The U.S. Supreme Court's 2007 decision in KSR International v. Teleflex altered the obviousness inquiry under 35 U.S.C. § 103 in determining whether a claimed invention passes muster under the Patent Act. The KSR Court admonished the U.S. Court of Appeals for the Federal Circuit for its rigid application of the "teaching, suggestion, or motivation test" and instead introduced flexibility into the inquiry by allowing factfinders to exercise common sense. The Federal Circuit recently revisited this topic in B/E Aerospace v. C&D Zodiac, holding that the U.S. Patent Trial and Appeal Board did not err when it used common sense to supply a missing claim limitation and invalidate two B/E Aerospace patents directed to space-saving technologies for aircraft enclosures, such as lavatories, closets and galleys.

Case Background

Zodiac challenged two B/E Aerospace patents, U.S. Patent No. 9,073,641 and U.S. Patent No. 9,440,742, in an inter partes review proceeding before the PTAB after being sued by its rival in the Eastern District of Texas for patent infringement. Each of the patents-in-suit contained a two-page written description teaching "an enclosure with contoured walls designed to 'reduce or eliminate the gaps and volumes of space required between lavatory enclosures and adjacent structures.'" Claim 1 of the '641 patent, which the parties agreed was representative of the challenged claims, requires that an exterior wall of the lavatory includes a first recess for part of an inclined seat back and a second recess for a portion of a seat support. The pair of recesses allow the seat to be positioned closer to the lavatory, making more efficient use of the space available.

Zodiac alleged that the challenged claims were obvious over the "Admitted Prior Art," which Zodiac defined as certain portions of the challenged patents, and U.S. Patent No. 3,738,497 to Betts. The Board agreed, concluding that Betts' contoured wall design met the "first recess" claim limitation and that one of skill in the art (in this case, an airplane interior designer) would have been motivated to modify the Admitted Prior Art's flat wall with Betts' contoured wall because such a modification would add space to the airplane cabin by allowing the seat to be moved further aft. The Board determined that adding the second recess was obvious both because it was merely "application of a known technology (i.e., Betts) for its intended purpose with a predictable result" and "'it would have been a matter of common sense' to incorporate a second recess."

Federal Circuit Appeal

B/E appealed the Board's decision to the Federal Circuit. While B/E did not challenge the finding that Betts taught the claimed "first recess" or dispute that a skilled artisan, interested in maximizing cabin space, would have been motivated to combine Betts with the Admitted Prior Art, it argued that the Board improperly incorporated a second recess not disclosed in the prior art.

The Federal Circuit panel disagreed, affirming the Board's conclusion that a skilled artisan would have used common sense to incorporate the second recess into the combination of references. In doing so, the panel focused on the Board's conclusion that the claims did not pass muster either under the traditional obviousness analysis or the common-sense approach and noted that the Board's invocation of common sense was supported by more than eight pages of "reasoned analysis and evidentiary support."

The court cited to KSR and its progeny, reiterating that while "common sense cannot be used as a 'wholesale substitute for reasoned analysis and evidentiary support,'" "courts must 'consider common sense, common wisdom, and common knowledge' in analyzing obviousness." Drawing parallels to Perfect Web Technologies v. InfoUSA, a 2009 Federal Circuit decision affirming a district court's use of common sense to supply a missing claim limitation, the court noted that the technology at issue was similarly simple and merely involved repetition of an existing element (the "first recess") to achieve the missing claim limitation (the "second recess").

On appeal, B/E also argued that the Board improperly relied on three "design drawings" that Zodiac had submitted as part of its IPR petition as evidence that lower recesses to receive a seat support were known in the art. B/E asserted that the drawings were not "patents" or "printed publications" under 35 U.S.C. § 311(b) and should therefore be excluded from the proceeding. The Board denied B/E's motion to exclude, saying that the drawings were considered only for the purpose of identifying the relevant skill in the art and thus need not qualify as "printed publication prior art." The Federal Circuit did not reach the issue of whether the Board "ran afoul of § 311(b)" by considering the drawings, however, noting that "[t]he Board fully articulated its conclusion of obviousness" and that its finding of obviousness independent of the design drawings was supported by "substantial evidence."

The precise contours of when common sense can be applied to provide claim elements that are missing from the prior art remain unclear. However, B/E Aerospace v. C&D Zodiac provides several pointers. The court's analysis frequently referred to the simplicity of the technology and the fact that the value of saving space in aircraft cabins was well known at the time of invention. In other words, the panel analyzed obviousness from the perspective of an airplane interior designer-who already had the goal of moving a seat as far back as possible-faced with the problem of the seat support butting up against the lavatory wall. Furthermore, the designer already had a recess in the lavatory wall for the seat back. In that context, it is easy to see how the panel concluded adding another recess to the wall is merely common sense.

Implications for Patent Applicants

In evaluating inventions and preparing patent applications, applicants should consider the complexity of the technology and what they admit as prior art. In particular, with simple technologies, applicants should avoid admitting the problem addressed by the invention is known or discuss prior solutions in their applications unless doing so supports an argument for non-obviousness (e.g., if the known solutions are deficient and the invention is a radically different approach). Applicants should also consider the range of possible solutions and how similar their inventions are to existing solutions for related problems. In the case of B/E's patent, to move the seat further back, there were only two options for addressing the seat support: make it smaller or add a recess for it. Furthermore, there was no meaningful distinction between adding a recess for the seat back and adding a recess for the seat support. Both problems involved a physical component of the seat colliding with the lavatory wall, and both solutions were adding a recess. Therefore, to the extent possible, applicants should identify differences between the novel features of the invention included to solve a problem and prior art solutions to similar problems.

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