DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 02/20/2026 amending Claims 1, 8 – 10, and 14 - 16 has been entered. Claims 1 – 5, 7 – 18, and 20 are examined.
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.
Claims 1, 3 – 5, 8, and 10 – 17 are rejected under 35 U.S.C. 103 as being unpatentable over Sargisson et al. (4,446,696) in view of Miller et al. (11,391,298) in view of Newton et al. (5,867,979) in view of Apke, “Boeing 787: All Electric Engines”, ASEN 5063, December 15, 2009, hereinafter “Apke” as evidenced by Sheyman et al. (6,390,785).
Regarding Claim 1, Sargisson teaches, in Fig. 1, the invention as claimed, including a gas turbine engine being a three-stream gas turbine engine (Fig. 1) defining an axial direction (along longitudinal rotational axis of said three-stream gas turbine engine), the three-stream gas turbine engine comprising: a low pressure shaft (16); a primary fan (38) operatively coupled with the low pressure shaft (16); a mid-fan (12) positioned downstream of the primary fan (38) and operatively coupled with the low pressure shaft (16); a low pressure turbine (24) operatively coupled with the low pressure shaft (16).
Sargisson is silent on wherein the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline.
Miller teaches, in Figs. 1 – 3, a similar turbofan gas turbine engine (10) having a primary fan (14, 40) is an unducted fan (shown in Fig. 1, Col. 3, ll. 55 - 60) having unducted fan blades (40) rotatable about a longitudinal centerline (12) and unducted fan guide vanes (50) not rotatable (fixed to outer casing 18) about the longitudinal centerline (12). Miller teaches, in Col. 3, ll. 60 – 67, “Additionally, the plurality of outlet guide vanes 50 are provided to increase an efficiency of the fan section 14 as well as to provide other benefits, such as, for example, decreasing an amount of noise generated by the turbofan engine 10, by directing a flow of air from the plurality of fan blades 40 of the fan section 14”.
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson with the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, taught by Miller, because all the claimed elements, i.e., a three-stream gas turbine engine defining an axial direction, the three-stream gas turbine engine comprising: a low pressure shaft, a primary fan operatively coupled with the low pressure shaft, a mid-fan positioned downstream of the primary fan and operatively coupled with the low pressure shaft, a low pressure turbine operatively coupled with the low pressure shaft, and the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, were known in the art, and one skilled in the art could have substituted the unducted fan and unducted fan guide vanes arrangement, taught by Miller, for the primary fan of Sargisson, with no change in their respective functions, to yield predictable results, i.e., the unducted fan and unducted fan guide vanes arrangement would have facilitated increasing the efficiency of the unducted fan section while also decreasing an amount of noise generated by the unducted turbofan engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
Sargisson, i.v., Miller, is silent on a method of generating electric power with an electric machine, the method comprising: rotating a rotor of the electric machine relative to a stator of the electric machine with the shaft of the gas turbine engine during an operating condition of the gas turbine engine, wherein rotating the rotor of the electric machine relative to the stator of the electric machine comprises generating an electric machine power during the operating condition and generating a low pressure turbine power during the operating condition.
