Court Opinion

ID: 2669609
Source: CourtListenerOpinion
Date Created: 2014-04-11 15:39:21.126789+00
Date Added: 2024-06-11T13:03:59.075585
License: Public Domain

NOTE: This disposition is nonprecedential.

  United States Court of Appeals
      for the Federal Circuit
                ______________________

      JACK O. CARTNER AND MOTRIM, INC.,
               Plaintiffs-Appellants,

                           v.

                ALAMO GROUP, INC.,
               Defendant-Cross-Appellant
                ______________________

                   2013-1293, -1314
                ______________________

    Appeals from the United States District Court for the
Northern District of Ohio in No. 07-CV-1589, Judge
Lesley Brooks Wells.
                ______________________

                Decided: April 11, 2014
                ______________________

   PHILIP J. MOY, JR., Fay Sharpe LLP, of Cleveland,
Ohio, argued for plaintiffs-appellants.

    BRYAN A. SCHWARTZ, Benesch, Friedlander, Coplan &
Aronoff, LLP, of Cleveland, Ohio, argued for defendant-
cross-appellant.
                 ______________________
   Before DYK, MOORE, and WALLACH, Circuit Judges.
2                             CARTNER    v. ALAMO GROUP, INC.

WALLACH, Circuit Judge.
     This is a patent infringement case in which Jack O.
Cartner and Motrim, Inc. (“Cartner”) asserted infringe-
ment of claims 5 and 12 of U.S. Patent No. 5,197,284
(“the ’284 patent”) against Alamo Group, Inc. (“Alamo”).
After years of litigation, including a prior appeal to this
court, the parties agreed to a consent judgment of nonin-
fringement, which the district court entered on March 2,
2010. Soon after, Alamo moved for exceptional-case
attorney fees under 35 U.S.C. § 285 (2006). The district
court found the case was exceptional and awarded Alamo
$358,516.44 in post-appeal litigation attorney fees and
costs. Cartner appeals the district court’s exceptional
case finding, and Alamo cross appeals the amount of the
attorney fees award. Because the district court properly
found this case exceptional, and because it did not abuse
its discretion in determining the fee award, this court
affirms.
                      BACKGROUND
                    I. The ’284 Patent
    Hydraulically-driven motors are often used to power
lawn mowers, ditchers, and similar equipment. Prior art
hydraulic motors without an effective deceleration system
were problematic, because: (1) the cutting blades could
continue to freewheel and cause damage to the surround-
ing area, or (2) the motor could come to a “precipitous
stop,” placing “great strain[ ]” on the motor and “the
fasteners connecting the cutting blade to the motor.” ’284
patent col. 1 ll. 25–49. The ’284 patent claims systems
and methods for decelerating a hydraulic motor by using
a “deceleration circuit.” Id. col. 1 ll. 13–16. The ’284
invention “gradually brings a hydraulic motor to a stop”
after communication is blocked between the motor and
the pump. Id. col. 2 ll. 58–60. Figure 1 depicts the pre-
ferred embodiment of the claimed deceleration circuit.
CARTNER   v. ALAMO GROUP, INC.                            3

Id. Fig. 1. The system includes a hydraulic pump 10, a
hydraulic motor 20, and a hydraulic circuit that connects
the pump to the motor. The hydraulic circuit has three
fluid lines: (1) the first fluid line 14 extends from the
pump 10 to the motor 20 through a control valve 16, (2)
the second fluid line 24 extends between the control valve
16 and the motor 20, and (3) the third fluid line 40 con-
nects the first fluid line to the second fluid line, and
includes a relief valve 42 and a flow control orifice 44.
    The control valve 16 must be in the “open” position for
the hydraulic motor to operate. When the control valve
16 is open, fluid is pumped from the reservoir 12 through
fluid line 14, past the motor 20, down the second fluid line
4                               CARTNER   v. ALAMO GROUP, INC.

