MTU Aero Engines AG

Patent Trials and Appeals Board

Oct 29, 2020

2019006970 (P.T.A.B. Oct. 29, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/090,845 04/05/2016 Carsten SCHOENHOFF 6570-P50292 6934
13897 7590 10/29/2020
Abel Schillinger, LLP
5929 Balcones Drive
Suite 300
Austin, TX 78731
EXAMINER
KANG, EDWIN G
ART UNIT PAPER NUMBER
3741
NOTIFICATION DATE DELIVERY MODE
10/29/2020 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
hmuensterer@abel-ip.com
mail@Abel-IP.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte CARSTEN SCHOENHOFF, RUDOLF STANKA,
ERICH STEINHARDT, CLAUS RIEGLER,
STEPHEN ROYSTON WILLIAMS, HANS-PETER HACKENBERG,
ECKART HENRICH, STEFAN WEBER, KLAUS PETER RUED,
HERMANN KLINGELS, PATRICK WACKERS,
CHRISTOPH BICHLMAIER, STEFAN BUSAM,
MATTHIAS KROBOTH, and NORBERT HUEBNER
____________

Appeal 2019-006970
Application 15/090,845
Technology Center 3700
____________

Before EDWARD A. BROWN, MICHAEL L. HOELTER, and
JAMES A. WORTH, Administrative Patent Judges.

BROWN, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellant1 seeks review under 35 U.S.C. § 134(a) of the Examiner’s
decision rejecting claims 1–20.2 We have jurisdiction under 35 U.S.C.
§ 6(b). We affirm.

1 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies the real party in interest as MTU Aero
Engines AG. Appeal Br. 3.
2 Appellant indicates that an appeal is pending in co-pending Application
15/090,805 (Appeal 2019-006583), which appeal may have the potential to
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CLAIMED SUBJECT MATTER
Claims 1, 19, and 20 are independent claims. Claim 1 recites a
turbofan aircraft engine, claim 19 recites a passenger jet comprising the
turbofan aircraft engine of claim 1, and claim 20 recites a method of
reducing the noise emission of a turbofan aircraft engine. Appeal Br. 19, 21
(Claims App.). Claim 1, reproduced below, illustrates the claimed subject
matter on appeal.
1. A turbofan aircraft engine, wherein the turbofan aircraft
engine comprises:
a primary duct including a combustion chamber;
a first turbine disposed downstream of the combustion
chamber;
a compressor disposed upstream of the combustion
chamber and coupled to the first turbine; and
a second turbine disposed downstream of the first turbine
and coupled to a fan for feeding a secondary duct of the
turbofan aircraft engine, a bypass ratio of an inlet area of the
secondary duct to an inlet area of the primary duct being at least
7;
and wherein the second turbine comprises at least a first stage
and a second stage and each stage comprises a number of stator
vanes each having a mean radius r, a quotient r/n of the mean
radius of a stator vane r expressed in inches divided by the
number of stator vanes n being at least 0.18 for the first stage.
Id. at 19 (Claims App.).

affect, or be affected by, the instant appeal. Reply Br. 2. We note however,
that the Board rendered a Decision on that appeal on July 2, 2020.
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REJECTIONS ON APPEAL3
Claims 1–20 are rejected under 35 U.S.C. § 112(a) as failing to
comply with the written description requirement. Final Act. 3.
Claims 1–20 are rejected under 35 U.S.C. § 112(a) as failing to
comply with the enablement requirement. Final Act. 9.
Claims 1–20 are rejected under 35 U.S.C. § 103 as unpatentable over
Pratt and Whitney, “PW 1100G-JM Secondary Airflow and Lubrication
Systems,” Aug. 2014 (hereinafter, “Pratt and Whitney”) and Wadia (US
2017/0138202 A1, published May 18, 2017). Final Act. 30.