Newton teaches, in Fig. 1 and Col. 4, ll. 9 - 35, a similar gas turbine engine (10) having a low pressure turbine (19) operatively coupled with a shaft (20) and an electric machine (36 – generator – Col. 4, ll. 5 - 10) operatively coupled with the shaft (20), the electric machine (36) having a stator (non-rotating portion of generator) and a rotor (rotating portion of generator), the rotor rotatable with the shaft (20). Newton teaches, in Col. 1, ll. 60 – 65 and Col. 4, ll. 5 – 15, that the electric machine (36 - generator) rotor was independently driven by shaft (20) to provide electric power to the aircraft, i.e., the electric machine function as an electric generator. Newton teaches, in Col. 1, ll. 60 – 65 and Col. 4, ll. 5 – 15, a method of generating electric power with an electric machine (36), the method comprising: rotating a rotor (rotating portion of generator) of the electric machine (36) relative to a stator (non-rotating portion of generator) of the electric machine (36) with the shaft (20) of the gas turbine engine during an operating condition of the gas turbine engine (when the gas turbine engine was operating and generating propulsive thrust), wherein rotating the rotor of the electric machine (36) relative to the stator of the electric machine (36) comprises [The following is the designed and intended purpose of a low pressure turbine rotating the rotor of an electric machine/electric generator to generate power, i.e., electricity.] generating an electric machine power during the operating condition and generating a low pressure turbine power during the operating condition (when the gas turbine engine was operating and generating propulsive thrust). It has been held that “Under the principles of inherency, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will inherently perform the claimed process. In re King, 801 F.2d 1324, 231 USPQ 136 (Fed. Cir. 1986)”; MPEP 2112.02.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, with the a method of generating electric power with an electric machine, the method comprising: rotating a rotor of the electric machine relative to a stator of the electric machine with the shaft of the gas turbine engine during an operating condition of the gas turbine engine, wherein rotating the rotor of the electric machine relative to the stator of the electric machine comprises generating an electric machine power during the operating condition and generating a low pressure turbine power during the operating condition, taught by Nelson, because all the claimed elements, i.e., the three-stream gas turbine engine comprising: a primary fan, a mid-fan, and a low pressure turbine all coupled to the same shaft and an electric machine/generator having a stator and a rotor coupled to the shaft, were known in the art, in combination each one of the components would perform the same function as it did separately, and one skilled in the art could have combined the elements as claimed by known methods, with no change in their respective functions, to yield predictable results, i.e., during operation of the three-stream gas turbine engine combustion gases would have been expanded through the low pressure turbine resulting in mechanical rotational power to rotate the shaft and thus rotate the primary fan and the mid-fan to produce propulsive thrust and rotate the rotor of the electric machine/generator to generate electricity to power various electronics on the three-stream gas turbine engine and the aircraft propelled by the three-stream gas turbine engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(A).
Sargisson, i.v., Miller and Newton, teaches the invention as claimed and as discussed above; except, wherein a ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45.
Apke teaches, on Pg. 7 equation 3, a power balance equation to calculate turbine power (left-hand side) equal to the sum of the power requirements (right-hand side) of a compressor (equivalent to the mid-fan), fan (equivalent to the primary fan), and generator (equivalent to the electric machine power).
PNG
media_image1.png
375
1203
media_image1.png
Greyscale
As evidenced by Sheyman, in Col. 6, ll. 45 – 55, the equation to calculate the work performed by a compressor (wc). The compressor equation also applied to a fan like the primary fan and the mid-fan because a fan was essentially a single stage axial compressor. As evidenced by Sheyman, in Col. 6, l. 65 to Col. 7, l. 10, the equation to calculate the work output by a turbine (wt). The specific heat at constant pressure (Cp) for air was 1.0035 kJ/kg-K. The absolute temperature (in Kelvin) just upstream of (Tn) and just downstream of (Tn+1) a compressor or a turbine were used to calculate the respective work. Multiplying the work by the mass flow rate (ṁ) through the fan, compressor, or turbine yields the power required to drive the fan or compressor or yields the power output by the turbine. To simplify the calculations equation 3 assumed an “ideal” system where there were no losses, i.e., everything was 100% efficient. However, in real world systems nothing was 100% efficient. For example, Apke teaches, on Pg. 8, last paragraph, that conventional electric generators (conventional name for the claimed “electric machine”) operated between 35% - 65% efficiency, with the lower efficiency being for larger power draws, i.e., efficiency decreases as the magnitude of the electrical power output increased. At 50% efficiency for an electric generator/machine, when a turbine drove the electric generator/machine with 100 units of energy (in the form of mechanical rotational power) said electric generator/machine would have output only 50 units of energy (in the form of electricity). Examiner takes Official Notice that at the time of the invention it was well known in the gas turbine art that a fan, compressor, and turbine of a conventional gas turbine engine had isentropic efficiencies of around 90%. Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to be less than or equal to the maximum power output by the turbine. If the maximum power output by the turbine was normalized to one (1) then the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to equal one (1) or be less than (1). Using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.1, then the power required by the mid-fan plus the primary fan would have been 0.9. In other words, 90% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Conversely, using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.45, then the power required by the mid-fan plus the primary fan would have been 0.55. In other words, 55% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Obviously, the mid-fan and the primary fan having to split only 55% of the maximum power output by the low-pressure turbine would have only been able to compress a lower respective mass flows of air (ṁMF + ṁF) compared to a greater respective mass flows of air (ṁMF + ṁF) when the mid-fan and the primary fan had to split 90% of the maximum power output by the low-pressure turbine.
