  United States Court of Appeals
      for the Federal Circuit
                 ______________________

   AMERICAN AXLE & MANUFACTURING, INC.,
              Plaintiff-Appellant

                            v.

NEAPCO HOLDINGS LLC, NEAPCO DRIVELINES
                   LLC,
           Defendants-Appellees
          ______________________

                       2018-1763
                 ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:15-cv-01168-LPS, Chief Judge
Leonard P. Stark.
                 ______________________

                Decided: October 3, 2019
                ______________________

    JAMES RICHARD NUTTALL, Steptoe & Johnson, LLP,
Chicago, IL, argued for plaintiff-appellant. Also repre-
sented by JOHN LLOYD ABRAMIC, KATHERINE H. JOHNSON,
ROBERT KAPPERS.

   DENNIS J. ABDELNOUR, Honigman LLP, Chicago, IL, ar-
gued for defendants-appellees. Also represented by J.
MICHAEL HUGET, SARAH E. WAIDELICH, Ann Arbor, MI.

   SCOTT A. M. CHAMBERS, Porzio, Bromberg & Newman,
2        AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




PC, Washington, DC, for amici curiae Christopher Frerk-
ing, Christopher Michael Holman, David Lund, Walter
Matystik, Adam Mossoff, Kristen J. Osenga, Michael
Risch, Mark F. Schultz, Ted M. Sichelman, Brenda M. Si-
mon, Jonathan Stroud, David O. Taylor. Also represented
by MATTHEW ZAPADKA, Bass, Berry & Sims, PLC, Washing-
ton, DC.
                ______________________

    Before DYK, MOORE, and TARANTO, Circuit Judges.
        Opinion for the court filed by Circuit Judge DYK.
    Dissenting opinion filed by Circuit Judge MOORE.
DYK, Circuit Judge.
    American Axle & Manufacturing, Inc. (“AAM”) sued
Neapco Holdings LLC and Neapco Drivelines LLC (collec-
tively, “Neapco”) alleging infringement of claims of U.S. Pa-
tent No. 7,774,911 (“the ’911 patent”). 1 The parties filed
cross-motions for summary judgment as to the eligibility of
the asserted claims of the ’911 patent under 35 U.S.C.
§ 101. The district court granted Neapco’s motion and held
that the asserted claims are ineligible under § 101. We
agree and therefore affirm.




    1   AAM’s complaint alleged infringement of two other
patents—U.S. Patent Nos. 8,176,613 (“the ’613 patent”)
and 8,528,180 (“the ’180 patent”). During claim construc-
tion, the district court held the asserted claims of the ’613
patent indefinite. Neapco Mot. for Summary Judgment at
3, American Axle & Manuf., Inc. v. Neapco Hldgs. LLC, No.
15-01168 (D. Del. Aug. 11, 2017), ECF No. 150. AAM also
dropped the asserted claims of the ’180 patent. Id. Neither
the ’613 nor the ’180 patent is at issue on appeal.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS              3



                        BACKGROUND
                               I
     The ’911 patent generally relates to a method for man-
ufacturing driveline propeller shafts (“propshafts”) with
liners that are designed to “attenuat[e] . . . vibrations
transmitted through a shaft assembly.” ’911 patent, col. 1,
ll. 6–7. Propshafts are “employed [in automotive vehicles]
to transmit rotary power in a driveline.” Id. col. 1, ll. 38–
39. Because these propshafts are typically made of a “rel-
atively thin-walled steel or aluminum tubing [they] can be
receptive to various driveline excitation sources.” Id. col.
1, ll. 40–42. These excitation sources, in turn, can cause
the propshaft to vibrate in three modes: bending mode,
torsion mode, and shell mode. Id. col. 1, ll. 42–44. The ’911
patent describes these vibration modes as follows:
    Bending mode vibration is a phenomenon wherein
    energy is transmitted longitudinally along the
    shaft and causes the shaft to bend at one or more
    locations. Torsion mode vibration is a phenomenon
    wherein energy is transmitted tangentially
    through the shaft and causes the shaft to twist.
    Shell mode vibration is a phenomenon wherein a
    standing wave is transmitted circumferentially
    about the shaft and causes the cross-section of the
    shaft to deflect or bend along one or more axes.
Id. col. 1, ll. 44–52. These vibration modes correspond to
different frequencies. Because such vibrations cause unde-
sirable noise, “techniques [had, prior to the ’911 patent,]
been employed to attenuate vibrations in propshafts in-
cluding the use of weights and liners.” Id. col. 1, ll. 53–54.
     One prior art method of attenuation involved the use of
liners. Liners are hollow tubes made of a fibrous material
(like cardboard) with outer resilient members that “fric-
tionally engage the inner diameter of the [propshaft].” Id.
col. 6, ll. 56–65. Liners, like propshafts, vibrate at different
4     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




frequencies, and depending on the frequencies at which
they vibrate, may damp the vibration of the propshaft into
which they are inserted. When certain variables related to
the liner are changed (i.e., when the liner is “tuned”), the
frequencies at which that liner vibrates, and therefore the
liner’s ability to damp the vibration of that propshaft,
changes. See, e.g., id. col. 7–8. It was known in the prior
art to alter the mass and stiffness of liners to alter their
frequencies to produce dampening. Indeed, this was suffi-
ciently well known that prior art patents disclosed the use
of particular materials to achieve dampening. See, e.g., id.
col. 2, lines 5–37.
     Other prior art methods of dampening also existed, in-
cluding the use of weights. For example, the ’911 patent
describes plugs or weights that are inserted to frictionally
engage a propshaft and act as resistive attenuation means
to damp bending mode vibrations. Id. col. 1, line 53–col. 2,
l. 4. The patent also discloses a prior art damper that is
inserted into a hollow shaft and frictionally engages the in-
side of the shaft by using a pair of resilient members. Id.
col. 2, ll. 5–10.
      Two types of attenuation are relevant here: resistive
attenuation and reactive attenuation. “[R]esistive attenu-
ation of vibration refers to a vibration attenuation means
that deforms as vibration energy is transmitted through
it . . . so that the vibration attenuation means absorbs . . .
the vibration energy.” Id. col. 1, ll. 61–65. A liner that is
properly tuned to attenuate shell mode vibration through
resistive attenuation “matches” the shell mode vibration
(i.e., a particular natural frequency) of the propshaft such
that it absorbs the shell mode vibration of the propshaft.
J.A. 2000–02. “[R]eactive attenuation of vibration refers to
a mechanism that can oscillate in opposition to the vibra-
tion energy [of the propshaft] to thereby ‘cancel out’ a por-
tion of the vibration energy.” ’911 patent, col. 2, ll. 15–18.
Thus, to design a liner to perform reactive attenuation of a
bending mode vibration “the liner frequency must match
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS          5



the propshaft frequency and involve translation of the liner
to effectively couple with the propshaft bending mode.”
AAM Op. Br. 6 (citing J.A. 2076–77, 4036–37, 5218).
    The district court treated independent claims 1 and 22
of the ’911 patent as representative of the asserted claims
(claims 1–6, 12, 13, 19–24, 26, 27, 31, 34–36). Those two
claims recite:
   1. A method for manufacturing a shaft assembly of
   a driveline system, the driveline system further in-
   cluding a first driveline component and a second
   driveline component, the shaft assembly being
   adapted to transmit torque between the first
   driveline component and the second driveline com-
   ponent, the method comprising:
   providing a hollow shaft member;
   tuning at least one liner to attenuate at least two
   types of vibration transmitted through the shaft
   member; and
   positioning the at least one liner within the shaft
   member such that the at least one liner is config-
   ured to damp shell mode vibrations in the shaft
   member by an amount that is greater than or equal
   to about 2%, and the at least one liner is also con-
   figured to damp bending mode vibrations in the
   shaft member, the at least one liner being tuned to
   within about ±20% of a bending mode natural fre-
   quency of the shaft assembly as installed in the
   driveline system.
                         *   *   *
   22. A method for manufacturing a shaft assembly
   of a driveline system, the driveline system further
   including a first driveline component and a second
   driveline component, the shaft assembly being
   adapted to transmit torque between the first
6      AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