ANALYSIS
Claims 1–20 – Enablement
The enablement requirement of 35 U.S.C. § 112(a) requires the as-
filed disclosure to be sufficiently complete to enable a person of ordinary
skill in the art at the time of the invention to make and use the claimed
invention without undue experimentation. In re Wands, 858 F.2d 731, 737
(Fed. Cir. 1988). Factors to be considered by the PTO in determining
whether a disclosure would require undue experimentation are discussed in
Wands.4 See MPEP § 2164.01(a). When rejecting a claim for lack of
enablement, the PTO has the initial burden to provide “a reasonable

3 The rejection of claims 1–20 under 35 U.S.C. § 112(b) has been
withdrawn. Ans. 47; Final Act. 7.
4 The “Wands factors” include (1) the quantity of experimentation necessary,
(2) the amount of direction or guidance presented, (3) the presence or
absence of working examples, (4) the nature of the invention, (5) the state of
the prior art, (6) the relative skill of those in the art, (7) the predictability or
unpredictability of the art, and (8) the breadth of the claims. Id.
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explanation” of why it believes the specification is not enabling. In re
Wright, 999 F.2d 1557, 1561–62 (Fed. Cir. 1993). If the PTO meets this
initial burden, the burden then shifts to Appellant to show that one of
ordinary skill in the art could have practiced the claimed invention without
undue experimentation. In re Strahilevitz, 668 F.2d 1229, 1232 (CCPA
1982). An enablement rejection can be based on either scope of enablement
or on total lack of enablement for any subject matter within the scope of the
claims. In re Cortright, 165 F.3d 1353, 1356 (Fed. Cir. 1999). As for scope
of enablement, “the applicant’s specification must enable one of ordinary
skill in the art to practice the full scope of the claimed invention without
‘undue experimentation.’” Wright, 999 F.2d at 1561 (citations omitted).
Claims 1 and 20 recite the limitation “a bypass ratio of an inlet area of
the secondary duct to an inlet area of the primary duct being at least 7.”
Appeal Br. 19, 21 (Claims App.). Claims 2 and 3 depend from claim 1 and
recite the bypass ratio is at least 8 and at least 9, respectively. Id. at 19. As
for claim 1, the Examiner finds that the Specification describes, “the bypass
ratio in the turbofan aircraft engine of the present invention is at least 7, but
will often be at least 8, e.g., at least 9, at least 10, or at least 11,” but finds
that the disclosure does not enable a bypass ratio of, for example, 20, 30, or
40. Final Act. 10–11 (citing Spec. 6, ll. 13–15). The Examiner analyzes
multiple Wands factors and determines that, on the whole, the
experimentation needed to make and use the claimed subject matter based on
the disclosure would be undue. Id. at 11–12. The Examiner’s position for
the bypass ratio limitation recited in claims 2, 3, and 20 is substantially the
same as for claim 1. Id. at 13–16, 26–27.
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Claim 1 further recites the limitation “a quotient r/n of the mean
radius of a stator vane r expressed in inches divided by the number of stator
vanes n being at least 0.18 for the first stage.” Appeal Br. 19 (Claims App.).
Claim 20 recites a similar limitation. Id. at 21. Claims 4, 5, and 6 each
depend from claim 1 and recite the quotient r/n of the first stage is 0.19,
0.195, and 0.20, respectively. Id. at 19. Claim 7 depends from claim 3 and
recites the same quotient r/n limitation as claim 6. Id. at 20. As for claim 1,
the Examiner finds that the Specification describes, “the quotient r/n of the
first stage of the second turbine will often be higher than 0.18, e.g., at least
0.19, or at least 0.20. It will often not be higher than 0.26, e.g., not higher
than 0.25, or not higher than 0.24,5” but finds that the Specification “does
not describe how a larger quotient, for example 0.3, 3, or 30 would be
enabled.” Final Act. 12 (citing Spec. 6, ll. 16–18). The Examiner analyzes
the same Wands factors for the quotient r/n limitation as for the bypass ratio
limitation, and determines that the experimentation needed to make and use
the claimed subject matter based on the disclosure would be undue. Id. at
12–13. The Examiner’s position as to the quotient r/n of the first stage
limitation recited in claims 4–7 and 20 is substantially the same as for claim
1. Id. at 16–20.
Further, claims 8, 9, and 10 depend from claim 1 and recite “the
quotient r/n of the second stage is at least 0.17,” “at least 0.175,” and “at
least 0.18,” respectively. Appeal Br. 20 (Claims App.). Claim 11 depends
from claim 9 and recites “the quotient r/n of the first stage is at least 0.19.”
Id. As for claim 8, the Examiner notes that the Specification describes, “the