24, and back into the reservoir 12. This hydraulic circuit
causes the motor to rotate for the purpose of, e.g., turning
blades to cut the grass.
    Closing the control valve 16 traps the fluid in the up-
per portions of the fluid lines, and “gradually brings [the]
hydraulic motor to a stop.” Id. col. 2 l. 58. When the
control valve is closed, the third fluid line transports fluid
between the first and second fluid lines, “thereby enabling
the motor to continue turning.” Id. col. 2 ll. 50–51. The
relief valve 42 and flow control orifice 44, located in the
third fluid line, “restrict[ ] the rate of fluid flow” past the
motor, id. col. 2 ll. 51–53, and “limit[ ] the speed” at which
the fluid can flow past the motor, id. col. 2 ll. 19–20. The
motor eventually comes to a complete stop.
    Asserted claim 5 recites:
    A hydraulic motor deceleration system comprising:
    a pump;
    a hydraulic motor;
    a hydraulic circuit interconnecting said pump and
        said motor, said circuit comprising:
    a first hydraulic fluid line extending between said
         pump and said motor,
    a first control valve located in said first fluid line
         for controlling the communication of fluid be-
         tween said pump and said motor,
    a second hydraulic fluid line interconnecting said
        control valve and said motor,
    a third hydraulic fluid line interconnecting said
        first and second hydraulic lines,
    a relief valve located in said third fluid line, and
    a flow control orifice located in said third fluid
        line, and said flow control orifice being con-
CARTNER   v. ALAMO GROUP, INC.                              5

        stantly operative, said third fluid line allowing
        a flow of hydraulic fluid from said second fluid
        line to said first fluid line even when said con-
        trol valve is in a closed position, as regulated
        by said relief valve, and wherein said flow con-
        trol orifice limits the speed with which such
        flow takes place.
Id. col. 8 l. 48–col. 9 l. 4 (emphasis added to relevant claim
language). The other asserted claim, claim 12, states:
    A method for decelerating a hydraulic motor when
    the motor is disconnected from a hydraulic pump,
    said method comprising:
    providing a hydraulic circuit interconnecting the
        motor and the pump, said hydraulic circuit in-
        cluding first and second hydraulic fluid lines
        which communicate, respectively, with an in-
        let and an outlet of said motor and a first
        valve which controls a flow of hydraulic fluid
        from said pump to said motor through at least
        one of said first and second fluid lines;
    blocking a flow of fluid from said motor to said
        pump;
    allowing a flow of fluid between said first and sec-
        ond fluid lines without a loss of fluid thereby
        enabling said motor to continue turning; and
    allowing the speed of rotation of said motor by re-
        stricting the rate of flow or fluid through said
        first and second fluid lines wherein said step
        of slowing comprises the subsidiary steps of:
    providing a third hydraulic fluid line which selec-
        tively communicates said first and second flu-
        id lines as regulated by a relief valve; and
    providing a flow control orifice in said third fluid
        line, said flow control orifice being constantly
6                             CARTNER   v. ALAMO GROUP, INC.

       operative to throttle fluid flow through said
       third fluid line.
Id. col. 10 ll. 1–26 (emphases added to relevant claim
terms).
         II. The Parties and Procedural History
    Plaintiff-Appellant Motrim sells industrial mowing
and trimming equipment and is the exclusive licensee of
the ’284 patent. Cartner is Motrim’s president and the
named inventor of the ’284 patent. Alamo also supplies
mowing and trimming equipment, including the two
different brands of mowers accused in this case: (1) the
Tiger mowers and (2) the Alamo mowers.
    On May 30, 2007, Cartner filed a patent infringement
complaint against Alamo, asserting, inter alia, claims 5
and 12 of the ’284 patent. In particular, Cartner asserted
claim 12 against the Alamo mowers, and claims 5 and 12
against the Tiger mowers. On May 21, 2008, the district
court issued an order construing the disputed claim
terms. Cartner v. Alamo Grp., Inc. (Cartner I), No. 1-07-
CV-1589, 2008 WL 2169005 (N.D. Ohio, May 21, 2008).
The parties then filed a joint stipulation that the court’s
construction of one phrase in claims 5 and 12—“said flow
control orifice being constantly operative”—rendered the
claims invalid for lack of written description under 35
U.S.C. § 112, and the district court entered final judgment
of patent invalidity.
    Cartner appealed, and this court modified the con-
struction of the “control orifice” limitation and vacated
and remanded the judgment of invalidity on June 17,
2009. Cartner v. Alamo Grp., Inc. (Cartner II), 333 F.
App’x 565 (Fed. Cir. 2009). On remand, the parties re-
sumed discovery in the district court with respect to
infringement. In January 2010, Cartner contacted Ala-
mo’s counsel to propose dismissing the action with preju-
dice. The parties filed a Joint Motion for Consent
CARTNER   v. ALAMO GROUP, INC.                             7