    driveline component and the second driveline com-
    ponent, the method comprising:
    providing a hollow shaft member;
    tuning a mass and a stiffness of at least one liner,
    and
    inserting the at least one liner into the shaft mem-
    ber;
    wherein the at least one liner is a tuned resistive
    absorber for attenuating shell mode vibrations and
    wherein the at least one liner is a tuned reactive
    absorber for attenuating bending mode vibrations.
’911 patent, col. 10, ll. 10–27; id. col. 11, ll. 24–36 (empha-
ses added). The district court construed the term tuning to
mean “controlling the mass and stiffness of at least one
liner to configure the liner to match the relevant frequency
or frequencies.” J.A. 15. No party contests the district
court’s construction on appeal.
     According to the ’911 patent’s specification, prior art
liners, weights, and dampers that were designed to individ-
ually attenuate each of the three propshaft vibration
modes—bending, shell, and torsion—already existed. ’911
patent, col. 1, l. 53–col. 2, l. 38. But these prior art damping
methods were assertedly not suitable for attenuating two
vibration modes simultaneously. See id. Thus, the patent
identified “a need in the art for an improved method for
damping various types of vibrations in a hollow shaft” that
“facilitates the damping of shell mode vibration as well as
the damping of bending mode vibration” simultaneously.
Id. col. 2, ll. 39–43. AAM argues that the inventive concept
to which these claims are directed is the tuning of a liner
in order to produce frequencies that dampen both the shell
mode and bending mode vibrations simultaneously.
   AAM urges both that it “conceiv[ed] of the novel and
unconventional concept of ‘tuning’ a liner,” and that it
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS            7



conceived of a tuned liner that “unlike previous dampers
and absorbers . . . [can] dampen multiple types of vibra-
tion” simultaneously. AAM Op. Br. 13. AAM explains that
“particular liners that are specifically tuned to match and
damp multiple vibration modes and are utilized to manu-
facture improved propshafts . . . w[ere] entirely new and
far from well-understood” at the time of the ’911 patent.
AAM Op. Br. 27. Neither the claims nor the specification
describes how to achieve such tuning. The specification
also discloses a solitary example describing the structure
of a tuned liner, but does not discuss the process by which
that liner was tuned. ’911 patent, col. 8, ll. 4–23.
                              II
    AAM sued Neapco on December 18, 2015, alleging in-
fringement of the ’911 patent. The parties filed cross-mo-
tions for summary judgment as to patent eligibility under
§ 101. On February 27, 2018, the district court granted
Neapco’s motion for summary judgment, and denied AAM’s
cross-motion, holding that the asserted claims of the ’911
patent were invalid because they claim ineligible subject
matter under § 101.
     The district court concluded that “the Asserted Claims
as a whole are directed to laws of nature: Hooke’s law and
friction damping.” J.A. 10. The district court held that the
claims’ direction to tune a liner to attenuate to different
vibration modes amounted to merely “instruct[ing] one to
apply Hooke’s law to achieve the desired result of attenu-
ating certain vibration modes and frequencies” without
“provid[ing] [a] particular means of how to craft the liner
and propshaft in order to do so.” J.A. 17. Hooke’s law is an
equation that describes the relationship between an ob-
ject’s mass, its stiffness, and the frequency at which the ob-
ject vibrates. Friction damping is damping that “occur[s]
due to the resistive friction and interaction of two surfaces
that press against each other as a source of energy dissipa-
tion.” J.A. 1604. Because the district court determined
8     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




that the claimed “additional steps consist of well-under-
stood, routine, conventional activity already engaged in by
the scientific community . . . and those steps, when viewed
as a whole, add nothing significant beyond the sum of their
parts taken separately,” it concluded that the claims were
not patent eligible. J.A. 16 (quoting Mayo Collaborative
Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 79–80
(2012)).
    AAM appeals. We have jurisdiction under 28 U.S.C.
§ 1291. We review a district court’s grant of summary
judgement de novo, applying the same test on review that
the district court applied. Summary judgment is appropri-
ate where “there is no genuine dispute as to any material
fact and the movant is entitled to judgment as a matter of
law.” Fed. R. Civ. P. 56(a). The issue of patent eligibility
under § 101 is a question of law, reviewed de novo. In re
BRCA1– and BRCA2– Based Hereditary Cancer Test Pa-
tent Litig., 774 F.3d 755, 759 (Fed. Cir. 2014). “While pa-
tent eligibility is ultimately a question of law,” the
underlying issue of “[w]hether something is well-under-
stood, routine, and conventional to a skilled artisan at the
time of the patent is a factual determination.” Berkheimer
v. HP Inc., 881 F.3d 1360, 1369 (Fed. Cir. 2018).
                       DISCUSSION
    Section 101 provides that “any new and useful process,
machine, manufacture, or composition of matter, or any
new and useful improvement thereof” may be eligible to ob-
tain a patent. 35 U.S.C. § 101. But the Supreme Court has
long recognized that § 101 “contains an important implicit
exception: Laws of nature, natural phenomena, and ab-
stract ideas are not patentable.” Ass’n for Molecular Pa-
thology v. Myriad Genetics, Inc., 569 U.S. 576, 589 (2013)
(brackets omitted) (quoting Mayo, 566 U.S. at 70). The Su-
preme Court has stated that “without this exception, there
would be considerable danger that the grant of patents
would ‘tie up’ the use of such tools and thereby ‘inhibit
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS            9



future innovation premised upon them.’”         Id. (quoting
Mayo, 566 U.S. at 73).
     Our analysis of § 101 follows the Supreme Court’s two-
step test established in Mayo and Alice Corp. Pty. Ltd. v.
CLS Bank International, 573 U.S. 208 (2014). At step one
of the Mayo/Alice test, we ask whether the claims are di-
rected to a law of nature, natural phenomenon, or abstract
idea. Alice, 573 U.S. at 217 (citing Mayo, 566 U.S. at 77).
If the claims are so directed, we then ask whether the
claims embody some “inventive concept”—i.e., whether the
claims contain “an element or combination of elements that
is ‘sufficient to ensure that the patent in practice amounts
to significantly more than a patent upon the ineligible con-
cept itself.’” Id. at 217–18 (brackets omitted) (quoting
Mayo, 566 U.S. at 72–73).
                              I
    To determine what the claims are “directed to” at step
one, we look to the “focus of the claimed advance.” See, e.g.,
Trading Techs Int’l, Inc. v. IBG LLC, 921 F.3d 1378, 1384
(Fed. Cir. 2019). 2 There is no legal principle that a claim
to a method of manufacturing cannot be directed to a nat-
ural law, nor are there any cases saying so. The ’911 patent
discloses a method of manufacturing a driveline propshaft
containing a liner designed such that its frequencies atten-
uate two modes of vibration simultaneously.




