United Technologies Corporation

Patent Trials and Appeals Board

Aug 2, 2021

2020003846 (P.T.A.B. Aug. 2, 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.
14/044,971 10/03/2013 Karl L. Hasel 67097-2151PUS2;PA24002U 5715
54549 7590 08/02/2021
CARLSON, GASKEY & OLDS/PRATT & WHITNEY
400 West Maple Road
Suite 350
Birmingham, MI 48009
EXAMINER
NGUYEN, ANDREW H
ART UNIT PAPER NUMBER
3741
NOTIFICATION DATE DELIVERY MODE
08/02/2021 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):
ptodocket@cgolaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KARL L. HASEL
Appeal 2020-003846
Application 14/044,971
Technology Center 3700

Before LINDA E. HORNER, JOSEPH A. FISCHETTI, and
SCOTT A. DANIELS, Administrative Patent Judges.

DANIELS, 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 1–3, 5, 7–10, 12, 14–17, 19–21, 23–26,
28–30, and 32–34. See Final Act. 1. We have jurisdiction under
35 U.S.C. § 6(b).
We affirm.

1 We use the term “Appellant” to refer to “applicant” as defined in 37 C.F.R.
§ 1.42. Appellant identifies the real party in interest as United Technologies
Corporation. Appeal Br. 1.
Appeal 2020-003846
Application 14/044,971
2
CLAIMED SUBJECT MATTER
The claims are directed to a gas turbine engine with a geared
architecture. Spec. 11; Appeal Br. 13. Claims 1, 8, 15, and 20 are
independent.
Claim 1, reproduced below with particular limitations of interest
highlighted, is illustrative of the claimed subject matter:
1. A gas turbine engine comprising:
a fan having a drive shaft and a plurality of fan blades that
direct air into a bypass duct and into an engine core;
a geared architecture rotatably coupled to the fan drive
shaft; and
a first compressor section and a second compressor section
upstream of the first compressor section, wherein the gas turbine
engine has a core temperature at an exit of the first compressor
section in a range of 1150 to 1350 degrees Fahrenheit at take-off,
wherein a ratio of a fan stream exhaust velocity divided by
a primary stream exhaust velocity is in a range of 0.75 to 0.90,
and
wherein a ratio of a volume of air passing into the bypass
duct divided by a volume of air passing into the engine core is
greater than 8.0;
wherein a ratio of air pressure across a fan blade of the
plurality of fan blades is less than 1.45 at about 35,000 feet and
when operating at about a 0.80 Mach number cruise power
condition;
a first turbine section driving the fan through the geared
architecture such that the fan and the second compressor section
rotate at different speeds, the first turbine section including a
plurality of turbine rotors, wherein a ratio between a total
number of the plurality of fan blades and a total number of the
turbine rotors is between 3.3 and 8.6; and
a second turbine section driving the first compressor
section, wherein the first turbine section drives the second
Appeal 2020-003846
Application 14/044,971
3
compressor section, the plurality of turbine rotors of the first
turbine section is at least 5 but no more than 6 turbine rotors, and
the second turbine section includes 2 turbine rotors.
REFERENCES
The prior art relied upon by the Examiner is:
Name Reference Date
Rosen US 3,747,343 July 24, 1973
Allmon US 5,257,903 Nov. 2, 1993
Mao US 6,630,244 Bl Oct. 7, 2003
Decker US 2006/0228206 Al Oct. 12, 2006
Moniz US 7,195,447 B2 Mar. 27, 2007
Chir US 2010/0303616 Al Dec. 2, 2010
Cloft US 2011/0167790 Al July 14, 2011
Guha2 Journal of Propulsion and
Power, Vol. 17, No. 5
Sept.-Oct. 2001
REJECTIONS
I. Claims 1–3, 5, 7–10, 12, 14–17, and 19 are rejected under pre-
AIA 35 U.S.C. § 103(a) as unpatentable over Cloft, Guha,
Allmon, Housley, Mao, Decker, and Chir.
II. Claims 20, 21, and 23–26 are rejected under pre-AIA 35 U.S.C.
§ 103(a) as unpatentable over Cloft, Guha, Allmon, Housley,
Decker, and Rosen.
III. Claims 28–30 are rejected under pre-AIA 35 U.S.C. § 103(a) as
unpatentable over Cloft, Guha, Allmon, Housley, Rosen, Mao,
Decker, and Chir.