Therefore, the numerical value of the ratio of the electric machine power to the low-pressure turbine power was recognized as a result-effective variable, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that decreasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding increasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed greater mass flows of air. Conversely, the recognized result is that increasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding decreasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed lesser mass flows of air. Therefore, since the general conditions of the claim, i.e. that the gas turbine engine had a ratio of the electric machine power to the low-pressure turbine power, were disclosed in the prior art by Apke, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art at the time of the invention to modify the three-stream gas turbine engine of Sargisson, i.v., Miller and Newton, to have the ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45. Furthermore, the range of greater than 0.1 and less than 0.45 for the ratio of the electric machine power to the low pressure turbine power is recognized by the Examiner to be a very broad range, and a range that an ordinarily skilled artisan would have found to be obvious before the effective filing date of the claimed invention.
It has been held that “[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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980); MPEP 2144.05(II)(B). In Smith v. Nichols, 88 U.S. 112, 118-19 (1874) the Supreme Court held that “a change in form, proportions, or degree "will not sustain a patent". It was held that "It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions.", In re Williams, 36 F.2d 436, 438 (CCPA 1929); MPEP 2144.05(II)(A). The claimed numerical range of the ratio of the electric machine power to the low pressure turbine power was merely carrying forward of an original patented conception involving only change of proportions doing the same thing as the original invention, by substantially the same means, and is therefore not such an invention as will sustain a patent.
Regarding Claim 10, Sargisson teaches, in Fig. 1, the invention as claimed, including an operating condition (when the gas turbine engine was operating and generating propulsive thrust) of a gas turbine engine, the gas turbine engine being a three-stream gas turbine engine (Fig. 1) defining an axial direction (along longitudinal rotational axis of said three-stream gas turbine engine), the three-stream gas turbine engine comprising: a low pressure shaft (16); a primary fan (38) operatively coupled with the low pressure shaft (16); a mid-fan (12) positioned downstream of the primary fan (38) and operatively coupled with the low pressure shaft (16); a low pressure turbine (24) operatively coupled with the low pressure shaft (16), wherein the low pressure turbine [The following is the designed and intended purpose of the low pressure turbine.] generates a low pressure turbine power.
Sargisson is silent on said the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline.
Miller teaches, in Figs. 1 – 3, a similar turbofan gas turbine engine (10) having a primary fan (14, 40) is an unducted fan (shown in Fig. 1, Col. 3, ll. 55 - 60) having unducted fan blades (40) rotatable about a longitudinal centerline (12) and unducted fan guide vanes (50) not rotatable (fixed to outer casing 18) about the longitudinal centerline (12). Miller teaches, in Col. 3, ll. 60 – 67, “Additionally, the plurality of outlet guide vanes 50 are provided to increase an efficiency of the fan section 14 as well as to provide other benefits, such as, for example, decreasing an amount of noise generated by the turbofan engine 10, by directing a flow of air from the plurality of fan blades 40 of the fan section 14”.
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson with the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, taught by Miller, because all the claimed elements, i.e., a three-stream gas turbine engine defining an axial direction, the three-stream gas turbine engine comprising: a low pressure shaft, a primary fan operatively coupled with the low pressure shaft, a mid-fan positioned downstream of the primary fan and operatively coupled with the low pressure shaft, a low pressure turbine operatively coupled with the low pressure shaft, and the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, were known in the art, and one skilled in the art could have substituted the unducted fan and unducted fan guide vanes arrangement, taught by Miller, for the primary fan of Sargisson, with no change in their respective functions, to yield predictable results, i.e., the unducted fan and unducted fan guide vanes arrangement would have facilitated increasing the efficiency of the unducted fan section while also decreasing an amount of noise generated by the unducted turbofan engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
Sargisson, i.v., Miller, is silent on an electric machine for said gas turbine engine, the electric machine comprising: a stator; and a rotor rotatable relative to the stator to generate an electric machine power during an operating condition of the gas turbine engine, said shaft operatively coupled with the rotor of the electric machine, said low pressure turbine generates a low pressure turbine power when the electric machine generates the electric machine power.
