United States Court of Appeals 

for the Federal Circuit ______________________ 

ABT SYSTEMS, LLC,

Plaintiff-Appellant

THE UNIVERSITY OF CENTRAL FLORIDA BOARD 

OF TRUSTEES, on behalf of the University of Central Florida,

Plaintiff

v.

EMERSON ELECTRIC CO.,

Defendant-Cross-Appellant

______________________ 

2014-1618, 2014-1700

______________________ 

Appeals from the United States District Court for the 

Eastern District of Missouri in No. 4:11-cv-00374-AGF,

Judge Audrey G. Fleissig.

______________________ 

Decided: August 19, 2015

______________________ 

 MICHAEL P. MAZZA, Michael P. Mazza, LLC, Glen 

Ellyn, IL, argued for plaintiff-appellant. Also represented 

by DANA D. ALVARADO. 

 LINDA E.B. HANSEN, Foley & Lardner LLP, Milwaukee, WI, argued for defendant-cross-appellant. Also 

represented by JEFFREY COSTAKOS, KADIE M. JELENCHICK. 
2 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

______________________ 

Before PROST, Chief Judge, CLEVENGER, and SCHALL,

Circuit Judges. 

SCHALL, Circuit Judge. 

This is a patent case. The University of Central Florida (“University”) is the assignee of U.S. Patent No. 

5,547,017 (“the ’017 patent”), titled “Air Distribution Fan 

Recycling Control.” The patent is licensed to ABT Systems, LLC (“ABT”). ABT and the University sued Emerson Electric Co. (“Emerson”) and three other defendants 

in the United States District Court for the Northern

District of Illinois for infringement of claims 1–5 of the 

’017 patent. Eventually, the case was transferred to the 

United States District Court for the Eastern District of 

Missouri and proceeded to trial before a jury against 

Emerson alone after its three co-defendants settled. 

Following trial, the jury found the asserted claims not 

invalid by reason of obviousness and infringed by Emerson’s “Big Blue” thermostats. Based on a royalty rate of 

$2.25 per unit, the jury awarded damages in the amount 

of $311,379 on sales of 138,891 thermostats. ABT Sys., 

LLC v. Emerson Elec. Co., No. 4:11-cv-00374-AGF, 2013 

WL 5567713, at *2 (E.D. Mo. Oct. 9, 2013).

ABT appeals three rulings of the district court relating to damages. It contends these rulings were erroneous 

and impacted its damages award. For its part, Emerson 

cross-appeals the district court’s denial of its motion for 

judgment as a matter of law (“JMOL”) that claims 1–5 of 

the ’017 patent are invalid by reason of obviousness. See 

id. at *3. 

For the reasons set forth below, we hold that the district court erred in denying Emerson’s motion for JMOL of 

invalidity. We therefore reverse the judgment of noninvalidity, vacate the judgment of infringement, and 

remand the case to the district court for dismissal of the 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 3

complaint. In view of this disposition, it is not necessary 

for us to address ABT’s appeal, which is rendered moot. 

BACKGROUND

I.

Armin Rudd is the sole inventor named on the ’017 

patent. He assigned the patent to the University, his 

employer at the time of the invention. The University 

then licensed the patent to ABT. The technology involved 

in the ’017 patent relates to heating, ventilation, and air 

conditioning (“HVAC”) systems. 

The ’017 patent explains that prior art thermostats 

for forced-air HVAC systems typically have two modes of 

operation for the system fan. The first is for operating the 

fan only when there is a call for heating or cooling from 

the thermostat. This is necessary in order to distribute 

air from the heating or cooling elements to the space to be 

conditioned. Often, this is referred to as a thermostat’s

“auto” mode. The patent also explains that some prior art 

thermostats include settings for continuous system fan 

operation (i.e., “constant fan mode”), causing the fan to 

run irrespective of a call for heating or cooling. 

The ’017 patent claims an apparatus for running an 

HVAC system fan intermittently during periods when 

there is no call for heating or cooling. In particular, the 

’017 patent claims a forced central air system with a 

“recycle control” for periodic fan operation when the 

system is not heating or cooling. The periodic 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 “constant fan mode” operation. Claim 1 is the 

only independent claim at issue. It reads as follows:

1. A fan recycling control apparatus for a central 

air conditioning (CAC) system comprising:

a circulating fan;
4 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

a central air conditioning system with ducts to 

distribute cooled and heated conditioned air 

throughout a building;

a thermostat for activating and deactivating both 

the central air conditioning system and the circulating fan;

said activating causing a continuous fan operation, said deactivating causing no fan operation, 

said thermostat further having a selectable constant fan mode, and

a recycle control for periodically activating and

deactivating only the circulating fan after a preselected time period, since the central air conditioning system has been deactivated, or the circulating 

fan has been deactivated from the selectable constant fan mode.

