Cedar Lane Tech Inc v. Dwyer Instruments LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Cedar Lane Technologies Inc. (Canada)
  • Defendant: Dwyer Instruments, LLC (Delaware)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 3:25-cv-00962, W.D. Wis., 12/17/2025
• Venue Allegations: Venue is alleged to be proper based on Defendant maintaining an established place of business within the Western District of Wisconsin.
• Core Dispute: Plaintiff alleges that Defendant’s unspecified ventilation control products infringe a patent directed to a method for retrofitting existing ventilation systems with air quality sensors to enable automatic, high-speed contaminant removal.
• Technical Context: The technology relates to intelligent HVAC control systems capable of automatically responding to specific, localized air quality events, such as the presence of carbon monoxide or smoke.
• Key Procedural History: The complaint does not mention any prior litigation, licensing history, or post-grant proceedings related to the patent-in-suit.

Case Timeline

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

U.S. Patent No. 7,632,178 - "Ventilation blower controls employing air quality sensors"

The Invention Explained

• Problem Addressed: The patent addresses the shortcomings of conventional ventilation systems, which often rely on manual switches that can be forgotten or inefficient occupancy timers that activate blowers unnecessarily (’178 Patent, col. 2:8-16). Existing automated systems may not react to specific, acute air quality problems until the system happens to turn on during a scheduled cycle (’178 Patent, col. 2:47-51).
• The Patented Solution: The invention is a method for retrofitting an existing ventilation system to grant it intelligent, event-driven control. This is achieved by adding one or more air quality sensors (e.g., for smoke or carbon monoxide) and wiring them to a relay (’178 Patent, col. 2:55-58). The relay’s contacts are connected to the ventilation system’s pre-existing "Remote Switch" terminals, an input which is designed to force the system into a continuous, high-speed mode of operation, thereby rapidly evacuating contaminants upon detection (’178 Patent, col. 2:35-38; Fig. 3).
• Technical Importance: This approach allows for the enhancement of standard, previously installed ventilation systems with automated, safety-oriented features without requiring the replacement of the entire HVAC unit (’178 Patent, col. 2:32-38).

Key Claims at a Glance

• The complaint does not specify which claims are asserted, referring only to "exemplary claims" in an exhibit not provided with the complaint (Compl. ¶11). The patent contains one independent claim, Claim 1, which is a method claim.
• The essential elements of independent Claim 1 are:
  • Providing an existing ventilation system having fans and a remote switch terminal for setting a high-speed mode.
  • Adding a relay to the system.
  • Inserting at least one air quality sensor in a specific location.
  • Connecting the relay's contacts to the remote switch terminals.
  • Connecting the air quality sensor(s) in a parallel network to the relay, so that detection of an abnormal condition by a sensor activates the relay and sets the high-speed mode.
• The complaint does not explicitly reserve the right to assert dependent claims but refers to infringing "one or more claims" (Compl. ¶11).

III. The Accused Instrumentality

Product Identification

• The complaint refers to "Exemplary Defendant Products" that are purportedly identified in charts within an "Exhibit 2" (Compl. ¶11, ¶16).

Functionality and Market Context

• Exhibit 2, which allegedly contains details about the accused products and claim charts, was not filed with the public version of the complaint. Therefore, the complaint does not provide sufficient detail for analysis of the accused instrumentality's specific name, features, or functionality (Compl. ¶17).

IV. Analysis of Infringement Allegations

The complaint states that Exhibit 2 contains claim charts comparing the asserted claims to the accused products, but this exhibit is not available for analysis (Compl. ¶16-17). The narrative alleges that the accused products "practice the technology claimed" and "satisfy all elements" of the asserted claims (Compl. ¶16). Without the specific allegations from the charts, analysis is limited to potential issues raised by the patent and the general nature of the complaint. No probative visual evidence provided in complaint.

• Identified Points of Contention:
  • Method vs. Product Infringement: A central legal question may arise from the assertion of a method claim (Claim 1) against a defendant that primarily sells products. The infringement analysis will likely depend on theories of indirect infringement (inducement) or on allegations of direct infringement based on Defendant’s own internal use and testing of its products (Compl. ¶12, ¶15).
  • Scope of "Retrofitting": The claim is for "retrofitting an existing ventilation system." A potential point of contention is whether the use of Defendant's products constitutes "retrofitting" as understood in the patent, or if the products are intended for new installations or function as standalone systems, which may fall outside the claim's scope.
  • Technical Equivalence: The patented method requires connecting a relay to "remote switch terminals" to set a "high speed mode of operation" (’178 Patent, cl. 1). The factual analysis will question whether the accused products are used with ventilation systems that possess such terminals and whether Defendant’s user instructions direct a connection that achieves this specific outcome.

V. Key Claim Terms for Construction

• The Term: "retrofitting an existing ventilation system"

• Context and Importance: This phrase appears in the preamble of Claim 1 and sets the context for all subsequent steps. The definition of this term is critical because it may limit the claim's applicability to the modification of pre-installed systems, potentially excluding new installations or integrated systems. Practitioners may focus on this term to dispute whether the accused activity falls within the claimed scenario.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification’s focus on making existing systems "especially easy to retrofit" with sensors, specifically mentioning prior art Honeywell systems, could support an interpretation where "retrofitting" includes adding any new sensory and control functionality to a previously installed unit (’178 Patent, col. 2:35-36).
  • Evidence for a Narrower Interpretation: The term "existing" could be interpreted to require that the ventilation system be fully installed and operational before the claimed method is performed. This might support an argument that the claim does not cover the assembly of a new system that includes Defendant’s components from the outset.

• The Term: "remote switch terminal"

• Context and Importance: This term recites a specific hardware interface on the "existing ventilation system." Infringement requires a connection to this type of terminal. The dispute will likely center on how broadly this structural and functional limitation is defined.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: A party may argue the term should be construed functionally to mean any input connection that, when activated, causes the system to enter a continuous high-speed mode, regardless of its specific label or electronic design.
  • Evidence for a Narrower Interpretation: The specification describes this feature in the context of specific prior art systems where it serves as a simple interface for "continuous high speed operation" (’178 Patent, col. 2:36-38). This context could support a narrower construction limited to a dedicated, simple two-contact input intended for an external manual switch, as distinct from a more complex data or bus interface.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendant sells the accused products and distributes "product literature and website materials" that allegedly instruct end users on how to use the products in a manner that infringes the ’178 Patent (Compl. ¶14-15).
• Willful Infringement: The complaint does not use the word "willful" but lays a foundation for such a claim by alleging that service of the complaint and its (unavailable) claim charts provided Defendant with "actual knowledge of infringement," after which Defendant allegedly continued its infringing activities (Compl. ¶13-14).

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

• A primary issue will be one of infringement theory: given that the patent’s only independent claim is a method claim for "retrofitting," can Plaintiff successfully prove infringement against a product manufacturer? The case may turn on whether Plaintiff can establish the specific elements of induced infringement or, alternatively, prove direct infringement through Defendant’s internal testing activities.
• A second core issue will be one of definitional scope: can the term "retrofitting an existing ventilation system" be construed to cover the manner in which Defendant’s products are marketed and installed? The outcome may depend on whether the accused activities are found to be modifications of pre-installed systems or part of new system installations.
• Finally, a key evidentiary question arises from the complaint’s reliance on an unfiled exhibit. The initial phase of litigation will likely focus on discovering which specific "Exemplary Defendant Products" are accused and what evidence Plaintiff possesses to demonstrate that these products are used to perform each step of the claimed method.