5 The phrase “[i]t will often not be higher than” a number implies that, in
some cases, it will be higher than that number. Spec. 6, ll. 17–18.
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quotient r/n of the second stage of the second turbine is not particularly
limited, but will often be at least 0.17, e.g., at least 0.175, or at least 0.18. It
will usually be not higher than 0.22, e.g., not higher than 0.21, or not higher
than 0.20,” but finds that the Specification “does not describe how a larger
quotient, for example 0.3, 3, or 30 would be enabled.” Final Act. 20 (citing
Spec. 6, ll. 19–23) (emphasis added). The Examiner analyzes the same
Wands factors as done for the bypass ratio and quotient r/n for the first stage
limitations, and determines that undue experimentation would be needed to
make and use the claimed subject matter based on the disclosure. Id. at 20–
21. The Examiner’s position as to the quotient r/n of the second stage
limitation recited in claims 9 and 10 is substantially the same as for claim 8.
Id. at 22–24.
Appellant contends that the claims comply with the enablement
requirement. Appeal Br. 10. Appellant refers to the Examiner’s position for
the bypass ratio values recited in claims 1–3 and 20, and the quotient r/n for
the first stage values recited in claims 1, 4–7, and 20. Id. Appellant asserts,
“since both the bypass ratio and the quotient r/n depend on only two
variables which can readily be varied, it is apparent to one of ordinary skill
in the art how any bypass ratio and any quotient r/n (which makes technical
sense) can be achieved.” Id. Appellant further asserts, “[i]n this case not
even experimentation (which would theoretically even be permissible, as
long as it is not undue) is required.” Id.
These contentions are unpersuasive. The pertinent issue is not
whether a skilled artisan would have the requisite skill to change the inlet
area of a secondary duct and an inlet area of a primary duct to change the
corresponding bypass ratio, as claimed, or to change the mean radius of a
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stator vane and the number of stator vanes in a first stage, as claimed, in
view of the disclosure. Rather, the issue is whether the disclosure provides
enablement for a turbofan aircraft engine in which both the bypass ratio and
the quotient r/n lack an upper limit.
It appears to be Appellant’s position that no experimentation would be
needed to determine an upper limit for the bypass ratio or the quotient r/n for
the first stage. Appeal Br. 10. As noted above, the Specification describes
“the bypass ratio . . . will often be . . . at least 11” and “the quotient r/n of the
first stage . . . will often not be higher than 0.26.” However, the
Specification provides no guidance about how much higher than 11 the
bypass ratio can be, or how much higher than 0.26 the quotient r/n of the
first stage can be. Absent such guidance, we are unpersuaded that no
experimentation would be needed to determine both of these upper limits,
especially in the same turbofan aircraft engine. Appellant does not explain
persuasively how this would be possible.
Furthermore, Appellant does not address the Examiner’s analysis of
additional Wands factors, namely, the breadth of the claim, the state of the
prior art, the amount of direction or guidance presented, or the presence or
absence of working examples. See Appeal Br. 10. Accordingly, Appellant
does not apprise us of error in the Examiner’s analysis of any Wands factor
for claim 1.
As to enablement of open-ended limitations, we note:
Open-ended claims are not inherently improper, as for all
claims, their appropriateness depends on the particular facts of
the invention, the disclosure, and the prior art. They may be
supported if there is an inherent, albeit not precisely known,
upper limit and the specification enables one of skill in the art
to approach that limit.
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See Scripps Clinic & Research Foundation v. Genentech, Inc., 927 F.2d
1565, 1572 (Fed. Cir. 1991) (citing In re Fisher, 427 F.2d 833 (CCPA
1970)). Here, Appellant’s disclosure does not describe any numerical value
of an inherent, practical upper limit of either the bypass ratio or the quotient
r/n for the first stage, nor does Appellant direct us to any guidance in the
disclosure that would enable one of skill in the art to achieve such upper
limits. Hence, Appellant does not show persuasively that one of ordinary
skill in the art would be able to make and use a turbofan aircraft engine in
which both the bypass ratio and the quotient r/n for the first stage have
respective inherent upper limits, as broadly encompassed by the claim
language.
As to claims 8–11, the Specification discloses that the quotient r/n of
the second stage of the second turbine is not particularly limited, the
disclosure does not describe any numerical value of an inherent, practical
upper limit of the quotient r/n for the second stage, and Appellant does not
direct us to any guidance in the disclosure that would enable one of skill in
the art to achieve an upper limit.
Claim 13 depends from claim 1 and recites that “the quotient r/n of
the first stage is not higher than 0.26.” Appeal Br. 20 (Claims App.).
Appellant correctly notes that “claim 13 provides an upper value for the
quotient of r/n and thus, a range for this quotient.” Appeal Br. 11.
However, because claim 13 also incorporates a bypass ratio of at least 7
from claim 1, Appellant’s contention that the rejection of claim 13 lacks
merit is unpersuasive.
For the above reasons, we are not persuaded that the supporting
disclosure adequately apprises those skilled in the art, in light of the
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knowledge of those ordinary artisans, how to make and to use the subject
matter recited in claims 1–20 throughout the entire claim scope. Thus, we
sustain the rejection of claims 1–20 under the enablement requirement of 35
U.S.C. § 112(a).

