PTAB

IPR2020-00594

Ashworth Bros Inc v. Laitram LLC

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1. Case Identification

2. Patent Overview

  • Title: Positive-Drive Spiral Conveyor
  • Brief Description: The ’645 patent discloses a spiral conveyor system featuring a conveyor belt that is positively driven without slip along a helical path around a rotating central drive tower. The invention focuses on the configuration of drive members on the tower, which include a lower portion that angles outwardly toward the bottom to facilitate smooth engagement and disengagement of the belt.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 are obvious over Pupp in view of Roinestad.

  • Prior Art Relied Upon: Pupp (Patent 6,062,375) and Roinestad (Patent 3,349,659).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Pupp discloses all elements of the challenged claims except for the specific tapered geometry of the drive tower's lower portion. Pupp teaches a spiral conveyor with a rotatable drive tower, parallel drive members, and a conveyor belt that is positively driven "without slip" by engaging the inside edge of the belt. The drive tower in Pupp is described as substantially cylindrical. Roinestad was cited for its teaching of using tapered and non-tapered sections on a drive tower to provide a system where the belt is smoothly driven under low tension.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Pupp's positive, non-slip drive system with Roinestad's known technique of using tapered drive members. The motivation would be to solve the well-known problem of high belt tension in spiral conveyors by incorporating Roinestad's tension-reducing tapered tower design into Pupp's effective positive-drive system. This was presented as a predictable design choice to optimize performance.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because both references are in the same field of spiral conveyor systems. Modifying the surface geometry of a drive tower, as taught by Roinestad, is a predictable mechanical art that would be expected to work as intended when applied to the positive-drive system of Pupp.

Ground 2: Claims 1-4 are anticipated by Heber under 35 U.S.C. §102.

  • Prior Art Relied Upon: Heber (Patent 7,347,316).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Heber anticipates every limitation of claims 1-4. Heber itself discloses a spiral conveyor with a tapered drive tower. Critically, Heber expressly incorporates by reference the entire disclosure of Pupp. Therefore, the Heber reference was argued to legally contain all teachings from Pupp (including the positive "without slip" drive) in combination with Heber's own disclosure of a drive tower with a tapered surface. This combination, contained within the single Heber reference, allegedly discloses a spiral conveyor with a tapered, positive-drive tower and a non-slip belt, thereby anticipating the claims. Petitioner emphasized that the examiner of the parent application overlooked this incorporation by reference, leading to an improper allowance.

Ground 3: Claims 1-4 are obvious over Roinestad2 in view of Roinestad.

  • Prior Art Relied Upon: Roinestad2 (Patent 4,741,430) and Roinestad (Patent 3,349,659).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Roinestad2, like Pupp, discloses a positively driven spiral conveyor system with a drive tower that rotates around a vertical axis. Roinestad2’s drive members have outwardly projecting ridges that engage the inner edge of the belt to drive it "without slip." The secondary reference, Roinestad (by the same inventor), was again relied upon for its disclosure of combining tapered and non-tapered sections along the height of a drive tower to reduce belt tension.
    • Motivation to Combine: The motivation was argued to be the same as in Ground 1: to improve the design of Roinestad2’s positive-drive system by incorporating the known benefits of a tapered drive tower taught by Roinestad. A POSITA would have been motivated to combine the teachings to create a system that is both positively driven (per Roinestad2) and operates with lower, more smoothly managed belt tension (per Roinestad). The fact that both patents share the same inventor was presented as further evidence of the close relationship between the technologies.
    • Expectation of Success: A POSITA would reasonably expect that combining the features would be successful, as it involves applying a known tension-reduction technique (tapered tower sections) to a standard positive-drive conveyor system within the same predictable field of art.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 1-4 are obvious over Heber alone (Ground III) and obvious over Heber in view of Roinestad (Ground IV), relying on similar arguments that Heber's teachings, particularly its incorporation of Pupp, either render the claims obvious or make the combination with Roinestad's tapered tower design obvious.

4. Key Claim Construction Positions

  • Petitioner argued that the limitation "without slip" is critical, as it was added during prosecution of the parent ’388 patent to overcome a rejection. Two constructions were proposed:
    • 1. Plain and Ordinary Meaning: The term means a structure that eliminates "overdrive," which is a known issue in friction-drive systems. Petitioner argued that the prior art, particularly Pupp, explicitly teaches a positive engagement to prevent such slip.
    • 2. Prosecution History Estoppel: Alternatively, if the term is construed more narrowly based on the patentee's arguments during prosecution, it would be limited to the specific geometry shown in the ’645 patent’s figures (e.g., a tapered region above a non-tapered region on the drive member ridge). Petitioner argued that even under this narrower construction, the claims are obvious because combining a standard positive-drive system with a tapered tower was a simple and predictable design choice.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-4 of the ’645 patent as unpatentable.