Whirlpool Corp v. Broan Nutone LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Whirlpool Corporation (Delaware)
  • Defendant: Broan-Nutone LLC (Wisconsin)
  • Plaintiff's Counsel: Nyemaster Goode, P.C.; BOYLE FREDRICKSON S.C.
• Case Identification: 2:25-cv-01752, E.D. Wis., 03/27/2026
• Venue Allegations: Venue is asserted as proper in the Eastern District of Wisconsin because Defendant is a Wisconsin company that resides in the district, has a regular and established place of business in the district, and a substantial part of the events giving rise to the claims occurred there.
• Core Dispute: Plaintiff alleges that Defendant's "EZ1 Installation System" for undercabinet ventilation hoods infringes three U.S. patents directed to simplified mounting methods and systems.
• Technical Context: The technology at issue relates to mounting brackets and methods designed to enable a single person to easily and accurately install a ventilation hood beneath a kitchen cabinet.
• Key Procedural History: The complaint alleges that Defendant had pre-suit knowledge of the asserted patent family, citing the application that matured into the lead patent during the prosecution of its own patents and having litigated issues related to it in a separate lawsuit. The complaint also notes that Plaintiff sent a letter to Defendant identifying the lead patent prior to filing suit.

Case Timeline

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

U.S. Patent No. 9,523,507 - "Method for Mounting Undercabinet Ventilation Hood"

• Patent Identification: U.S. Patent No. 9,523,507, "Method for Mounting Undercabinet Ventilation Hood," issued December 20, 2016 Compl. ¶14

The Invention Explained

• Problem Addressed: The patent's background describes conventional methods for installing ventilation units as often requiring two people-one to hold the heavy unit in place at eye-level while another inserts and tightens bolts ʼ507 Patent, col. 2:5-10 This process is described as difficult and prone to misalignment issues, particularly for non-professional installers ʼ507 Patent, col. 2:1-18
• The Patented Solution: The invention is a method that allows a single person to perform the installation ʼ507 Patent, col. 2:20-24 An installer first secures specialized support brackets to the underside of a cabinet ʼ507 Patent, col. 5:25-39 The ventilation hood can then be hung from "support tabs" on these brackets by inserting the tabs into corresponding "slots" on the hood's top panel. The hood is then shifted rearward, causing it to ride up on ramped surfaces of the support tabs to sit snugly against the cabinet, fully supported by the brackets before final fastening ʼ507 Patent, col. 5:41-55
• Technical Importance: The claimed method simplifies the installation process, reduces labor requirements from two people to one, and improves the ease of alignment for a common home appliance ʼ507 Patent, col. 2:20-24

Key Claims at a Glance

• The complaint asserts independent claim 1 Compl. ¶60
• The essential steps of claim 1 are:
  • Securing first and second brackets to the underside of a cabinet, where each bracket includes a "locator tab" for positioning against a rear wall and "support tab(s)" extending below the cabinet.
  • Inserting each support tab into a respective slot on the top panel of the ventilation hood.
  • Shifting the hood rearward, causing parts of its top panel to be received within "slits" formed by the brackets, thereby hanging the hood from the brackets.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,317,093 - "System for Mounting Undercabinet Ventilation Hood"

• Patent Identification: U.S. Patent No. 10,317,093, "System for Mounting Undercabinet Ventilation Hood," issued June 11, 2019 Compl. ¶18

The Invention Explained

• Problem Addressed: The patent addresses the same technical problem as the parent ʼ507 Patent: the difficulty, labor, and alignment challenges inherent in traditional two-person ventilation hood installations ʼ093 Patent, col. 2:10-18
• The Patented Solution: Rather than a method, the ʼ093 Patent claims a physical system comprising the components that enable the simplified installation ʼ093 Patent, abstract The system includes a set of specialized brackets and a ventilation hood. The brackets feature a main body, a locator tab for positioning, and at least one support tab that, in combination with the main body, defines a "slit." The ventilation hood is designed with slots on its top panel to receive these support tabs, allowing the hood to be hung with portions of its top panel captured within the brackets' slits ʼ093 Patent, col. 2:32-54
• Technical Importance: This system provides the physical apparatus to transform a two-person installation task into a more efficient and accurate one-person job ʼ093 Patent, col. 2:20-24

Key Claims at a Glance

• The complaint asserts independent claim 1 Compl. ¶81
• The essential components of claim 1 are:
  • A set of first and second brackets configured for mounting, each including a main body, a locator tab, and at least one support tab that defines a "slit" in combination with the main body.
  • A ventilation hood with a top panel containing slots designed to receive the support tabs, which allows the hood to hang from the brackets with portions of its top panel received in the slits.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,948,200 - "System for Mounting Undercabinet Ventilation Hood"

• Patent Identification: U.S. Patent No. 10,948,200, "System for Mounting Undercabinet Ventilation Hood," issued March 16, 2021 Compl. ¶22
• Technology Synopsis: The ʼ200 Patent, part of the same patent family, also claims a system for simplified ventilation hood mounting Compl. ¶92 Compl. ¶96 The claimed invention focuses on a bracket with "distinct aligning and hanging structure," where the hanging structure incorporates a "support tab establishing a ramp" '200 Patent, col. 7:60-62 When the ventilation hood is hung on this tab via a slot, the ramp is configured to force the hood upward against the underside of the cabinet, ensuring a tight fit '200 Patent, col. 8:3-9
• Asserted Claims: The complaint asserts independent claim 11 Compl. ¶96
• Accused Features: The complaint alleges that both "Bracket Design 1" and "Bracket Design 2" of Defendant's EZ1 system include the claimed "distinct aligning and hanging structure" Compl. ¶100 The aligning structure is alleged to be features that locate the bracket vertically or laterally, while the hanging structure is alleged to be a support tab that forms a ramp Compl. ¶¶101-102

