PTAB

IPR2024-00835

Godbersen Smith Construction Co v. Guntert & Zimmerman Const Div Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Swing Leg Assembly for a Paving Machine
  • Brief Description: The ’318 patent describes a slipform paver for laying concrete that includes a swing leg assembly with a sensor-based control system. The system is designed to coordinate the rotation of a crawler track with the pivoting of an associated swing leg, ensuring the crawler track remains oriented in the paving direction regardless of the swing leg's angle.

3. Grounds for Unpatentability

Ground 1: Obviousness over CIII and Rio - Claims 1-8 are obvious over CIII in view of Rio.

  • Prior Art Relied Upon: CIII (Commander III New Generation Trimmer/Paver Operator/Service Manual G21 Controls) and Rio (Patent 7,523,995).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that CIII, a manual for a commercial slipform paver, disclosed a swing-leg assembly with nearly all the physical components of the claimed invention, including a swing leg, a jacking column, a crawler track, and a hydraulic steering cylinder for rotating the track. However, CIII required time-consuming manual adjustments to reposition the swing legs and re-center the steering. Petitioner argued that Rio, which described a road-milling machine, taught the missing control system elements. Rio disclosed using a first sensor to detect the pivot angle of a swing arm and a second sensor to detect the rotational angle of a track. A controller used these signals to automatically counter-rotate the track to maintain its orientation as the swing arm pivoted.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Rio's automated control system and compact rotary actuator with CIII's paver to solve CIII's known problems. The motivation was to replace CIII's bulky steering cylinder and inefficient manual adjustment process with an automated system that would improve maneuverability, increase the speed of adjustments, reduce labor costs, and minimize the risk of operator error. Rio explicitly provided a solution for the precise problem of coordinating swing leg and track movement on heavy road-construction machinery.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involved applying a known control system (Rio) to a known mechanical platform (CIII) to achieve a predictable improvement. The use of rotary actuators and sensor-based feedback loops was well-known in the art for steering heavy machinery, and Rio's system was already proven to function as intended on analogous equipment.

Ground 2: Obviousness over CIII, Rio, and Smolders - Claims 2-7 are obvious over CIII and Rio in view of Smolders.

  • Prior Art Relied Upon: CIII, Rio, and Smolders (Patent 6,481,924).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination in Ground 1 to address the "hinge bracket" limitation recited in claim 2 and its dependent claims (3-7). Petitioner argued that CIII already disclosed a hinge bracket for its swing leg in its three-track configuration. Smolders was introduced as additional prior art teaching the benefit of using hinge brackets on multiple swing-leg assemblies in a slip-form paver. Smolders disclosed a paver with multiple pivoting devices, each coupled to the machine frame with a hinge bracket to allow for adjustment.
    • Motivation to Combine: For the four-track paver configuration resulting from the CIII and Rio combination, a POSITA would have been motivated to incorporate hinge brackets as taught by CIII's own alternative configuration and reinforced by Smolders. The motivation was to facilitate the easy attachment and removal of each swing-leg assembly. This would improve maintenance, allow for greater flexibility in paving configurations, and reduce manufacturing costs by enabling the same swing leg components to be used in both three-track and four-track setups.
    • Expectation of Success: The expectation of success was high, as this modification involved incorporating a standard, well-known component (a hinge bracket) for its intended and predictable purpose. Since CIII already successfully used a hinge bracket in one configuration, and references like Smolders confirmed its utility in multi-leg pavers, a POSITA would have confidently expected it to work in the proposed combination.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under 35 U.S.C. § 325(d) would be inappropriate. Although the asserted prior art (CIII, Rio, Smolders) and prior PTAB decisions invalidating a related patent were submitted to the USPTO during prosecution via Information Disclosure Statements (IDS), the Examiner never used these references in any rejection. Petitioner contended the Examiner committed a material error by allowing the claims without providing any analysis of this highly relevant prior art, especially given that the PTAB had already found substantially similar claims unpatentable over the same references.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-8 of the ’318 patent as unpatentable.