Ex Parte Willett et al

Patent Trial and Appeal Board

Sep 10, 2018

13449657 (P.T.A.B. Sep. 10, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/449,657 04/18/2012
30024 7590 09/12/2018
NIXON & V ANDERHYE, P.C.
901 NORTH GLEBE ROAD, 11 TH FLOOR
ARLINGTON, VA 22203
FIRST NAMED INVENTOR
Fred Thomas Willett JR.
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
254303/839-2375 (AMK) 5192
EXAMINER
WHITE, ALEXANDER A
ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
09/12/2018 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):
PTOMAIL@nixonvan.com
pair_nixon@firsttofile.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte FRED THOMAS WILLETT JR.,
MICHAEL EARL MONTGOMERY, PETER JOHN EISENZOPF,
and RICHARD JAMES MILLER
Appeal2017-010190
Application 13/449,657 1
Technology Center 3700
Before MICHAEL C. ASTORINO, CYNTHIA L. MURPHY, and
ROBERT J. SILVERMAN, Administrative Patent Judges.
ASTORINO, Administrative Patent Judge.
DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), the Appellants appeal from the
Examiner's decision rejecting claims 1-5, 7-13, 19, and 20. We have
jurisdiction over the appeal under 35 U.S.C. § 6(b).
We REVERSE.
1 According to the Appellants, "[t]he real party in interest is General
Electric Company." Appeal Br. 3.
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Application 13/449,657
STATEMENT OF THE CASE
Subject Matter on Appeal
The Appellants' "invention relates to seal clearances in rotary
machines and, more particularly, to a static seal for a turbine assembly
providing for greater clearance during transient operation and tighter
clearance during steady state operation." Spec. ,r 1.
Claims 1, 5, 13, and 19 are the independent claims on appeal.
Claim 1, reproduced below, is illustrative of the subject matter on appeal. 2
1. A stator seal for a turbine assembly, the stator seal comprising:
a seal base securable to a turbine stator and including an
annular inner surf ace; and
an abradable coating disposed on the annular inner
surface, the abradable coating having a predefined cross-
sectional profile including
a transient operation section that facilitates axial
expansion and
a steady state operation section that facilitates a
tighter clearance,
the transient operation section and the steady state
operation section being oriented in an axial direction to
accommodate the axial expansion,
wherein the transient operation section of the
abradable coating is positioned adjacent a projected axial
position of rotating seal teeth during transient operation
and
the steady state operation section of the abradable
coating is positioned adjacent a projected axial position of
the rotating seal teeth during steady state operation, and
2 The Appeal Brief' s Claims Appendix recites a version of the claims that
was not entered. See Ans. 3. The claims on appeal were last recited in an
Amendment, filed August 17, 2016 ("Amendment"), and rejected by the
Examiner in the Final Office Action, mailed Sept. 23, 2016. See id.
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wherein the transient operation section is positioned
on only one axial side of the steady state operation section
for each of the rotating seal teeth.
Rejections
To facilitate our analysis, we set forth the grounds of rejection in a
different order than presented in the Examiner's Answer and Appeal Brief.
First, we will discuss the Examiner's rejection based on Zheng and Strock,
and then the rejections that add one or more of Duval, Care, and
Buddenbohm. These rejections consist of:
I. Claims 1, 2, 4, and 20 stand rejected under (pre-AIA)
35 U.S.C. § I03(a) as being unpatentable over Zheng
(US 2011/0285090 Al, published Nov. 24, 2011) and Strock et al.
(US 8,100,640 B2, issued Jan. 24, 2012) ("Strock" or "Strock
Patent")3 (Final Act. 3---6);
II. Claim 3 stands rejected under (pre-AIA) 35 U.S.C.
§ I03(a) as being unpatentable over Zheng, Strock, and Duval et al.