Newton teaches, in Fig. 1 and Col. 4, ll. 9 - 35, a similar gas turbine engine (10) having a low pressure turbine (19) operatively coupled with a shaft (20) and an electric machine (36 – generator – Col. 4, ll. 5 - 10) operatively coupled with the shaft (20), the electric machine (36) having a stator (non-rotating portion of generator) and a rotor (rotating portion of generator), the rotor rotatable with the shaft (20), the rotor (rotating portion of generator) rotatable relative to the stator (non-rotating portion of generator) to generate an electric machine power (electricity) during an operating condition of the gas turbine engine, said low pressure turbine (19) generates a low pressure turbine power when the electric machine (36) generates the electric machine power. Newton teaches, in Col. 1, ll. 60 – 65 and Col. 4, ll. 5 – 15, that the electric machine (36 - generator) rotor was independently driven by shaft (20) which was driven by the low pressure turbine to provide electric power to the aircraft, i.e., the electric machine function as an electric generator. It has been held that “Under the principles of inherency, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will inherently perform the claimed process. In re King, 801 F.2d 1324, 231 USPQ 136 (Fed. Cir. 1986)”; MPEP 2112.02.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, with the electric machine comprising: a stator; and a rotor rotatable relative to the stator to generate an electric machine power during an operating condition of the gas turbine engine, said shaft operatively coupled with the rotor of the electric machine, said low pressure turbine generates a low pressure turbine power when the electric machine generates the electric machine power, taught by Nelson, because all the claimed elements, i.e., the three-stream gas turbine engine comprising: a primary fan, a mid-fan, and a low pressure turbine all coupled to the same shaft and an electric machine/generator having a stator and a rotor coupled to the shaft, were known in the art, in combination each one of the components would perform the same function as it did separately, and one skilled in the art could have combined the elements as claimed by known methods, with no change in their respective functions, to yield predictable results, i.e., during operation of the three-stream gas turbine engine combustion gases would have been expanded through the low pressure turbine resulting in mechanical rotational power to rotate the shaft and thus rotate the primary fan and the mid-fan to produce propulsive thrust and rotate the rotor of the electric machine/generator to generate electricity to power various electronics on the three-stream gas turbine engine and the aircraft propelled by the three-stream gas turbine engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(A).
Sargisson, i.v., Miller and Newton, teaches the invention as claimed and as discussed above; except, wherein a ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45.
Apke teaches, on Pg. 7 equation 3, a power balance equation to calculate turbine power (left-hand side) equal to the sum of the power requirements (right-hand side) of a compressor (equivalent to the mid-fan), fan (equivalent to the primary fan), and generator (equivalent to the electric machine power).
