United States Court of Appeals
`for the Federal Circuit
`______________________
`
`MTD PRODUCTS INC.,
`Appellant
`
`v.
`
`ANDREI IANCU, UNDER SECRETARY OF
`COMMERCE FOR INTELLECTUAL PROPERTY
`AND DIRECTOR OF THE UNITED STATES
`PATENT AND TRADEMARK OFFICE,
`Intervenor
`______________________
`
`2017-2292
`______________________
`
`Appeal from the United States Patent and Trademark
`Office, Patent Trial and Appeal Board in No. IPR2016-
`00194.
`
`______________________
`
`Decided: August 12, 2019
`______________________
`
`JOHN SALVATORE CIPOLLA, Calfee, Halter & Griswold
`LLP, Cleveland, OH, argued for appellant. Also repre-
`sented by ANDREW ALEXANDER, TRACY SCOTT JOHNSON,
`MARK MCDOUGALL.
`
` PETER JOHN SAWERT, Office of the Solicitor, United
`States Patent and Trademark Office, Alexandria, VA, ar-
`gued for intervenor. Also represented by THOMAS W.
`KRAUSE, PHILIP J. WARRICK.
`
`

`

`2
`
`MTD PRODS. INC. v. IANCU
`
` ______________________
`
`Before REYNA, TARANTO, and STOLL, Circuit Judges.
`STOLL, Circuit Judge.
`The Toro Company sought inter partes review of
`claims 1–16 of U.S. Patent No. 8,011,458 before the U.S.
`Patent and Trademark Office’s Patent Trial and Appeal
`Board. The Board instituted review and, in its final writ-
`ten decision, held the challenged claims obvious under
`35 U.S.C. § 103. Critical to its decision, the Board deter-
`mined that the claim term “mechanical control assem-
`bly . . . configured to” perform certain functions is not a
`means-plus-function term subject to 35 U.S.C. § 112, ¶ 6.
`MTD Products Inc., owner of the ’458 patent, appeals the
`Board’s decision.
`We conclude that the Board erred by conflating corre-
`sponding structure in the specification with a structural
`definition for the term, and by misinterpreting certain
`statements in the prosecution history. Under the appropri-
`ate legal framework, we conclude that the term “mechani-
`cal control assembly” is a means-plus-function term
`governed by § 112, ¶ 6. We therefore vacate the Board’s
`obviousness conclusion, which was predicated on its incor-
`rect claim construction, and remand for further proceed-
`ings consistent with this opinion. Because we are
`persuaded by MTD’s primary argument, we do not reach
`its alternative arguments.
`BACKGROUND
`I
`The ’458 patent discloses a steering and driving system
`for zero turn radius (“ZTR”) vehicles, with specific refer-
`ence to ZTR lawn mowers. ’458 patent col. 1 ll. 17–21. The
`patented system is designed to provide a more intuitive
`steering mechanism to operators of ZTR vehicles. Id. at
`col. 1 ll. 20–38. In contrast to prior art systems that
`
`

`

`MTD PRODS. INC. v. IANCU
`
`3
`
`reverse in the opposite direction of a forward motion turn,
`the claimed invention permits ZTR vehicles to turn in the
`same direction both forward and backwards. Id. at col. 1
`ll. 20–47. The claimed steering mechanism thus mimics
`the forward and backward movements of an automobile.
`The term “mechanical control assembly” appears in
`both claims 1 and 9, the only independent claims of the
`’458 patent. Claim 1 recites:
`1. A vehicle capable of making a small radius turn,
`comprising:
`a frame;
`a left drive wheel and a right drive wheel,
`both coupled to the frame;
`two independent left and right drive units,
`the left drive unit coupled to the left drive
`wheel via an axle and the right drive unit
`coupled to the right drive wheel via another
`axle;
`a steering device coupled to the frame;
`a speed control member coupled to the
`frame; and
`a mechanical control assembly coupled to
`the left and right drive units that is config-
`ured to actuate the left and right drive
`units based on a steering input received
`from the steering device and a speed input
`received from the speed control member;
`the mechanical control assembly being con-
`figured such that if the speed control mem-
`ber is shifted from (a) a forward position in
`which the left drive wheel is rotating in a
`forward direction at a first forward speed
`and the right drive wheel is rotating in a
`
`