2 Guha, Optimum Fan Pressure Ratio for Bypass Engines with Separate
or Mixed Exhaust Streams, Journal of Propulsion and Power, Volume 17,
No. 5 (September-October 2001).
Appeal 2020-003846
Application 14/044,971
4
IV. Claims 32 and 33 are rejected under pre-AIA 35 U.S.C.
§ 103(a) as unpatentable over Cloft, Guha, Allmon, Housley,
Rosen, Mao, Decker, and Chir.
V. Claim 34 is rejected under pre-AIA 35 U.S.C. § 103(a) as
unpatentable over Cloft, Guha, Allmon, Housley, Rosen, Mao,
Decker, Chir, and Moniz.
OPINION
Rejection I
Appellant argues claims 1–3, 5, 7–10, 12, 14–17, and 19 as a group,
and we select claim 1 as representative. Claims 2, 3, 5, 7–10, 12, 14–17, and
19 stand or fall with claim 1. 37 C.F.R. § 41.37(c)(l)(iv).
The Examiner finds that Cloft discloses the main components of a gas
turbine engine including fan 20 directing air into bypass duct 40 and engine
core 12, a fan drive shaft, a low pressure turbine and compressor, a high
pressure turbine and compressor, and a planetary gear system 22, i.e. geared
architecture, connected between the high pressure turbine and the fan. Final
Act. 2–3. The Examiner finds also that Cloft teaches the claimed bypass
ratio, that is—where the ratio of a volume of air passing into the bypass duct
divided by the air passing into engine core is greater than 8.0. Id. at 3.
The Examiner finds that Cloft does not disclose a specific core
exhaust temperature, but that Allmon and Mao teach that it was known in
the art to have a high pressure turbine exhaust of 1100 to 1600 degrees
Fahrenheit encompassing the claimed 1150 to 1350 degree Fahrenheit range.
Id. at 4. The Examiner further finds that Guha teaches a velocity ratio of .81
that is within the range of .75 to .90 recited in claim 1. Id. at 3–4. The
Examiner determines that Guha teaches “the velocity ratio is a results-
Appeal 2020-003846
Application 14/044,971
5
effective variable, affecting specific fuel consumption and maximum
specific thrust” and thus optimizing the velocity ratio was within the level of
ordinary skill in the art. Id. at 3. The Examiner also finds that Cloft and
Guha both disclose optimization of fan pressure ratio at bucket speed, and
that a person of ordinary skill in the art would have found it obvious to
provide a fan pressure ratio of 1.3 at bucket speed “in order to achieve a
desired specific thrust and specific fuel consumption.” Id. at 7.
The Examiner explains that Cloft is silent as to a specific ratio
between the number of fan blades and low pressure turbine rotors that is
between 3.3 and 8.6. Id. at 5. However, the Examiner finds that Decker
teaches a fan having 18 blades and that the number of fan blades is a result-
effective variable because it was well known to those of skill in the art that
the number of blades effect tip solidity and aerodynamic efficiency. Id.
According to the Examiner, Housley discloses that optimizing the number of
turbine rotors was known in the art to affect airflow through the turbine. Id.
The Examiner determined that it would have been obvious to a person of
ordinary skill in the art to utilize in Cloft’s engine, a fan with 18 blades and a
turbine rotor count of 5 to 6, to obtain a ratio between 3.3 and 8.6 as called
for in claim 1. Id. at 6. The Examiner finds that combining Decker’s fan
blades and Housley’s low pressure rotor count as a ratio would have been a
simple substitution of prior art elements, which a person of ordinary skill in
the art would try to optimize in order to yield better engine efficiency and
yield predictable results. Id.
Appellant presents arguments pertaining specifically to two
limitations in claim 1 which we set out under separate headings below.
