Obviousness is a mixed question of law and fact.  Thus, when a jury reaches a verdict on the issue of obviousness, the Federal Circuit defers to the jury’s factual findings that are supported by substantial evidence.  Practitioners should take note when the Federal Circuit overturns a jury’s finding of obviousness or nonobviousness.  These situations, as demonstrated in the recent case of ABT Systems, LLC v. Emerson Electric Co., Nos. 2014-1618, -1700 (Fed. Cir. Aug. 19, 2015), often involve a strong showing of obviousness or nonobviousness that can highlight how practitioners may invoke or defend against 35 U.S.C. § 103 in their own cases.

The asserted patent in this case, U.S. Patent No. 5,547,017 (“the 017 patent”), titled “Air Distribution Fan Recycling Control,” is directed to techniques for running an HVAC system fan intermittently during periods when a thermostat is not requesting heating or cooling.  As described in the ’017 patent, this “recycle control” feature involves periodic fan operation when the system is not heating or cooling, where the fan operation begins “a preselected time period” after the fan stops at the end of a heating or cooling cycle, or after the termination of a “constant fan mode” operation.  The purported benefits of this technique, as described in the specification, include reduced air stagnation, dilution of point sources of indoor air pollution, improved air cleaning, and reduced energy consumption.

The ’017 patent was assigned from the inventor to the University of Central Florida, which in turn licensed the patent to ABT Systems, LLC.  The University and ABT sued several defendants for alleged infringement of the ’017 patent, including Emerson Electric Co.  In particular, they alleged that the Comfort Circulating Fan Feature of Emerson’s “Big Blue” thermostat infringed the ’017 patent.

During a jury trial, Emerson challenged the ’017 patent as being obvious in view of four prior art references.  In particular, Emerson argued that the claims of the ’017 patent would have been obvious in view of U.S. Patent No. 2,013,136 (“Cornelius”); U.S. Patent No. 4,838,482 (“Vogelzang”); U.S. Patent No. 2,953,908 (“Petrone”); and/or U.S. Patent No. 5,020,332 (“Nakatsuno”).  They jury rejected this invalidity defense and found the asserted claims of the ’017 patent infringed by Emerson.  Following the verdict, Emerson filed a motion for judgment as a matter of law (JMOL) to set aside the verdict, which the district court denied.  Emerson appealed from the denial of its JMOL motion, and the plaintiffs also appealed on issues relating to damages.

On appeal, the Federal Circuit held that the district court erred in denying Emerson’s JMOL motion based on obviousness.  In doing so, the Federal Circuit substantively reviewed the four prior art references asserted by Emerson and concluded that no reasonable jury could have found, in light of KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007), that the asserted claims were not obvious.

As described by the Federal Circuit, Cornelius discloses a furnace air circulation fan that “intermittently” cycles on and off, using a “timing device,” when there is no call for heat from a thermostat.  But Cornelius does not expressly teach the timer being tied to the deactivation of the heating elements, as recited in claim 1 of the ’017 patent.  Vogelzang discloses an HVAC system with a “cycle position” option on a thermostat, as well as periodic fan operation when there is no call for heating or cooling.  Like Cornelius, Vogelzang does not explicitly teach running a fan periodically based on when heating or cooling elements are deactivated.  Petrone discloses a control for a fan such that the fan stops when the call for cooling ends, at which point there is a delay before the fan begins to operate independent of a call for cooling.  This delay occurs in order to allow sufficient time for water to drain from the cooling coils, thus preventing moisture from being blown into the air.  Nakatsuno discloses how a fan may be operated for a “predetermined time Δt1 after the stop of the compressor.”  Further, Nakatsuno teaches that the fan may also be “intermittently driven” to enhance comfort and minimize energy consumption.

The Federal Circuit framed the issue of obviousness as being whether a person of ordinary skill would have combined disclosure from Petrone and Nakatsuno, regarding “single-shot” fan operation as a function of the time when heating or cooling cycles end, with disclosure from Cornelius and Vogelzang, regarding periodic fan cycles during periods of time when there is no call for heating or cooling.  The plaintiffs’ expert opined that one could not simply “plug [ ]” the former references into the latter, and that there would be “logistical and enablement issues” if they were combined. ABT Sys., Nos. 2014-1618, -1700, slip op. at 14 (alteration in original) (citation omitted). On the other hand, Emerson’s expert testified that “it would have been a logical and ordinary step for a person of skill in the art to use the prior art to create a periodic fan that is dependent on the end of a heating or cooling cycle.”  Id. at 14-15. The Federal Circuit sided with Emerson, relying on the KSR rationale that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result.”  Id. at 17 (quoting KSR, 550 U.S. at 416).  According to the Federal Circuit, the timer of Vogelzang or Cornelius, as modified by the predetermined and compressor-dependent interval of Nakatsuno or Petrone, would have yielded a predictable result, namely, “the system fan would activate periodically following the end of a heating or cooling cycle.”  Id.

The Federal Circuit further explained that, even if the references themselves do not provide a motivation to combine their teachings, a court “may find a motivation to combine prior art references in the nature of the problem to be solved.”  Id. at 18 (quoting Ruiz v. A.B. Chance Co., 357 F.3d 1270, 1276 (Fed. Cir. 2004)).  Accordingly, based on Vogelzang and the nature of its “problem to be solved,” it would have been “nearly obvious from that disclosure itself to set the periodic fan to run as a function of when the heating or cooling cycle ended.”  Id.

Having found that Emerson raised a prima facie case of obviousness, the Federal Circuit also considered the plaintiffs’ evidence of purported secondary considerations of nonobviousness, including commercial success and long-felt need.  As the Federal Circuit found, this evidence could not rebut the showing of obviousness since there was no evidence of a “nexus” between the alleged secondary considerations and the claimed invention.

While ABT Systems involved a litigation appeal, its application of obviousness rationales is instructive for those involved in drafting or prosecuting patent applications.  Practitioners should appreciate how strong an obviousness position may be even where there is no express teaching in the references to combine them in the manner recited in the challenged claims.  Indeed, in ABT Systems, the obviousness position was so strong that the Federal Circuit was willing to overturn the jury’s finding of nonobviousness, which involved factual determinations to which the Federal Circuit had to “assign due deference.”  Id. at 11.  At the same time, practitioners should note that, in ABT Systems, “all of the claimed limitations [we]re expressly found in the cited prior art references.”  Id. at 21.  Thus, ABT Systems did not involve a situation where the obviousness rationale left a “gap” that was to be filled in by “common knowledge” or other undisclosed teachings.  Thus, for situations involving such gaps, practitioners still have a range of arguments at their disposal to attack the underlying obviousness rationale.