Ex Parte Cheng et al

Patent Trial and Appeal Board

Oct 31, 2012

11435950 (P.T.A.B. Oct. 31, 2012)

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.
11/435,950 05/17/2006 Kenny Cheng 67097-502; EH-11630 7142
54549 7590 11/01/2012
CARLSON, GASKEY & OLDS/PRATT & WHITNEY
c/o CPA Global
P.O. Box 52050
Minneapolis, MN 55402
EXAMINER
EASTMAN, AARON ROBERT
ART UNIT PAPER NUMBER
3745
MAIL DATE DELIVERY MODE
11/01/2012 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte KENNY CHENG, SIEW KONG LEE, and ENG THONG ONG
____________

Appeal 2010-005426
Application 11/435,950
Technology Center 3700
____________

Before GAY ANN SPAHN, MICHAEL C. ASTORINO, and
WILLIAM A. CAPP, Administrative Patent Judges.

SPAHN, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-005426
Application 11/435,950

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STATEMENT OF THE CASE
Kenny Cheng et al. (Appellants) seek our review under 35 U.S.C.
§ 134 of the Examiner’s rejection of claims 1, 3-17, and 19 under 35 U.S.C.
§ 103(a) as unpatentable over Cheng (US 2005/0178750 A1, pub. Aug. 18,
2005) and Clark (US 2005/0132569 A1, pub. Jun. 23, 2005).
1
Appellants
cancelled claims 2 and 18. We have jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.

The Claimed Subject Matter
The claimed subject matter “relates to repair of gas turbine engine
components and, more particularly, to a method for restoring a sulphidation
section of a turbine airfoil platform and an eroded turbine airfoil trailing
edge.” Spec. 1, para. [0002]. Claim 1, reproduced below, is illustrative of
the subject matter on appeal.
1. A method of restoring a gas turbine
engine component, including the steps of:
(a) depositing a filler material onto
sulphidation pit portions of a sulphidation
section of a turbine engine component; and
(b) laser consolidating the filler material to
produce a restored surface.