Judgment on February 22, 2010, and the district court
entered the consent judgment of noninfringement on
March 2, 2010.
    On March 16, 2010, Alamo filed a motion to declare
the case exceptional pursuant to 35 U.S.C. § 285. Alamo
contended Cartner’s infringement claims were frivolous
because they ignored multiple limitations in claims 5 and
12, including: (1) claim 12’s limitation that the “motor is
disconnected from a hydraulic pump” (the “disconnected”
limitation), (2) claim 12’s requirement that there is no
loss of fluid between the first and second fluid lines dur-
ing deceleration (the “loss of fluid” limitation), and (3)
claim 5 and 12’s limitation that the relief valve in the
third fluid line regulates the flow of fluid between the
second and first fluid lines (the “relief valve” limitation).
    The motion was referred to the magistrate judge, who
found, by clear and convincing evidence, that the case was
exceptional. Over Cartner’s objection, the district court
adopted the magistrate judge’s recommendation that
Alamo had proved the case was exceptional under 35
U.S.C. § 285. Cartner v. Alamo Grp., Inc. (Cartner III),
No.1:07-CV-1589, 2011 WL 4457665 (N.D. Ohio Sept. 23,
2011). The district court referred the matter back to the
magistrate judge to determine the amount of the attorney
fee award.
    Alamo requested attorney fees and costs in the
amount of $608,899.55, calculated from August 10, 2007,
the date when Alamo provided Cartner with a copy of the
Tiger mower schematics. The magistrate judge granted-
in-part and denied-in-part, awarding $358,516.44 in
attorney fees and costs calculated from June 17, 2009, the
date of this court’s decision in Cartner II vacating the
district court’s invalidity judgment. The district court
again adopted the magistrate judge’s recommendation,
this time over Alamo’s objection. Cartner v. Alamo Grp.,
8                             CARTNER   v. ALAMO GROUP, INC.

Inc. (Cartner IV), No. 1:07-CV-1589, 2013 WL 943844
(N.D. Ohio Mar. 8, 2013).
    Cartner filed a timely appeal, and Alamo noted a
cross-appeal. This court has jurisdiction pursuant to 28
U.S.C. § 1295(a)(1) (2012).
                       DISCUSSION
    On appeal, Cartner argues its infringement conten-
tions were objectively reasonable and that the district
court clearly erred in finding the case exceptional. Alamo
cross appeals the attorney fees award, contending Cart-
ner’s infringement arguments became frivolous long
before this court’s invalidity decision, and arguing the fee
award should be calculated from an earlier date.
    A “court in exceptional cases may award reasonable
attorney fees to the prevailing party.” 35 U.S.C. § 285.
For an award of attorney fees under § 285, the prevailing
party must “establish by clear and convincing evidence
that the case is ‘exceptional,’” and “a court must deter-
mine whether an award of attorneys’ fees is appropriate
and, if so, the amount of the award.” Highmark, Inc. v.
Allcare Health Mgmt. Sys., Inc., 687 F.3d 1300, 1308 (Fed.
Cir. 2012).
    One way to show a case is exceptional is to prove liti-
gation misconduct, which “includes advancing frivolous
arguments during the course of the litigation or otherwise
prolonging litigation in bad faith.” Id. at 1315–16; see
also Taurus IP, LLC v. DaimlerChrysler Corp., 726 F.3d
1306, 1328 (Fed. Cir. 2013) (“[A] case can be found excep-
tional when a party prolongs litigation in bad faith.”); see
also id. (explaining “the rule that a party cannot assert
baseless infringement claims and must continually assess
the soundness of pending infringement claims, especially
after an adverse claim construction”). An argument is
frivolous when it is “at least objectively unreasonable” at
the time it was made. Highmark, 687 F.3d at 1316. This
CARTNER   v. ALAMO GROUP, INC.                           9