`

`4
`
`MTD PRODS. INC. v. IANCU
`
`forward direction at a second forward
`speed that is less than the first forward
`speed as a result of the steering device be-
`ing in a first right turn position to (b) a re-
`verse position while the first right turn
`position of the steering device is main-
`tained, then the left drive wheel will rotate
`in a reverse direction at a first reverse
`speed and the right drive wheel will rotate
`in a reverse direction at a second reverse
`speed that is less than the first reverse
`speed.
`Id. at col. 7 l. 63–col. 8 l. 24 (emphasis added to highlight
`portion of disputed claim term). Claim 9 is identical to
`claim 1 in substantial part, adding only the further limita-
`tion of:
`the mechanical control assembly also being config-
`ured to cause the vehicle to execute a zero-radius
`turn when the speed control member is in a maxi-
`mum forward position and the steering device is in
`a maximum turn position.
`Id. at col. 9 ll. 13–16 (emphasis added).
`While the patent specification does not expressly refer
`to a “mechanical control assembly,” it discloses a preferred
`embodiment that includes a “ZTR control assembly.” Id. at
`col. 3 ll. 41–42. The specification describes components of
`the ZTR control assembly and its inputs, outputs, and link-
`ages. Id. at col. 3 l. 41–col. 4 l. 57.
`II
`Toro petitioned for inter partes review of the ’458 pa-
`tent in November 2015, arguing that the challenged claims
`were invalid as anticipated or obvious. MTD responded
`that the term “mechanical control assembly” is a means-
`plus-function term, and that the asserted prior art did not
`disclose the claim term’s corresponding structure. In
`
`

`

`MTD PRODS. INC. v. IANCU
`
`5
`
`support of its argument, MTD introduced expert testimony
`indicating that “mechanical control assembly” has no rea-
`sonably well-understood meaning in the art. Specifically,
`MTD’s expert testified that “mechanical control assembly”
`is a nonce term that is not used in common parlance and
`does not bring to mind any specific structure to a person of
`ordinary skill in the art. J.A. 1366. He explained that the
`term is used as a black box recitation for structure and, at
`most, amounts to a collection of various parts. J.A. 1248,
`1366. He further demonstrated that the term is used in
`various prior patents and publications to describe a wide
`variety of structures with varying functions. J.A. 1367–69
`(noting that “mechanical control assembly” is used generi-
`cally to describe mechanisms for infusion pumps, digital
`firing systems, flush tanks, endoscopes, transmissions, and
`engine outputs).
`Toro did not expressly contradict MTD’s evidence that
`
`“mechanical control assembly” did not have a well-under-
`stood structural meaning. Instead, Toro responded that a
`person of ordinary skill in the art would understand the
`term to denote a specific structure in the context of the
`’458 patent specification. Specifically, Toro argued that the
`“ZTR control assembly” disclosed in the specification pro-
`vides an express structural definition for the claimed “me-
`chanical control assembly.” J.A. 2201–03. Toro also
`argued that MTD admitted that the term “mechanical con-
`trol assembly” conveys particular structure when it distin-
`guished the patent claims from a prior art reference during
`prosecution. J.A. 2203.
`
`The Board initially agreed with MTD, stating that
`when viewed “in isolation, the genericness of this term
`bears similarities to other words or phrases that have been
`held to be subject to § 112, ¶ 6 . . . such as ‘mechanism,’ ‘el-
`ement,’ ‘device,’ ‘link member,’ and ‘control mechanism.’”
`Toro Co. v. MTD Prods. Inc., No. IPR2016-00194,
`2017 WL 1969747, at *9 (P.T.A.B. May 10, 2017) (first cit-
`ing Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1350
`
`

