DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 08/05/2026 has been entered.
Response to Arguments
Applicant’s arguments, see Page 7 of the response, filed 08/05/2026, with respect to the rejection of Claim 12 under 35 U.S.C. §112(b), have been fully considered and are persuasive. The indefiniteness has been removed from Claim 12; therefore, the rejection of Claim 12 under 35 U.S.C. §112(b) has been withdrawn.
Applicant's arguments filed 08/05/2026, regarding the rejections made under 35 U.S.C. §102(a)(1), have been fully considered but they are not persuasive. The applicant argues that the previously cited prior art Pietrobon fails to disclose the added limitation to Claims 1 and 14 of the forward segment deflecting the core gas flow away from the blade tip surface at the leading edge, and therefore the applicant argues that the rejections made under 35 U.S.C. §102(a)(1) should be withdrawn. The Office respectfully disagrees. The limitation of the forward segment deflecting the core gas flow away from the blade tip surface at the leading edge is a functional limitation; it is describing what the forward segment does rather than what the forward segment is. When the prior art structure is substantially identical to the claimed structure, claimed functions are presumed to be inherent (see MPEP 2112.01(I)), and the burden shifts to the applicant to show that the two structures are not substantially identical. In this case, the prior art structure was substantially identical to the previously claimed structure (shown in the Final Rejection mailed on 05/05/2026), and the only additional structure added to the claimed gas turbine engine is each rotor blade being arranged along the axial centerline relative to the forward segment aft end surface, which is also disclosed by the prior art in Pietrobon (Figures 2-3). Therefore, the prior art structure is still substantially identical to the claimed structure, and thus the claimed functions, including the forward segment deflecting the core gas flow away from the blade tip surface at the leading edge, still can be performed by the prior art structure. Because of this, the applicant’s arguments are not persuasive, and Claims 1 and 14 still are rejected under 35 U.S.C. §102(a)(1).
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-7 and 9-19 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Pietrobon (US Patent No: 9,500,095).
Regarding Claim 1: Pietrobon discloses a gas turbine engine (Figure 1, No. 10) having an axial centerline (Figure 1), the gas turbine engine comprising a compressor section (14); a combustor section (16); and a turbine section (18), wherein the turbine section includes a vane stage (22, 64) and a rotor stage (24, 66), wherein the rotor stage comprises a bladed rotor and an annular shroud (66) having a circumference (Figure 4); wherein the vane stage is disposed forward of and adjacent the rotor stage (Figures 2-3), and the annular shroud is independent of the vane stage (Figures 2-3); wherein the bladed rotor includes a disk (inherent part of a rotor) and a plurality of rotor blades (24) extending radially outward from the disk (Figure 2), wherein each rotor blade has a leading edge, a trailing edge, and a blade tip surface extending between the leading and trailing edges (Figures 2-3); and wherein the annular shroud is disposed radially outside of the bladed rotor (Figures 2-3) and comprises a primary segment (Figure 3, see previous OA) and a forward segment (see previous OA), the primary segment and the forward segment extend around the entire circumference of the annular shroud (Figures 2-4); and wherein the primary segment has a PS forward end surface (see previous OA) and a PS inner radial surface (see previous OA); and wherein the forward segment is disposed forward of the rotor blades (Figure 3) and is configured to deflect core gas flow away from a blade tip gap disposed between the PS inner radial surface and the blade tip surface of each said rotor blade of the plurality of rotor blades (functional limitation – the structure of the prior art forward segment is the same as the claimed forward segment and thus can perform the same functions are the claimed forward segment, including deflect core gas flow away from a blade tip gap disposed between the PS inner radial surface and the blade tip surface of each said rotor blade. See MPEP 2112.01), wherein the forward segment has an FS inner radial surface that extends between an FS forward end surface and an FS aft end surface (see previous OA), and wherein each rotor blade is arranged along the axial centerline relative to the FS aft end surface (Figures 2-3) such that the forward segment deflects the core gas flow away from the blade tip surface at the leading edge (functional limitation – the structure of the prior art forward segment is the same as the claimed forward segment and thus can perform the same functions are the claimed forward segment, including deflect core gas flow away from a blade tip gap at the leading edge. See MPEP 2112.01).
Regarding Claim 2: Pietrobon discloses the gas turbine engine of Claim 1, wherein the forward segment extends from the PS inner radial surface radially inward a distance (Figure 3), such that the FS inner radial surface is disposed radially inward of the blade tip surfaces of the rotor blades (Figure 3).
Regarding Claim 3: Pietrobon discloses the gas turbine engine of Claim 2, wherein the FS inner radial surface is disposed radially inward of the blade tip surfaces of the rotor blades at the leading edge of the respective rotor blades (Figure 3).
Regarding Claim 4: Pietrobon discloses the gas turbine engine of Claim 2, wherein the FS forward end surface is disposed contiguous with the PS forward end surface (Figure 3).
Regarding Claim 5: Pietrobon discloses the gas turbine engine of Claim 4, wherein at least a portion of the FS forward end surface is co-planar with the PS forward end surface (Figure 3).
Regarding Claim 6: Pietrobon discloses the gas turbine engine of Claim 4, wherein the FS inner radial surface is disposed radially inward of the blade tip surfaces of the rotor blades (Figure 3).
