MTU Aero Engines AG

Patent Trials and Appeals Board

Apr 21, 2021

2020005278 (P.T.A.B. Apr. 21, 2021)

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.
15/364,892 11/30/2016 Carsten Schoenhoff 5038.1253 9664
23280 7590 04/21/2021
Davidson, Davidson & Kappel, LLC
589 8th Avenue
22nd Floor
New York, NY 10018
EXAMINER
GILLENWATERS, JACKSON N
ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
04/21/2021 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):
ddk@ddkpatent.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte CARSTEN SCHOENHOFF, MARTIN PERNLEITNER, KLAUS
WITTIG, MANFRED DOPFER, MARCUS WOEHLER, WILFRID
SCHUETTE, CHRISTOPH BICHLMAIER, RUDOLF STANKA, and
NORMAN CLEESATTEL
____________

Appeal 2020-005278
Application 15/364,892
Technology Center 3600
____________

Before BIBHU R. MOHANTY, BRADLEY B. BAYAT, and
AMEE A. SHAH, Administrative Patent Judges.

MOHANTY, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF THE CASE
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 11–24. We have jurisdiction under
35 U.S.C. § 6(b).

SUMMARY OF THE DECISION
We REVERSE.

1 We use the word Appellant to refer to “applicant” as defined in 37 C.F.R.
§ 1.42(a). Appellant identifies the real party in interest as MTU Aero
Engines AG (Appeal Br. 2).
Appeal 2020-005278
Application 15/364,892

2

CLAIMED SUBJECT MATTER
The Appellant’s claimed invention relates to a rotor blade for a gas
turbine (Spec., para. 1). Claim 11, reproduced below, is representative of
the subject matter on appeal.

11. A rotor blade for a gas turbine, the rotor blade comprising:
a blade root element; and
a stream deflection portion adjoining the blade root element in a
longitudinal direction of the blade, respective centroids of blade cross-
sectional areas of the stream deflection portion residing on a common
stacking axis,
wherein, starting from a first centroid of a first blade cross-
sectional area adjoining the blade root element, the stacking axis
extends within a cone whose apex resides within the first centroid, the
cone having a cone height extending orthogonally to a plane of the
blade cross-sectional area, an angle of the cone being greater than 0°
and smaller than or equal to 4°.

THE REJECTIONS
The Examiner relies upon the following as evidence in support of the
rejections:
Name Reference Date
Donnerhack US 2009/0133380 A1 May 28, 2009
Higgs-Walker GB260411 Oct. 13, 1925
Nakajima JP4299301 Apr. 24, 2009

The following rejections are before us for review:
1. Claims 11–18, 21, 23, and 24 are rejected under 35 U.S.C.
§ 103 as unpatentable over Nakajima and Higgs-Walker.
2. Claims 19, 20, and 22 are rejected under 35 U.S.C. § 103 as
unpatentable over Nakajima, Higgs-Walker, and Donnerhack.
Appeal 2020-005278
Application 15/364,892

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FINDINGS OF FACT
We have determined that the findings of fact in the Analysis section
below are supported at least by a preponderance of the evidence2.

ANALYSIS
The Appellant argues that the rejection of record is improper because
the cited prior art fails to disclose or suggest the rotor blade centroids on a
common stacking axis in a cone with “an angle of the cone being greater
than 0° and smaller than or equal to 4°” (App. Br. 4, Reply Br. 2).
In contrast, the Examiner has determined that the rejection of record is
proper and the cited modification in the combination of references for “an
angle of the cone being greater than 0° and smaller than or equal to 4°”
would have been obvious through “routine experimentation” in order “to
produce the optimum results for the reduction of stresses at the thin edges of
the turbine blade” (Final Act. 5, Ans. 3–5).
We agree with the Appellant. Here, Nakajima does disclose a turbine
blade 100 with centroids O placed along a stacking line L (Fig. 1). Higgs-
Walker discloses a turbine blade in which the blade is inclined along a radial
line to reduce stresses (Fig. 3, col. 5, lines 8–17). The argued claim
limitation requires that
wherein, starting from a first centroid of a first blade cross-sectional
area adjoining the blade root element, the stacking axis extends within
a cone whose apex resides within the first centroid, the cone having a
cone height extending orthogonally to a plane of the blade cross-