’017 patent claim 1 (emphases added). Dependent claims 

2–5 set forth limitations directed to specific types of 

HVAC system heating and cooling modes. They also set 

forth limitations relating to various types of heat sources 

for the system.

The specification of the ’017 patent touts the benefits 

of running the fan periodically after a preselected time 

from heating or cooling deactivation based on fan “recycle 

control.” Those benefits include reduced air stagnation, 

dilution of point sources of indoor air pollution, and 

improved air cleaning. At the same time, periodic “recycle 

control” is said to reduce energy consumption in comparison to the “constant fan mode” operation of prior art 

thermostats. 

II.

Emerson manufactures various products, including 

thermostats for use in HVAC systems. One of Emerson’s 

products is the Big Blue thermostat, so named because of 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 5

its blue user interface screen. In 2009, ABT and the 

University sued Emerson for patent infringement, alleging that the so-called Comfort Circulating Fan Feature 

(“CFF”) of the Big Blue thermostat infringed claims 1–5 of 

the ’017 patent. As noted, following trial, the jury found 

the asserted claims not invalid as obvious and infringed

and awarded ABT damages. 

At trial, in support of its invalidity defense, Emerson 

relied primarily on four prior art references in the field of 

HVAC systems and thermostats. Specifically, it argued

that the asserted claims of the ’017 patent would have 

been obvious in view of U.S. Patent No. 2,013,136, to 

Frank Cornelius (“Cornelius”); U.S. Patent No. 4,838,482, 

to John Vogelzang (“Vogelzang”); U.S. Patent No. 

2,953,908, to Dan Petrone et al. (“Petrone”); and/or U.S. 

Patent No. 5,020,332, to Eiji Nakatsuno et al. (“Nakatsuno”). After the jury found the ’017 patent not invalid and 

infringed, Emerson filed a motion for JMOL to set aside 

the verdict. 

The district court denied Emerson’s motion. ABT 

Sys., 2013 WL 5567713, at *1, *3. The court reasoned 

that “[t]he jury could have reasonably found, based upon 

the evidence, that the prior art relied upon by Defendant 

did not disclose ‘periodic’ fan operation that was dependent upon the deactivation of the heating or cooling function of the system, and further that was adaptable to 

modern air conditioning systems.” Id. at *3. The court 

stated: “The jury could have also found from the evidence 

that there was a long-felt need for a periodic fan recycle 

control as disclosed in the Rudd Patent.” Id. The court 

continued that it could not “say as a matter of law that 

the claimed invention is not more than the predictable 

use of prior art elements according to their established 

functions.” Id. (internal quotation marks omitted). 

Emerson timely cross-appealed the district court’s denial 
6 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

of its motion. We have jurisdiction pursuant to 28 U.S.C. 

§ 1295(a)(1). 

DISCUSSION

I.

The standard for reviewing the grant or denial of 

JMOL is not unique to patent law; the law of the regional 

circuit therefore applies. Finisar Corp. v. DirecTV Grp., 

Inc., 523 F.3d 1323, 1328 (Fed. Cir. 2008). The Eighth 

Circuit has instructed that decisions on motions for JMOL 

are to be reviewed de novo, using the same standard that

the trial court applied. Penford Corp. v. Nat’l Union Fire 

Ins. Co., 662 F.3d 497, 503 (8th Cir. 2011). JMOL against 

a party on an issue is appropriate if “the court finds that a 

reasonable jury would not have a legally sufficient evidentiary basis to find for the party on that issue.” Fed. R.

Civ. P. 50(a). In deciding a JMOL motion, “all reasonable 

inferences [are to be drawn] in favor of the nonmoving 

party without making credibility assessments or weighing 

the evidence.” Penford, 662 F.3d at 503 (quoting Phillips 

v. Collings, 256 F.3d 843, 847 (8th Cir. 2001)). 

The standard for determining the validity of patent 

claims is governed by our precedent. We have held that 

invalidity must be established by clear and convincing 

evidence. Transocean Offshore Deepwater Drilling, Inc. v. 

Maersk Drilling USA, Inc., 699 F.3d 1340, 1347 (Fed. Cir. 

