PTAB

IPR2013-00305

Gatekeeper Systems Inc v. Dane Technologies Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Power-Assisted Cart Retriever with Attenuated Power Output
  • Brief Description: The ’836 patent discloses a motorized shopping cart retriever featuring an electronic controller designed to limit the power supplied to the vehicle's drive system. The controller incorporates two distinct power limits: a primary, self-activating limit based on its internal temperature to prevent damage to itself, and a secondary, selectable limit to prevent overloading by limiting the number of carts that can be moved.

3. Grounds for Unpatentability

Ground 1: Obviousness over Schugt and the Curtis 1237 Manual - Claims 1-4 and 6-7 are obvious over Schugt in view of the Curtis 1237 Manual.

  • Prior Art Relied Upon: Schugt (Patent 6,220,379) and the Curtis 1237 Manual (a September 2000 technical manual).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Schugt disclosed the foundational elements of the claimed invention, namely a motorized shopping cart retriever with an electric motor, drive system, and a controller. However, Schugt’s controller lacked the specific dual power-limiting features recited in the claims. Petitioner asserted that the Curtis 1237 Manual, describing a commercially available motor controller, taught the missing limitations. Specifically, the manual disclosed a "thermal protection" feature that automatically reduces the current limit when the controller's internal temperature exceeds a threshold (the claimed "first power limit" based on a temperature-sensing feature). The manual also disclosed a programmable "main current limit" that allows an operator to select a maximum current between 50% and 100% of the controller's rating (the claimed "second power limit" that is selectable and less than the first).
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine the off-the-shelf Curtis 1237 controller with the Schugt retriever to achieve the predictable benefits of overheating and overload protection. The Curtis manual explicitly stated its controllers were for "small electric vehicles" and "industrial applications," making it a natural choice. Furthermore, Petitioner highlighted that the Patent Owner, in its own provisional application, had identified Curtis controllers as "exemplary" for use in cart retrievers, providing a strong motivation for the combination.
    • Expectation of Success: A POSITA would have had a high expectation of success, as this combination involved the simple substitution of a known, commercially available controller into a standard electric vehicle to achieve the controller's advertised functions. Petitioner noted that the Patent Owner itself successfully incorporated these controllers into its commercial QuicKart products years before filing the patent application.

Ground 2: Obviousness over Schugt and Konrad - Claims 1-4, 6-7, 10, and 12 are obvious over Schugt in view of Konrad.

  • Prior Art Relied Upon: Schugt (Patent 6,220,379) and Konrad (Patent 4,423,362).

  • Core Argument for this Ground:

    • Prior Art Mapping: Similar to the first ground, Petitioner relied on Schugt to teach the basic cart retriever. To supply the claimed controller features, Petitioner pointed to Konrad, a 1983 patent for an electric vehicle control system that was not considered during the original prosecution. Petitioner argued Konrad disclosed a "thermal cutback circuit" responsive to the temperature of a power regulator semiconductor, which forces a reduction in the current limit value (teaching the first power limit). Konrad also disclosed a separate, "manually-adjustable current limit" that could be set between a maximum and minimum value (teaching the second, selectable power limit).
    • Motivation to Combine: Petitioner argued a POSITA would have been motivated to incorporate the control system of Konrad into the Schugt retriever to implement the well-understood functions of protecting the motor and control electronics from thermal damage and current overloads. Since Konrad's system was designed for an "electrically powered vehicle," applying its protective features to another such vehicle like Schugt's was a logical design choice.
    • Expectation of Success: The combination was presented as the application of well-known motor controller functions to a known vehicle type. Petitioner argued that because Konrad demonstrated such power limits were standard features in electric motor controller design decades before the ’836 patent's priority date, combining them with a cart retriever would yield only predictable results.

  • Additional Grounds: Petitioner asserted additional obviousness challenges that built upon the two primary combinations. Grounds based on applicant-admitted prior art were used to challenge claim 5 (attenuating voltage), arguing the patent specification admitted this was well-known. Grounds incorporating the Electric Motors Handbook were used to challenge claims 8-12, arguing it was obvious to use the claimed system with various common motor types (e.g., brushless DC, AC, series wound DC) described in the handbook.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-12 of the ’836 patent as unpatentable under 35 U.S.C. §103.