Black & Decker US Inc v. Christy Inc

1. Case Identification

• Case #: IPR2015-00468
• Patent #: 7,082,640
• Filed: December 9, 2014
• Petitioner(s): Black & Decker (U.S.) Inc. and Stanley Black & Decker, Inc.
• Patent Owner(s): Christy, Inc.
• Challenged Claims: 1-18

2. Patent Overview

• Title: Ambient Air Backflushed Filter Vacuum
• Brief Description: The ’640 patent discloses a vacuum cleaner with multiple filters that are cleaned by sequentially backflushing them with ambient air. The system uses the main vacuum source's suction to draw outside air backward through one filter at a time, while the other filters continue normal operation, thereby dislodging collected particles without requiring a secondary compressed air source.

3. Grounds for Unpatentability

Ground 1: Anticipation by Hayden - Claims 1 and 10 are anticipated by Hayden.

• Prior Art Relied Upon: Hayden (Patent 5,108,473).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Hayden discloses every element of independent claims 1 and 10. Hayden teaches a vacuum system with a "dirty air chamber" (cannister) containing multiple filters, a suction blower (vacuum source), and diverter valves for each filter. Critically, Petitioner asserted that Hayden's valves are located "outside" the cannister, contrary to the Examiner's previous finding during prosecution, because they mount to a divider plate that separates the dirty air chamber from the clean air chamber. Petitioner contended that Hayden's solenoids perform the claimed function of the "means for sequentially operating said valves," switching each filter from the vacuum source to an atmospheric port to draw in ambient air for backflushing, using the suction from the other normally-operating filters.
  • Key Aspects: A central part of this ground was re-interpreting Hayden's structure to argue the Examiner erred during prosecution by incorrectly concluding Hayden's valves were "inside" the cannister.

Ground 2: Obviousness over Core System & Controller - Claims 1, 4-6, 10, and 13-15 are obvious over Hayden in view of Wellan.

• Prior Art Relied Upon: Hayden (Patent 5,108,473) and Wellan (Patent 3,680,285).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Hayden discloses the core vacuum structure with ambient air backflushing. Wellan, which teaches an electronic controller for a filter cleaning system, supplies the specific timing control features recited in the dependent claims. Wellan's solid-state electronic controller is taught to set both the "intermittent time" (the duration of the backflush pulse, analogous to Wellan's "Pulse On-Time") and the "cycle time" (the total time for a full cleaning sequence).
  • Motivation to Combine: A POSITA would combine these references because Hayden explicitly stated that providing an "automatic, periodic cleaning cycle controller" was a necessary component and considered within the ordinary skill in the art. Wellan provided a known, conventional electronic controller for precisely this purpose in a similar filter system. The combination was presented as the predictable implementation of a known controller (Wellan) into a system (Hayden) that expressly called for one.
  • Expectation of Success: A POSITA would have a high expectation of success because both references use solenoid-actuated valves, and incorporating Wellan's electronic timer to trigger Hayden's solenoids was a straightforward application of known control principles to achieve automated operation.

Ground 3: Obviousness over Core System & Valve Mechanics - Claims 7-9 and 16-18 are obvious over Hayden, DE219, and Howeth.

• Prior Art Relied Upon: Hayden (Patent 5,108,473), DE219 (German Application DE10101219A1), and Howeth (Patent 4,465,497).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground builds on Hayden's base system to add specific valve mechanics. Petitioner argued that Hayden’s flap valve could be replaced with the reciprocating piston valve taught by DE219 to meet the "piston reciprocally disposed between said two ports" limitation of claims 7 and 16. Howeth was cited for its teaching of using a spring to bias an actuator in a similar ambient air backflushing system, satisfying the "means biasing said piston" limitation. Hayden's existing solenoids were alleged to meet the "means for overcoming said bias" limitation in claims 8 and 17.
  • Motivation to Combine: A POSITA would be motivated to incorporate the valve design from DE219 into Hayden because DE219 explicitly described its reciprocating piston valve as being interchangeable with other valve types, such as the flap valves used in Hayden. The inclusion of a biasing spring from Howeth was argued to be a simple, well-known mechanical feature to ensure a valve returns to its normal position, representing a common design choice.
  • Expectation of Success: Success was expected as this involved substituting known, interchangeable mechanical components (a piston valve for a flap valve) and adding a common design element (a return spring) to perform their well-understood functions.

• Additional Grounds: Petitioner asserted numerous additional obviousness challenges, primarily building upon the foundational combinations listed above. These grounds included:

  • Using Eiben (Patent 3,224,172) as an alternative or supplement to Hayden to more explicitly teach valves located outside a cannister.
  • Combining Wellan's controller with the Hayden/Eiben combination.
  • Combining the valve mechanics of DE219 and Howeth with the various Hayden, Eiben, and Wellan combinations.
  • Adding von Stackelberg (Patent 6,767,380) to the primary combinations to teach a duct and baffle structure for creating a vortex airflow, as recited in claims 2-3 and 11-12.

4. Key Claim Construction Positions

• "Ambient Air" / "Drawn": Petitioner argued these terms must be construed together to mean "air from the area surrounding the outside of the vacuum cleaning machine that has not been forced or compressed" and is "pulled in by negative pressure only." This construction was based on the specification's explicit denouncement of forced or compressed air systems and repeated prosecution history arguments distinguishing the invention from prior art that used secondary fans or recirculated air. This construction was central to differentiating the claimed invention from prior art like Nelson and Finigan.
• "Means for Sequentially Operating...": Petitioner contended this is a means-plus-function term governed by 35 U.S.C. §112(f). The function is switching the valves between the vacuum source and ambient air. The corresponding structure disclosed in the '640 patent specification was identified as the solenoids (e.g., 61, 62, 63) that physically operate the valves, but not the controller (17) that merely times the solenoids' activation. This narrow construction was important for the anticipation argument against Hayden, which also uses solenoids.
• "Means for Setting Said Intermittent Time" / "Means for Setting a Cycle Time": These were also identified as means-plus-function terms corresponding to structures within the controller (17). The "intermittent time" structure was argued to be the backflush timer (103) in the electronic embodiment, and the "cycle time" structure was the delay timer (102).

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-18 of the ’640 patent as unpatentable under 35 U.S.C. §§ 102 and 103.