(US 2011/0103940 Al, published May 5, 2011) ("Duval") (Final
Act. 9-10);
III. Claims 8 and 12 stand rejected under (pre-AIA)
35 U.S.C. § I03(a) as being unpatentable over Zheng, Strock, and
3 In the Final Office Action and the Examiner's Answer, the Examiner cites
figures and paragraphs from the US Patent Application Publication of Strock
et al. (US 2009/0110536 Al, pub. Apr. 30, 2009) ("Strock Pub.") instead of
the US Patent of Strock. See Ans. 4--5. For example, in the Answer the
Examiner "directs attention to Figs. 3A & 3B of Strock." Id. at 4. Although
the US Patent of Strock lacks Figs. 3A & 3B (Reply Br. 1 ), the US Patent
Application Publication of Strock et al. includes Figs. 3A & 3B.
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Care (US 2004/0022625 Al, published Feb. 5, 2004) (Final Act. 18-
19); and
IV. Claim 11 stands rejected under (pre-AIA) 35 U.S.C.
§ I03(a) as being unpatentable over Zheng, Strock, Care, and
Buddenbohm (US 4,652,209, issued Mar. 24, 1987) (Final Act. 21).
Second, we will discuss the Examiner's rejection based on Zheng and
Sech, and then the rejections that add one or more of Duval, Dodd, Ruecker,
Care, and Buddenbohm. These rejections consist of:
V. Claims 1, 2, and 20 stand rejected under (pre-AIA)
35 U.S.C. § I03(a) as being unpatentable over Zheng and Sech et al.
(US 5,791,871, issued Aug. 11, 1998) ("Sech") (Final Act. 6-9);
VI. Claim 3 stands rejected under (pre-AIA) 35 U.S.C.
§ I03(a) as unpatentable over Zheng, Sech, and Duval (Final Act. 10-
11);
VII. Claims 5, 7, and 13 stand rejected under (pre-AIA)
35 U.S.C. § I03(a) as being unpatentable over Zheng, Sech, Dodd
(US 5,899,660, issued May 4, 1999), and Ruecker (DE 2745130 Al,
published Apr. 12, 1979) (Final Act. 11-18);
VIII. Claims 8-10 and 12 stand rejected under (pre-AIA)
35 U.S.C. § I03(a) as being unpatentable over Zheng, Sech, and Care
(Final Act. 19-21 );
IX. Claim 11 stands rejected under (pre-AIA) 35 U.S.C.
§ I03(a) as being unpatentable over Zheng, Sech, Care, and
Buddenbohm (Final Act. 22); and
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X. Claim 19 stands rejected under (pre-AIA) 35 U.S.C.
§ 103(a) as being unpatentable over Zheng and Sech (Final Act. 22-
24).
ANALYSIS
Rejections I-IV
Independent claim 1 recites a "stator seal for a turbine assembly,"
which includes an abradable coating disposed on a seal base's annular inner
surface. See Amendment 2. Claim 1 requires that the abradable coating has
a transient operation section and steady state operation section that are
positioned adjacent a projected axial position of rotating seal teeth during
transient and steady state operations, respectively. See id. Claim 1 recites
that the abradable coating's "transient operation section is positioned on
only one axial side of the steady state operation section for each of the
rotating seal teeth." Id.
The Examiner rejects claim 1 based on the combined teachings of
Zheng and Strock (i.e., Rejection I). The Examiner finds that Zheng teaches
a stator seal having seal base 322. Final Act. 3. The Examiner finds that
seal base 322 includes a transient operation section 324, 326, 330, 333
positioned on only one axial side of steady state operation section 328, 331,
333 for each rotating seal teeth 316, 318, 319. Id. at 3--4 ( citing Zheng,
Figs. 4, 5); see Zheng ,r 24, Fig. 3. The Examiner finds that Zheng fails to
teach an abradable coating.