1
In the Final Office Action mailed February 9, 2009, the Examiner rejected
claim 20 under 35 U.S.C. § 112, first paragraph, as failing to comply with
the enablement requirement, and under 35 U.S.C. § 112, second paragraph,
as being indefinite for lack of antecedent basis with respect to two different
limitations. Final Rej. 3. In the Answer, the Examiner withdrew both
rejections of claim 20. Ans. 7-8. As there are no pending rejections against
claim 20, we assume that the Examiner now objects to claim 20 as being
dependent upon a rejected base claim (i.e., claim 1).
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OPINION
Claims 1 and claims 3-7
The Examiner finds that Cheng substantially discloses the method of
claim 1, except Cheng does not disclose that “the sulphidation section
includes sulphidation pits and filling the sulphidation pit portions to produce
the restored surface.” Ans. 4. To cure the deficiency of Cheng, the
Examiner turns to Clark for its teaching of “laser cladding the damaged
portion without its removal (abstract).” Id. The Examiner concludes that it
would have been obvious to one of ordinary skill in the art “to combine laser
cladding the damaged portion without its removal as taught in Clark . . . with
the method disclosed by Cheng . . . for the purposes of reducing machining
time.” Id.
Appellants argue that the repair taught by Clark is for mechanically
worn or eroded areas and that one of ordinary skill in the art would not
necessarily expect that the repair of Clark would extend to sulphidation
damage. Reply Br. 2. In other words, Appellants note that Cheng is
concerned with sulphidation, which is the result of a corrosive attack of
sulphates on the base metal such that the base metal has a chemically altered
structure, and this is dissimilar to the mechanical or erosive wear taught by
Clark. Id. Appellants point out that in Cheng, the “sulphidation sections are
normally removed (p. 2, paragraph [0025], lines 9-11), presumably to
remove the chemically altered material,” and Appellants further argue that
the Cheng and Clark “references as a whole do not suggest that it is . . .
[un]necessary to remove a sulphidation damaged portion before repairing the
article, as the Examiner alleges.” Id.
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We agree with Appellants that the corrosive damage or sulphidation
described in Cheng may affect the base metal by giving it a chemically
altered structure. Reply Br. 2. Because of the chemically altered structure
of the base metal, Cheng teaches to use “abrasive cleaning, such as grit blast
cleaning, . . . to remove most of the sulphidation from a sulphidation
affected section 20 on the blade” and if the abrasive cleaning “leave[s] the
platform 16 thin and outside of the applicable parameters[,] . . . . [t]o repair
the platform 16 after abrasive cleaning” by removal of the sulphidation
affected section 20 from the platform 16 by any suitable technique, such as
by cutting, shaping or finishing by machine. Cheng, para. [0025].
Clark, on the other hand, teaches a repair method using laser cladding
“to build-up those faces 300 [of the piston crown 101] that have receded”
due to mechanical or erosive wear in an internal combustion engine. Clark,
p. 1, paras. [0002], [0005], and [0013]. As argued by Appellants, “Clark
does not teach cladding without removal of a damaged area,” but rather “[i]n
Clark, the area being repaired is a worn area, which inherently includes
removal through wear on the part.” Reply. Br. 2. Thus, we agree with
Appellants that “one of skill in the art would not necessarily expect that the
repair of Clark extends” in particular, to the sulphidation damage disclosed
by Cheng. Thus, we find that the reasoning the Examiner provides for
combining Clark with Cheng, i.e., “to combine laser cladding the damaged
portion without its removal as taught in Clark . . . with the method disclosed
by Cheng . . . for the purposes of reducing machining time,” does not have a
rational underpinning. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 418
(2007) (holding that “rejections on obviousness grounds cannot be sustained
by mere conclusory statements; instead, there must be some articulated
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reasoning with some rational underpinning to support the legal conclusion of
obviousness.”).
Accordingly, we do not sustain the Examiner’s rejection of claim 1,
and claims 3-7 dependent thereon, under 35 U.S.C. § 103(a) as unpatentable
over Cheng and Clark.
Claim 8
Claim 8 is directed to a gas turbine engine including a compressor
section, a combustion section, and a turbine section having a turbine air foil.
The turbine air foil is recited to be “restored according to the method recited
in claim 1.”
In the instant case, the Examiner finds that Cheng discloses “a gas
turbine engine including a compressor section, a combustion section, and a
turbine section, the turbine section having a turbine airfoil. Ans. 5 (citing
Cheng, p. 1, para. [0002]). The Examiner concludes that the claimed
restored turbine airfoil is obvious in view of Cheng’s turbine airfoil and
method of repairing sulphidation damage as modified by Clark’s repair of
erosion damage to a piston. In our view, the Examiner has not presented a
sound basis for reaching this conclusion because Clark’s method of repairing
a part using laser cladding is based on mechanical or erosive wear, not
sulphidation or chemical/corrosive wear as is occurring in Cheng. See also
Reply Br. 2. Thus, for the reasons discussed supra with respect to claim 1,
we determine that a person of ordinary skill in the art would not necessarily
expect that Clark’s repair of mechanical or erosive damage extends to the
sulphidation damage disclosed by Cheng and therefore, the reasoning the
Examiner provides for combining Clark with Cheng does not have rational
underpinning.
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Accordingly, we do not sustain the Examiner’s rejection of claim 8
under 35 U.S.C. § 103(a) as unpatentable over Cheng and Clark.
Claims 9-14
Claim 9 recites “[a] method of restoring a gas turbine engine
component, including the steps of: (a) depositing a laser cladding on an
eroded trailing edge of a turbine airfoil; and (b) producing a restored trailing
edge thickness.” App. Br., Clms. App’x.
The Examiner finds that Cheng discloses the above-quoted steps (a)
and (b) (Ans. 5 (citing Cheng, Abstract)) and also discloses a repair method
“for ‘repairing an article, such as turbine parts of a rotary gas turbine engine
. . . .’” (Ans. 10 (citing Cheng, Abstract)). The Examiner concludes that it
would have been obvious to a person of ordinary skill in the art to repair the
trailing edge of an airfoil and the person of ordinary skill in the art “would
have a reasonable expectation of success that if the damage were caused by
sulphidation or erosion that the same repair method would work equally as
well.” Ans. 10-11.
Appellants argue that Cheng “does not disclose an eroded trailing
edge of a turbine airfoil as claimed,” but rather, “refers to sulphidation, not
erosion.” App. Br. 8 (citing Cheng, Fig. 2, element 20). Appellants also
argue that “one of ordinary skill in the art would not interpret the damaged
portion in Cheng to be erosion on a trailing edge of an airfoil,” and
“sulphidation should not be interpreted as being equivalent to erosion,”
because “[s]ulphidation is a chemical corrosion mechanism . . . and erosion
is inherently a physical wear mechanism.” Id. Appellants also argue that
“the Examiner’s allegation that a person of ordinary skill in the art would
have a reasonable expectation of success for repairing damage caused by
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sulphidation or erosion with the same repair method is . . . unsupported, as
the Cheng reference seems to be directed primarily to sulphidation . . . and
does not suggest use with” mechanical or erosive wear damage as is
occurring in Clark. Id. (citing Cheng, p. 1, para. [0001]).
We agree with the Appellants. Cheng teaches using laser cladding to
repair damage caused by sulphidation or corrosion damage. Cheng, Figs. 2,
3, and 7, and para. [0025]. Similarly, Clark teaches using laser cladding in a
repair method; however, the laser cladding is to repair the face 300 of an
internal combustion engine’s piston crown 101 that has receded due to
mechanical or erosive wear. Clark, p. 1, paras. [0002], [0005], and [0013].
Thus, for the reasons stated supra with respect to claim 1, a person of
ordinary skill in the art would not combine Cheng’s repair method of
sulphidation or corrosion damage with Clark’s method of repair for
mechanical wear or erosion damage for the reason set forth by the Examiner.
Accordingly, we do not sustain the Examiner’s rejection of claim 9,
and claims 10-14 dependent thereon, under 35 U.S.C. § 103(a) as
unpatentable over Cheng and Clark.
Claims 15, 16, 17, and 19
Claim 15 is directed to a gas turbine engine component and recites “a
turbine airfoil platform including sulphidation section having sulphidation
pits” and “a restored platform surface that includes a laser cladding portion
bonded to said sulphidation section such that the laser cladding portions fills
the sulphidation pits.” App. Br., Clms. App’x.
The Examiner makes similar findings to those discussed with respect
to independent claim 1 supra. Ans. 7 and 11-12.
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Appellants present similar arguments to those discussed with respect
to claim 1 supra. App. Br. 9 and Reply Br. 4.
For the same reasons as discussed supra with respect to claim 1, we
do not sustain the Examiner’s rejection of claim 15, and claims 16-19
dependent thereon, under 35 U.S.C. § 103(a) as unpatentable over Cheng
and Clark.

DECISION
We reverse the Examiner’s decision to reject claims 1, 3-17, and 19.

REVERSED

ELD