court reviews de novo whether an argument was objec-
tively unreasonable. Id.
     An attorney fees award under § 285 “‘must bear some
relation to the extent of the misconduct,’” so an argument
that was frivolous for only part of the litigation must be
limited accordingly. Id. (quoting Special Devices, Inc. v.
OEA, Inc., 269 F.3d 1340, 1344 (Fed. Cir. 2001)). A fee
award under § 285 may only “compensate a party for the
‘extra legal effort to counteract the [ ] misconduct.’” Id.
(quoting Beckman Instr., Inc. v. LKB Produkter AB, 892
F.2d 1547, 1553 (Fed. Cir. 1989)) (alteration in original).
The district court’s award of attorney fees is reviewed for
an abuse of discretion. MarcTec, LLC v. Johnson &
Johnson, 664 F.3d 907, 916 (Fed. Cir. 2012).
                     I. Cartner’s Appeal
       A. The “Without a Loss of Fluid” Limitation
    The district court held it was frivolous for Cartner to
argue that the Tiger mowers read on claim 12’s “without a
loss of fluid” limitation. Cartner III, 2011 WL 2169005, at
*3. Claim 12 recites a method for decelerating a hydrau-
lic motor, including the steps of “blocking a flow of fluid
from [the] motor to [the] pump” and “allowing a flow of
fluid between [the] first and second fluid lines without a
loss of fluid thereby enabling said motor to continue
turning.” ’284 patent col. 10 ll. 13–15 (emphasis added).
    Cartner added the “without a loss of fluid” limitation
after the Patent and Trademark Office (“PTO”) examiner
rejected claim 12 (then proposed claim 18) as anticipated
by several patents, including U.S. Patent No. 4,732,076 to
Ewald (“Ewald”). See J.A. 103, 114. Cartner argued to
the PTO that proposed claim 18 was patentable over
Ewald, because Ewald lost at least some fluid into the
reservoir during deceleration, and thus did not circulate
fluid between the first and second fluid lines “without a
loss of fluid.” J.A. 115.
10                             CARTNER   v. ALAMO GROUP, INC.

    After reviewing this prosecution history, the district
court determined that “reasonable review” of the Tiger
mower schematic, which Alamo gave to Cartner early in
the litigation, “indicates the similarity between the Tiger
and the Ewald systems in that both evidence a loss of
fluid to the tank.” Cartner III, 2011 WL 4457665, at *3.
Because Cartner had disclaimed such a system to obtain
the ’284 patent, the district court held it was unreasona-
ble for Cartner to allege that the Tiger mowers met this
limitation.
   The Tiger mowers decelerate by opening logic valve
2A (depicted below), and allowing fluid to flow from the
pump, through the bypass line, into the reservoir.

J.A. 938. This normal deceleration process does not
recirculate fluid between the first and second lines “with-
out a loss of fluid,” but instead requires diverting fluid to
the tank.
CARTNER   v. ALAMO GROUP, INC.                               11

    Cartner nevertheless argues that he reasonably be-
lieved the Tiger mower could meet the “without a loss of
fluid” limitation “under conditions of emergency shut-
down.” Appellants’ Reply Br. 5. Suddenly shutting down
the motor could establish a third fluid line between the
motor’s input and output lines, according to Cartner,
because “the pump would cease to operate and the spin-
ning motor would act as a pump, creating suction on its
intake side.” Id. at 4. Cartner’s proposed third line
passes from the second line to the first line through the
brake relief valve and the makeup line, as shown in
Figure 7 below:

J.A. 943 (proposed third line in bold). Cartner maintains
the proposed third line could bring fluid from the second
fluid line (line B) to the first fluid line (line A) as required
by claim 12. See ’284 patent col. 10 ll. 1–3, 13–15 (claim-
12                            CARTNER   v. ALAMO GROUP, INC.