Claims 1–20 – Written Description
As noted above, claim 1 recites a bypass ratio “being at least 7.” The
Examiner indicates that “[b]ypass ratios rang[ing] from 2 to upwards of 15”
are known but finds that the disclosure “does not describe a bypass ratio of
20, 30, or 40.” Final Act. 3. The Examiner finds that the Specification only
describes, “the bypass ratio in the turbofan aircraft engine of the present
invention is at least 7, but will often be at least 8, e.g., at least 9, at least 10,
or at least 11.” Id. at 3–4 (citing Spec. 6, ll. 13–15). The Examiner states,
“[i]t is not known how to make a bypass ratio of 20, 30 or 40” and the “[t]he
disclosure does not state whether the bypass inlet area is increased, the core
inlet area is decreased, or some combination of both to reach a bypass ratio
of 20, 30 or 40.” Id. at 4 (emphasis omitted). The Examiner’s position for
the bypass ratio limitation recited in claims 2, 3, and 20 is substantially the
same as for claim 1. Id. at 4–5, 9.
Further for claim 1, the Examiner finds that the disclosure does not
describe a ratio of 0.3, 3, or 30 for the quotient r/n of the first stage, but only
states, “the quotient r/n of the first stage of the second turbine will often be
higher than 0.18, e.g., at least 0.19, or at least 0.20. It will often not be
higher than 0.26, e.g., not higher than 0.25, or not higher than 0.24.” Final
Act. 4 (emphasis omitted) (citing Spec. 6, ll. 17–19). The Examiner states,
“[i]t is not known how to make a quotient r/n of 0.3, 3, or 30,” and “[t]he
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disclosure does not state whether r or n or both are varied in order to obtain a
quotient of 0.3, 3, or 30.” Id. (emphasis omitted). The Examiner’s position
as to the quotient r/n of the first stage limitation recited in claims 4–7 and 20
is substantially the same as for claim 1. Id. at 5–6, 9.
As to claim 8, the Examiner finds that the disclosure describes that
“the quotient r/n of the second stage of the second turbine is not particularly
limited, but will often be at least 0.17, e.g., at least 0.175, or at least 0.18. It
will usually be not higher than 0.22, e.g., not higher than 0.21, or not higher
than 0.20,” but finds that the disclosure does not describe how to make a
larger quotient of 0.3, 3, or 30. Final Act. 7 (citing Spec. 6, ll. 19–23)
(emphasis added). The Examiner’s position as to the quotient r/n of the
second stage limitation recited in claims 9 and 10 is substantially the same as
for claim 8. Id. at 7–8.
The test for sufficiency under the written description requirement of
35 U.S.C. § 112(a) “is whether the disclosure of the application relied upon
reasonably conveys to those skilled in the art that the inventor had
possession of the claimed subject matter as of the filing date.” Ariad
Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en
banc). To have “possession,” “the specification must . . . show that the
inventor actually invented the invention claimed.” Id.
The purpose of the written description requirement is to
prevent an applicant from later asserting that he invented that
which he did not; the applicant for patent is therefore required
to “recount his invention in such detail that his future claims
can be determined to be encompassed within his original
creation.”
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Amgen Inc. v. Hoechst Marion Roussel Inc., 314 F.3d 1313, 1330 (Fed. Cir.
2003) (citing Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1561 (Fed. Cir.
1991)).
Appellant contends that the claims do not recite a bypass ratio of 20,
30 or 40, or a quotient r/n of 0.3, 3, or 30. Appeal Br. 7. We agree with
Appellant insofar as the claims do not expressly recite any one of these
numerical values of the bypass ratio or quotient r/n of the first stage or
second stage. But although claims 1–11 and 20 do not expressly recite any
one of the specific numerical values of the bypass ratio or quotient r/n stated
by the Examiner, both the bypass ratio and the quotient r/n lack recited
upper limit in these claims. We are unpersuaded that the numerical values
stated by the Examiner are not encompassed by these claims solely because
the values are not expressly recited.