2012); see also Commil USA, LLC v. Cisco Sys., Inc., 135 

S. Ct. 1920, 1929 (2015) (noting that Congress is presumed to have chosen a “clear and convincing standard” 

to overcome the presumption of validity of an issued 

patent). A patent claim is invalid for obviousness if the

“differences between the subject matter sought to be 

patented and the prior art are such that the subject 

matter as a whole would have been obvious at the time 

the invention was made to a person having ordinary skill 

in the art to which said subject matter pertains.” 35 

U.S.C. § 103(a) (2006). Obviousness under 35 U.S.C. 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 7

§ 103 is a mixed question of fact and law. Transocean, 

699 F.3d at 1347. On appeal from a jury verdict on the 

issue of obviousness, “we review all of the jury’s explicit 

and implicit factual findings for substantial evidence. We 

then examine the legal conclusion [on the issue] de novo 

to determine whether it is correct in light of the factual 

findings that we find adequately supported.” Kinetic 

Concepts, Inc. v. Smith & Nephew, Inc., 688 F.3d 1342, 

1360 (Fed. Cir. 2012).

II.

A.

Emerson asks us to vacate the district court’s denial 

of JMOL and to hold claims 1–5 of the ’017 patent obvious

in view of the Cornelius, Vogelzang, Petrone, and/or 

Nakatsuno prior art references. 

Cornelius describes a furnace system with a circulation fan that cycles on and off when there is no call for 

heat from the thermostat. It teaches the ability “to intermittently start and stop” the fan when there is no call 

for heat in order to “circulate air within the house.” 

Cornelius col. 9 ll. 23–42. Cornelius discloses a “timing 

device” for “operating the [circulation fan] motor at predetermined intervals,” so as to keep the room condition 

maintained “from the standpoint of temperature, air 

motion and cleanliness.” Id. Cornelius does not expressly 

teach the timer being tied to the deactivation of the 

heating elements, as required by claim 1 of the ’017 

patent. 

Vogelzang discloses an HVAC system that provides 

for movement of air and prevents stagnation through a 

“cycle position” option on a thermostat. Vogelzang col. 2 

ll. 36–46 (“A conventional fan cycler 35 is connected to 

energize the fan relay 33 periodically such as several 

times an hour to maintain periodic air flow through the 

air cleaner 30 and to move the air about in the space 10.”). 
8 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

Vogelzang explains that the “invention is concerned with 

a means for cycling the operation of the fan during periods when there is no operation of the heating apparatus 

or cooling apparatus.” Id. col. 1 ll. 31–40. Like Cornelius, 

Vogelzang discloses periodic fan operation when there is 

no call for heating or cooling. Also like Cornelius, Vogelzang does not explicitly teach running the fan periodically 

as a direct function of when the heating or cooling elements are deactivated. It instead relies on a timer that is 

energized when a user places the thermostat in the “cycle 

position.” Id. col. 2 ll. 46–48.

The Petrone patent describes a control for a fan in a 

forced-air cooling system. The fan of Petrone 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. Petrone col. 6 ll. 64–71, col. 7 ll. 7–15 (“fan motor 

will be stopped and at a predetermined time delay thereafter . . . the time delay switch will cause reenergization 

of the fan motor”). The delay in Petrone is described as 

permitting sufficient time for water to drain from the 

cooling coils so as not to allow moisture to be blown into 

the area to be cooled. Id. col. 4 ll. 18–22. Petrone does 

not disclose periodic circulation of air after deactivation of 

the cooling elements, but, instead, just a “single-shot” fan 

operation for purposes of coil drainage. 

Similar to Petrone, Nakatsuno discloses a system 

wherein the system fan “may be operated for a length of 

time Δt2 a predetermined time Δt1 after the stop of the 

compressor.” Nakatsuno col. 10 ll. 7–15 (“the drive and 

stop of the indoor fan may be operatively associated with 

the drive and stop of the compressor”); see also id. at Fig. 

11(a). Unlike Petrone, however, Nakatsuno suggests that 

the fan may also be “intermittently driven . . . to improve . . . comfortableness and also to minimize . . . energy 

consumption” during periods when there is no call for 

heating or cooling from the system. Id. col. 9 l. 67 to col. 

10 l. 6. 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 9

B.

Citing KSR International Co. v. Teleflex Inc., 550 U.S. 

398, 416–17 (2007), Emerson argues that claims 1–5 of 

the ’017 patent would have been obvious because they 

represent a “combination of familiar elements according 

to known methods” that does no more than “yield predictable results.” As it did in the district court, Emerson 

focuses on the “recycle control” limitation in the last 

paragraph of claim 1, since the parties agree that the 

other limitations of claim 1, as well as the added limitations of claims 2–5, were known in the prior art. In that 

regard, Emerson contends that Mr. Rudd admitted at 

trial that the motivation for “recycle control,” as well as 

the means for implementing “recycle control,” were known 

in the art. Emerson states that Mr. Rudd admitted that a 

pause immediately following the end of a cooling cycle is

necessary to prevent moisture from blowing back into the 

system. Emerson also states that Mr. Rudd conceded that 

having a fan run periodically after the end of a cooling 

cycle would necessarily save energy when compared to 

running a fan continuously in a “constant fan mode.” 