ing a method comprising “allowing a flow of fluid between
[the] first and second fluid lines”).
    The limitation requires more, however; the fluid must
flow through the third line “without a loss of fluid” to the
tank. Id. col. 10 ll. 14. Cartner explains that “[w]hether
any fluid would flow to the tank would be a function of the
dynamic pressure conditions at that time.” Appellants’
Reply Br. 4. Cartner’s theory is that such “dynamic
pressure conditions” would at least sometimes circulate
fluid “without any loss of fluid” to the reservoir. Id.
Cartner effectively argues that the Tiger mower infringes
the “without a loss of fluid” limitation whenever “some
fluid recirculates” past the motor. J.A. 927 (magistrate
judge’s Report & Recommendation). This argument is
objectively unreasonable because “by that interpretation
there would be no ‘loss of fluid’ in Ewald’s device either.”
J.A. 927.
    The district court properly held it was frivolous to ar-
gue the Tiger mower infringed when “reasonable review”
of the Tiger schematic showed its similarity to the prior
art Ewald system. Cartner III, 2011 WL 4457665, at *3.
Cartner does not contest that the Tiger schematic depicts
a system similar to Ewald in this respect.
CARTNER   v. ALAMO GROUP, INC.                               13

See J.A. 942 (showing the Ewald diagram on the left, and
the Tiger schematic on the right). The district court
correctly concluded it was objectively unreasonable for
Cartner to argue the Tiger mower could meet the “without
a loss of fluid” limitation when that limitation was added
to distinguish a system that was, in relevant part, the
same as the Tiger mower.
     B. The “Regulated by a Relief Valve” Limitation
     Claims 5 and 12 recite a third fluid line that “selec-
tively communicates [the] first and second fluid lines as
regulated by [a] relief valve.” ’284 patent col. 9 l. 1, col. 10
l. 22 (emphasis added). The parties agreed this limitation
requires that the “‘[r]elief valve controls whether and how
much fluid may flow’” in the third line. Cartner III, 2011
WL 4457665, at *4.
     As discussed, Cartner argues the Tiger mowers con-
tain a third fluid line that flows from the second fluid line
to the first fluid line through the brake relief valve and
the makeup line. In his arguments on the “without a loss
of fluid” limitation, Cartner stated the fluid would follow
this path during an emergency shutdown, when “dynamic
pressure conditions” diverted the fluid away from its
normal route into the reservoir. See Appellants’ Br. 30;
Reply Br. 2, 4. In an attempt to also meet the “regulated
by a relief valve” limitation, Cartner argues it is the brake
relief valve in the Tiger mower, not the dynamic pressure
conditions, that “controls” fluid in the proposed “third
line.” The district court found this contention frivolous,
because “Mr. Cartner himself acknowledged factors other
than the brake relief valve on the Tiger mower regulated
‘whether and how much fluid’ flowed through the Tiger
mower ‘makeup line.’” Cartner III, 2011 WL 4457665, at
*3.
    On appeal, Cartner argues the brake relief valve does
“control” how much fluid flows through the third line
because the brake relief valve must be open for fluid to
14                             CARTNER   v. ALAMO GROUP, INC.

follow that path. Appellants’ Br. 26–27, 31–32. Although
conceding the brake relief valve is not the sole mechanism
controlling such flow, Cartner contends that the parties’
agreed construction requires only that the relief valve
“controls” the flow, not that it “solely controls” it. Appel-
lants’ Reply Br. 6.
    The district court properly determined this argument
was frivolous and contradicted by Cartner’s own argu-
ments on the “without a loss of fluid” limitation. Cartner
himself states that fluid will travel down this proposed
third fluid line only when (1) there is an emergency
shutdown and (2) the dynamic pressure conditions force
the fluid to recirculate past the motor, instead of following
the second fluid line toward the reservoir. See, e.g., id. at
4. Although the brake relief valve must be open for the
fluid to follow this path, there is no reasonable argument
that the brake relief valve “controls whether and how
much fluid may flow.” The district court correctly held
Cartner’s arguments with respect to the “relief valve”
limitation were frivolous.
             C. The “Disconnected” Limitation
     Finally, the district court found Cartner engaged in
litigation misconduct with respect to claim 12’s “discon-
nected” limitation. In particular, it found: (1) Cartner’s
literal infringement argument was frivolous, and (2)
Cartner pursued its doctrine of equivalents argument in
bad faith. J.A. 9.
    The preamble of claim 12 recites a method for decel-
erating a hydraulic motor “when the motor is disconnect-
ed from a hydraulic pump.” 1 ’284 patent col. 10 l. 2.