Appellant argues that the Examiner has not established that one of ordinary
skill in the art would have simply substituted the teachings of Decker and
Appeal 2020-003846
Application 14/044,971
6
Housley and determined a fan blade count to turbine rotor ratio between 3.3
and 8.6 in combination with Cloft’s geared engine for the ostensible reason
of increasing engine efficiency. Appeal Br. 6. Also, Appellant argues that
the Examiner has not established that the Guha teaches the claimed ratio of
exhaust velocities in the context of a geared engine. Id. at 8.
ratio of fan blades and turbine rotors
Appellant initially argues that the Examiner fails to show that the
teachings of Decker and Housley, for direct drive engines without geared
architecture, would have been obvious to use in a geared gas turbine engine.
Id. In addition, relying on In re Antonie, 559 F.2d 618, 620 (CCPA 1977),
Appellant argues that the relationship between the number of fan blades and
the turbine count is not a result-effective variable and, up to now, a person of
ordinary skill in that art would not have recognized the ratio of fan blades
and turbine rotors’ relationship as effecting engine efficiency. Id. at 6–7.
The Examiner responds that Appellant has not shown or explained
how the claimed “geared architecture,” arguably not found in Decker or
Housley, makes a difference when determining efficiency aspects of the
claimed fan blade to turbine rotor count ratio. See Ans. 3 (“nowhere in
Cloft, Housley, or Decker is it disclosed that the gearing arrangement
precludes modifying turbine rotor counts or fan blade counts, nor does
Appellant provide any evidence in support thereof”). The Examiner
contends that it was well known by those of ordinary skill designing geared
and direct drive gas turbine engines to modify the fan blade count as taught
by Decker and also the turbine rotor count as taught by Housley. See id. at 4
(citing Cloft ¶ 19) (Cloft stating that “this disclosure is applicable to other
gas turbine engines including direct drive turbofans”). In sum, the Examiner
finds that varying the number of fan blades and turbine rotors is a well-
Appeal 2020-003846
Application 14/044,971
7
known technique using known variables providing predicable effects on
engine efficiency regardless of the engine being geared or not. Id. at 5. The
Examiner further finds that Antonie is inapplicable in this circumstance
because the number of fan blades and turbine rotor count are well-known
variables effecting engine efficiency and because Appellant has provided no
evidence that the claimed range is critical or achieves unexpected results.
Id. at 5–6.
Ratio of exhaust velocities in a geared engine
Appellant next argues that there is no evidence that Guha discloses a
ratio of exhaust velocities for a geared engine. Id. at 8. Appellant argues
that geared architecture creates a speed difference between the fan drive
turbine and the fan resulting in a corresponding change in fan stream exhaust
velocity and primary stream exhaust velocity. Id. at 9. Appellant argues
that Guha fails to disclose making any particular change in the turbine
count/pressure relative to exhaust stream velocity in the context of a geared
engine. Id. Therefore, Appellant contends, the Examiner has not shown a
motivation to alter Cloft’s low pressure turbine count to achieve the claimed
exhaust velocities. Id.
The Examiner responds that neither Croft nor Guha discloses that a
geared engine precludes the modification of the exhaust velocity. Ans. 7.
The Examiner finds that Guha teaches an exhaust velocity ratio within the
claimed range and that it was well known in designing gas turbine engines to
