Simpson Strong Tie Co Inc v. Columbia Insurance Co

1. Case Identification

• Case #: PGR2019-00063
• Patent #: 10,316,510
• Filed: September 5, 2019
• Petitioner(s): Simpson Strong-Tie Company Inc.
• Patent Owner(s): Columbia Insurance Company
• Challenged Claims: 1-20

2. Patent Overview

• Title: Hanger for Structural Component
• Brief Description: The ’510 patent relates to a joist hanger for connecting a structural component to a wall with fire-resistant sheathing. The hanger includes a channel-shaped portion to receive the component, a connection portion to attach to the wall, and an extension portion creating a specific gap between them, which is disclosed as being large enough to receive two layers of 5/8-inch thick sheathing, but too small for three layers.

3. Grounds for Unpatentability

Ground 1: Claims 1-19 Lack Written Description under 35 U.S.C. §112(a)

• Prior Art Relied Upon: N/A
• Core Argument for this Ground:
  • Petitioner argued that the key limitation—"too small to permit three layers of 5/8 inch thick sheathing to be received"—is a negative limitation that was added during prosecution to overcome prior art rejections.
  • Petitioner asserted that the original specification lacks any support for this upper boundary. The specification allegedly describes an embodiment with two layers of sheathing merely as an open-ended example, stating that "other configurations of fire retardant sheathing are within the scope of the present invention."
  • The petition contended that because the specification does not mention or disavow the use of three or more layers of sheathing, the inventor did not possess the claimed invention with its specific upper limit at the time of filing, rendering the claims invalid for lack of written description.

Ground 2: Claims 1-19 are Anticipated by Brekke’370 under 35 U.S.C. §102

• Prior Art Relied Upon: Brekke (Application # 2015/0184370) ("Brekke’370").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that due to the lack of written description for the negative limitation, claims 1-19 are not entitled to their earliest claimed priority date. This results in an effective filing date after the publication of Brekke’370, which is a continuation from the ’510 patent’s family and shares the same specification.
  • Petitioner asserted that Brekke’370, now qualifying as prior art, discloses every element of claims 1-19. Although Brekke’370 does not disclose the negative "upper bound" of the claimed range, it explicitly discloses a hanger designed for two layers of 5/8” sheathing. Petitioner argued that the disclosure of a single value falling within a claimed range is sufficient to anticipate the entire range.

Ground 3: Claims 1-20 are Obvious over Gilb’155 in view of Bundy and Allan under 35 U.S.C. §103

• Prior Art Relied Upon: Gilb (Patent 4,261,155) ("Gilb'155"), Bundy (Patent 9,394,680), and Allan (Patent 4,827,684).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner contended that Gilb'155 disclosed the core structural elements of the claimed hanger, including a channel-shaped portion, an extension portion, and a connection portion with top and back flanges for mounting to a wall. However, Gilb’155 did not teach the specific spacing of the extension portion required by the claims. Bundy allegedly supplied this missing element, teaching an analogous hanger with an extension portion specifically sized to accommodate two layers of 5/8” thick sheathing, noting this was a preferred embodiment for fire-rated construction. Allan was cited for the general teaching that it was common practice to install sheathing (like drywall) around such hangers by notching or cutting it to fit.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the hanger design of Gilb'155 with the specific, preferred sheathing dimension from Bundy. The motivation was to apply a known spacing that complied with established building codes for fire-resistance to a known hanger design to achieve the predictable benefit of a fire-rated installation. Allan demonstrated that integrating sheathing with hangers was a routine and well-understood practice.
  • Expectation of Success: The combination involved substituting a known, advantageous dimension for another, which would have yielded predictable results without requiring undue experimentation.

• Additional Grounds: Petitioner asserted that claim 20 is indefinite under §112(b) because the term "large enough" lacks an upper limit and is based on the ambiguous term "the drywall," which comes in various thicknesses. Petitioner also asserted numerous additional obviousness challenges, including grounds based on Tsukamoto (Japanese Application No. 19991014482) and Timony (Application # 2005/0155307) as primary references, combined with secondary references like Bundy and Allan to supply the claimed sheathing dimensions and other features.

4. Key Claim Construction Positions

• "too small to permit three layers of 5/8 inch thick sheathing...": Petitioner argued this negative limitation defines a measurable range. Because two layers of 5/8" sheathing equate to 1¼" and three layers equate to 1⅞", a POSITA would understand this range to be "at least 1¼ inches but less than 1⅞ inches." This construction was central to the written description and anticipation arguments.
• "formed as one piece": For the purpose of its arguments, Petitioner adopted the Patent Owner's apparent construction from a related district court case, which includes devices with elements that were originally separate but later joined together (e.g., by welding). This construction was important for the obviousness ground involving Gilb'155, which has separable parts.

5. Relief Requested

• Petitioner requested the institution of a post-grant review and the cancellation of claims 1-20 of Patent 10,316,510 as unpatentable.