     1  Cartner does not contest that the preamble consti-
tutes a limitation of claim 12. See Applied Materials, Inc.
v. Adv. Semiconductor Materials Am., Inc., 98 F.3d 1563,
1572–73 (Fed. Cir. 1996) (“Whether a preamble stating
CARTNER   v. ALAMO GROUP, INC.                            15

During the Markman proceeding in the district court,
Cartner argued the “disconnected” limitation means that
“[t]he pump is not delivering pressurized hydraulic fluid
to the motor.” J.A. 68. The district court rejected this
broad interpretation, instead concluding the “mechanical
condition of disconnection” in claim 12 requires that “the
pump and motor are not connected, such that fluid cannot
flow from the pump to the motor.” Cartner I, 2008 WL
2169005, at *10.
    Cartner did not contest this claim construction on ap-
peal to this court, but nonetheless continued to assert
infringement on remand until moving to dismiss the case
on February 22, 2010. The district court found that “[a]ny
allegation of literal infringement” after the claim con-
struction order was frivolous. Cartner III, 2011 WL
4457665, at *4. Cartner conceded it would be frivolous to
argue the Alamo and Tiger mowers literally meet the
“disconnected” limitation, but argued it was “prepared to
assert infringement” under the doctrine of equivalents.
Appellants’ Br. 36. The district court rejected this argu-
ment, finding that Cartner’s “presumptive reliance upon
an unrevealed theory of infringement by equivalents[ ]
amount[ed] to bad faith sufficient to find exceptional
circumstances under § 285.”       Cartner III, 2011 WL
4457665, at *4 (explaining Cartner “provide[d] no indica-
tion, during the entire prosecution of the case, that it
regarded the ‘disconnected’ limitation as an infringement
by equivalents”).
    On appeal, Cartner says he was not required to dis-
close his reliance on the doctrine of equivalents. Although

the purpose and context of the invention constitutes a
limitation of the claimed process is determined on the
facts of each case in light of the overall form of the claim,
and the invention as described in the specification and
illuminated in the prosecution history.”).
16                            CARTNER   v. ALAMO GROUP, INC.

the Northern District of Ohio’s current local patent rules
require disclosure of doctrine of equivalents contentions,
N.D. Ohio Local Patent Rule 3.1, Cartner argues those
rules did not become effective until October 22, 2009, over
two years after this case was filed, Appellants’ Br. 34.
The district court could have applied the new rules to this
action pursuant to Local Patent Rule 1.6, but apparently
never did. See N.D. Ohio Local Patent Rule 1.6 (“For
actions pending before the effective date, the Court will
confer with the parties and apply these rules as the Court
deems practicable.”). Accordingly, Cartner maintains
that “unless served with an interrogatory asking whether
[he was] relying on the doctrine of equivalents, [he was]
under no obligation to voluntarily reveal during fact
discovery this aspect of [his] theory of the case to Alamo.”
Appellants’ Br. 34.
    However, Alamo did serve Cartner with exactly that
interrogatory. It asked Cartner to “[d]escribe in detail
how the asserted patent claims apply or correspond to
each Accused Product, providing a claim(s) chart explain-
ing how each limitation of the asserted patent claims is
present in each Accused Product.” J.A. 659. Cartner
provided an amended response after the adverse claim
construction, 2 in which he continued to allege that various
aspects of the Alamo and Tiger mowers literally met each
relevant claim limitation. He did not mention the doc-
trine of equivalents. See J.A. 663–64. In spite of Cart-
ner’s ongoing duty pursuant to Fed. R. Civ. P. 26(e)(1)(A),
he never disclosed his intention to rely on the doctrine of
equivalents to meet the “disconnected” limitation. See
Fed. R. Civ. P. 26(e)(1)(A) (requiring parties to supple-