`

`6
`
`MTD PRODS. INC. v. IANCU
`
`(Fed. Cir. 2015) (en banc); then citing Mas-Hamilton Grp.
`v. LaGard, Inc., 156 F.3d 1206, 1215 (Fed. Cir. 1998); and
`then citing Toro Co. v. Deere & Co., 355 F.3d 1313, 1325
`(Fed. Cir. 2004)). The Board also determined that the “lan-
`guage reciting what the mechanical control assembly is
`‘configured to’ do . . . fits the mold of functional language
`because it describes the mechanical control assembly by
`what it does.” Id. The Board thus concluded that “the
`claim language of the disputed phrase is primarily, but not
`entirely, functional, which tends to favor [MTD]’s position
`that § 112, ¶ 6 applies.” Id.
`
`The Board agreed with Toro, however, that the ’458 pa-
`tent specification weighed against application of § 112, ¶ 6.
`Id. at *10. Citing the parties’ briefs, the Board stated that
`“[t]he parties agree that the claimed ‘mechanical control
`assembly’ is referred to in the specification as a ‘ZTR con-
`trol assembly.’” Id. According to the Board, a person of
`ordinary skill in the art would understand “mechanical
`control assembly” to denote structure because “the specifi-
`cation illustrates and describes the specific structure that
`makes up the ZTR control assembly, and how it connects to
`and operates with other components.” Id.
`
`The most persuasive piece of evidence to the Board,
`however, was the prosecution history. Id. at *9 (“The factor
`that weighs most heavily in [the] determination is the pros-
`ecution history.”). According to the Board, MTD admitted
`that the term “mechanical control assembly” connotes spe-
`cific structure by asserting that the claims recite “a me-
`chanical control assembly that is structurally different
`from what [the asserted prior art] discloses.” Id. The
`Board emphasized MTD’s statements that “the claim lan-
`guage at issue concerns the configuration of the claimed
`mechanical control assembly” and “the claimed configura-
`tion is indeed structural.” Id. (emphases in original). The
`Board concluded that these statements “present[] strong
`evidence that the disputed phrase should be understood as
`a structural limitation rather than a means-plus-function
`
`

`

`MTD PRODS. INC. v. IANCU
`
`7
`
`limitation under § 112 ¶ 6.” Id. at *11. Relying on the spec-
`ification and prosecution history, the Board ultimately de-
`termined that “mechanical control assembly” is not
`governed by § 112, ¶ 6. Id.
`DISCUSSION
`I
`This appeal requires us to address whether a particu-
`
`lar claim limitation is drafted in means-plus-function for-
`mat. Whether claim language invokes 35 U.S.C. § 112, ¶ 61
`is a legal question of claim construction that we review de
`novo. Williamson, 792 F.3d at 1346. We review the
`Board’s factual findings underlying this inquiry for sub-
`stantial evidence. EnOcean, GmbH v. Face Int’l Corp.,
`742 F.3d 955, 959 (Fed. Cir. 2014).
`
`Under this court’s guidance in Williamson, we begin by
`asking whether the claim limitation employs the word
`“means.” Williamson, 792 F.3d at 1348. If it does not, we
`apply a rebuttable presumption that the term conveys suf-
`ficiently definite structure and is not subject to § 112, ¶ 6.
`Id. A challenger can rebut the presumption by demonstrat-
`ing “that the claim term fails to ‘recite sufficiently definite
`structure’ or else recites ‘function without reciting suffi-
`cient structure for performing that function.’” Id. (quoting
`Watts v. XL Sys., Inc., 232 F.3d 877, 880 (Fed. Cir. 2000)).
`The “essential inquiry is not merely the presence or ab-
`sence of the word ‘means’ but whether the words of the
`
`1 Because the issue date of the ’458 patent is Septem-
`ber 6, 2011, and neither the ’458 patent nor the application
`from which it issued ever contained a claim with an effec-
`tive filing date on or after September 16, 2012, the version
`of 35 U.S.C. § 112 that applies here is the one preceding
`the changes made by the America Invents Act. See Leahy-
`Smith America Invents Act, Pub. L. No. 112-29, 125 Stat.
`284, 296, § 4(c) (2011).
`
`