PNG
media_image1.png
375
1203
media_image1.png
Greyscale
As evidenced by Sheyman, in Col. 6, ll. 45 – 55, the equation to calculate the work performed by a compressor (wc). The compressor equation also applied to a fan like the primary fan and the mid-fan because a fan was essentially a single stage axial compressor. As evidenced by Sheyman, in Col. 6, l. 65 to Col. 7, l. 10, the equation to calculate the work output by a turbine (wt). The specific heat at constant pressure (Cp) for air was 1.0035 kJ/kg-K. The absolute temperature (in Kelvin) just upstream of (Tn) and just downstream of (Tn+1) a compressor or a turbine were used to calculate the respective work. Multiplying the work by the mass flow rate (ṁ) through the fan, compressor, or turbine yields the power required to drive the fan or compressor or yields the power output by the turbine. To simplify the calculations equation 3 assumed an “ideal” system where there were no losses, i.e., everything was 100% efficient. However, in real world systems nothing was 100% efficient. For example, Apke teaches, on Pg. 8, last paragraph, that conventional electric generators (conventional name for the claimed “electric machine”) operated between 35% - 65% efficiency, with the lower efficiency being for larger power draws, i.e., efficiency decreases as the magnitude of the electrical power output increased. At 50% efficiency for an electric generator/machine, when a turbine drove the electric generator/machine with 100 units of energy (in the form of mechanical rotational power) said electric generator/machine would have output only 50 units of energy (in the form of electricity). Examiner takes Official Notice that at the time of the invention it was well known in the gas turbine art that a fan, compressor, and turbine of a conventional gas turbine engine had isentropic efficiencies of around 90%. Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to be less than or equal to the maximum power output by the turbine. If the maximum power output by the turbine was normalized to one (1) then the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to equal one (1) or be less than (1). Using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.1, then the power required by the mid-fan plus the primary fan would have been 0.9. In other words, 90% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Conversely, using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.45, then the power required by the mid-fan plus the primary fan would have been 0.55. In other words, 55% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Obviously, the mid-fan and the primary fan having to split only 55% of the maximum power output by the low-pressure turbine would have only been able to compress a lower respective mass flows of air (ṁMF + ṁF) compared to a greater respective mass flows of air (ṁMF + ṁF) when the mid-fan and the primary fan had to split 90% of the maximum power output by the low-pressure turbine.
Therefore, the numerical value of the ratio of the electric machine power to the low-pressure turbine power was recognized as a result-effective variable, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that decreasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding increasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed greater mass flows of air. Conversely, the recognized result is that increasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding decreasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed lesser mass flows of air. Therefore, since the general conditions of the claim, i.e. that the gas turbine engine had a ratio of the electric machine power to the low-pressure turbine power, were disclosed in the prior art by Apke, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art at the time of the invention to modify the three-stream gas turbine engine of Sargisson, i.v., Miller and Newton, to have the ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45. Furthermore, the range of greater than 0.1 and less than 0.45 for the ratio of the electric machine power to the low pressure turbine power is recognized by the Examiner to be a very broad range, and a range that an ordinarily skilled artisan would have found to be obvious before the effective filing date of the claimed invention.
It has been held that “[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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980); MPEP 2144.05(II)(B). In Smith v. Nichols, 88 U.S. 112, 118-19 (1874) the Supreme Court held that “a change in form, proportions, or degree "will not sustain a patent". It was held that "It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions.", In re Williams, 36 F.2d 436, 438 (CCPA 1929); MPEP 2144.05(II)(A). The claimed numerical range of the ratio of the electric machine power to the low pressure turbine power was merely carrying forward of an original patented conception involving only change of proportions doing the same thing as the original invention, by substantially the same means, and is therefore not such an invention as will sustain a patent.
Regarding Claim 14, Sargisson teaches, in Fig. 1, the invention as claimed, including a three-stream gas turbine engine (Fig. 1) comprising: a low pressure shaft (16); a primary fan (38) operatively coupled with the low pressure shaft (16); a mid-fan (12) positioned downstream of the primary fan (38) and operatively coupled with the low pressure shaft (16), the mid-fan having mid-fan blades (two shown in Fig. 1); a low pressure turbine (24 - coupled with the shaft 16) wherein the low pressure turbine [The following is the designed and intended purpose of the low pressure turbine.] generates a low pressure turbine power.
Sargisson is silent on wherein the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline.
Miller teaches, in Figs. 1 – 3, a similar turbofan gas turbine engine (10) having a primary fan (14, 40) is an unducted fan (shown in Fig. 1, Col. 3, ll. 55 - 60) having unducted fan blades (40) rotatable about a longitudinal centerline (12) and unducted fan guide vanes (50) not rotatable (fixed to outer casing 18) about the longitudinal centerline (12). Miller teaches, in Col. 3, ll. 60 – 67, “Additionally, the plurality of outlet guide vanes 50 are provided to increase an efficiency of the fan section 14 as well as to provide other benefits, such as, for example, decreasing an amount of noise generated by the turbofan engine 10, by directing a flow of air from the plurality of fan blades 40 of the fan section 14”.