    2   Accord Intellectual Ventures I LLC v. Capital One
Fin. Corp., 850 F.3d 1332, 1338 (Fed. Cir. 2017); Intellec-
tual Ventures I LLC v. Erie Indemnity Co., 850 F.3d 1315,
1325 (Fed. Cir. 2017); Affinity Labs of Tex., LLC v.
DIRECTV, LLC, 838 F.3d 1253, 1257–58 (Fed. Cir. 2016);
Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1335 (Fed.
Cir. 2016); Genetic Techs. Ltd. v. Merial LLC, 818 F.3d
1369, 1375–76 (Fed. Cir. 2016).
10     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




      The claims are directed to tuning liners—i.e., “control-
ling a mass and stiffness of at least one liner to configure
the liner to match the relevant frequency or frequencies.”
J.A. 15. As is clear from the specification itself, most as-
pects of the ’911 patent were well known in the art. It was
known that driveline propshafts were prone to bending,
shell, and torsion mode vibrations. ’911 patent, col. 1, ll.
38–52. It was known that shell mode vibrations could be
damped by resistive attenuation and that bending mode vi-
brations could be damped by reactive attenuation. Id. col.
1, l. 53–col. 2, l. 38. It was also known that a liner or weight
could be designed specifically to have a frequency that
would allow it to function as either a resistive attenuation
means or as a reactive attenuation means. Id. AAM does
not dispute that these features were known in the art.
AAM agrees that the selection of frequencies for the liners
to damp the vibrations of the propshaft at least in part in-
volves an application of Hooke’s law.
     Hooke’s law is a natural law that mathematically re-
lates the mass and/or stiffness of an object to the frequency
with which that object oscillates (vibrates). Here, both par-
ties’ witnesses agree that Hooke’s law undergirds the de-
sign of a liner so that it exhibits a desired damping
frequency pursuant to the claimed invention. For example,
Neapco’s expert, Dr. Becker, stated that the tuning limita-
tions claim “nothing more than Hooke’s law . . . [and/or] the
law of nature / natural phenomenon for friction damping.”
J.A. 1603–05. Dr. Sun, one of the named inventors of the
’911 patent, stated in his deposition:
     Q. But to change the frequency of any damper, it
     comes down to basic physics, doesn’t it; changing
     the mass or the stiffness of that damper that will
     adjust the frequency?
     A. You change a tuned liner, yeah, by adjusting the
     controlling variables and to get to the tuning that
     is needed.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS           11



    Q. And one of those variables is stiffness, correct?
    A. Correct.
    Q. And one of them is the mass, correct?
    A. Yes.
J.A. 1757 (92:15–25). AAM’s engineering manager like-
wise admitted that “if [one] do[es] something to control the
stiffness [or mass]” of a liner—the variables directly impli-
cated by Hooke’s law—that person is “directly controlling
tuning.” J.A. 2547 (20:23–21:1). At the same time, the pa-
tent claims do not describe a specific method for applying
Hooke’s law in this context. They simply state that the
liner should be tuned to dampen certain vibrations. Thus,
the problem is that the claims’ instruction to tune a liner
essentially amounts to the sort of directive prohibited by
the Supreme Court in Mayo—i.e. “simply stat[ing] a law of
nature while adding the words ‘apply it.’” 566 U.S. at 72.
     But AAM argues that the claims are not merely di-
rected to Hooke’s law. AAM points to testimony suggesting
that tuning a liner such that it attenuates two different vi-
bration modes is a process that involves more than simple
application of Hooke’s law. For example, AAM’s expert, Dr.
Rahn, testified that a “liner is not a spring with a single
stiffness, it is a complex, distributed object with different
stiffnesses in different directions (e.g., shell and bending)
that depend on the location of the applied force and the
measured displacement.” J.A. 1928. Dr. Rahn in numer-
ous instances explained that liners are different from a sin-
gle spring–mass system as they “can bounce, they can rock,
they can deform, [and] they can bend.” J.A. 2505 (137:2–
4). In essence, AAM’s argument is that the system of the
invention (a driveline propshaft and its liner) is too com-
plex to be described by mere application of Hooke’s law,
which itself is a simple approximation of a single-degree-
of-freedom spring–mass system. AAM also appears to
12       AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




argue that liners had not previously been used to dampen
bending mode—as opposed to shell mode—vibrations. 3



     3   Contrary to the dissent at 6–7, the majority does
not assert that this point was not disputed on appeal. Alt-
hough raised on appeal, this argument by AAM was not
properly raised below. In the district court, AAM did not
make this claim in arguing for § 101 eligibility in any of its
relevant summary judgment filings—its motion for sum-
mary judgment in its favor, its reply in support of that mo-
tion, or its opposition to Neapco’s motion for summary
judgment. See J.A. 4330–36, 5236–37, 6094–96; see also
J.A. 6194, 7049 (supplemental summary judgment brief-
ings). Instead, in those filings, AAM identified as an in-
ventive concept only the idea of dual-mode dampening we
have identified. See J.A. 4330–36, 5236–37, 6094–96,
6194. Only at the oral hearing on summary judgment, af-
ter the papers that defined the issue were complete, did
AAM make this claim—in passing in one sentence, before
immediately invoking the dual-mode dampening notion as
the inventive concept. J.A. 7193–94.
     And the argument is not supported by the patent spec-
ification. While noting that certain prior art liners
(“[t]hese liners” referenced at col. 2, lines 23–38 of the ’911
patent) did not dampen bending mode vibrations, no sug-
gestion that prior art liners generally did not attenuate
bending mode vibrations appears in the patent specifica-
tion; and the specification notes that “the damper of the
[1963] ’406 patent appears to be a reactive damper for at-
tenuating bending mode vibration.” ’911 patent, col. 2,
lines 13–15 (citing U.S. Patent No. 3,075,406). The ’911
specification makes clear that this damper is a “liner” by
incorporating the ’361 patent “as if fully set forth in its en-
tirety.” ’911 patent, col. 6, lines 49–53. The incorporated
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS           13



    The problem with AAM’s argument is that the solution
to these desired results is not claimed in the patent. We
have repeatedly held that features that are not claimed are
irrelevant as to step 1 or step 2 of the Mayo/Alice analysis.
Alice, 573 U.S. at 221 (“[W]e must examine the elements of
the claim to determine whether it contains an ‘inventive
concept.’” (emphasis added)); Synopsis, Inc. v. Mentor
Graphics Corp., 839 F.3d 1138, 1149 (Fed. Cir. 2016) (“The
§ 101 inquiry must focus on the language of the Asserted
Claims themselves.”); Ariosa Diagnostics, Inc. v. Se-
quenom, Inc., 788 F.3d 1371, 1379 (Fed. Cir. 2015) (reject-
ing alleged inventive concept because it was “not the
invention claimed by the . . . patent” (emphasis added)); see
also Ariosa Diagnostics, Inc. v. Sequenom, Inc., 809 F.3d
1282, 1286 (Fed. Cir. 2015) (Lourie, J., concurring) (noting
that the appropriate focus is “on the claims we have rather
than those we might have had” (emphasis added)).
    The elements of the method here that AAM argues take
the patent outside the realm of ineligible subject matter—



’361 patent states: “Various kinds of vibration dampers
have been proposed heretofore. Typical of such dampers
are      the     liners      disclosed   in    U.S.    Patent
No[]. . . 3,075,406 . . . .” U.S. Patent No. 4,909,361, col. 1,
lines 16–18. Moreover, AAM’s own testing data shows that
prior art liners did in fact dampen bending mode vibra-
tions, as admitted by Dr. Sun, one of the named inventors
of the ’911 patent. Patentee’s technical expert suggested
that certain types of liners have not previously been used
to significantly dampen specific modes of vibration. Yet the
representative claims are not limited to any type of liner or
the dampening of specific bending modes. In any case, it
makes no difference to the section 101 analysis whether the
use of liners to attenuate bending mode vibrations was
known in the prior art.
14       AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




i.e., the mechanisms for achieving the desired result—are
not actually claimed in claim 1 or claim 22 of the patent.
To be sure, as AAM indicates in its brief, the process of tun-
ing a liner may involve extensive computer modelling and
experimental modal analysis, a process utilized in the prior
art. But even the patent specification recites only a nonex-
clusive list of variables that can be altered to change the
frequencies exhibited by a liner and a solitary example of a
tuned liner (though not the process by which that liner was
tuned). 4 Most significantly, the claims do not instruct how
the variables would need to be changed to produce the mul-
tiple frequencies required to achieve a dual-damping re-
sult, or to tune a liner to dampen bending mode vibrations.
    The trial-and-error process for determining the desired
frequencies was well-known. AAM makes clear in its open-
ing brief that “methods for determining natural