`

`8
`
`MTD PRODS. INC. v. IANCU
`
`claim are understood by persons of ordinary skill in the art
`to have a sufficiently definite meaning as the name for
`structure.” Id.
` One way to demonstrate that a claim limitation fails to
`recite sufficiently definite structure is to show that, alt-
`hough not employing the word “means,” the claim limita-
`tion uses a similar “nonce word that can operate as a
`substitute for ‘means’ in the context of § 112, para. 6.” Id.
`at 1350. Generic terms like “module,” “mechanism,” “ele-
`ment,” and “device” are commonly used as verbal con-
`structs that operate, like “means,” to claim a particular
`function rather than describe a “sufficiently definite struc-
`ture.” Id. Our case law is replete with guidance on
`whether or not a particular claim term is a “nonce” term.
`See, e.g., Zeroclick, LLC v. Apple Inc., 891 F.3d 1003, 1008
`(Fed. Cir. 2018) (holding that “program” and “user inter-
`face code” are not nonce words because they are “used not
`as generic terms or black box recitations of structure or ab-
`stractions, but rather as specific references to conventional
`graphical user interface programs or code”); Williamson,
`792 F.3d at 1350 (noting that “module” is a nonce term be-
`cause it “sets forth the same black box recitation of struc-
`ture for providing the same specified function as if the term
`‘means’ had been used”). In each case, a critical question
`is whether “the claim term is used in common parlance or
`by persons of skill in the pertinent art to designate struc-
`ture,” including either a particular structure or a class of
`structures. Skky, Inc. v. MindGeek, s.a.r.l., 859 F.3d 1014,
`1019 (Fed. Cir. 2017) (citing TecSec, Inc. v. Int’l Bus.
`Machs. Corp., 731 F.3d 1336, 1347 (Fed. Cir. 2013)) (hold-
`ing that the claim term “wireless device means” does not
`invoke § 112, ¶ 6 because it denotes a class of structures).
`In addition, even if the claims recite a nonce term fol-
`lowed by functional language, other language in the claim
`“might inform the structural character of the limitation-in-
`question or otherwise impart structure” to the claim term.
`Williamson, 792 F.3d at 1351. In assessing whether the
`
`

`

`MTD PRODS. INC. v. IANCU
`
`9
`
`claim limitation is in means-plus-function format, we do
`not merely consider the introductory phrase (e.g., “mechan-
`ical control assembly”) in isolation, but look to the entire
`passage including functions performed by the introductory
`phrase. See Apex Inc. v. Raritan Computer, Inc., 325 F.3d
`1364 (Fed. Cir. 2003). The ultimate question is whether
`“the claim language, read in light of the specification, re-
`cites sufficiently definite structure to avoid § 112, ¶ 6.” Me-
`dia Rights Techs. Inc. v. Capital One Fin. Corp., 800 F.3d
`1366, 1372 (Fed. Cir. 2015) (citing Robert Bosch, LLC v.
`Snap-On Inc., 769 F.3d 1094, 1099 (Fed. Cir. 2014)).
`In Apex, for example, the court concluded that the term
`“circuit” recited sufficient structure in the context of the
`claims at issue. 325 F.3d at 1372–73 (considering the use
`of the term “circuit” in the claim limitation “a first interface
`circuit for receiving keyboard and cursor control device sig-
`nals from the workstation”). Based on a dictionary defini-
`tion of the word “circuit,” the court reasoned that “the term
`‘circuit’ by itself connotes some structure,” and that “the
`term ‘circuit with an appropriate identifier such as ‘inter-
`face,’ ‘programming,’ and ‘logic,’ certainly identifies some
`structural meaning to one of ordinary skill in the art.” Id.
`at 1373. The court noted that the extrinsic evidence did
`not show that the term “circuit” was not understood to have
`structure, but rather “only that the term ‘circuit’ is under-
`stood . . . as a very broad term.” Id. at 1374. As neither the
`specification nor the prosecution history used the term “in
`a manner clearly inconsistent with the ordinary meaning,”
`the court held that the defendant failed to rebut the pre-
`sumption that § 112, ¶ 6 did not apply. Id. at 1373–74.
`In contrast, in Diebold Nixdorf, Inc. v. International
`Trade Commission, the court held that the term “cheque
`standby unit” for performing certain specified functions
`was governed by § 112, ¶ 6. 899 F.3d 1291, 1300 (Fed. Cir.
`2018). The court noted that “there is no evidence—in the
`form of dictionary definitions or otherwise—that ‘cheque
`standby unit’ was reasonably well understood by persons
`
`