Regarding Claim 7: Pietrobon discloses the gas turbine engine of Claim 6, wherein at least a portion of the FS inner radial surface is disposed parallel to the axial centerline of the gas turbine engine (Figure 3).
Regarding Claim 10: Pietrobon discloses the gas turbine engine of Claim 4, wherein the FS inner radial surface is a peak contiguous with the FS forward end surface and an FS aft end surface (Figure 3).
Regarding Claim 9: Pietrobon discloses the gas turbine engine of Claim 1, wherein a portion of the FS aft end surface is contiguous with the PS inner radial surface (Figures 2-3).
Regarding Claim 11: Pietrobon discloses the gas turbine engine of Claim 1, wherein the shroud is a circumferentially segmented structure (Figure 4).
Regarding Claim 12: Pietrobon discloses the gas turbine engine of Claim 1, wherein the primary segment and the forward segment are integral with one another (Figures 2-3).
Regarding Claim 13: Pietrobon discloses the gas turbine engine of Claim 12, wherein the vane stage (22, 64) is disposed contiguous with the rotor stage and axially upstream of rotor stage (Figure 2), wherein the vane stage includes an outer platform (64) disposed adjacent the shroud (Figures 2-3).
Regarding Claim 14: Pietrobon discloses a turbine rotor stage (Figure 2) having an axial centerline (Figure 1), comprising a bladed rotor that includes a disk (inherent part of the rotor) and a plurality of rotor blades (24) extending radially outward from the disk, wherein each rotor blade has a leading edge, a trailing edge, and a blade tip surface extending between the leading and trailing edges (Figures 2-3); and an annular shroud (66; Figure 4) disposed radially outside of the bladed rotor (Figures 2-3), wherein the shroud extends circumferentially around the bladed rotor (Figures 2-4), and includes a primary segment (see previous OA) and a forward segment (see previous OA), wherein the primary segment and the forward segment extend circumferentially around an entirety of the annular shroud (Figures 2-4), and the annular shroud is configured to be independent of an adjacent vane stage (22, 64) (Figures 2-3); wherein the primary segment has a PS forward end surface (see previous OA) and a PS inner radial surface (see previous OA); wherein the forward segment has an FS inner radial surface that extends between an FS forward end surface and an FS aft end surface (see previous OA), and the forward segment extends from the PS inner radial surface radially inward a distance, such that the FS inner radial surface is disposed radially inward of the blade tip surfaces of the rotor blades (Figures 2-3, see previous OA), wherein at least a portion of the FS aft end surface comprises an arcuate portion (see previous OA), and wherein each rotor blade is arranged along the axial centerline relative to the FS aft end surface (Figures 2-3) such that the forward segment deflects core gas flow away from the blade tip surface at the leading edge (functional limitation – the structure of the prior art forward segment is the same as the claimed forward segment and thus can perform the same functions are the claimed forward segment, including deflect core gas flow away from a blade tip gap at the leading edge. See MPEP 2112.01).
Regarding Claim 15: Pietrobon discloses the turbine rotor stage of Claim 14, wherein the FS forward end surface is disposed contiguous with the PS forward end surface (Figure 3).
Regarding Claim 16: Pietrobon discloses the turbine rotor stage of Claim 15, wherein at least a portion of the FS forward end surface is co-planar with the PS forward end surface (Figures 2-3).
Regarding Claim 17: Pietrobon discloses the turbine rotor stage of Claim 16, wherein at least a portion of the FS inner radial surface is disposed parallel to the axial centerline (Figures 2-3).
Regarding Claim 18: Pietrobon discloses the turbine rotor stage of Claim 14, wherein the primary and forward segments are integral with one another (Figures 2-3).
Regarding Claim 19: Pietrobon discloses the turbine rotor stage of Claim 14, wherein the shroud is a circumferentially segmented structure (Figure 4).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Pietrobon in view of Tanaka (US Patent No: 7,186,078).
Regarding Claim 22: Pietrobon discloses the gas turbine engine of Claim 1, wherein the FS forward end surface extends from the PS forward end surface to the FS inner radial surface (Figures 2-3); however, Pietrobon fails to disclose the FS forward end surface being angularly disposed relative to the PS forward end surface.
Tanaka teaches a gas turbine engine shroud (Figure 1, No. 35) comprising primary and forward segments with PS and FS forward end surfaces, respectively, the FS forward end surface being angularly disposed relative to the PS forward end surface (see below).
[AltContent: arrow][AltContent: arrow][AltContent: textbox (FS Forward End Surface)][AltContent: textbox (PS Forward End Surface)]
PNG
media_image1.png
372
200
media_image1.png
Greyscale
Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to make the FS forward end surface of Pietrobon angularly disposed relative to the PS forward end surface, as taught by Tanaka, for the purpose of further suppressing leakage of hot combustion gas to a low-pressure turbine case (Column 5, Lines 18-20).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL L SEHN whose telephone number is (571)270-3564. The examiner can normally be reached M-F 8:30 AM-6 PM, every other Friday off.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Courtney Heinle can be reached at 571-270-3508. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/MICHAEL L SEHN/Primary Examiner, Art Unit 3745
Prosecution Insights