use the exhaust ratio to optimize specific fuel consumption and maximum
specific thrust whether the engine was geared, or direct drive. Id.
Analysis
We agree with the Examiner as to both limitations, i.e. the exhaust
velocity ratio and the ratio of fan blades to turbine rotor count, that
Appeal 2020-003846
Application 14/044,971
8
Appellant has not shown that the lack of gearing in the gas turbine engines
of the secondary references precludes modification of a geared engine as
described in Cloft. We also agree with the Examiner that the modification
of the variables attributable to exhaust stream velocity, as well modification
of the number of fan blades and turbine rotor count for optimizing engine
efficiency “was known in the art and within the level of ordinary skill in the
art and would be implemented with a reasonable expectation of success.”
Ans. 4.
Considering the combination of Cloft with Decker and Housley, the
Examiner has set out a prima facie case of obviousness explaining that
Decker teaches that in a gas turbine engine the number of fan blades, e.g., 18
fan blades, is a result-effective variable “affecting tip solidity and
aerodynamic efficiency.” Ans. 5 (citing Decker ¶¶ 85–89). The Examiner
relies on Housley for teaching that the number of turbine rotors is also a
result-effective variable that affects airflow through the turbine. Id. (citing
Housley ¶ 15). Housley for example explains that in one embodiment “the
high pressure turbine 20 has two stages and the low pressure turbine 22 has
five stages, although it should be noted that different numbers of stages are
possible.” Housley ¶ 15. Based on these references, the Examiner reasons
that whether an engine was geared or direct drive “[m]odification of each of
these elements was known in the art and within the level of ordinary skill in
the art and would be implemented with a reasonable expectation of success.
Evidence is shown by Cloft, Housley, and Decker, which teach gas turbine
engines comprising the claimed turbine rotors and fan blade counts.”
Ans. 4.
We are not persuaded of error in the Examiner’s reasoning as it is
supported by evidentiary underpinnings and establishes a prima facie case of
Appeal 2020-003846
Application 14/044,971
9
obviousness. See In re Dillon, 919 F.2d 688, 692 (Fed. Cir. 1990) (If a
prima facie case of obviousness is established, the burden shifts to the
applicant to come forward with arguments and/or evidence to rebut the
prima facie case). The Examiner has shown, by a preponderance of the
evidence, that the fan blade and rotor count are known, result-effective
variables recognized as affecting engine efficiency in gas turbine engines.
See 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.”).
We are also not persuaded that the Examiner has erred in the
assessment of the facts and evidence on this record in view of In re Antonie.3
Appellant fails to show that engine efficiency is not a recognized function of
both the number of fan blades and turbine rotor count. This is different from
Antonie where there was no evidence that treatment capacity was a function
of either underlying variable. See In re Antonie, 559 F.2d at 620 (The Court
explaining that “[i]t is impossible to recognize, from the experiment taught
by El-Naggar, that ‘treatment capacity’ is a function of ‘tank volume’ or the
tank volume-to-contactor area ratio.”).
Appellant attempts to improperly place a burden on the Examiner to
prove no negative impact from the proposed modification by emphasizing
that Decker and Housley are direct drive gas turbine engines whereas Cloft
is a geared gas turbine engine. Appeal Br. 6, 9. Based on our review of the