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson with the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, taught by Miller, because all the claimed elements, i.e., a three-stream gas turbine engine defining an axial direction, the three-stream gas turbine engine comprising: a low pressure shaft, a primary fan operatively coupled with the low pressure shaft, a mid-fan positioned downstream of the primary fan and operatively coupled with the low pressure shaft, a low pressure turbine operatively coupled with the low pressure shaft, and the primary fan is an unducted fan having unducted fan blades rotatable about a longitudinal centerline and unducted fan guide vanes not rotatable about the longitudinal centerline, were known in the art, and one skilled in the art could have substituted the unducted fan and unducted fan guide vanes arrangement, taught by Miller, for the primary fan of Sargisson, with no change in their respective functions, to yield predictable results, i.e., the unducted fan and unducted fan guide vanes arrangement would have facilitated increasing the efficiency of the unducted fan section while also decreasing an amount of noise generated by the unducted turbofan engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
Sargisson, i.v., Miller, is silent on an electric machine operatively coupled with the low pressure shaft, the electric machine having a stator and a rotor, the rotor rotatable with the low pressure shaft, wherein said low pressure turbine generates a low pressure turbine power when the electric machine generates the electric machine power.
Newton teaches, in Fig. 1 and Col. 4, ll. 9 - 35, a similar gas turbine engine (10) having a low pressure turbine (19) operatively coupled with a low pressure shaft (20) and an electric machine (36 – generator – Col. 4, ll. 5 - 10) operatively coupled with the low pressure shaft (20), the electric machine (36) having a stator (non-rotating portion of generator) and a rotor (rotating portion of generator), the rotor rotatable with the low pressure shaft (20), the rotor (rotating portion of generator) rotatable relative to the stator (non-rotating portion of generator) to generate an electric machine power (electricity) during an operating condition of the gas turbine engine, said low pressure turbine (19) generates a low pressure turbine power when the electric machine (36) generates the electric machine power. Newton teaches, in Col. 1, ll. 60 – 65 and Col. 4, ll. 5 – 15, that the electric machine (36 - generator) rotor was independently driven by low pressure shaft (20) which was driven by the low pressure turbine to provide electric power to the aircraft, i.e., the electric machine function as an electric generator. It has been held that “Under the principles of inherency, if a prior art device, in its normal and usual operation, would necessarily perform the method claimed, then the method claimed will be considered to be anticipated by the prior art device. When the prior art device is the same as a device described in the specification for carrying out the claimed method, it can be assumed the device will inherently perform the claimed process. In re King, 801 F.2d 1324, 231 USPQ 136 (Fed. Cir. 1986)”; MPEP 2112.02.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, with the electric machine comprising: a stator; and a rotor rotatable relative to the stator to generate an electric machine power during an operating condition of the gas turbine engine, said shaft operatively coupled with the rotor of the electric machine, said low pressure turbine generates a low pressure turbine power when the electric machine generates the electric machine power, taught by Nelson, because all the claimed elements, i.e., the three-stream gas turbine engine comprising: a primary fan, a mid-fan, and a low pressure turbine all coupled to the same shaft and an electric machine/generator having a stator and a rotor coupled to the shaft, were known in the art, in combination each one of the components would perform the same function as it did separately, and one skilled in the art could have combined the elements as claimed by known methods, with no change in their respective functions, to yield predictable results, i.e., during operation of the three-stream gas turbine engine combustion gases would have been expanded through the low pressure turbine resulting in mechanical rotational power to rotate the shaft and thus rotate the primary fan and the mid-fan to produce propulsive thrust and rotate the rotor of the electric machine/generator to generate electricity to power various electronics on the three-stream gas turbine engine and the aircraft propelled by the three-stream gas turbine engine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(A).
Sargisson, i.v., Miller and Newton, teaches the invention as claimed and as discussed above; except, wherein a ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45.
PNG
media_image1.png
375
1203
media_image1.png
Greyscale
Apke teaches, on Pg. 7 equation 3, a power balance equation to calculate turbine power (left-hand side) equal to the sum of the power requirements (right-hand side) of a compressor (equivalent to the mid-fan), fan (equivalent to the primary fan), and generator (equivalent to the electric machine power).