     4  The patent discloses a nonexclusive list of variables
related to a liner that can be altered to change the frequen-
cies exhibited by the liner so that the liner attenuates cer-
tain vibration modes of the propshaft. These variables
include:
     mass, length and outer diameter of the liner 204,
     diameter and wall thickness of the structural por-
     tion 300, material of which the structural portion
     300 was fabricated, the quantity of resilient mem-
     bers 302, the material of which the resilient mem-
     bers 302 was fabricated, the helix angle 330 and
     pitch 332 with which the resilient member 302 are
     fixed to the structural portion 300, the configura-
     tion of the lip member(s) 322 of the resilient mem-
     ber 302, and the location of the liners 204 within
     the shaft member 200.
’911 patent, col. 7, l. 60–col. 8, l. 2.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS           15



frequencies and damping are well known in the art,” in-
cluding “testing for natural frequencies and damping of
propshafts by performing experimental modal analysis.”
AAM Op. Br. 8–11. While AAM may have discovered pa-
tentable refinements of this process, such as “us[ing] so-
phisticated FEA [finite element analysis] models during its
design process,” id. at 45, neither the specifics of any novel
computer modelling nor experimental modal analysis are
disclosed in the patent, much less included in the claims
themselves, and these unclaimed features cannot function
to remove claims 1 and 22 from the realm of ineligible sub-
ject matter. See ChargePoint, 920 F.3d at 766. This case
might well be significantly different, if, for example, spe-
cific FEA models were included in the claims. But, the
claims’ general instruction to tune a liner amounts to no
more than a directive to use one’s knowledge of Hooke’s
law, and possibly other natural laws, to engage in an ad
hoc trial-and-error process of changing the characteristics
of a liner until a desired result is achieved.
     The claiming of a natural law runs headlong into the
very problem repeatedly identified by the Supreme Court
in its cases shaping our eligibility analysis. See Mayo, 566
U.S. at 71–73; Parker v. Flook, 437 U.S. 584, 590–95 (1978);
Mackay Radio & Telegraph Co. v. Radio Corp. of Am., 306
U.S. 86, 94–101 (1939); O’Reilly v. Morse, 56 U.S. (15 How.)
62, 112–17 (1854). As the Supreme Court stated in Le Roy
v. Tatham, 55 U.S. (14 How.) 156, 174–75 (1853), “[a] pa-
tent is not good for an effect, or the result of a certain pro-
cess, as that would prohibit all other persons from making
the same thing by any means whatsoever.” The same ap-
proach is embodied by this court’s case law. 5



    5   See e.g., ChargePoint, Inc. v. SemaConnect, Inc.,
920 F.3d 759, 769–70 (Fed. Cir. 2019) (finding claims di-
rected to abstract idea where broad claim language “would
16     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




    This distinction between results and means is funda-
mental to the step 1 eligibility analysis, including in law-
of-nature cases, not just abstract-idea cases. See Diamond
v. Diehr, 450 U.S. 175, 191 (1981) (“We recognize, of course,
that when a claim recites a mathematical formula (or sci-
entific principle or phenomenon of nature), an inquiry must
be made into whether the claim is seeking patent protec-
tion for that formula in the abstract.” (emphasis added)).
In Interval Licensing, we reiterated the importance of this
distinction in describing prior Supreme Court cases in
which inventors “lost . . . claim[s] that encompassed all so-
lutions for achieving a desired result” because “the claims


cover any mechanism for implementing network communi-
cation on a charging station” rather than a specific way of
doing so); Interval Licensing LLC v. AOL, Inc., 896 F.3d
1335, 1345–46 (Fed. Cir. 2018) (claims ineligible “because
they consist of generic and conventional information acqui-
sition and organization steps that are connected to, but do
not convert, the abstract idea . . . into a particular concep-
tion of how to carry out that concept” (emphasis added));
Electric Power Grp., LLC v. Alstom S.A., 830 F.3d 1350,
1355–56 (Fed. Cir. 2016); see also Innovation Sci., LLC v.
Amazon.com, Inc., ___ F. App’x ___, 2019 WL 2762976, at
*4 (Fed. Cir. 2019) (claim directed to patent ineligible mat-
ter where it “s[ought] to capture the broad concept of
switching to a more secure server, rather than a specific
way to do so”); Univ. of Fla. Research Found., Inc. v. Gen.
Elec. Co., 916 F.3d 1363, 1368 (Fed. Cir. 2019) (finding
claims to be “directed to an abstract idea” where “[n]either
the ’251 patent, nor its claims, explains how the drivers do
the conversion that UFRF points to.”); Two-Way Media
Ltd. v. Comcast Cable Commc’ns, LLC, 874 F.3d 1329, 1337
(Fed. Cir. 2017) (“The claim requires the functional results
of ‘converting,’ ‘routing,’ ‘controlling,’ ‘monitoring,’ and ‘ac-
cumulating records,’ but does not sufficiently describe how
to achieve these results in a non-abstract way.”).
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS             17



failed to recite a practical way of applying an underlying
idea . . . [and] instead were drafted in such a result-ori-
ented way that they amounted to encompassing ‘the prin-
ciple in the abstract’ no matter how implemented.” 896
F.3d at 1343; see also Electric Power, 830 F.3d at 1355–56
(noting that “the essentially result-focused, functional
character of claim language has been a frequent feature of
claims held ineligible under § 101”). The same reasoning
is applicable here, notwithstanding the fact that the patent
here is directed to a natural law rather than an abstract
idea.
    The Supreme Court’s analysis in Parker v. Flook rein-
forces our conclusion that a claim to a natural law concept
without specifying the means of how to implement the con-
cept is ineligible under section 101. In Flook, the Supreme
Court considered the patent eligibility of a method for up-
dating alarm limits during catalytic conversion processes.
437 U.S. at 585. The method involved an initial step of
measuring temperature, a second step of using a formula
to calculate an updated alarm-limit value, and a final step
in which the alarm limit is adjusted to the updated value.
Id. But the patent “d[id] not purport to explain how to se-
lect . . . any of the . . . variables” involved, nor did it “pur-
port to contain any disclosure relating to the chemical
process at work, the monitoring of process variables, or the
means of setting off an alarm or adjusting an alarm sys-
tem.” Id. at 586, 588. The patentee argued that the in-
ventive part of the patent was the mathematical formula
used in the second step of the claimed method. Id. at 588.
The patentee further contended that his claimed invention
should be patent eligible because it was limited to a partic-
ular process and involved post-solution activity that en-
sured that the patent did not “wholly preempt [use of] the
mathematical formula.” Id. at 589–90.
    Nevertheless, the Court held that the patent contained
no patent-eligible invention. Id. at 594. The Court ex-
plained that “if a claim is directed essentially to a method
18    AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