The Examiner relies on Strock's teachings to cure the deficiencies of
Zheng with regard to claim 1. Final Act. 4--5. Notably, the Examiner finds
that Strock teaches abradable coating 34, 64, which includes transient 34 L,
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34T, 64L, 64T and steady state 34C, 64C operation sections. See id. (citing
Strock Pub., Figs. 2A-3B). Strock teaches that central portion 34C is
abraded (i.e., rubbed) by rotating blade 12. Strock Pub. ,r 19. The Examiner
does not find that Strock teaches using its abradable coating with seal teeth.
The Examiner concludes that combining the teachings of Zheng and Strock
results in the subject matter of independent claim 1. See Final Act. 3-5.
The Appellants argue that Zheng and Strock fail to "suggest the
structural modifications required of Zheng to meet the features of the
claimed invention." Appeal Br. 11. Put another way, the Appellants argue
that Strock would not "lead those of ordinary skill in the art to modify Zheng
to incorporate an abradable seal in the manner defined in claim 1." Id. at 10.
The Appellants also argue that the only reason to make the proposed
structural modification to Zheng' s seal is to meet the features of claim 1,
which amounts to improper hindsight. Id. at 11; see also Reply Br. 1-2.
The Appellants' position is persuasive.
The Examiner's rejection of independent claim 1 is based on the
notion that one of ordinary skill in the art would have combined teachings of
Zheng and Strock such that Zheng's recesses (e.g., 324, 326, 330, 333)
would be filled with Strock's abradable coating; then the abradable coating
would be partially removed by Zheng' s seal teeth ( e.g., 316, 318, 319)
during transient and steady-state operations. See Ans. 5. According to the
Examiner, the teachings of the references would have been combined
because:
Doing so would allow one to provide a means of protecting the
blades and seals while providing a minimum clearance to
increase engine efficiency, and to provide a means of producing
a more uniform abradable coating thickness that compensates for
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material loss and provides reduced heat transfer and thermal-
mechanical fatigue to the turbine engine components.
Final Act. 5; see Ans. 5 (citing Strock Pub. ,r,r 2, 22, 23, Figs. 3A, 3B).
However, the Examiner does not explain on the record how Zheng's
seal teeth are able to travel a path such that the portion of abradable coating
that remains has a uniform thickness to achieve the benefits asserted. Strock
teaches that despite some allowance - due to material choice of the
abradable coating - the benefits of having an abradable coating with a
uniform thickness may be achieved when the difference between the abraded
and non-abraded sections are between about 0.025 mm and about 0.125 mm.
See Strock Patent, col. 3, 11. 50-65. Although we understand that the general
movement of Zheng's seal teeth in its now-filled recesses would create some
type of profile, we fail to see adequate support for the Examiner's theory
that this profile would afford the uniform thickness that purportedly
motivates the proposed modification.
Thus, we do not sustain the Examiner's rejection of independent
claim 1, and claims 2, 4, and 20, which depend therefrom, as being
unpatentable over Zheng and Strock (Rejection I).
The rejections based on Zheng and Strock in combination with one or
more of Duval, Care, and Buddenbohm rely on the same inadequate
reasoning as discussed above. As such, we do not sustain the rejections
under 35 U.S.C. § 103(a) of: claim 3 as being unpatentable over Zheng,
Strock, and Duval (Rejection II); claims 8 and 12 as being unpatentable over
Zheng, Strock, and Care (Rejection III); and claim 11 as being unpatentable
over Zheng, Strock, Care, and Buddenbohm (Rejection IV).
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Rejections V-IX
The Examiner rejects claim 1 based on the combined teachings of
Zheng and Sech (i.e., Rejection V). For this rejection, the Examiner's
findings based on Zheng are identical to those discussed above with regard
to Rejection I. See Final Act. 6-7. As discussed above, the Examiner finds
that Zheng fails to teach an abradable coating.