III. The Accused Instrumentality

Product Identification

• The accused instrumentality is Defendant's "EZ1 Installation System," which is sold with undercabinet ventilation hoods Compl. ¶6 Compl. ¶34 The complaint identifies two specific bracket designs used in the system, "Bracket Design 1" and "Bracket Design 2" Compl. ¶36 Compl. ¶38

Functionality and Market Context

• The Accused Product is a mounting system designed to simplify the installation of ventilation hoods Compl. ¶5 Based on Defendant's alleged instructional materials, the system functions by having a user first attach the brackets to the underside of a cabinet Compl. ¶62 Compl. ¶70 The user then lifts the ventilation hood and inserts "support tabs" on the brackets into slots on the hood Compl. ¶64 Compl. ¶71 Finally, the user slides the hood backward, which engages the hood with the brackets and hangs it in place, allowing for final fastening Compl. ¶65 Compl. ¶72 The complaint provides a screenshot from an instructional video where the system is described as making "one-person installation safer, simpler and faster" Compl. p. 12

IV. Analysis of Infringement Allegations

9,523,507 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: A central question may be whether the accused bracket structure creates "slits established between the support tabs and main body portions" as required by the claim. The complaint provides an annotated photograph identifying such a slit on the accused bracket Compl. p. 16 The defense may argue that its product's geometry does not meet the patent's definition of a "slit."
  • Technical Questions: For this method claim, a key issue will be proof of direct infringement. The complaint alleges direct infringement by Defendant's own representatives in instructional videos Compl. ¶69, and induced infringement by customers following Defendant's manuals and videos Compl. ¶66 The visual from the complaint shows a Broan representative securing brackets to a cabinet Compl. p. 12 A court will examine whether the actions performed by users, as encouraged by Defendant, contain all steps of the claimed method.

10,317,093 Patent Infringement Allegations

• Identified Points of Contention:
  • Scope Questions: As this is a system claim, the dispute will focus on the physical structure of the accused brackets and hood as sold. The primary question is one of definitional scope: does the accused bracket, as a physical object, contain a structure that meets the claim limitation of a "support tab...defining, in combination with the main body, a slit"? The complaint's annotated photograph of the accused bracket explicitly labels the "Locator Tab," "Bracket Main Body," "Support Tab," "Connection Section," and "Slit," directly mapping the product to the claim language Compl. p. 16
  • Technical Questions: An issue may arise concerning the term "configured to be mounted." The defense might argue that while the brackets can be used in an infringing way, they are general-purpose and not specifically "configured" for the patented system. The complaint counters this by pointing to Defendant's own marketing and instructional materials that allegedly show only the infringing use Compl. ¶84

V. Key Claim Terms for Construction

• The Term: "slit" (from '507 Claim 1 and '093 Claim 1)
• Context and Importance: This term is central to the claimed invention, as the "slit" is the structural feature on the bracket that receives and captures a portion of the ventilation hood's top panel, allowing it to be hung. The infringement analysis for both the method of the '507 patent and the system of the '093 patent depends heavily on whether the accused brackets possess a "slit" within the claim's meaning.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification refers to the feature as a "slit or recess 140" ʼ093 Patent, col. 4:47-48, suggesting the term is not limited to a narrow, elongated opening and could encompass a wider variety of gaps or indentations that perform the same receiving function.
  • Evidence for a Narrower Interpretation: Figure 3 of the patent depicts a specific geometric relationship between the "slit 140," the "main body 95," the "connection section 130," and the "finger section 134" ʼ093 Patent, Fig. 3 A party could argue that the term "slit" should be construed as limited to the specific structure and arrangement shown in this preferred embodiment.

VI. Other Allegations

• Indirect Infringement: The complaint alleges inducement to infringe the '507 method patent. It asserts that Defendant encourages infringement by providing customers with product manuals and publishing instructional videos that demonstrate the steps of the patented method Compl. ¶51 Compl. ¶54 Compl. ¶66
• Willful Infringement: The complaint alleges that Defendant's infringement has been willful for all three asserted patents Compl. ¶74 Compl. ¶89 Compl. ¶106 The basis for this allegation is Defendant's alleged pre-suit knowledge of the patent family, stemming from its citation of the '507 patent during the prosecution of its own patents, its involvement in prior litigation related to the '507 patent, and its receipt of a letter from Plaintiff identifying the '507 patent Compl. ¶¶41-42 Compl. ¶45

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

• A core issue will be one of definitional scope: can the term "slit," which is central to the '507 and '093 patents, be construed to read on the specific physical structure of Defendant's "EZ1" mounting brackets? The complaint's visual evidence directly maps the accused product to this term, but the ultimate determination will rest on the court's claim construction.
• A key question for the '507 method patent will be one of infringing conduct: does the evidence, particularly Defendant's own instructional videos showing its representatives performing the installation, establish direct infringement of the claimed method? For inducement, the question will be whether Defendant's manuals and marketing materials specifically intended for customers to perform all steps of the patented method.