DETAILED ACTION
This is a non-final rejection in response to application filed 6/4/25. Claims 1-14 are currently pending.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Iwrey (US 2019/0078536) in view of Ostdiek et al. (US 2021/0108597) and further in view of Bart et al. (US 2005/0241291).
Regarding independent claim 1, Iwrey teaches a triple-flow aircraft turbine engine, including a gas generator 13 having along a longitudinal axis at least one compressor 14, a combustion chamber 16 and at least one turbine 18, the turbine engine comprising:
two coaxial annular walls, respectively internal 38 and external 24, extending around each other and defining therebetween a main annular duct for a main air flow [0021],
a rotor blading 22 extending radially across the main annular duct and forming a ducted propeller [0024];
an annular separator 30 arranged downstream of the rotor blading and between the two coaxial annular walls, the annular separator defining, with the internal and external coaxial annular walls respectively, two secondary flow annular ducts, respectively internal and external, for the secondary air flow, respectively internal and external, the separator comprising at an upstream end an annular nose 30L configured to split the main air flow into two and to form the secondary air flows [0021-0024];
stator elements 32 extending radially on the one hand through the main duct and on the other hand through the secondary flow annular ducts, the stator elements being connected to the annular nose [0024], and
wherein the stator elements comprise:
stationary guide vanes 32 which are distributed around the longitudinal axis and which each comprise a leading edge 32L located upstream of the nose 30, and trailing edges, respectively internal and external, located respectively in the internal and external secondary ducts, these stationary guide vanes being connected to the nose [0024], see fig. 2; and
variable-pitch guide vanes which are distributed about the longitudinal axis and which extend radially through at least one of the secondary ducts, each of the variable-pitch guide vanes comprising a leading edge and a trailing edge (see claim 15 of Iwrey).
Iwrey is silent to a non-ducted propeller disposed upstream of the external wall, or the leading edges of the variable pitch guide vanes are located upstream of the internal and/or external trailing edges of the stationary guide vanes, or the leading edges of the variable pitch guide vanes are located directly downstream of the internal and/or external trailing edges of the stationary guide vanes, and are separated by predetermined axial clearances from these trailing edges.
Ostdiek teaches a non-ducted propeller 20 upstream of the engine, combined with a downstream ducted fan 40 and a three-stream architecture [0043]. Ostdiek further discloses fixed or variable OGVs 43 and IGVs 44 for ducted fan, providing the downstream variable pitch concept [0044].
Bart teaches a downstream variable-pitch stage adjacent to and immediately downstream of a stationary structure, with each movable arm 51 positioned immediately behind a stationary arm 49 and actuated via an outer control ring 56, directly corresponding to variable pitch guide vanes 44 positioned downstream of stationary vane trailing edges at a defined axial clearance J and controlled by a system at the external wall.
It would have been obvious to one of ordinary skill in the art at the time of filing to modify Iwrey with the non-ducted propeller and downstream variable pitch vane stage as taught by Ostdiek and Bart as part of an obvious combination of known prior art structures, in this case the use the non-ducted propeller and downstream variable pitch vane stage in order to gain the benefit of efficient flow bifurcation management in both secondary ducts, as well as adding aerodynamic matching flexibility across varying engine operating conditions. See KSR; MPEP 2141 III A.
Regarding dependent claim 2, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein the number of the variable pitch guide vanes is greater than or equal to the number of the stationary guide vanes [0022].
Regarding dependent claim 3, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Ostdiek further teaches wherein the variable pitch guide vanes 44 are located in the internal secondary duct 72 [0044].
Regarding dependent claim 4, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein the trailing edges of the variable pitch guide vanes are located downstream of the external trailing edges of the stationary guide vanes [0022].
Regarding dependent claim 5, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein it further comprises a system for controlling the angular pitch of the variable pitch guide vanes, this system being mounted radially outwardly of the external wall [0022].
Regarding dependent claim 6, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein the variable pitch guide vanes 50 are located in the external secondary duct 13.
Regarding dependent claim 7, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Ostdiek further teaches wherein first variable pitch guide vanes 44 are located in the internal secondary duct 72, and second variable pitch guide vanes 43 are located in the external secondary duct 73.
Regarding dependent claim 8, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Ostdiek further teaches wherein it further comprises a common system for controlling the angular pitch of the first and second variable pitch guide vanes, or independent systems for controlling the angular pitch of the first and second variable pitch guide vanes respectively [0044].
Regarding dependent claim 9, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein it further comprises structural arms 49 distributed around the axis in the external secondary duct [0021].
Regarding dependent claim 10, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart teaches structural arms 49 in the outer grid 48 serving a load bearing function and stator vanes 45,46 in the main flow as aerodynamic guide vane stage [0021]. Reducing structural weight while maintaining further teaches wherein the number of structural arms is less than the number of stationary guide vanes would be a routine design optimization within ordinary skill, which is also supported by Iwrey, which teaches only some hollow airfoils carrying supports [0026].
Regarding dependent claim 11, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Bart further teaches wherein the structural arms 49 are connected to some of the stationary guide vanes.
Regarding dependent claim 12, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Ostdiek further teaches wherein the rotor blading is a fan or a compressor rotor blading [0043].
Regarding dependent claim 13 and 14, Iwrey in view of Ostdiek and further in view of Bart teaches the invention as claimed and discussed above. Iwrey in view of Ostdiek and further in view of Bart is silent to wherein the leading edges of the variable pitch guide vanes are located at a distance from the internal and/or external trailing edges of the stationary guide vanes, and wherein the distance is greater than 10% of the chord of one of the stationary guide vanes, OR wherein the distance is greater than or equal to 20%.
Iwrey teaches aerodynamic result achieved by axial separation between the vane leading edge and the splitter ring, permitting air to enter the core inlet without interacting with the vane leading edge during reverse thrust, avoiding negative incidence flow separation and maintaining core stability margin [0038]. Bart further recognizes that the positional relationship between the movable arms and stationary arms determines aerodynamic matching quality of the rear fan at different engine speeds, stating that the variable pitch stator is provided in order to ensure the rear fan is acceptably matched [0005].
Accordingly, the axial clearance between the vane trailing edges and the variable pitch vane leading edges is a result-effective variable: it is a variable whose optimization is recognized in the prior art as directly producing the desired result of aerodynamic interreference and adequate pitch actuation clearance. It would have been obvious to one of ordinary skill in the art at the time of the invention to modify the spacing between the leading edge of the variable pitch guide vanes from the internal and/or external trailing edges of the stationary guide vanes, and wherein the distance is -greater than 10% of the chord of one of these vanes, or equal to 20% of this chord as of Iwrey in view of Ostdiek and further in view of Bart, since it has been held that optimizing a result effective variable was an obvious extension of prior art teachings, In re Antoine, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (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.” MPEP 2144.05 I and II.
Conclusion
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/CRAIG KIM/
Primary Examiner
Art Unit 3741
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