`

`10
`
`MTD PRODS. INC. v. IANCU
`
`of ordinary skill in the art to refer to a structure or class of
`structures.” Id. at 1302. Instead, the extrinsic evidence
`demonstrated only that “a skilled artisan would under-
`stand the functional term ‘cheque standby unit’ to be any
`structure capable of performing the claimed function.” Id.
`at 1301. Further, neither the words of the claim nor the
`specification suggested a “structural limitation that might
`serve to cabin the scope of the functional term,” thus sup-
`porting the conclusion that the claim limitation was writ-
`ten in means-plus-function format. Id.
`
`Finally, we note that “[c]laims are interpreted in light
`of the written description supporting them, and that is true
`whether or not the claim construction involves interpreting
`a ‘means’ clause.” Inventio AG v. ThyssenKrupp Elevator
`Ams. Corp., 649 F.3d 1350, 1356 (Fed. Cir. 2011), overruled
`on other grounds by Williamson, 792 F.3d at 1339. For ex-
`ample, a patentee may avoid application of § 112, ¶ 6 by
`acting as a lexicographer and providing its own structural
`definition of a nonce term in the specification by “‘clearly
`set[ting] forth a definition of the disputed claim term’ other
`than its plain and ordinary meaning.” Thorner v. Sony
`Comput. Entm’t Am. LLC, 669 F.3d 1362, 1365 (Fed. Cir.
`2012) (citing CCS Fitness, Inc. v. Brunswick Corp.,
`288 F.3d 1359, 1366 (Fed. Cir. 2002)). Just as it is im-
`proper to “import[] limitations from the specification into
`the claims,” Phillips v. AWH Corp., 415 F.3d 1303, 1323
`(Fed. Cir. 2005), however, a preferred embodiment dis-
`closed in the specification cannot impart structure to a
`term that otherwise has none. As with all lexicography,
`“[i]t is not enough for a patentee to simply disclose a single
`embodiment.” Thorner, 669 F.3d at 1365. Rather, “the pa-
`tentee must ‘clearly express an intent’ to redefine the
`term.” Id. (quoting Helmsderfer v. Bobrick Washroom
`Equip., Inc., 527 F.3d 1379, 1381 (Fed. Cir. 2008)).
` With these background principles in mind, we turn to
`the claim language at issue in this case.
`
`