The Examiner relies on Sech' s teachings to cure the deficiencies of
Zheng with regard to claim 1. Final Act. 7. The Examiner finds that Sech
teaches a turbine engine rotor assembly blade outer air seal 44 having
abradable coating 54, 56, 58. Id. at 7-8. The Examiner finds that the first
54 and second 5 6 slots of Sech' s abradable coating correspond to a transient
operation section and central portion 58 of Sech's abradable coating
corresponds to a steady state operation section. See id. Notably, Sech
teaches that the abradable coating is abraded by rotor blade tip 38. Sech,
col. 3, 11. 38--43, Figs. 2-3. The Examiner does not find that Sech teaches
using its abradable coating with seal teeth.
The Examiner concludes that combining the teachings of Zheng and
Sech results in the subject matter of independent claim 1. See Final Act. 7-
8. More specifically, the Examiner concludes:
Since both Zheng and Sech teach stator seals, it would
have been obvious to one having ordinary skill in the art to
modify the stator seal of Zheng by providing that the stator seal
comprise an abradable coating disposed on the annular inner
surface, the abradable coating having a predefined cross-
sectional profile, wherein the abradable coating is positioned
adjacent a projected axial position of the rotating blades, and thus
seal teeth, during transient operation and steady state operation,
as taught by Sech. Doing so would allow one to accommodate
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axial movement of a rotor blade and avoid damage to the rotor
blade during axial movement.
Final Act. 8.
The Appellants argue that Sech' s teachings "would not lead those of
ordinary skill in the art to modify Zheng to meet the claimed structure."
Appeal Br. 12. The Appellants point out that in reference to the present
invention claim 1 requires "transient operation section 16 ... positioned on
only one axial side of the steady-state operation section 18 for each of the
rotating seal teeth." Id. Indeed, claim 1 recites "wherein the transient
operation section is positioned on only one axial side of the steady state
operation section for each of the rotating seal teeth." Amendment 2. The
Appellants' position is persuasive.
Sech teaches that during transient operations the abradable coating is
designed for radial movement of the rotor blade tip 38 and during aberrant
conditions the abradable coating is designed for axial movement of the rotor
blade tip 38. See Sech, col. 1, 11. 52-59, col. 3, 11. 9-15, 38--43, Figs. 1-2.
More specifically, Sech teaches:
During transient periods of operation where the thermal response
of the rotor stages 10, 12, 14, 16, differs from that of the outer case
28, the rotor blade tips 38 may extend radially outward and
engage the central portion 58 ... of the blade outer air seal 44,
abrading a percentage of the central portion 58 ....
Sech, col. 3, 11. 38--43 (emphasis omitted); see Appeal Br. 12. Sech teaches,
that during aberrant conditions "the forward 76 or aft 78 edge of the rotor
blade tip 38 travels into the relief provided by the first 54 or second 56 slot,
respectively." Sech, col. 3, 11. 56-59 (emphasis omitted). In the Appellants'
words, first slot 54 and second slot 56 "are provided to protect against
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damage to the leading and trailing edges of the tip in the event of extreme
axial motion of the rotor relative to the stator." Appeal Br. 12.
We find that Sech does not teach that during aberrant conditions rotor
blade tip 38 only moves axially in one direction. Indeed, first slot 54 and
second slot 56 are positioned on both sides of central potion 58 to
accommodate axial movement in the forward and aft directions. As such, if
one of ordinary skill in the art were to modify Zheng, in view of the
teachings of Sech, to "accommodate axial movement of a rotor blade"
during transient operation, the result would not be an abraded transient
section placed on only one axial side.
Thus, we do not sustain the Examiner's rejection of independent
claim 1, and claims 2 and 20, which depend therefrom, as being
unpatentable over Zheng and Sech (Rejection V).
The rejections based on Zheng and Sech in combination with one or
more of Duval, Care, and Buddenbohm rely on the same inadequate
reasoning as discussed above. As such, we do not sustain the rejections
under 35 U.S.C. § 103(a) of: claim 3 as being unpatentable over Zheng,
Sech, and Duval (Rejection VI); claims 8-10 and 12 as being unpatentable
over Zheng, Sech, and Care (Rejection VIII); and claim 11 as being
unpatentable over Zheng, Sech, Care, and Buddenbohm (Rejection IX).