Emerson contends that Cornelius, Vogelzang, and 

Nakatsuno all disclose a periodic fan used to circulate air 

to keep the air uniform in the air conditioned space, just 

as in claim 1 of the ’017 patent. Specifically, it states that 

Cornelius teaches a timer used to operate the system fan 

at predetermined intervals to maintain a desirable temperature; that Vogelzang indicates that periodically 

cycling the fan when there is no call for heating or cooling 

can move air throughout the space to prevent stagnation; 

and that Nakatsuno discloses a fan that can be run intermittently to improve comfort and conserve energy. 

Emerson points out that its expert, Dr. Sherman, testified 

that those three references all address the same air 

stagnation problem set forth in the ’017 patent. 
10 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

Emerson further urges that a person of ordinary skill 

would have been motivated to combine the prior art 

periodic fans of Cornelius, Nakatsuno, and Vogelzang 

with prior art timers to begin air circulation after an 

initial pause or delay. It reasons that if a person of ordinary skill had been assembling a thermostat in conjunction with the prior art periodic fan of Cornelius or 

Vogelzang, he or she would naturally have caused the fan 

to operate intermittently after the call for heating or 

cooling ended. Emerson contends that, since there would 

have been no need for the fan to circulate air immediately 

after the call for heating or cooling ended, as a matter of 

common sense, one of skill in the art would have inserted 

a pause before additional circulation was initiated. 

Moreover, in Emerson’s view, Petrone and Nakatsuno 

both teach a delay or pause in fan operation following the 

end of a heating or cooling cycle as being dependent on 

the time at which the heating or cooling cycle ends. 

Emerson therefore argues that under a proper application 

of KSR no reasonable jury could have found the asserted 

claims of the ’017 patent not obvious, and the district 

court thus erred in denying its motion for JMOL. 

In response, ABT first states that Emerson’s appeal is 

an attempt to retry credibility and factual determinations 

made by the jury. It argues that, in view of its verdict, 

the jury necessarily found ABT’s witnesses, Mr. Rudd and 

Dr. Siegel, more credible than Emerson’s technical expert, 

Dr. Sherman, and its prior art expert, Mr. Vogelzang. It 

contends also that the jury implicitly found that secondary considerations of obviousness, such as long-felt need, 

weighed in its favor. ABT asserts that the jury’s decision 

to credit its witnesses and to find secondary indicia of 

nonobviousness is supported by substantial evidence. 

Rather than mounting a strong challenge to the merits of Emerson’s theory of obviousness based on the disclosures of the prior art references, ABT takes the position 

that Emerson’s argument is flawed because the references 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 11

upon which it relies are either non-enabled or teach away. 

ABT first contends that Nakatsuno and Cornelius are 

non-enabling and, therefore, cannot be fully factored into

the obviousness analysis. Nakatsuno, it argues, only 

teaches “single-shot” fan operation after a cooling system

compressor deactivates. It states that Nakatsuno does 

not enable multiple, periodic fan cycles because only a 

single fan cycle is disclosed in the specification. Continuing, ABT argues that, like Nakatsuno, Cornelius is nonenabling because it does not disclose any electrical connection between the thermostat that controls the call for 

fan activation and the timer used to create periodic cycles

based on the end of heating. It states that the timer of 

Cornelius is not synced with the deactivation of the heating device, since the “timing device” operates “independently of temperature conditions.” Cornelius col. 1 ll.

46–50. Relatedly, ABT states that Vogelzang fails to 

disclose the periodic fan cycle being dependent on the last 

heating or cooling cycle. Finally, it urges that Nakatsuno 

and Petrone—the so-called “single-shot” fan operation 

references—teach away because they are for a purpose

(i.e., coil drainage) “unrelated” to the benefits described in 

the ’017 patent. Because ABT believes that Cornelius, 

Nakatsuno, Vogelzang, and Petrone are non-enabled or 

teach away, it argues that a person of skill in the art 

would have had no reason to combine their teachings. 

III.

Having considered the parties’ arguments and the evidence of record, we hold, as a matter of law, that the 

district court erred in denying Emerson’s motion for 

JMOL that claims 1–5 of the ’017 patent are invalid as 

obvious.

A.

Recognizing that nonobviousness was determined by a 

jury, we assign due deference to the jury’s verdict. In 

analyzing the jury’s decision, “[w]e first presume that the 
12 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

jury resolved the underlying factual disputes in favor of 

the verdict [] and leave those presumed findings undisturbed if they are supported by substantial evidence.” 

Kinetic Concepts, 688 F.3d at 1356–57 (quoting Jurgens v. 