     2  The district court’s claim construction order was
issued on May 21, 2008, and Cartner provided his amend-
ed response over two months later on August 8, 2008. See
Cartner I, 2008 WL 2169005; J.A. 660.
CARTNER   v. ALAMO GROUP, INC.                            17

ment interrogatory responses “in a timely manner” upon
learning “that in some material respect the disclosure or
response is incomplete or incorrect”).
    The district court found “Cartner was not forthright
in answering Alamo’s interrogatories, allowing Alamo to
mistakenly cull fact discovery and witness depositions
predicated on [Cartner’s] literal infringement theory.”
Cartner III, 2011 WL 4457665, at *4. On appeal, Cartner
argues he did not interpret the interrogatory to require
disclosure of his doctrine of equivalents theory and there-
fore did not act in bad faith by failing to disclose it. Oral
Arg. at 5:15–5:33, 6:10–6:30, Cartner v. Alamo Grp., Nos.
2013-1293, -1314, available at http://www.cafc.uscourts.
gov/oral-argument-recordings/all/cartner.html. Although
the interrogatory did not mention the doctrine of equiva-
lents by name, it asked Cartner to “[d]escribe in detail
how the asserted patent claims apply or correspond to
each Accused Product.” J.A. 659 (emphasis added). This
language is best interpreted to require disclosure of all
theories of infringement, including whether infringement
is under the doctrine of equivalents.
     While Cartner claims he had a good faith belief that
disclosure was not required, this court must defer to the
district court’s resolution of that factual question. Molins
PLC v. Textron, Inc., 48 F.3d 1172, 1186 (Fed. Cir. 1995)
(“[T]he district court judge is in the best position to moni-
tor parties’ litigation conduct.”); see also Highmark, 687
F.3d at 1310 (“We review factual findings as to subjective
bad faith for clear error.”). The district court found that
Cartner’s “reliance upon an unrevealed theory of in-
fringement by equivalents[ ] amount[ed] to bad faith
sufficient to find exceptional circumstances under § 285,”
Cartner III, 2011 WL 4457665, at *4, and this court is not
left with the “definite and firm conviction that the district
court was in error,” Alza Corp. v. Mylan Labs., Inc., 464
F.3d 1286, 1289 (Fed. Cir. 2006); see also Lighting World,
Inc. v. Birchwood Lighting, Inc., 382 F.3d 1354, 1366
18                            CARTNER   v. ALAMO GROUP, INC.

(Fed. Cir. 2004) (declining to “second-guess” the district
court’s finding on litigation misconduct absent a showing
that its findings were “clearly flawed”). 3
    This court need not determine whether this instance
of bad faith, standing alone, would adequately support an
exceptional case finding. It is sufficient to conclude that
the district court did not clearly err in finding this case
exceptional under the “totality of the circumstances.”
See Yamanouchi Pharm. Co. v. Danbury Pharmacal,
Inc., 231 F.3d 1339, 1347 (Fed. Cir. 2000) (“In assessing
whether a case qualifies as exceptional, the district court
must look at the totality of the circumstances.”); see also
Beckman Instr., Inc. v. LKB Produkter AB, 892 F.2d 1547,
1551–52 (Fed. Cir. 1989) (holding that “[v]iewed individu-
ally, the specific examples of vexatious conduct recited by
the district court [were] somewhat tenuous,” but “when
viewed together, we cannot say that the district court’s
finding of vexatious litigation was clearly erroneous”). In
light of Cartner’s frivolous arguments that the accused
products literally infringed the above three claim limita-
tions, and his bad faith conduct with respect to the doc-
trine of equivalents argument, the district court properly
found this case exceptional by clear and convincing evi-
dence. The only remaining question, therefore, is whether
the district court abused its discretion in determining the
amount of the attorney fee award.

     3  Cartner also challenges the district court’s deter-
mination that Cartner’s doctrine of equivalents theory is
barred by the vitiation doctrine. There is no need to
decide whether the vitiation doctrine renders Cartner’s
doctrine of equivalents argument “objectively unreasona-
ble,” because the district court’s bad faith finding ade-
quately addresses Cartner’s doctrine of equivalents
argument for claim 12’s “disconnected” limitation.
CARTNER   v. ALAMO GROUP, INC.                            19