`

`MTD PRODS. INC. v. IANCU
`
`11
`
`II
`The disputed claim limitation is lengthy and recites:
`a mechanical control assembly coupled to the left
`and right drive units that is configured to actuate
`the left and right drive units based on a steering
`input received from the steering device and a speed
`input received from the speed control member;
`the mechanical control assembly being configured
`such that if the speed control member is shifted
`from (a) a forward position in which the left drive
`wheel is rotating in a forward direction at a first
`forward speed and the right drive wheel is rotating
`in a forward direction at a second forward speed
`that is less than the first forward speed as a result
`of the steering device being in a first right turn po-
`sition to (b) a reverse position while the first right
`turn position of the steering device is maintained,
`then the left drive wheel will rotate in a reverse di-
`rection at a first reverse speed and the right drive
`wheel will rotate in a reverse direction at a second
`reverse speed that is less than the first reverse
`speed.
`’458 patent col. 8 ll. 7–24.
`At the outset, we agree with the Board that the term
`“mechanical control assembly” is similar to other generic,
`black-box words that this court has held to be nonce terms
`similar to “means” and subject to § 112, ¶ 6 because the
`term does not connote sufficiently definite structure to one
`of ordinary skill in the art. Toro, 2017 WL 1969747, at *9.
`We also agree with the Board that the rest of the “claim
`language of the disputed phrase is primarily, but not en-
`tirely, functional.” Id. While the claim language reciting
`that the mechanical control assembly is “coupled to the left
`and right drive units” connotes structure, the claim lan-
`guage reciting what the mechanical control assembly is
`
`

`

`12
`
`MTD PRODS. INC. v. IANCU
`
`“configured to” do is functional. In this respect, as the
`Board correctly recognized, the claim format tends to favor
`MTD’s position that § 112, ¶ 6 applies.2
`We also discern no error in the Board’s acceptance of
`MTD’s extrinsic evidence as showing that the term “me-
`chanical control assembly” does not have an established
`meaning in the art and instead merely operates as a ge-
`neric label for a collection of parts. Toro did not dispute
`MTD’s expert testimony that, in common parlance, “me-
`chanical control assembly” does not bring to mind any spe-
`cific structure to a person of ordinary skill in the art. J.A.
`1366. Toro likewise did not dispute MTD’s reliance on var-
`ious prior patents and publications that used “mechanical
`control assembly” to describe a wide variety of structures
`with varying functions.
` J.A. 1367–69 (noting that
`
`
`2 The Board also stated that construing the disputed
`phrase as a means-plus-function limitation “would seem to
`render the second part [of the claim’s recitation of a ‘me-
`chanical control assembly’] . . . superfluous” as it “would no
`longer serve to define functionally the structural features
`of the mechanical control assembly, as those features
`would be part and parcel of what [MTD] alleges is the cor-
`responding structure.” Toro, 2017 WL 1969747, at *9. We
`disagree. Both the first and second limitations following
`the two occurrences of the term “mechanical control assem-
`bly” recite functions associated with the “mechanical con-
`trol assembly”; i.e., (1) actuate the left and right drive units
`and (2) rotate the wheel in a particular direction based on
`the position of the speed control member. As we have held,
`“[w]here there are multiple claimed functions, as we have
`here, the patentee must disclose adequate corresponding
`structure to perform all of the claim functions.” William-
`son, 792 F.3d at 1351–52. Thus, the corresponding struc-
`ture for “mechanical control assembly” in the specification
`must perform both of these functions.
`
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`

`MTD PRODS. INC. v. IANCU
`
`13
`
`“mechanical control assembly” is used generically to de-
`scribe mechanisms for infusion pumps, digital firing sys-
`tems, flush tanks, endoscopes, transmissions, and engine
`outputs).
`We conclude that the Board erred, however, when it re-
`lied on the specification’s description of a “ZTR control as-
`sembly” to conclude that the claim term “mechanical
`control assembly” has an established structural meaning.
`While the parties agreed that the ZTR control assembly in
`the specification is the structure “corresponding to” the
`claimed mechanical control assembly, MTD did not agree
`that the specification expressly defines the claim term “me-
`chanical control assembly.” That the specification discloses
`a structure corresponding to an asserted means-plus-func-
`tion claim term does not necessarily mean that the claim
`term is understood by persons of ordinary skill in the art to
`connote a specific structure or a class of structures.
`Interpretation of an asserted means-plus-function lim-
`itation involves two steps. First, we determine if the claim
`limitation is drafted in means-plus-function format. As
`part of this step, we consider whether the claim limitation
`connotes “sufficiently definite structure” to a person of or-
`dinary skill in the art. If we conclude that the limitation is
`in means-plus-function format, the second step requires us
`to review the specification to identify the structure that
`performs the claimed function(s) and thus “corresponds to”
`the claimed means. While related, these two inquiries are
`distinct. In this case, however, the Board conflated these
`distinct inquiries, holding that the specification’s disclo-
`sure of corresponding structure demonstrates that the al-
`leged means-plus-function term is sufficiently definite so
`as to not invoke § 112, ¶ 6. The Board’s analysis implies
`that so long as a claim term has corresponding structure in
`the specification, it is not a means-plus-function limitation.
`This is not consistent with our prior decisions. Indeed, this
`view would seem to leave § 112, ¶ 6 without any applica-
`tion: any means-plus-function limitation that met the
`
`

