The Federal Circuit has affirmed two decisions by the Patent Trial and Appeal Board (PTAB or Board) that found Robert Bosch and Mercedes-Benz USA failed to prove challenged claims of two fuel injector patents for an internal combustion engine were obvious.
Westport Fuel Systems Canada Inc. owns US Patent Nos. 6,298,829 and 6,575,138, which relate to “an injection valve . . . which includes a passive hydraulic link.”
Robert Bosch LLC and Mercedes-Benz USA, LLC (together “Bosch”) filed petitions for inter partes review (IPR) of various claims of the patents.
The Board found that Bosch failed to prove that any of the challenged claims would have been obvious and Bosch appealed.
The court noted that Claim 1 of the ’829 patent was representative, and only limitation 1(e) was in dispute. It recites:
a hydraulic link assembly comprising a passive hydraulic link having a hydraulic fluid thickness through which said opening and closing forces are transmitted, whereby said hydraulic fluid acts substantially as a solid with said thickness being substantially constant while said actuator assembly is activated and wherein said thickness of said hydraulic link is adjustable while said actuator is not activated in response to changes in the dimensional relationship between components of said injection valve to maintain a desired valve needle lift upon activation of said actuator assembly.
(Emphasis added by court.)
Bosch contended that claim 1 would have been obvious over a combination of prior art references, Wirbeleit and Klügl.
In the Board’s view, Bosch failed to prove that Klügl satisfies limitation 1(e)’s requirement that the hydraulic fluid “acts substantially as a solid with said thickness being substantially constant.”
The only issue on appeal was whether the Board had substantial evidence to support its finding that Klügl does not disclose limitation 1(e).
The court noted that the disputed limitation requires, among other things, that “the hydraulic fluid acts substantially as a solid,” which the Board found Klügl does not disclose, since Klügl’s membrane 6 is “flexible,” meaning the fluid will change shape as the membrane flexes, which is inconsistent with the behavior of a solid.
The court found this was supported by
ample evidence in the form of credible expert testimony that Klügl only ever specifies and describes membrane 6 as a flexible membrane or element, and, thus, the membrane will tend to deform longitudinally upward where it contracts the drive piston and bulge outward where unconstrained in the annular area . . . between the edge of the drive piston 3 and the wall of transmission module 2.
Also, noted the court, Klügl explicitly describes membrane 6 as a “flexible membrane.”
Bosch also argued that even if membrane 6 of Klügl is flexible, the Board lacked substantial evidence to find that membrane 6 flexes during activation (also referred to as “actuation”), as is required of limitation 1(e).
However, said the court, “A reasonable mind could accept the Board’s logical determination that if Klügl’s membrane 6 is flexible and actually flexes when not actuated, then it remains flexible and will flex when actuated as well.”
The court rejected Bosch’s argument a skilled artisan would “readily be able to design Klügl’s injector” to minimize or avoid flexing altogether.
However, said the court, as the Board pointed out, this contradicted Klügl’s repeated teachings that its membrane is flexible.
The court also rejected Bosch’s allegations that the Board made procedural errors.
Thus, the court affirmed the judgement of the Board.
In this case, it appears that the patent was for a small, incremental change. Patent offices (including the US Patent and Trademark Office) appear to more readily allow patents for small mechanical and chemical changes than for similar minor changes in software.
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