Nortek Security & Control LLC v. The Chamberlain Group, Inc.

1. Case Identification

• Case #: IPR2018-01793
• Patent #: 6,741,052
• Filed: September 28, 2018
• Petitioner(s): Nortek Security & Control LLC, GTO Access Systems, LLC, and Nortek, Inc.
• Patent Owner(s): The Chamberlain Group, Inc.
• Challenged Claims: 1-35

2. Patent Overview

• Title: Control System and Method for a Movable Barrier Operator
• Brief Description: The ’052 patent relates to a control system for movable barrier operators, such as garage doors. The system features two modes of operation: a first "learning" mode where performance limits (e.g., force thresholds) are automatically determined, and a second "normal" mode where a user can perform post-determination, non-automatic adjustments to these limits via a human interface.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 1-16, 18, 22-25, and 27-35 over Duhame in view of Fitzgibbon-2000

• Prior Art Relied Upon: Duhame (Patent 5,218,282) and Fitzgibbon-2000 (Patent 6,107,765).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the core concepts of the ’052 patent were well-known and that Duhame discloses nearly all limitations of the challenged claims. Duhame teaches a control system for a motorized barrier that automatically determines adaptive torque limits and allows for manual, user-selected modification of those limits via potentiometers. To the extent Duhame does not explicitly teach a dedicated "learning mode" for initial setup, Fitzgibbon-2000 was introduced to supply this feature. Fitzgibbon-2000, whose inventor is the same as the ’052 patent’s inventor, explicitly teaches a "learn switch" to initiate a cycle that automatically determines and stores force and travel limits for the barrier.
  • Motivation to Combine: A person of ordinary skill in the art (POSA) would combine Duhame with Fitzgibbon-2000 to improve the safety and convenience of installation. Duhame’s iterative process for setting limits was described as cumbersome. A POSA would have been motivated to replace it with the more efficient, single-cycle "learn mode" taught by Fitzgibbon-2000 to achieve a fast and accurate initial setup of force and travel limits. The references are in the identical technical field of garage door openers, making the combination logical.
  • Expectation of Success: Petitioner asserted a POSA would have had a high expectation of success. Implementing a learning mode is a trivial software-based task, and both Duhame and Fitzgibbon-2000 provide detailed operational algorithms, making their combination straightforward.

Ground 2: Obviousness of Claims 17, 19-21, and 26 over Duhame, Fitzgibbon-2000, and Schindler

• Prior Art Relied Upon: Duhame (Patent 5,218,282), Fitzgibbon-2000 (Patent 6,107,765), and Schindler (Patent 4,638,433).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds on Ground 1 by adding Schindler to address claims requiring a limited range of user adjustment (i.e., less than 25% of the total potential applicable force). While Duhame teaches user modification of force thresholds, it does not explicitly limit the adjustment range. Schindler was introduced to teach the importance of limiting such adjustments for safety. It discloses setting force limits only "slightly as, for example, 10% above these required forces" to avoid creating a dangerous condition. Petitioner argued this 10% disclosure makes the claimed <25% range obvious.
  • Motivation to Combine: A POSA would have been motivated to incorporate Schindler's safety teachings into the system of Ground 1. Schindler explicitly warns that allowing a homeowner to set force limits too high can result in a dangerous situation. Therefore, a POSA would have been motivated by safety concerns to limit the range of user-manipulable force adjustments to prevent misuse, directly addressing the problem solved by the challenged claims.
  • Expectation of Success: Success would have been reasonably expected, as limiting the range of a user input is a simple and common design choice that could be implemented mechanically or electronically without difficulty.

Ground 3: Obviousness of Claims 1, 4-16, 18, 22, 27-33, and 35 over Leivenzon

• Prior Art Relied Upon: Leivenzon (WO 2000/072436).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Leivenzon, as a single reference, renders the claims obvious by teaching all of their key elements. Leivenzon describes a garage door opener system that automatically learns obstruction parameters during an initial open-and-close cycle (a "learning mode"). It divides the door's travel path into multiple segments and calculates characteristic resistance (force) thresholds for each. Critically, Leivenzon also explicitly teaches that a user can manually modify these predetermined resistance values via a "set up facility" after they have been automatically determined. This directly maps to the ’052 patent’s purported point of novelty: post-automatic-determination manual calibration.

4. Key Claim Construction Positions

• Petitioner argued that several terms should be construed as means-plus-function limitations under §112, ¶ 6. For each term, Petitioner identified the claimed function and the corresponding structure from the ’052 patent’s specification.
• Processor (claims 1, 8, 14, 18-19): The function was defined as automatically determining force thresholds in a first mode for use in a second mode. The structure was identified as a general-purpose processor programmed to perform functions disclosed in the specification, such as receiving user input and detecting forces in a learning mode.
• Learning means (claims 14-16): The function was defined as "sensing the at least some forces acting upon the movable barrier" during a learning mode. The corresponding structure was identified as "code for receiving input from sensors regarding the forces acting upon the motor."
• Control means (claims 22-26): The function included automatically measuring force and establishing a threshold in a first mode, and modifying and using that threshold in a second mode. The structure was identified as "a programmable platform that can be suitably programmed to function in accordance with the embodiments presented herein."

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §325(d) would be inappropriate because the petition presented prior art and arguments not previously considered by the USPTO. Specifically, the primary references of Duhame, Leivenzon, and Schindler were never considered by the Examiner during the original prosecution. Petitioner noted that while Fitzgibbon-2000 was cited in an Information Disclosure Statement (IDS), it was not substantively addressed or used in any rejection by the Examiner.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-35 of Patent 6,741,052 as unpatentable.