Ex Parte Cheng et al

Patent Trial and Appeal BoardOct 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 2 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). Appeal 2010-005426 Application 11/435,950 3 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. Appeal 2010-005426 Application 11/435,950 4 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 Appeal 2010-005426 Application 11/435,950 5 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. Appeal 2010-005426 Application 11/435,950 6 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 Appeal 2010-005426 Application 11/435,950 7 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. Appeal 2010-005426 Application 11/435,950 8 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