2 See Ethicon, Inc. v. Quigg, 849 F.2d 1422, 1427 (Fed. Cir. 1988)
(explaining the general evidentiary standard for proceedings before the
Patent Office).
Appeal 2020-005278
Application 15/364,892

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sectional area, an angle of the cone being greater than 0° and smaller
than or equal to 4°.

(Claim 1, emphasis added).
Here, the modification of Nakajima in view of Higgs-Walker requires
not only the combination of the these two references but also the further of
modification of the stacking axis extending both: “within a cone whose apex
resides within the first centroid, the cone having a cone height extending
orthogonally to a plane of the blade cross-sectional area” and “an angle of
the cone being greater than 0° and smaller than or equal to 4°”.
The Examiner has determined that the modification is not inventive
but rather determined through optimum workable ranges or routine
experimentation to optimize a result-effect variable in reducing the stresses
at thin edges of the blade. The Appellant at page 4 of the Appeal Brief
argues that the Specification at pages 8, 9, and 30 shows the critical nature
of the claimed angle of the cone being greater than 0° and smaller than or
equal to 4° and also that the cited prior art has no teaching that the claimed
range would be sufficient to reduce stresses. We agree that the prior art fails
to provide a teaching that the specific cone shape and angle range would be
sufficient to reduce stress or provide a reasonable expectation to do so or
that such a modification would have been obvious.
In KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) the Supreme
Court at 418 noted that in an obviousness analysis that“[R]ejections on
obviousness grounds cannot be sustained by mere conclusory statements;
instead, there must be some articulated reasoning with some rational
underpinning to support the legal conclusion of obviousness”. Here, the
cited rejection lacks articulated reasoning with rational underpinnings in
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Application 15/364,892

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order to modify the cited combination of references of Nakajima in view of
Higgs-Walker to further be modified to specifically include the argued
limitations of both the cone shape and specific angle range as claimed
without impermissible hindsight. Further it is unclear that such a claimed
cone and angle range would reduce the stresses with a reasonable
expectation of success. Here, the articulation for the additional modification
in the combination of the “an angle of the cone being greater than 0° and
smaller than or equal to 4°” through “routine experimentation” require both
a specific shape in the cone shape and a specific range of the angle, and the
cited rejection lacks articulated reasoning with rational underpinnings to
show a reasonable expectation of success obviousness without hindsight.
For this reason the rejection of claim 11 is not sustained. The rejection of
dependent claims 12–18, 21, 23, and 24 is not sustained for the same reasons
given above. The rejection of claims 19, 20, and 22 under 35 U.S.C. § 103
as unpatentable over Nakajima, Higgs-Walker, and Donnerhack is not
sustained for the same reasons given above as the Donnerhack reference
fails to cure the deficiency in the rejection of the base claim.

CONCLUSIONS OF LAW
We conclude that Appellant has shown that the Examiner erred in
rejecting claims 11–18, 21, 23, and 24 under 35 U.S.C. § 103 as
unpatentable over Nakajima and Higgs-Walker.
We conclude that Appellant has shown that the Examiner erred in
rejecting claims 19, 20, and 22 under 35 U.S.C. § 103 as unpatentable over
Nakajima, Higgs-Walker, and Donnerhack.

Appeal 2020-005278
Application 15/364,892

6

DECISION SUMMARY
In summary:
Claim(s)
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
11–18, 21,
23, 24
103 Nakajima,
Higgs-Walker
11–18, 21,
23, 24
19, 20, 22 103 Nakajima,
Higgs-Walker,
Donnerhack
19, 20, 22
Overall
Outcome
11–24

REVERSED