Appellant also contends that, even if claim 1 theoretically
encompasses bypass ratios of 1000 or even higher, one of ordinary skill in
the art would recognize that such bypass ratio values “make no technical
sense whatsoever.’” Appeal Br. 9.
First, the Examiner finds that the Specification does not describe a
bypass ratio of 20, 30, or 40, but the Examiner does not mention a value of
“1000 or even higher.” Second, the Examiner points out that “[a] bypass
ratio of 40 is at least 7. Furthermore, [c]laim 1 . . . recite[s] a quotient r/n
being at least 0.18 which encompasses quotients r/n of 0.3, 3, or 30. A
quotient r/[n] of 30 is at least 1.8.” Ans. 48. The Examiner has construed
claim 1, for example, to encompass such higher values because both the
bypass ratio and quotient r/n have no recited upper limit. We agree with
Appellant insofar as the Examiner has not established a legal basis to require
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Appellant to demonstrate possession of technically nonsensical (i.e.,
unachievable) numerical values of the bypass ratio or quotient r/n ratio in
order to meet the written description requirement. However, the Examiner
has stated that claim 1 encompasses a bypass ratio of 20 and a quotient r/n
value of 0.3, values much smaller than the value Appellant focuses on.
Appellant does not explain persuasively why a bypass ratio of 20 or a
quotient r/n value of 0.3, for example, is technically nonsensical.
Appellant also asserts that the Examiner has pointed to literature
“which reflects the knowledge of those skilled in the art as to what is
technically feasible/reasonable.” Appeal Br. 9. Appellant does not,
however, identify what particular information this literature reflects is
“technically feasible/reasonable,” or explain specifically how this
information shows what upper limits of the bypass ratio and quotient r/n
limitations recited in claim 1, for example, Appellant had possession of.
Appellant further contends that the Examiner has provided no
evidence that shows those skilled in the art “cannot be assumed to know how
certain bypass ratios and ratios r/n which can reasonably be considered to be
encompassed by the instant claims can be achieved.” Appeal Br. 9.
This contention does not indicate what bypass ratio and quotient r/n
upper limit values “can reasonably be considered to be encompassed” by
claim 1. In other words, this contention does not indicate particular upper
values of these limitations Appellant’s disclosure reasonably conveys to
those skilled in the art that the inventors had possession of. In this regard,
the highest numerical value of the bypass ratio described in the Specification
is “at least 11” (Spec. 6, ll. 13–15), and the Specification does not explicitly
describe a quotient r/n value higher than 0.26 (id. at 6, ll. 16–18). However,
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a bypass ratio of 11 and a quotient r/n value of 0.26 as upper limits are not
substantially greater than the values of at least 7 and at least 0.18 recited in
claim 1, that is, the disclosed lower values of the ranges.
Appellant does not direct us to any disclosure that explicitly describes,
or implies, any numerical value of a maximum technically achievable upper
limit of the bypass ratio or quotient r/n of the claimed turbofan aircraft
engine. Contending that a technically sensible upper limit of these
limitations exists and would be understood by one skilled in the art is
different from Appellant actually demonstrating possession of an invention
that encompasses those upper limits. Moreover, Appellant does not
persuasively show possession of a (i.e., the same) turbofan aircraft engine in
which both the bypass ratio and quotient r/n have a technically achievable
upper limit, as broadly encompassed by the claim language.
Again, Appellant correctly notes that “claim 13 provides an upper
value for the quotient of r/n and thus, a range for this quotient.” Appeal Br.
10. However, because claim 13 also incorporates a bypass ratio of at least 7
from claim 1, Appellant’s contention that the rejection of claim 13 lacks
merit is unpersuasive.
Thus, we sustain the rejection of claims 1–20 under the written
description requirement of 35 U.S.C. § 112(a).