McKasy, 927 F.2d 1552, 1557 (Fed. Cir. 1991)). Next, we

“examine the [ultimate] legal conclusion [of nonobviousness] de novo to see whether it is correct in light of the 

presumed jury fact findings.” Id. at 1357 (quoting 

Jurgens, 927 F.2d at 1557) (second alteration added). In 

recreating the facts as they may have been found by the 

jury, and in applying the Graham factors, “we assess the 

record evidence in the light most favorable to the verdict 

winner.” Richardson-Vicks, Inc. v. Upjohn Co., 122 F.3d 

1476, 1479 (Fed. Cir. 1997). The Graham factors are: (1) 

the scope and content of the prior art; (2) the differences 

between the prior art and the claims at issue; (3) the level 

of ordinary skill in the art at the time of the invention; 

and (4) objective evidence of nonobviousness. Graham v. 

John Deere Co., 383 U.S. 1, 17–18 (1966). In this case, 

there are few, if any, relevant differences between the 

parties’ understanding of the scope and content of the 

prior art, the differences between the prior art and the 

claims, and the level of ordinary skill in the art. 

As seen, the issue of nonobviousness revolves around 

the “recycle control” limitation of claim 1. That limitation

reads as follows:

[A] recycle control for periodically activating and

deactivating only the circulating fan after a preselected time period, since the central air conditioning system has been deactivated, or the circulating 

fan has been deactivated from the selectable constant fan mode. 

’017 patent claim 1 (emphases added). 

Both ABT’s expert, Dr. Siegel, and Emerson’s expert, 

Dr. Sherman, agreed that Nakatsuno discusses intermittent or periodic cycling, but only directly teaches a “single-
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 13

shot” fan cycle after a predetermined delay following

deactivation of the central air system. Dr. Siegel, explained that “[s]o that is to say there is not a periodic 

recycling of the fan [disclosed in Nakatsuno]. There is a 

single time after the air conditioning has finished its job 

of cooling, satisfied the thermostat, where the fan shuts 

off one time to allow the coil to drain.” Trial Tr. at 

107:18–22, ABT Sys., No. 4:11-cv-00374-AGF (E.D. Mo. 

Feb. 20, 2013), ECF No. 486. Nakatsuno, according to Dr. 

Siegel, addresses the problem of draining the coils after a 

cooling cycle. Dr. Siegel acknowledged, however, that 

Nakatsuno discusses “intermittent fan operation.” Id. at 

155:4–21. Dr. Siegel testified similarly with respect to the 

Petrone reference—and Dr. Sherman did not disagree: 

that it only discloses a “single-shot” fan for purposes of 

coiling drainage. Dr. Siegel’s testimony is supported by 

the record; we must therefore presume that the jury 

resolved any factual disputes about Nakatsuno’s and 

Petrone’s “single-shot” fan operation in ABT’s favor. 

Thus, a reasonable juror could have found that, while

technology for activating a fan after a predetermined time 

period following the end of a heating or cooling cycle 

existed in the prior art, it may have been implemented as 

a single event at the end of a cooling cycle for purposes of 

draining cooling coils.

The experts also were in general agreement with regard to the prior art teaching periodic fan cycling during a

period where there is no call for heating or cooling. Dr. 

Siegel testified that the timers of Cornelius and Vogelzang are not described as being directly associated with, 

or linked to, the end of a heating or cooling cycle. Further, both Dr. Siegel and Dr. Sherman agreed that the 

timer of Cornelius is not explicitly reset after the end of a 

heating or cooling cycle. In that regard, Dr. Siegel explained that Cornelius’s timer “could make the fan go on 

and off on a predetermined cycle but it couldn’t control 

that -- couldn’t link that to the operation of the thermo-
14 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

stat or the rest of the system.” Id. at 112:17–20. In other 

words, according to Dr. Siegel, Cornelius does not teach 

“activating and deactivating only the circulating fan after 

a preselected time period, since the central air conditioning system has been deactivated,” as set forth in claim 1. 

Vogelzang likewise does not teach a periodic fan that

operates as a function of when a heating or cooling cycle 

ends. Like Cornelius, Vogelzang discloses a timer that 

may be unassociated with the deactivation of the heating 

and cooling cycles.

B.

In view of the undisputed facts, as well as those that 

are presumed to have been resolved by the jury in ABT’s 

favor, the issue of obviousness thus turns on whether, at 

the time of the Rudd invention, a person of ordinary skill 

would have combined elements from the several prior art 

references. Specifically, the question is whether a person 

of skill would have combined references that disclose 

“single-shot” fan operation as a function of the time when 

heating or cooling cycles end with references that teach 

periodic fan cycles during periods of time when there is no 

call for heating or cooling.