3 Appellant mischaracterizes Antonie, asserting that absent disclosure in the
prior art “the claimed relationship is not a result effective variable.” Appeal
Br. 7. Appellant has provided no evidence to contradict the Examiner’s
finding that one of skill in the art would have recognized from the teachings
of the prior art that engine efficiency is affected by, and therefore a function
of, both the number of fan blades and turbine rotor count.
Appeal 2020-003846
Application 14/044,971
10
prior art, we agree with the Examiner that “[a]ll of the features of the engine
discussed above were known to be modified by one of ordinary skill in the
art.” Ans. 4. Optimization of known parameters is not unique, and in any
obviousness analysis “if a technique has been used to improve one device,
and a person of ordinary skill in the art would recognize that it would
improve similar devices in the same way, using the technique is obvious
unless its actual application is beyond his or her skill.” KSR Int’l Co. v.
Teleflex Inc., 550 U.S. 398, 401 (2007). As discussed above, the Examiner
provided adequate evidence and reasoning showing a benefit in engine
efficiency from the proposed modification of Cloft’s geared engine. Final
Act. 4; Ans. 9.
Additionally, where the difference between the claimed invention and
the prior art is some range or other variable within the claims, Appellant
must show that the particular range is critical, generally by showing that the
claimed range achieves unexpected results relative to the prior art range. In
re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990). Appellant has not
shown that the ranges are critical or achieve unexpected results. As such, we
do not find sufficient evidence in this record that the particular ranges
claimed are the result of an improvement over prior art ranges “different in
kind and not merely in degree from the results of the prior art.” In re
Huang, 100 F.3d 135, 139 (Fed. Cir. 1996) (quoting Aller, 220 F.2d at 456).
Accordingly, having considered the Examiner’s rejection of claim 1 in
light of each of Appellant’s arguments and the evidence of record, we
disagree with Appellant and agree with the Examiner’s findings that Cloft,
Guha, Allmon, Housley, Mao, Decker, and Chir render obvious claim 1. We
sustain the Examiner’s rejection of claim 1, as well as the Examiner’s
Appeal 2020-003846
Application 14/044,971
11
rejection of claims 2, 3, 5, 7–10, 12, 14–17, and 19, which Appellant does
not argue separately.
Rejection II
Appellant argues claims 20, 21, and 23–26 as a group, and we select
claim 20 as representative. Claims 21 and 23–26 stand or fall with claim 20.
37 C.F.R. § 41.37(c)(l)(iv).
Appellant argues initially that claim 20, which recites the same
exhaust velocity ratio and fan blade to turbine rotor count ratio as claim 1, is
allowable for the same reasons as claims 1, 8, and 15 above. Appeal Br. 11.
Because we found no error in the rejection of claims 1, 8, and 15, we find no
error in the rejection of claim 20 for the same reasons. Appellant offers
additional arguments with respect to claim 20 which we address below.
Compared to claim 1, independent claim 20 includes the additional
limitation of “a first compressor section and a second compressor section
upstream of the first compressor section, wherein the second compressor
section is a three stage compressor.” For this limitation, the Examiner turns
to Allmon which discloses a gas turbine engine having a three stage low
pressure compressor. Final Act. 8–9. Based on Allmon, the Examiner finds
that it was within the level of ordinary skill and knowledge in the art to
utilize a low pressure compressor with three stages in a gas turbine engine,
and that substituting Allmon’s three stage compressor into Cloft’s engine
yields nothing more than predictable results.
Appellant argues that the Examiner has not adequately supported the
combination of Allmon with Cloft. Appeal Br. 11. Appellant argues that
the Examiner has not provided a motivation to combine Allmon and Cloft
because Cloft is a geared engine where the fan rotates at a different speed
than the low pressure compressor, and is therefore different from Allmon’s
Appeal 2020-003846
Application 14/044,971
12
direct drive engine. Id. Appellant also argues that the Examiner has not
provided any evidence that a person of ordinary skill in the art would have
used a three stage low pressure compressor while maintaining the exhaust
velocity ratio within the claimed range. Id.