Independent claims 5 and 13, like claim 1, require a transient
operation section to be positioned "on only one axial side of the steady state
operation section for each of the rotating seal teeth." Amendment 2--4. The
Examiner's rejection of claims 5 and 13 is based on the same inadequate
reasoning as the Examiner's rejection of claim 1 as unpatentable over Zheng
and Sech (Rejection V). Compare Final Act. 6-8 with id. at 11-18. For the
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rejections of independent claims 5 and 13, and dependent claim 7, the
Examiner further relies on teachings from Dodd and Ruecker. Id. at 11-18.
However, the Examiner's use of the teachings of Dodd and Ruecker does not
cure the deficiency in the inadequate reasoning discussed above. Thus, for
reasons similar to those discussed above with regard to the rejection of claim
1 as being unpatentable over Zheng and Sech (Rejection V), we do not
sustain the Examiner's rejection of claims 5, 7, and 13 as being unpatentable
over Zheng, Sech, Dodd, and Ruecker (Rejection VII).
RejectionX
Independent method claim 19 recites, "disposing the abradable
coating such that an axial length of the steady state operation section is
greater than an axial length of the rotating seal teeth." Amendment 4. The
Examiner finds that Zheng teaches disposing seal base 322 such that an axial
length of the steady state operation section 328, 330, 334 is greater than an
axial length of the rotating seal teeth 316, 318, 319 (Final Act. 22-23 ( citing
Zheng, Figs. 3-5)), but not "disposing the abradable coating such that an
axial length of the steady state operation section is greater than an axial
length of the rotating seal teeth," as recited in independent claim 19
( Amendment 4 ( emphasis added)).
To remedy this deficiency, the Examiner turns to Sech's teaching of
an abradable coating. Final Act. 23-24. Although the Examiner finds that
Sech teaches an abradable coating 54, 56, 58, the Examiner does not find
that Sech teaches an "abradable coating such that an axial length of the
steady state operation section is greater than an axial length of the rotating
seal teeth," as recited in claim 19.
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We note that the Examiner finds that Sech's abradable coating has a
central portion 58 that corresponds to a steady state operation section. Final
Act. 24. Insofar as central portion 58 corresponds to a steady state operation
section, it is clear that the axial length of central portion 58 is not greater
than an axial length of rotor blade tip 38. Sech, Figs. 1-3; see also Appeal
Br. 12, 17. Moreover, we note that Sech's rotor blade tip 38 does not
include seal teeth; and, as indicated above, independent claim 19 requires
"seal teeth."
The Examiner determines that the combined teachings of Zheng and
Sech would have resulted in claim 19's requirement of "disposing the
abradable coating such that an axial length of the steady state operation
section covers a substantial length of the rotating blades, and is thus greater
than an axial length of rotating seal teeth, as taught by Sech." Final Act. 24.
In this case, we fail to understand how the Examiner adequately supports
this determination. First, Sech's teachings of the abradable coating's central
portion 58 is particular to its relationship to the structure and function of
rotor blade tip 38; among other things, Sech's abradable coating does not
interact with seal teeth. Second, even if we were to overlook this first point,
the relative length of central portion 58 to rotor blade tip 38 (i.e., the
structure that abrades the coating's central portion 58) is the reverse of the
subject matter of claim 19, i.e., "disposing the abradable coating such that an
axial length of the steady state operation section is greater than an axial
length of the rotating seal teeth"; the axial length of central portion 58 is not
greater than an axial length of rotating blade tip 38.
Thus, we do not sustain the Examiner's rejection of independent
claim 19 as being unpatentable over Zheng and Sech (Rejection X).
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DECISION
We REVERSE the Examiner's decision rejecting claims 1-5, 7-13,
19, and 20.
REVERSED
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