Dr. Siegel testified that there would have been no motivation to combine elements of Cornelius and/or Vogelzang with Petrone and/or Nakatsuno to create a periodic 

fan cycle that was dependent on the end of a cooling or 

heating cycle. In his view, the references do not explain 

how a person of skill might “plug[]” the “single-shot” fan 

references into the periodic cycle references, and he stated 

that there would be logistical and enablement issues in

making a “single-shot” system work with “heating, constant fan and cooling” modes. Id. at 116:20–118:22. Dr. 

Siegel also testified that the prior art references do not 

show the control logic required by the claims of the ’017 

patent. In response, Dr. Sherman took the position that it 

would have been a logical and ordinary step for a person 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 15

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. 

The parties agree that Vogelzang sets forth every limitation of asserted claim 1 except tying periodic fan cycles 

directly to the deactivation of the heating or cooling 

elements or to the end of “constant mode” operation. 

Indeed, Vogelzang addresses the same problem identified 

by the ’017 patent (i.e., air stagnation during periods 

without heating or cooling) in a nearly identical manner. 

Vogelzang discloses a “cycle position” option for a thermostat having a “conventional fan cycler . . . connected to 

energize the fan relay” so that it can “maintain periodic 

air flow through the air cleaner 30 and . . . move the air 

about in the space.” Vogelzang col. 2 ll. 36–42. Vogelzang 

also describes energizing the relay for a “predetermined 

number of times each hour to cycle fan relay 33 such as[]

6 short operations each hour.” Id. col. 2 ll. 43–46. The 

reason for this, the patent explains, is to cycle the fan 

“during periods when there is no operation of the heating 

apparatus or cooling apparatus” in order to “provide for 

the treatment of the air through by [sic] the air cleaner.” 

Id. col. 1 ll. 32–38. Vogelzang, though, does not necessarily start the periodic cycle based on the deactivation of the 

heating and cooling elements. 

For its part, Cornelius discloses elements similar to 

Vogelzang. It teaches a furnace that works in conjunction 

with a thermostat and a timing device “to intermittently 

start and stop the [circulation fan] motor 14 for ventilating a room or rooms when the room thermostat 110 does 

not call for heat.” Cornelius col. 9 ll. 23–26. As in Vogelzang and the ’017 patent, the stated purpose of the invention is to address stagnation, temperature, and 

cleanliness. Id. col. 9 ll. 40–42; see also id. col. 9 ll. 26–34 

(“In particular this scheme is adapted for the ventilation 

of sleeping rooms where the windows remain closed 

during the night and when the room thermostat is manu-
16 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

ally or automatically lowered to produce a temperature of, 

say, 55° F. There are many nights when the furnace 

would not operate as the house would not cool to this 

temperature.”). Cornelius does not, however, disclose a 

“constant fan mode,” as required by claim 1. And, it does 

not teach necessarily setting the timing device as a function of the end of a heating cycle. 

Nakatsuno, however, does disclose operation of a system fan at a predetermined time following the deactivation of an air conditioning compressor. Nakatsuno states, 

in relevant part:

As far as the intermittent operation of the indoor 

fan is concerned, the drive and stop of the indoor 

fan may be operatively associated with the drive 

and stop of the compressor as shown in FIG. 11(a) 

and, alternatively, the indoor fan may be operated 

for a length of time Δt2 a predetermined time Δt1 

after the stop of the compressor as shown in FIG. 

11(b). 

Nakatsuno col. 10 ll. 7–15 (emphases added); see also id.

at Figs. 11(a), (b). Nakatsuno thus discloses using the 

end of a cooling cycle as part of the function for turning on 

the system fan during periods where there is no call for 

heating or cooling. Additionally, even presuming that

Nakatsuno fails to disclose periodic fan cycles by only 

specifically describing a “single-shot” fan, it plainly suggests such cycles: 

[An] indoor fan can be intermittently driven at the 

predetermined number of revolution [sic] regardless of whether the compressor is being operated 

or held still, so that the difference between respective temperatures in top and bottom regions in the 

space to be air-conditioned can be minimized by 

the circulation effect thereby to improve the comfortableness and also to minimize the energy consumption.
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 17

Id. col. 9 l. 67 to col. 10 l. 6 (emphasis added).1

In KSR, the Supreme Court instructed 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.” 550 U.S. at 416. The 

Court stated that “[i]f a person of ordinary skill can 

implement a predictable variation [of a prior art reference 

with other prior art components], § 103 likely bars its 

patentability.” Id. at 417. Here, the timer of Vogelzang

or Cornelius, modified by the predetermined and compressor-dependent interval of Nakatsuno or Petrone, 

would have yielded a predictable result: the system fan 

would activate periodically following the end of a heating 

or cooling cycle—the invention claimed in the ’017 patent.2

1 Petrone teaches a fan that stops when the call for 

cooling ends and restarts after a predetermined interval. 