of calculating, using a mathematical formula, even if the
solution is for a specific purpose, the claimed method is
nonstatutory.” Id. at 595 (quoting In re Richman, 563 F.2d
1026, 1030 (C.C.P.A. 1977)). It first noted that limiting the
law of nature described in the patentee’s mathematical for-
mula to application in a specific process did not transform
the subject matter to which the patent was directed into
eligible matter. Id. at 593. Though the Court went on to
state that the use of a mathematical formula or law of na-
ture did not alone make a claim patent ineligible, it ex-
plained that what was required was “an inventive
application of the principle.” Id. at 593–94. Such an in-
ventive application, the Court concluded, was not present
in the patented method. The process to which the claims
were directed (catalytic conversion of hydrocarbons) was
well known, as were the use of alarm limits to trigger
alarms, repeated recalculation and readjustment of alarm-
limit values, and the use of computers for automatic moni-
toring-alarming. Id. at 594. Because the Court found that
the purportedly new formula itself was only a mathemati-
cal one, which it deemed a “principle” akin for eligibility
analysis to an existing natural relationship, id. at 589, and
given that nothing else in the patent claims exhibited more
than conventional pre- and post-solution activity, it con-
cluded that the patent was directed to nonstatutory mat-
ter. Id. at 594–95.
    Diehr, on the other hand, involved a situation in which
a patent claimed a new and specific process of molding rub-
ber products “which incorporate[d] in it a more efficient so-
lution of the [Arrhenius] equation” (a natural law). 450
U.S. at 188. Though the Supreme Court in Diehr explained
that a mathematical formula itself was not patent eligible
subject matter, it concluded that the alleged invention
claimed in that case was patent eligible. The invention in-
volved a new rubber-curing process with a specific and de-
tailed series of steps (one of which included the use of a
natural law) that limited the possibility of preempting the
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS          19



natural law itself. Id. at 187–88, 191–92. In Diehr, unlike
this case, “[t]hese other steps apparently added to the for-
mula something that in terms of patent law’s objectives
had significance—they transformed the process into an in-
ventive application of the formula.” Mayo, 566 U.S. at 81
(discussing Diehr, 450 U.S. at 187). Nevertheless, the
Court reaffirmed Flook’s teaching that “[a] mathematical
formula does not suddenly become patentable subject mat-
ter simply by having the applicant acquiesce to limiting the
reach of the patent for the formula to a particular techno-
logical use” nor through the addition of “token postsolution
activity.” Diehr, 450 U.S. at 191–92 & n.14.
    Like the claims in Flook, the claims of the ’911 patent
are directed to the utilization of a natural law (here,
Hooke’s law and possibly other natural laws) in a particu-
lar context. As in Flook, where the patent did not disclose
how variables were measured nor the means by which the
alarm system functioned, the claims here do not disclose
how target frequencies are determined or how, using that
information, liners are tuned to attenuate two different vi-
bration modes simultaneously. The claims here simply in-
struct the reader to tune the liner—a process that, as
explained above, merely amounts to an application of a nat-
ural law (Hooke’s law) to a complex system without the
benefit of instructions on how to do so. 6 The breadth of



    6    The specification makes this much clear, as it de-
scribes tuning in terms of the result achieved, rather than
the particular process by which the result is accomplished.
For instance, the specification states that “a liner 204 will
be considered to be tuned to a relevant frequency if it is
effective in attenuating vibration at the relevant fre-
quency.” ’911 patent, col. 8, ll. 28–31. Later in the same
column, the patent gives an example of a “liner [that is]
considered to be tuned to a relevant shell mode frequency
20    AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




these claims is illustrated by AAM’s admission during the
claim construction hearing that one could infringe the
claims of the ’911 patent “[e]ven if you didn’t try to [tune]
and didn’t know you did it.” J.A. 699.
     Finally, though we recognize that AAM may be correct
in its assertion that the system involved in the ’911 patent
is more complex than just a bare application of Hooke’s law,
and that other laws of nature may be relevant, that does
not render the subject matter patent eligible. What is
missing is any physical structure or steps for achieving the
claimed result of damping two different types of vibrations.
The focus of the claimed advance here is simply the concept
of achieving that result, by whatever structures or steps
happen to work.
    The dissent suggests that the failure of the claims to
designate how to achieve the desired result is exclusively
an issue of enablement. Dissent Op. at 2, 11–14. Both the
Supreme Court cases and our cases addressing section 101
have held otherwise, as the earlier discussion demon-
strates. Enablement is concerned with whether the “the
specification of a patent… teach[es] those skilled in the art
how to make and use the full scope of the claimed inven-
tion.” In re Wright, 999 F.2d 1557, 1561 (Fed. Cir. 1993).
Section 101 is concerned with whether the claims at issue
recite a natural law, not whether the specification has ad-
equately described how to make and use the concretely
claimed structures and steps. The Supreme Court in Mayo
made clear that section 101 serves a different function
than enablement. Mayo, 566 U.S. at 90 (“[T]o shift the pa-
tent-eligibility inquiry entirely to these later [statutory]
sections risks creating significantly greater legal


if it damps shell mode vibrations by an amount that is
greater than or equal to about 2%.” Id. at col. 8, ll. 44–47.
This makes clear that the concept of tuning embodied by
the patent is merely results-oriented.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS         21



uncertainty, while assuming that those sections can do
work that they are not equipped to do.”). Moreover, even
if, as the dissent says, the specification gives one ade-
quately concrete embodiment, which we need not decide,
that is not enough: O’Reilly established long ago that an
inadequately concrete claim is not saved from ineligibility
by the presence of adequate concrete recitations in the
specification or in other claims. 56 U.S. at 112–20 (holding
eighth claim ineligible while upholding first seven claims).
                             II
    As to Mayo/Alice step 2, nothing in the claims qualifies
as an “inventive concept” to transform the claims into pa-
tent eligible matter. AAM contends that the claims include
numerous inventive concepts that were neither previously
known, nor conventional or routine. AAM’s arguments in
this respect essentially amount to an assertion that prior
to the ’911 patent, liners had never been tuned to damp
propshaft vibrations and, more specifically, liners had not
been used to damp two different vibration modes simulta-
neously. This amounts to no more than an elaborated ar-
ticulation of its reasons as to why the claims are not
directed to a natural law (reasons we have already re-
jected).
    The claimed advance is simply controlling various
known characteristics of the liner so as to achieve attenua-
tion of two vibration modes simultaneously, whether that
is by changing the mass or thickness of the liner, altering
the location of the liner in the propshaft, or modifying any
other physical attributes that will produce the claimed
dual-attenuation. AAM admits that it was well known “in
the automotive industry [to] test for natural frequencies
and damping of propshafts by performing experimental
modal analysis.” AAM Op. Br. 8. As explained above, this
direction to engage in a conventional, unbounded trial-and-
error process does not make a patent eligible invention,
22       AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




even if the desired result to which that process is directed
would be new and unconventional.
     Nor does the direction in claim 1 to “position” the liner
within the propshaft add an inventive concept. Under the
claim language itself, and as reaffirmed by the district
court’s now-undisputed construction, positioning is not
part of tuning. And even if it were, the specification makes
clear that it was well known to position dampers in the
propshaft so as to maximize vibration damping. See, e.g.,
’911 patent, col. 1, ll. 57–60. Notably, AAM does not appear
to argue that positioning was more than conventional. In
listing alleged inventive concepts in its opening brief, AAM
does not include positioning.
    The remaining steps of claims 1 and 22, like the steps
involved in the Flook patent, amount to no more than con-
ventional pre- and post-solution activity. As the Supreme
Court made clear in Flook, neither such conventional addi-
tions, nor the limiting of the use of a natural law or math-
ematical formula to a particular process suffices to create
patent eligibility. 7
     Claims 1 and 22 are not patent eligible. 8



     7   AAM does not appear to argue on appeal that the
numerical limitations in claim 1 represent an inventive
concept. In any event, as explained above, these limita-
tions describe a desired result but do not instruct how the
liner is tuned to accomplish that result.
    8    To the extent that AAM’s opening summary judg-
ment brief as to § 101 patent eligibility can be understood
to argue that there are disputed issues of material fact as
to whether the patent discloses an inventive concept, it re-
lies only on Dr. Rahn’s testimony that dual-damping of
bending mode and shell mode vibrations was new and un-
conventional. AAM Mot. for Summary Judgment at 8–9,
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS          23