`

`14
`
`MTD PRODS. INC. v. IANCU
`
`statutory requirements, i.e., which includes having corre-
`sponding structure in the specification, would end up not
`being a means-plus-function limitation at all.
`While we agree with the Board that the specification
`plays a role in assessing whether particular claim language
`invokes § 112, ¶ 6, we do not agree that the patent specifi-
`cation at issue here renders the nonce term “mechanical
`control assembly” sufficiently structural to a person of or-
`dinary skill in the art. The specification does not demon-
`strate that the patentee intended to act as its own
`lexicographer and define the nonce term “mechanical con-
`trol assembly” as the “ZTR control assembly” of the pre-
`ferred embodiment. Indeed, the specification does not even
`refer to a “mechanical control assembly.” Furthermore, the
`functional language in the claim limitation suggests a
`broader meaning of the generic term “mechanical control
`assembly,” as it specifically adds to the “mechanical control
`assembly” limitation the ability to execute a zero radius
`turn. ’458 patent col. 9 ll. 13–16. Interpreting the “me-
`chanical control assembly” as the “ZTR”—or zero-turn-ra-
`dius—control assembly would render this functional
`language superfluous.
`We are also not persuaded by the Board’s interpreta-
`tion of the prosecution history. While it would have
`avoided uncertainty and argument had MTD shared its
`current view that the claim limitation is written in means-
`plus-function format during the original prosecution,
`MTD’s statements did not clearly disclaim such an inter-
`pretation. Rather, MTD’s statements indicated that the
`phrase “mechanical control assembly configured to” per-
`form certain functions must be given weight because it con-
`notes structure and thus is not merely an intended use.
`These statements were not made within the context of
`§ 112, ¶ 6. Moreover, stating that the limitation connotes
`structure and has weight is not inconsistent with claiming
`in means-plus-function format since means-plus-function
`limitations connote structure (i.e., corresponding structure
`
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`

`MTD PRODS. INC. v. IANCU
`
`15
`
`and their equivalents) and have weight. Furthermore, as
`MTD explained, its interpretation of the claims as being in
`means-plus-function format during inter partes review was
`based on this court’s intervening law in Williamson.
`J.A. 1204. Given the lack of any clear and undisputed
`statement foreclosing application of § 112, ¶ 6, we conclude
`that the Board erred in giving dispositive weight to the
`equivocal statements it cited in the prosecution history.
`CONCLUSION
`We conclude that the Board erred by using the exist-
`ence of corresponding structure in the specification to con-
`clude that “mechanical control assembly” has a sufficiently
`definite structure to evade § 112, ¶ 6. The Board also erred
`by giving improper weight to out-of-context statements in
`the prosecution history. We hold that the remaining evi-
`dence and the Board’s factual findings demonstrate that
`the term “mechanical control assembly . . . configured to”
`perform certain functions in independent claims 1 and 9 of
`the ’458 patent is governed by § 112, ¶ 6. We therefore va-
`cate the Board’s decision and remand for further proceed-
`ings consistent with this opinion.
`VACATED AND REMANDED
`COSTS
`
`Costs to Appellant.
`
`