However, it does not teach such operation for the purpose 

of alleviating air stagnation. Rather, it teaches a delay 

for purposes of allowing the cooling coils to drain condensation. Petrone col. 4 ll. 18–22, col. 7 ll. 7–15.

2 The cited references do not “teach away,” as ABT 

argues, because it is clear that none come near to “‘criticiz[ing], discredit[ing], or otherwise discourag[ing]’ investigation into the invention claimed.” DePuy Spine, Inc. v. 

Medtronic Sofamor Danek, Inc., 567 F.3d 1314, 1327 (Fed. 

Cir. 2009) (quoting In re Fulton, 391 F.3d 1195, 1201 

(Fed. Cir. 2004)). Additionally, ABT’s suggestion that 

Cornelius and Nakatsuno are non-enabled is misplaced, 

since even “[a] non-enabling reference may qualify as 

prior art for the purpose of determining obviousness,” 

Symbol Tech., Inc. v. Opticon, Inc., 935 F.2d 1569, 1578 

(Fed. Cir. 1991), and even “an inoperative device . . . is 

prior art for all that it teaches,” Beckman Instruments, 

 
18 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

It is well settled that, even where references do not 

explicitly convey a motivation to combine, “any need or 

problem known in the field of endeavor at the time of 

invention and addressed by the patent can provide a 

reason for combining the elements in the manner 

claimed.” Id. at 420. We have made clear that “a 

court . . . may find a motivation to combine prior art 

references in the nature of the problem to be solved.” 

Ruiz v. A.B. Chance Co., 357 F.3d 1270, 1276 (Fed. Cir. 

2004). As pertinent here, “this form of motivation to 

combine evidence is particularly relevant with simpler 

mechanical technologies.” Id.; see also Pro-Mold & Tool 

Co., Inc. v. Great Lakes Plastics, Inc., 75 F.3d 1568, 1573 

(Fed. Cir. 1996).

In our view, if, at the time of the invention claimed in 

the ’017 patent, a person of ordinary skill had looked at 

Vogelzang, he or she would have found it nearly obvious 

from that disclosure itself to set the periodic fan to run as 

a function of when the heating or cooling cycle ended. 

That is because the nature of the problem to be solved in 

both the ’017 patent and Vogelzang (as well as Cornelius 

and Nakatsuno) is to alleviate air stagnation during 

periods of no heating or cooling. As Dr. Sherman testified, “a person of ordinary skill would realize that the 

easiest and best thing to do would be to start with an off 

period, a delay before doing this cycling since the purpose 

is to mix the air and the air has just been mixed.” Trial 

Tr. at 69:20–25, ABT Sys., No. 4:11-cv-00374-AGF (E.D. 

Mo. Feb. 19, 2013), ECF No. 485. Thus, setting a delay 

timer or control based on the end of the heating or cooling 

cycle, similar to the concept in Nakatsuno or Petrone, 

would have been naturally implemented by a person 

skilled in the art. In other words, it would have been 

Inc. v. LKB Produkter AB, 892 F.2d 1547, 1551 (Fed. Cir. 

1989).

 
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 19

obvious to set the timer of Vogelzang or Cornelius based 

on the end of a heating or cooling cycle, as disclosed in 

Nakatsuno (or Petrone), regardless of for how long the 

time interval was to be set. 

C. 

The fourth Graham factor, objective evidence of nonobviousness, includes factors such as “commercial success, 

long-felt but unresolved need, failure of others, copying, 

and unexpected results.” Ruiz v. A.B. Chance Co., 234 

F.3d 654, 663 (Fed. Cir. 2000); see also id. at 667 (explaining that “secondary considerations, when present, must be 

considered in determining obviousness”). As noted, in 

arguing in support of the district court’s denial of Emerson’s JMOL motion, ABT relies on the considerations of 

commercial success and long-felt need, the latter of which 

was cited by the district court in its opinion. ABT Sys., 

2013 WL 5567713, at *3. We are not persuaded by ABT’s 

argument.

ABT’s reliance on commercial success is undermined 

as a matter of law by ABT’s failure to introduce evidence 

related to the nexus between periodic fan operation and 

the commercial success of products embodying the invention claimed in the ’017 patent. See Demaco Corp. v. F. 

Von Langsdorff Licensing Ltd., 851 F.2d 1387, 1391 (Fed. 

Cir. 1988) (explaining that “nexus” is used to “designate a 

legally and factually sufficient connection between the 

proven success and the patented invention”). The items

that ABT presented as evidence in support of its commercial success argument were, in large part, advertisements 

and press releases for Mr. Rudd’s products, not market 

share information or industry praise or recognition for the 

novelty of the fan recycler feature claimed in the ’017 

patent. See In re Huang, 100 F.3d 135, 140 (Fed. Cir. 