The Examiner responds that one of ordinary skill in the art would
have considered the references not in isolation, but in combination, and been
capable of, modifying Cloft’s geared gas turbine engine to include a three
stage compressor. Ans. 10. The Examiner points out that obviousness
requires no express disclosure of the claimed invention in the prior art, and
that the test for obviousness “is what the combined teachings of the
references would have suggested to those of ordinary skill in the art.” Id.
(citing In re Keller, 642 F.2d 413 (CCPA 1981)).
We agree with the Examiner that the prior art references include well-
known elements of gas turbine engines and must be considered for their
teachings as a whole. See KSR, 550 U.S. at 415–16 (a “patent for a
combination which only unites old elements with no change in their
respective functions . . . obviously withdraws what already is known into the
field of its monopoly and diminishes the resources available to skillful
men.”) (quoting Great Atlantic & Pacific Tea Co. v. Supermarket Equip.
Corp., 340 U.S. 147, 152-153 (1950)). Attacking Allmon, or any of the
secondary references, simply for not being geared gas turbine engines, does
not show that a person of ordinary skill in the art would fail to consider, or
be unable to implement, a three stage low pressure turbine in a geared gas
turbofan engine. As the Examiner explains, the rejection relies on the
combination of the three stage low pressure turbine in Allmon, and Cloft’s
geared drive. Appellant’s arguments attack the secondary references, e.g.,
Allmon, in isolation, whereas the Examiner’s proposed combination is
Appeal 2020-003846
Application 14/044,971
13
predicated on a combination of the teaching of a geared drive in Cloft and
the three stage low pressure turbine in Allmon. See In re Merck & Co., 800
F.2d 1091, 1097 (Fed. Cir. 1986) (“Non-obviousness cannot be established
by attacking references individually where the rejection is based upon the
teachings of a combination of references”).
Also, we find no error in the Examiner’s finding that a three stage
compressor was known in the art of gas turbine engine design and would
have been compatible with the claimed exhaust fan ratio. Ans. 10–11. The
Examiner concludes that regardless of the number of compressor stages, the
“[r]atio of fan stream exhaust velocity to primary stream exhaust velocity
may be optimized. Modification of each of these elements was known in the
art and within the level of ordinary skill in the art and would be implemented
with a reasonable expectation of success.” Id. at 11. Again, we have no
persuasive evidence or technical argument from Appellant that a person of
ordinary skill in the art would have been unable to incorporate a three stage
compressor section into Cloft’s geared engine including doing so at the
claimed exhaust velocity ratio range. Thus, we are not apprised of Examiner
error.
Having considered the Examiner’s rejection of claim 20 in light of
each of Appellant’s arguments and the evidence of record, we disagree with
Appellant and agree with the Examiner’s findings that Cloft, Guha, Allmon,
Housley, Decker, and Rosen render obvious claim 20. We sustain the
Examiner’s rejection of claim 20, as well as the Examiner’s rejection of
claims 21 and 23–26, which Appellant does not argue separately.
Rejections III through V
Appellant argues that claims 28–30 and 32–34, which depend from
independent claim 20 and independent claim 1 respectively, are allowable
Appeal 2020-003846
Application 14/044,971
14
for the same reasons as the independent claims. Appeal Br. 12. Since we
have found no error in the rejection of claims 1 and 20, we likewise find no
error in the rejections of claims 28–30 and 32–34.
CONCLUSION
The Examiner’s decision to reject claims 1–3, 5, 7–10, 12, 14–17, 19–
21, 23–26, 28–30, and 32–34 is affirmed.
DECISION SUMMARY
In summary:
Appeal 2020-003846
Application 14/044,971
15
Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–3, 5, 7–
10, 12, 14–
17, 19
103 Cloft, Guha,
Allmon, Housley,
Mao, Decker, Chir
1–3, 5, 7–
10, 12, 14–
17, 19

20, 21, 23–
26
103 Cloft, Guha,
Allmon, Housley,
Decker, Rosen
20, 21, 23–
26

28–30 103 Cloft, Guha,
Housley, Allmon,
Rosen, Mao,
Decker, Chir
28–30
32, 33 103 Cloft, Guha,
Allmon, Housley,
Rosen, Mao,
Decker, Chir
32, 33
34 103 Cloft, Guha,
Allmon, Housley,
Rosen, Mao,
Decker, Chir,
Moniz
34
Overall
Outcome
1–3, 5, 7–
10, 12, 14–
17, 19–21,
23–26, 28–
30, 32–34

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) (2019).

AFFIRMED