                             III
     Having determined that independent claims 1 and 22
are not patent eligible under § 101, we need not separately
determine eligibility of the dependent claims. The district
court found independent claims 1 and 22 collectively repre-
sentative of all the asserted claims. AAM did not argue be-
fore the district court that the dependent claims change the
outcome of the eligibility analysis. Nor did AAM make
such an argument in its opening brief on appeal. Although
at oral argument AAM disagreed that claims 1 and 22 are
representative of the others and stated that it never ac-
ceded to such a finding, Oral Arg. 30:07–40, it was unable
to identify any part of its opening brief that presented such
an argument and admitted that it was “not suggesting that
the other claims should come out differently,” id. at 30:40–
31:16. We therefore find any such argument waived. See
Affinity Labs, 838 F.3d at 1256 n.1 (treating certain claims
as representative where no meaningful argument made
that other claims are materially different); Electric Power,
830 F.3d at 1352.
                       CONCLUSION
        Because we conclude that the asserted claims of the
’911 patent are directed to ineligible subject matter under
§ 101, we affirm.
                       AFFIRMED
                           COSTS
    No costs.




American Axle & Manuf., Inc. v. Neapco Hldgs. LLC, No.
15-01168 (D. Del. Aug. 11, 2017), ECF No. 160. But as ad-
dressed in detail above, dual-damping is merely a desired
result and, without more, is insufficient to make the ’911
patent eligible pursuant to § 101.
  United States Court of Appeals
      for the Federal Circuit
                  ______________________

   AMERICAN AXLE & MANUFACTURING, INC.,
              Plaintiff-Appellant

                             v.

NEAPCO HOLDINGS LLC, NEAPCO DRIVELINES
                   LLC,
           Defendants-Appellees
          ______________________

                        2018-1763
                  ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:15-cv-01168-LPS, Chief Judge
Leonard P. Stark.
                 ______________________

MOORE, Circuit Judge, dissenting.
    The majority’s decision expands § 101 well beyond its
statutory gate-keeping function and the role of this appel-
late court well beyond its authority. The majority opinion
parrots the Alice/Mayo two-part test, but reduces it to a
single inquiry: If the claims are directed to a law of nature
(even if the court cannot articulate the precise law of na-
ture) then the claims are ineligible and all evidence of non-
conventionality will be disregarded or just plain ignored.
The majority rejects the notion that claims which contain
an “inventive concept” survive the gatekeeper. In the
words of the majority, “it makes no difference to the section
101 analysis whether the use of liners to attenuate bending
2     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




mode vibration was known in the prior art.” Maj. at 13. I
am deeply troubled by the majority’s disregard for the sec-
ond part of the Alice/Mayo test, its fact finding on appeal
and its repeated misrepresentation of the record, in each
instance to the patentee’s detriment; all when we are to be
applying the summary judgment standard no less.
    The majority’s concern with the claims at issue has
nothing to do with a natural law and its preemption and
everything to do with concern that the claims are not ena-
bled. Respectfully, there is a clear and explicit statutory
section for enablement, § 112. We cannot convert § 101 into
a panacea for every concern we have over an invention’s
patentability, especially where the patent statute ex-
pressly addresses the other conditions of patentability and
where the defendant has not challenged them.
     The district court held that the claims at issue are in-
eligible under § 101 because they are directed to a natural
law, specifically, “applications of Hooke’s law with the re-
sult of friction damping.” J.A. 11. Even the majority does
not agree with the district court that the claims are di-
rected to Hooke’s Law. Instead the majority concludes that
the claims are ineligible because they are “directed to the
utilization of a natural law (here, Hooke’s law and possibly
other natural laws) in a particular context.” Maj. at 19; see
also Maj. at 20 (“though we recognize that AAM may be
correct in its assertion that the system involved in the ’911
patent is more complex than just a bare application of
Hooke’s law, and that other laws of nature may be relevant,
that does not render the subject matter patent eligible”).
Section 101 is monstrous enough, it cannot be that now you
need not even identify the precise natural law which the
claims are purportedly directed to. The “focus of the
claimed advance,” as repeatedly alleged by the patentee, is
to use liners (a physical liner) positioned inside a drive
shaft to reduce shell mode vibration and bending mode vi-
bration. The claims at issue are directed to methods of
manufacturing shaft assemblies for driveline systems for
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS           3



automotive vehicles using liners to reduce specific types of
vibration. See ’911 Patent Claims. Claim 1, for instance,
recites:
    A method for manufacturing a shaft assembly of a
    driveline system, the driveline system further in-
    cluding a first driveline component and a second
    driveline component, the shaft assembly being
    adapted to transmit torque between the first
    driveline component and the second driveline com-
    ponent, the method comprising:
        providing a hollow shaft member;
        tuning at least one liner to attenuate at
        least two types of vibration transmitted
        through the shaft member; and
        positioning the at least one liner within the
        shaft member such that the at least one
        liner is configured to damp shell mode vi-
        brations in the shaft member by an amount
        that is greater than or equal to about 2%,
        and the at least one liner is also configured
        to damp bending mode vibrations in the
        shaft member, the at least one liner being
        tuned to within about ±20% of a bending
        mode natural frequency of the shaft assem-
        bly as installed in the driveline system.
As the patentee argues, the dependent claims further nar-
row the physical characteristics of the liners to be used and
their positioning within the drive shaft: “Several depend-
ent claims, for example, recite particular liner materials
(e.g., cardboard or paperboard) and structures (helically-
wrapped resilient member). . . . claims 12, 13, 19, 26, 27,
4       AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




31.” Appellant’s Reply Br. at 27. 1 I do not see how these
claims are directed to a natural law. And even if part one
of the Alice/Mayo test was satisfied here, there is a part
two. The claims will not be held ineligible (remember § 101
is meant to be a gatekeeper) if the claims contain an “in-
ventive concept.” There are many here, articulated in the
claims themselves, about which there exist at least ques-
tions of fact which should have precluded summary judg-
ment. Argued below, and throughout the briefing on
appeal and during oral argument to this panel, the pa-
tentee maintains that liners had never before been used to
reduce bending mode vibration. See Appellant’s Br. at 12,
25–26, 27, 35, 57–60, 63, and 65 n.5; Appellant’s Reply Br.


    1    I do not agree with the majority’s conclusion that
claims 1 and 22 are representative. First, Neapco never
argued that claims 1 and 22 should be representative and
in fact argued the dependent claims separately. See Dkt.
150 (Neapco’s Mot. for Summ. J.) at 32–33. Second, AAM
expressly argued that they are not representative. AAM’s
statement that the dependent claims should not come out
differently does nothing more than confirm that it believes
all of the claims are patent-eligible. Third, the majority
inaccurately states the patentee did not argue limitations
of the dependent claims. AAM’s briefs provide multiple ref-
erences to the type of material and other limitations found
only in the dependent claims as providing the inventive
concepts which are not routine or conventional. See, e.g.,
Appellant’s Br. at 13–14, 36, 57–58, and 64–65. Merely by
way of example, dependent claim 31 limits the material for
the liner to cardboard among others. AAM claimed using
a “cardboard liner to reduce bending mode vibrations” was
an “inventive concept” and not “conventional or routine.”
Id. at 57–58. It is inappropriate in light of these facts for
the majority to sua sponte declare the claims representa-
tive and ignore the expressly argued dependent claims and
limitations.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS             5