1996) (“This court has noted in the past that evidence 

related solely to the number of units sold provides a very 

weak showing of commercial success, if any.”); Demaco, 
20 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

851 F.2d at 1392 (“When the thing that is commercially 

successful is not coextensive with the patented invention . . . the patentee must show prima facie a legally 

sufficient relationship between that which is patented 

and that which is sold.”). Also, there is no evidence in the 

record that Emerson’s products were sold as a result of 

the Big Blue’s CFF recycler feature. The record is thus 

lacking evidence that the alleged success of Emerson’s 

product in the market was driven by any novel aspect of 

the claimed invention. J.T. Eaton & Co. v. Atl. Paste & 

Glue Co., 106 F.3d 1563, 1571 (Fed. Cir. 1997) 

(“[C]ommercial success of the product must be due to the 

merits of the claimed invention beyond what was readily 

available in the prior art.”). 

We are also not persuaded by ABT’s argument that 

commercial success is demonstrated by the number of 

licenses taken under the ’017 patent. While licenses can 

sometimes tilt in favor of validity in close cases, they

cannot by themselves overcome a convincing case of 

invalidity without showing a clear nexus to the claimed 

invention. Iron Grip Barbell Co. v. USA Sports, Inc., 392 

F.3d 1317, 1324 (Fed. Cir. 2004) (“Our cases specifically 

require affirmative evidence of nexus where the evidence 

of commercial success presented is a license, because it is 

often ‘cheaper to take licenses than to defend infringement suits.’”); SIBIA Neurosciences, Inc. v. Cadus Pharm. 

Corp., 225 F.3d 1349, 1358 (Fed. Cir. 2000) (“[T]he mere 

existence of these licenses is insufficient to overcome the 

conclusion of obviousness, as based on the express teachings in the prior art that would have motivated one of 

ordinary skill to modify [other prior art].”). Here, ABT 

points to no evidence that the licenses it cites were taken 

based on the merits of the invention claimed in the ’017 

patent. See Iron Grip, 392 F.3d at 1324.

ABT’s argument that there was a long-felt need for 

the invention embodied in the claims of the ’017 patent 

likewise does not lead us to a different result. The disclo-
ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 21

sures of the prior art references—and especially Vogelzang’s “cycle position” option for running a system fan 

“during periods when there is no operation of the heating 

apparatus or cooling apparatus” to help mix air—

eliminate any serious contention that there was a longfelt need for the invention claimed in the ’017 patent. See

Ormco Corp. v. Align Tech., Inc., 463 F.3d 1299, 1311–12

(Fed. Cir. 2006) (“[I]f the feature that creates the commercial success was known in the prior art, the success is not 

pertinent.”). ABT’s argument of a long-felt need ignores 

the scope of claim 1, which does not set forth limits on 

how long or how often periodic fan operation is to be 

performed. In addition, claim 1 does not limit in any way

the control logic for implementing such periodic operation. 

D.

In sum, even assuming that the jury correctly resolved pertinent factual disputes in favor of ABT, the 

prior art still renders the claims of the ’017 patent obvious 

as a matter of law. See Boston Sci. Scimed, Inc. v. Cordis 

Corp., 554 F.3d 982, 990 (Fed. Cir. 2009) (“When we 

consider that, even in light of a jury’s findings of fact, the 

references demonstrate an invention to have been obvious, we may reverse its obviousness determination.”); 

Richardson-Vicks, 122 F.3d at 1479 (a jury verdict “does 

not mean that we are free to abdicate our role as the 

ultimate decision maker on the question of obviousness. 

That decision remains within our province”). Here, all of 

the claimed limitations are expressly found in the cited 

prior art references. At the same time, the motivation or 

rationale for combining those references can be found in 

the nature of the problem addressed, if not directly from

the disclosures of the references themselves. Finally, 

ABT’s argument based upon secondary considerations of 

nonobviousness is not supported by the record. Thus, we 

hold that claims 1–5 of the ’017 patent are invalid as a 

matter of law by reason of obviousness.
22 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. 

CONCLUSION

For the foregoing reasons, we vacate the district 

court’s denial of Emerson’s JMOL motion and reverse the 

judgment that claims 1–5 of the ’017 patent are not

invalid as obvious. We also vacate the judgment of infringement. The case is remanded to the district court for 

entry of judgment in favor of Emerson and dismissal of 

ABT’s complaint. 

REVERSED-IN-PART, VACATED-IN-PART, and 

REMANDED

COSTS

Each party shall bear its own costs.