent, a dispute may arise over whether the accused cord’s shield layer constitutes "a first... line and a second... line coupled in series," or if it is a single conductive shield that does not meet this structural limitation.
  • Technical Questions: A key technical question for both patents is what the internal circuitry and physical construction of the accused power cords actually are. The complaint’s evidence consists of high-level marketing materials, raising the question of what discovery or reverse engineering will reveal about whether the accused products’ internal operations match the specific functions and structures required by the claims.

V. Key Claim Terms for Construction

"open circuit detection unit" (’883 Patent, Claim 6)

Context and Importance

This term appears to be central to the novelty of the ’883 Patent. Its construction will likely determine the scope of infringement, as the dispute may focus on whether the accused devices contain a structure that meets this definition or merely a conventional circuit that happens to fail open. Practitioners may focus on this term because it distinguishes the invention from prior art that only tested internal components.

Intrinsic Evidence for Interpretation

  • Evidence for a Broader Interpretation: The claim describes the unit functionally, as being "configured to cause the switch drive module to control the switch unit to disconnect... when the... leakage current detection line has an open circuit" (’883 Patent, col. 9:15-21). This functional language could support an interpretation that covers any circuit achieving this result.
  • Evidence for a Narrower Interpretation: The specification describes specific embodiments of the "open circuit detection unit 200," which includes distinct components like diodes and resistors (e.g., D3, R5, D4, R6) arranged in a particular topology (’883 Patent, Fig. 5; col. 5:56-62). This could support an argument that the term is limited to the disclosed structures or their equivalents.

"a first leakage current detection line and a second leakage current detection line coupled in series" (’724 Patent, Claim 1)

Context and Importance

This term defines the physical and electrical structure of the core safety feature. Infringement will depend on whether the accused power cords are built with two distinct, series-coupled conductive shield lines or a single shield.

Intrinsic Evidence for Interpretation

  • Evidence for a Broader Interpretation: The claim describes the lines as forming "a current path from a first point... to a second point... then to a second point... and then to a first point" (’724 Patent, col. 5:57-6:4), which describes a loop. This could arguably be read on a single, continuous conductor arranged to form such a path.
  • Evidence for a Narrower Interpretation: The use of "first... line and a second... line" suggests two separate elements. The patent figures, such as Figure 3A, explicitly label two distinct shield layers, 241 and 242, which are described as being coupled in series (’724 Patent, Fig. 3A; col. 3:41-42). This suggests the claim requires two physically separate conductive lines.

VI. Other Allegations

Indirect Infringement

The complaint alleges active inducement of infringement against Defendants Zhongshan Kaper and Zhongshan Lianchang (Compl. ¶¶67, 84, 101, 118). The factual basis for this allegation is that these defendants supply the allegedly infringing power cords to U.S. customers (e.g., Tripp Lite) and encourage sellers to advertise the benefits of the LCDI feature, with the specific intent to encourage infringing sales and uses in the United States (Compl. ¶¶67-69, 84-86).

Willful Infringement

The complaint does not contain an explicit count for willful infringement. However, it alleges that the defendants have known of the asserted patents since at least the filing of the original or amended complaint (Compl. ¶¶64-66, 81-83, 98-100, 115-117). The prayer for relief requests that the court declare the case "exceptional" and award attorneys' fees under 35 U.S.C. § 285, which can be predicated on a finding of willful infringement (Compl. p. 26).

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

  • A core issue will be one of structural correspondence: Can Plaintiff produce evidence, beyond high-level marketing materials, that the physical construction and internal circuitry of the accused power cords actually embody the specific designs claimed in the patents—namely, the automated "open circuit detection unit" of the ’883 Patent or the "first and second leakage current detection line coupled in series" of the ’724 Patent?
  • A second key issue will turn on claim scope: Will the court construe claim terms like "open circuit detection unit" broadly based on their function, or narrowly based on the specific circuit diagrams shown in the patent specifications? The outcome of claim construction for these key terms will be critical to the infringement analysis.
  • Finally, a central question for liability beyond direct infringement will be one of intent: Can Plaintiff prove that the manufacturing defendants, in supplying power cords to U.S. distributors and sellers, acted with the specific intent to encourage infringing acts by third parties, as required to establish induced infringement?