Obviousness over Pratt and Whitney and Wadia
The Examiner finds that Pratt and Whitney discloses most limitations
of claim 1. Final Act. 32–33. More particularly, the Examiner finds that
Pratt and Whitney discloses a turbofan aircraft engine comprising, inter alia,
a second turbine (LPT) comprising a first stage (V1, T1) and a last stage
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(V3, T3), where these stages each comprise a number of stator vanes (“V’s”)
each having a mean radius r. Id. The Examiner concedes that Pratt and
Whitney does not disclose the limitation “a quotient r/n of the mean radius
of a stator vane r expressed in inches divided by the number of stator vanes n
being at least 0.18 for the first stage,” as recited in claim 1. Id. at 33.
The Examiner relies on Wadia as teaching that “vane solidity affects
turbine performance and efficiency,” where “blade solidity is a function of
vane chord and blade pitch” and “blade pitch is a function of the mean
radius . . . and the number of blades.” Final Act. 33 (citing Wadia ¶¶ 3, 26,
28, 32, 36). Therefore, the Examiner determines, “the number of stator
vanes and [the] mean radius of a stator vane (vane solidity) are result
effective variables that control turbine performance and efficiency.” Id. at
34 (citing In re Antonie, 559 F.2d 618, 620 (CCPA 1977)). The Examiner
also determines that the quotient r/n of at least 0.18 for the first stage is an
obvious optimization of the prior art obtainable by an ordinary skilled
worker through routine experimentation. Id. (citing In re Aller, 220 F.2d
454, 456 (CCPA 1955) (“‘[W]here the general conditions of a claim are
disclosed in the prior art, it is not inventive to discover the optimum or
workable ranges by routine experimentation.’”). The Examiner concludes
that it would have been obvious to one of ordinary skill in the art, in view of
Wadia, to modify Pratt and Whitney to meet the quotient r/n limitation to
optimize turbine performance and efficiency. Id.
Appellant contends that the Examiner has misinterpreted Wadia’s
disclosure regarding vane span Sv, which can be considered to correspond
roughly to the recited mean radius of a stator vane. Appeal Br. 13. In
support, Appellant reproduces paragraphs 37–41 of Wadia. Id. at 13–15.
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Appellant contends that it is apparent from Wadia that the vane span Sv
plays no role in increasing the turbine performance and efficiency. Id. at 15.
Rather, Appellant contends, Wadia discloses that reducing the chord length
in the mid-span region of vanes can reduce the solidity σ of vanes, thereby
increasing the efficiency of the turbine assembly. Id.; see Wadia ¶¶ 39, 41,
Fig. 3 (showing blade cord c in axial direction A). Thus, Appellant
contends, one of ordinary skill in the art would have had no reason to try to
optimize the vane span, let alone the quotient of the vane span and the
number of vanes in a turbine stage. Id.
In response, the Examiner maintains that the vane span affects