                  II. Alamo’s Cross Appeal
    The district court awarded Alamo $358,516.44 in at-
torney fees and costs from June 17, 2009, the date of this
court’s decision in Cartner II, until December 21, 2011,
the date of Alamo’s fee-petition reply brief to the magis-
trate judge. 4 The district court adopted the magistrate
judge’s finding that June 17, 2009, was “‘the appropriate
date [from which to award fees] because it was the earli-
est date upon which all issues of claim construction had
been resolved.’” Cartner IV, 2013 WL 943844, at *4
(quoting J.A. 1106). Although some of the conduct under-
lying the exceptional case finding predated Cartner II, the
district court explained “it was only then that [Cartner’s]
continued assertions of infringement became clearly
unjustified. At that point, with all issues of claim con-
struction resolved, [Cartner] had no reasonable basis
upon which to prolong litigation, but [he] did so nonethe-
less.” Id.
    On appeal, Alamo contends that Cartner’s arguments
became frivolous much earlier in the litigation, and that
the district court abused its discretion in failing to award
fees as of an earlier date. Alamo argues there was no
reason to delay accrual of fees until Cartner II, because
that appeal “had nothing to do with the three claim
limitations” at issue here. Cross Appellant’s Br. 36.
“Rather, the prior appeal concerned the proper construc-
tion of a different claim term, ‘said flow control orifice
being constantly operative.’” Id. (quoting J.A. 408).
    A district court abuses its discretion when its “deci-
sion is based on clearly erroneous findings of fact, is based
on erroneous interpretations of the law, or is clearly
unreasonable, arbitrary[,] or fanciful.” Forest Labs., Inc.

    4    Neither party contests the end date of the fee
award.
20                             CARTNER   v. ALAMO GROUP, INC.

v. Abbott Labs., 339 F.3d 1324, 1328 (Fed. Cir. 2003)
(internal quotation marks and citation omitted). It was
reasonable for the district court to start calculating the
attorney fee award as of this court’s prior decision in
Cartner II, which resolved invalidity and rendered all
claim constructions final. The district court’s exceptional
case finding was closely tied to constructions of the rele-
vant claim limitations. At least two of Cartner’s argu-
ments were found unreasonable in view of the relevant
claim constructions: (1) the “relief valve” limitation was
found frivolous in light of the parties’ agreed-upon con-
struction, and (2) the “disconnected” limitation was found
frivolous in light of the district court’s claim construction.
Although the “without a loss of fluid” limitation arguably
became frivolous as of August 10, 2007, when Cartner
received the Tiger schematic, this limitation applies only
to the Tiger mowers, not the Alamo mowers. To the
extent Alamo contends the district court should have
calculated different start dates for the Alamo mowers and
the Tiger mowers, the district court did not abuse its
discretion in selecting one date applicable to all accused
products.
    Alamo further argues “the latest date that the case
against both the Tiger and Alamo mowers became frivo-
lous” was May 21, 2008, the date of the district court’s
claim construction decision in Cartner I. Cross Appel-
lant’s Br. 40. However, Cartner I’s construction of the
“control orifice” limitation also rendered claims 5 and 12
invalid for lack of written description. Cartner reasonably
appealed the proper construction of that claim term and
prevailed. See Cartner II, 333 Fed. App’x at 565. It would
be error to require Cartner to pay Alamo’s attorney fees
and costs for litigating an appeal in which Cartner pre-
vailed. See Phonometrics, Inc. v. Westin Hotel Co., 350
F.3d 1242, 1250 (Fed. Cir. 2003) (holding the district court
erred by awarding attorney fees incurred in connection
with the nonmovant’s successful appeals).
CARTNER   v. ALAMO GROUP, INC.                           21

    This court’s decision in Cartner II vacated the invalid-
ity judgment and left Cartner free to pursue infringe-
ment, at which point Cartner was plainly unjustified in
prolonging the litigation. See MarcTec, 664 F.3d at 919–
21 (holding it was litigation misconduct for a plaintiff to
“persist[ ] in advancing unfounded arguments that unnec-
essarily extended [the] litigation,” and that plaintiff’s
“decision to continue the litigation after claim construc-
tion” supported the exceptional case finding). The district
court’s award of $358,516.44 properly reflects the “extra
legal effort” Alamo had to expend to “counteract [Cart-
ner’s] misconduct.” See Highmark, 687 F.3d at 1316
(quoting Beckman, 892 F.2d at 1553). The attorney fees
award is affirmed.
                        CONCLUSION
    For the foregoing reasons, and because this court
finds Cartner’s remaining arguments unpersuasive, the
district court’s exceptional case finding and attorney fees
award under 35 U.S.C. § 285 are affirmed.
                        AFFIRMED
   No costs.