at 2, 15 (“Prior art liners were used to provide general
broadband damping of shell mode vibrations, but liners
were not used to dampen bending mode vibrations prior to
the claimed invention.”), 19 (“It was inventive to use a liner
to damp bending mode vibrations”), 24–25, and 29. The
argument that liners were never before used to attenuate
bending mode vibrations was AAM’s first and one of its
strongest non-conventionality arguments. AAM’s opening
brief set this forth on the very first page of its step-two ar-
gument:
    1. The Claims Contain Inventive Concepts and Are
    Not Conventional or Routine
                          *   *    *
    [T]he asserted claims include at least the following in-
    ventive concepts:
       •   using a cardboard liner to reduce bending
           mode vibrations;
       •   using a cardboard liner to reduce bending and
           shell mode vibrations;
       •   tuning a cardboard liner by controlling its char-
           acteristics;
       •   controlling the characteristics of a cardboard
           liner such that it matches and damps bending
           mode vibrations;
       •   controlling the characteristics of a cardboard
           liner such that it damps bending mode vibra-
           tions by oscillating in opposition to a specific
           propshaft bending mode frequency; and
       •   controlling the characteristics of a cardboard
           liner such that it matches and damps vibration
           of multiple different types of propshaft vibra-
           tion, e.g., both bending and shell mode vibra-
           tions.
6     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




Appellant’s Br. at 57–58.
     The majority rejects this “inventive concept” in its §
101 analysis, first as inaccurate (a fact finding made by the
majority on appeal and contrary to all the evidence of rec-
ord) and second as irrelevant. Let’s begin with the major-
ity’s claim that the patent itself discloses the use of liners
to reduce bending mode vibration: “According to the ’911
patent’s specification, prior art liners, weights, and damp-
ers that were designed to individually attenuate each of the
three propshaft vibration modes—bending, shell and tor-
sion—already existed.” Maj. at 6. And again, citing the
patent, the majority claims, “It was also known that a liner
or weight could be designed specifically to have a frequency
that would allow it to function as either a resistive attenu-
ation means [shell mode vibration] or as a reactive attenu-
ation means [bending mode vibration]. AAM does not
dispute that these features were known in the art.” Maj.
at 10. These statements are false.
     The patent admits that liners had been used to reduce
shell mode vibration. ’911 patent at 2:23–36. It then
states: “These liners, however, do not appear to be suitable
for bending mode vibration or torsion mode vibration.” Id.
at 2:36–38. The patent discloses prior use of plugs,
weights, and dampers to attenuate bending mode vibra-
tions, but stresses that liners were not suitable. The pa-
tentee explained that before the ’911 patent, liners were
not used, car manufacturers shoved masses of wadded up
cardboard into the propshaft to reduce bending vibrations.
Oral Arg. 6:46–7:11. More than a dozen times in the briefs
and during oral argument the patentee argued that the use
of liners to attenuate bending mode vibration was one of its
inventive concepts. Without regard for the arguments
made, the majority declares “AAM does not dispute that
these features were known in the art.” Maj. at 10. Yes, it
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS          7



certainly did dispute this more than a dozen times. 2 In
fact, AAM’s counsel corrected the court when a member of
the majority tried to suggest that liners to attenuate bend-
ing mode were known in the prior art:
   Judge: “None of that is new, there were liners,
   there were changes to the liners to make them
   dampen, right? That was not new.”
   AAM: “The liners had never been used to damp
   bending mode.”




   2    In a footnote, the majority suggests that while the
patentee made the argument throughout its briefing and
argument on appeal, it was not properly raised below. Maj.
at 12 n.3. There is no doubt the district court understood
the argument as having been made and Neapco did not ar-
gue otherwise:
   THE COURT: “So what is it that is not conven-
   tional in the claims other than the application of
   Hooke’s law?
   MR. NUTTALL: Tuning a liner to target a specific
   bending mode was new and different and nobody
   thought you could do that or should do that before,
   much less coupling that with also being tuned to a
   shell mode vibration.”
The majority stops short of saying that it deems the argu-
ment waived, and in fact then decides the fact question
which was disputed in the briefs before us by the parties.
The majority likely does not find the argument waived be-
cause Neapco never alleges it was waived and it is axio-
matic that one can waive waiver. See, e.g., Norwood v.
Vance, 591 F.3d 1062, 1068 (9th Cir. 2010) (It is “well-es-
tablished” that a party can “‘waive waiver’ implicitly by
failing to assert it.”).
8     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




Oral Arg. 6:46–49. Even Neapco acknowledged that the
patent states that liners had not been used to attenuate
bending mode vibrations. See Appellee’s Br. at 8. Neapco
never disputed the patentee’s claim that liners had never
been used to dampen bending mode vibration. It matters
not at all to the majority that the patentee alleges that lin-
ers had not been used to reduce bending mode vibration,
and that Neapco presented no argument or evidence to con-
tradict that. The majority has decided to make its own fact
finding that prior art liners had been used. The majority
finds that U.S. Patent No. 3,075,406, never introduced as
evidence in this case or cited by either party, which dis-
closes a rigid cylindrical metal bar with two circular ends
resembling a metal dumbbell—is a liner. Thus, according
to the majority, there is at least one liner in a single prior
art patent which was used to reduce bending mode. This
is a fact question, nobody argued it, and reasonable minds
could disagree over whether a dumbbell is a liner. Moreo-
ver, a disclosure in a single patent does not establish that
the use of liners to attenuate bending mode vibration was
“well-understood, routine, conventional activity” as re-
quired by the Supreme Court.
    Doubling down, the majority then claims that the pa-
tentee’s own testing proved that prior art liners “did in fact
dampen bending mode vibrations.” Maj. at 13. I fail to see
how the patentee’s invention that liners could be used, the
very invention for which they have obtained patent protec-
tion, supports the majority’s finding that liners were
known in the prior art to be used to reduce bending mode
vibration. To be clear, there is no record evidence that lin-
ers had been used to dampen bending mode vibration much
less that the use of liners to dampen bending mode vibra-
tion was routine and conventional. The patentee argued
throughout that one of the inventive concepts present in
every single claim of the patent was the novel use of liners
to reduce bending mode vibration. Ultimately, the major-
ity says the inventive concept “makes no difference to the
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS            9



section 101 analysis.” Maj. at 13. I understand this to be
an outright rejection of the second step of the Alice/Mayo
test. The majority explains: “Section 101 is concerned with
whether the claims at issue recite a natural law, not
whether the specification has adequately described how to
make and use the concretely claimed structures and steps.”
Maj. at 21. This statement of law is just plain wrong. Miss-
ing is any recognition that the Alice/Mayo test is a two-part
test and that the second step has meaning. The concretely
claimed structures and steps, as in these claims, are ex-
actly what can move the claim from ineligible to eligible by
virtue of step 1 or step 2.
    There are additional alleged “inventive concepts”
which I will briefly mention. The claims include limita-
tions which get progressively more detailed about the
structure and positioning of the liner inside the drive shaft.
The patentee argues throughout that the position of the
liner inside the shaft (an express claim element) is one of
the characteristics to be controlled in attenuating bending
mode vibration. See Appellant’s Br. at 14, 36, 42, and 65.
The patentee alleges throughout that the concept of tuning
a liner, i.e. controlling the characteristics of a liner to
dampen vibration of any given system is an inventive con-
cept. See id. at 27–28, and 57–67; Appellant’s Reply Br. at
2, 16, and 18–29. The particular characteristics of the
tuned liner will depend on the characteristics of the drive
shaft it is being used in (for example the natural frequen-
cies, which are inherent properties of each shaft). 3 See ’911
patent at 7:44–55; Appellant’s Br. at 4, 6, 46, and 53.



