PTAB

IPR2016-00194

Toro Co v. MTD Products Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Steering and Driving Systems Related Vehicles
  • Brief Description: The ’458 patent discloses small radius and zero-turn radius (ZTR) vehicles using independent left and right drive units. The core of the invention is a mechanical control assembly that accepts inputs from a steering device (e.g., a steering wheel) and a speed control member to ensure the vehicle steers conventionally and maintains the same turning arc when transitioning between forward and reverse motion.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-16 by Barnes

  • Prior Art Relied Upon: Barnes (U.K. Patent App. No. GB 2,303,829).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Barnes discloses every element of claims 1-16. Barnes teaches a control system for a skid-steer vehicle with independent hydrostatic drive units for the left and right sides. It explicitly discloses using a steering wheel as a "steering input member" and a lever as a "speed input member." Petitioner contended that the mechanical control assembly in Barnes (e.g., Fig. 4), which uses a system of cams and followers, is configured to perform the exact function that was added to the ’458 patent claims during prosecution to overcome prior art. Specifically, Barnes’s system mathematically and mechanically ensures that when an operator shifts from forward to reverse while holding a turn, the relative speeds of the inner and outer drive wheels are maintained, causing the vehicle to travel along the same turning arc. Barnes also expressly discloses the ability to execute a zero-radius turn by operating the drive units at equal and opposite speeds.
    • Key Aspects: Petitioner asserted that the central patentability argument for the ’458 patent—maintaining a consistent turn arc in forward and reverse—is not just present but is a primary teaching of Barnes.

Ground 2: Anticipation of Claims 1 and 9 by Richard

  • Prior Art Relied Upon: Richard (Great Britain Published Specification No. 968,260).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Richard, published in 1964, anticipates independent claims 1 and 9. Richard is directed to a control arrangement for vehicles with independent transmissions for each side (e.g., tracked tractors) and expressly addresses the problem of unconventional steering when reversing a turn. Richard’s mechanical control system, using slideways and connecting rods, is configured to ensure that the turning pivot point remains on the same side of the vehicle when switching between forward and reverse, allowing the vehicle to follow the same arc. Petitioner asserted this is the same functionality claimed in the ’458 patent. Richard’s system also discloses independent drive units, a steering device (levers), a separate speed control member, and the ability to perform a zero-radius turn by moving one track forward and the other in reverse.

Ground 3: Obviousness of Claims 2-8 and 10-16 over Richard in view of Barnes

  • Prior Art Relied Upon: Richard (GB Specification No. 968,260) and Barnes (U.K. Patent App. No. GB 2,303,829).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed the dependent claims, which add limitations such as the steering device being a "steering wheel" (claims 2 and 10) and the use of "hydrostatic drive units" (claims 8 and 16). Petitioner argued that Richard discloses the core mechanical control assembly for conventional steering, but uses levers. Barnes explicitly teaches that steering control for such vehicles can be implemented with either levers or a steering wheel, noting that with a steering wheel, "the driver expects a normal motor car response." Richard also discloses the use of hydraulic drive units as one embodiment of its independent transmissions.
    • Motivation to Combine: A POSITA would combine Richard and Barnes because they are in the same field of differential-steered vehicles and address the same problems. A POSITA would be motivated to replace the levers in Richard’s system with the steering wheel taught by Barnes to achieve Richard’s stated goal of replicating conventional driving controls, a predictable and well-known substitution. Improving the user interface and steering performance by using a familiar steering wheel would have been an obvious design choice.
    • Expectation of Success: A POSITA would have had a high expectation of success, as substituting a steering wheel for levers was a known and interchangeable design choice for controlling differential drive vehicles.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 1-16 are obvious over Barnes in view of general POSA knowledge, and that claims 1 and 9 are obvious over Richard in view of general POSA knowledge. These grounds argued that if any minor claim element was deemed not explicitly disclosed, it would have been an obvious modification for a POSA to implement.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-16 of the ’458 patent as unpatentable.