increasing turbine efficiency and performance. Ans. 51. The Examiner
submits that blade solidity σv is expressed by the equation: σv = cvNv/2πSv,
where cv is the vane chord, Nv is the number of vanes, and Sv is the vane
span taken at the middle one-half or middle 50% of the vane span. Id. at 52.
The Examiner rewrites this equation to read: σv = (cv/2π)/(Sv/Nv), which the
Examiner submits shows that blade solidity is a direct function of the
quotient Sv/Nv. Id. at 53.
The applicable legal principles for the optimization of a claimed
variable are as follows:
“[W]here the general conditions of a claim are disclosed in the
prior art, it is not inventive to discover the optimum or
workable ranges by routine experimentation.” Aller, 220 F.2d
at 456. This rule is limited to cases in which the optimized
variable is a “result-effective variable.” In re Antonie, 559 F.2d
618, 620 (CCPA 1977); see [In re] Boesch, 617 F.2d [272,] 276
[(CCPA 1980)] (“[D]iscovery of an optimum value of a result
effective variable ... is ordinarily within the skill of the art.”).
In re Applied Materials, Inc., 692 F.3d 1289, 1295 (Fed. Cir. 2012).
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We agree with Appellant that the Examiner has not established, with
sufficient evidence, that the recited quotient r/n is recognized as a result-
effective variable, rendering its optimization within the ordinary skill in the
art. Appellant points out that the rewritten equation shows that vane solidity
is also a function of the vane chord (cv), and thus, even assuming the
Examiner’s position has merit, one of ordinary skill in the art would not
have tried to optimize the claimed quotient r/n, but rather, the product of this
quotient and the vane chord. Reply Br. 4–5 (citing Ans. 53). We agree with
Appellant that the Examiner has not explained why, regardless of the value
of the vane chord in the rewritten equation, one of ordinary skill would,
nonetheless, have necessarily arrived at an optimum value of the quotient r/n
of at least 0.18, as claimed. Id. at 5.
Accordingly, we do not sustain the rejection of claim 1, and claims 2–
18 depending therefrom, as unpatentable over Pratt and Whitney and Wadia.
We also do not sustain the rejection of claim 19 as it incorporates the
limitations of claim 1.
The method of claim 20 comprises, inter alia, “adjusting a mean
radius of a stator vane r and the number of stator vanes of the first stage n so
that a quotient r/n of the mean radius of the stator vane r expressed in inches
divided by the number of stator vanes n is at least 0.18.” We do not sustain
the rejection of claim 20 as unpatentable over Pratt and Whitney and Wadia
for reasons similar to those for claim 1.

Appeal 2019-006970
Application 15/090,845

17
CONCLUSION
In summary:
Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–20 112(a) Enablement 1–20
1–20 112(a) Written Description 1–20
1–20 103 Pratt and Whitney,
Wadia
1–20
Overall
Outcome
1–20

TIME PERIOD FOR RESPONSE

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).

AFFIRMED