    3   And the ’911 patent’s specification explains how to
tune liners to attenuate those vibrations. For example, the
specification explains that different characteristics of the
liners are controlled corresponding to the structure of the
propshaft. ’911 patent at 7:56–8:43. It even provides a
10     AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




    The majority claims: “What is missing is any physical
structure or steps for achieving the claimed result of damp-
ing two different types of vibration. The focus of the
claimed advance here is simply the concept of achieving
that result, by whatever structures or steps happen to
work.” Maj. at 20. The “focus of the claimed advance,” as
repeatedly alleged by the patentee and as expressly
claimed, is to insert a liner (a concretely identified physical
liner) inside a drive shaft to reduce shell mode vibration
and bending mode vibration. See, e.g., claims 1 & 22. The
dependent claim limitations further narrow this “identified
physical structure.” Claims limit the material from which
the liner can be made, for example, cardboard. See claims
19 & 31. Other claims limit the physical structure of the
liner itself. It can extend helically (claims 13 & 27) or lon-
gitudinally (claims 14 & 28) or circumferentially (claims 15
& 29). The liner includes a “plurality of fingers” (claims 18
& 33). And the claims limit where the liner can be placed
within the shaft. Claim 20 for example requires the liner
to be positioned within the shaft symmetrically about a
bending anti-node. It is remarkable that the majority
thinks that claims with all of these very physical, very con-
crete, very structural limitations are nonetheless “missing
any physical structure or steps.” It is not, as the majority
claims, “whatever structures or steps happen to work.”
Maj. at 20. It is a physical liner positioned inside the shaft.
    The tuned liner element is the crux of what bothers the
majority in this case. The majority’s true concern with
these claims is not that they are directed to Hooke’s Law
(because this is clearly a much more complex system not
limited to varying mass and stiffness), but rather the pa-
tentee has not claimed precisely how to tune a liner to
dampen both bending and shell mode vibrations. As the



particular example of tuned liners for use in a propshaft
with specific dimensions. Id. at 8:2–23.
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS              11



following quotes from the majority demonstrate, their
problem with these claims is not one of eligibility, but ra-
ther one of enablement:
       •   “Most significantly, the claims do not instruct
           how the variables would need to be changed to
           produce the multiple frequencies required to
           achieve a dual-damping result.” Maj. at 14–15.
       •   “[T]he claims’ general instruction to tune a liner
           amounts to no more than a directive to use one’s
           knowledge of Hooke’s law, and possibly other
           natural laws, to engage in an ad hoc trial-and-
           error process of changing the characteristics of a
           liner until a desired result is achieved.” Maj. at
           15.
       •   “The claims here simply instruct the reader to
           tune the liner . . . without the benefit of instruc-
           tions on how to do so.” Maj. at 19–20.
       •   “The problem is it really doesn’t tell you how to
           do it, right? It says ‘do tuning,’ but it doesn’t tell
           you how to do the tuning.” Oral Arg. at 1:35–42
           (Judge).
       •   “Looking at this patent, you couldn’t tell how to
           do it. Someone skilled in the art wouldn’t know
           how to do it. You would need additional infor-
           mation, right?” Oral Arg. at 2:09–2:16 (Judge).
       •   “That is just a statement of the result, it doesn’t
           tell you how to do it . . . it doesn’t tell you how to
           change the variables, right?” Oral Arg. at 5:50–
           6:15 (Judge).
       •   “Basically it is done by trial-and-error. You start
           with a computer program and then you do trial
           and error to come to the correct result, right?”
           Oral Arg. at 12:04–11 (Judge).
12    AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




       •   “The real question here is do we have anything
           more than a result? Even if you use all of these
           different variables, it doesn’t really tell you how
           to use the variables. And that’s the problem.”
           Oral Arg. at 21:40–22:20 (Judge).
       •   “The more variables there are, the more difficult
           it is to know how to do it, and the more guidance
           that’s needed, and there is none as to the use of
           all these variables other than just use a lot of
           variables and figure it out.” Oral Arg. at 27:10–
           23 (Judge).
       •   “The claims themselves don’t even provide you
           with a list of variables, there are a lot of different
           variables, done by trial and error, and all the
           claims are telling you is here is a desirable result
           and use trial and error to get there.” Oral Arg.
           at 29:20–36 (Judge).
       •   “At least what I am listening for, and I have been
           focused on throughout this is . . . is it only make
           and place a liner so that two damping effects oc-
           cur, you figure out how? That seems to me kind
           of the question that we are struggling with.”
           Oral Arg. at 35:17–38 (Judge).
    “[T]o be enabling, the specification of a patent must
teach those skilled in the art how to make and use the full
scope of the claimed invention without ‘undue experimen-
tation.’” See Genentech, Inc. v. Novo Nordisk A/S, 108 F.3d
1361, 1365 (Fed. Cir. 1997). There is undue experimenta-
tion when “the trial and error required to practice the
claimed invention could be unduly laborious.” Old Town
Canoe Co. v. Confluence Holdings Corp., 448 F.3d 1309,
1320 (Fed. Cir. 2006). And whether undue experimenta-
tion is required is a question of fact. Transocean Offshore
Deepwater Drilling, Inc. v. Maersk Contractors USA, Inc.,
617 F.3d 1296, 1305 (Fed. Cir. 2010). The majority faults
the ’911 patent because the claims themselves fail to
AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS           13



describe “how to achieve such tuning.” Maj. at 7. The ma-
jority concludes, apparently de novo, that too much “trial
and error” would be required to determine how to tune a
particular liner to the frequencies associated with a given
propshaft. The majority advises that if the claims had
themselves mentioned using computer modeling to deter-
mine how to tune the liner, it may have made all the dif-
ference. Yet, earlier the majority explains that such
computer modeling and experimental modal analysis was
already used in the prior art. How does adding a limitation
to the claims to “use a computer program to figure out how
to tune the liners” alleviate the majority’s concern that
these claims are directed to a natural law? Surely, this is
the first time adding software to a claim would make it el-
igible. The majority acknowledges that there is a very spe-
cific example given in the patent with precise dimensions,
weights, lengths, materials, positioning, etc. See ’911 pa-
tent at 8:2–23. Whether this disclosure combined with the
knowledge of a skilled artisan would permit that skilled ar-
tisan to tune a liner to a given propshaft in order to reduce
bending mode vibrations without undue experimentation
is exactly and precisely the enablement test pursuant to §
112. A patentee’s failure to enable his invention renders
the claims invalid under § 112, it does not, however, render
the claims ineligible under § 101. The ’911 patent claims
include a concretely identified physical structure—a liner
inserted inside the propshaft—to reduce vibrations. Ac-
cording to the majority, it is not enough that a skilled arti-
san reading the specification would know how to tune a
liner to the frequency of any given propshaft—the claims
themselves must recite these steps. To be clear, according
to the majority, even if these claims are enabled, they are
still ineligible because the claims themselves didn’t teach
how. This is now the law of § 101. The hydra has grown
another head.
    Today, the majority concludes that the ’911 patent
claims are not eligible because they do not teach a skilled
14    AMERICAN AXLE & MANUFACTURING v. NEAPCO HOLDINGS




artisan how to tune a liner. The majority holds that they
are directed to some unarticulated number of possible nat-
ural laws apparently smushed together and thus ineligible
under § 101. The majority concludes that the inventive
concepts “make no difference.” Section 101 simply should
not be this sweeping and this manipulatable. It should not
be used to invalidate claims under standards identical to
those clearly articulated in other statutory sections, but
not argued by the parties. It should not subsume § 112. It
should not convert traditional questions of fact (like undue
experimentation) into legal ones. The majority’s validity
goulash is troubling and inconsistent with the patent stat-
ute and precedent. The majority worries about result-ori-
ented claiming; I am worried about result-oriented judicial
action. I dissent.