As evidenced by Sheyman, in Col. 6, ll. 45 – 55, the equation to calculate the work performed by a compressor (wc). The compressor equation also applied to a fan like the primary fan and the mid-fan because a fan was essentially a single stage axial compressor. As evidenced by Sheyman, in Col. 6, l. 65 to Col. 7, l. 10, the equation to calculate the work output by a turbine (wt). The specific heat at constant pressure (Cp) for air was 1.0035 kJ/kg-K. The absolute temperature (in Kelvin) just upstream of (Tn) and just downstream of (Tn+1) a compressor or a turbine were used to calculate the respective work. Multiplying the work by the mass flow rate (ṁ) through the fan, compressor, or turbine yields the power required to drive the fan or compressor or yields the power output by the turbine. To simplify the calculations equation 3 assumed an “ideal” system where there were no losses, i.e., everything was 100% efficient. However, in real world systems nothing was 100% efficient. For example, Apke teaches, on Pg. 8, last paragraph, that conventional electric generators (conventional name for the claimed “electric machine”) operated between 35% - 65% efficiency, with the lower efficiency being for larger power draws, i.e., efficiency decreases as the magnitude of the electrical power output increased. At 50% efficiency for an electric generator/machine, when a turbine drove the electric generator/machine with 100 units of energy (in the form of mechanical rotational power) said electric generator/machine would have output only 50 units of energy (in the form of electricity). Examiner takes Official Notice that at the time of the invention it was well known in the gas turbine art that a fan, compressor, and turbine of a conventional gas turbine engine had isentropic efficiencies of around 90%. Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to be less than or equal to the maximum power output by the turbine. If the maximum power output by the turbine was normalized to one (1) then the sum of the power required by the mid-fan plus the primary fan plus the electric machine/generator had to equal one (1) or be less than (1). Using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.1, then the power required by the mid-fan plus the primary fan would have been 0.9. In other words, 90% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Conversely, using basic math, if the ratio of the electric machine power to the low-pressure turbine power is equal to 0.45, then the power required by the mid-fan plus the primary fan would have been 0.55. In other words, 55% of the maximum power output by the low-pressure turbine would have gone to driving both the mid-fan and the primary fan to compress their respective mass flows of air. Obviously, the mid-fan and the primary fan having to split only 55% of the maximum power output by the low-pressure turbine would have only been able to compress a lower respective mass flows of air (ṁMF + ṁF) compared to a greater respective mass flows of air (ṁMF + ṁF) when the mid-fan and the primary fan had to split 90% of the maximum power output by the low-pressure turbine.
Therefore, the numerical value of the ratio of the electric machine power to the low-pressure turbine power was recognized as a result-effective variable, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that decreasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding increasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed greater mass flows of air. Conversely, the recognized result is that increasing the numerical value of the ratio meant that the mid-fan and the primary fan would have been driven by a corresponding decreasing percentage of the maximum power output by the low-pressure turbine so that they would have compressed lesser mass flows of air. Therefore, since the general conditions of the claim, i.e. that the gas turbine engine had a ratio of the electric machine power to the low-pressure turbine power, were disclosed in the prior art by Apke, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art at the time of the invention to modify the three-stream gas turbine engine of Sargisson, i.v., Miller and Newton, to have the ratio of the electric machine power to the low pressure turbine power is greater than 0.1 and less than 0.45. Furthermore, the range of greater than 0.1 and less than 0.45 for the ratio of the electric machine power to the low pressure turbine power is recognized by the Examiner to be a very broad range, and a range that an ordinarily skilled artisan would have found to be obvious before the effective filing date of the claimed invention.
It has been held that “[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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980); MPEP 2144.05(II)(B). In Smith v. Nichols, 88 U.S. 112, 118-19 (1874) the Supreme Court held that “a change in form, proportions, or degree "will not sustain a patent". It was held that "It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions.", In re Williams, 36 F.2d 436, 438 (CCPA 1929); MPEP 2144.05(II)(A). The claimed numerical range of the ratio of the electric machine power to the low pressure turbine power was merely carrying forward of an original patented conception involving only change of proportions doing the same thing as the original invention, by substantially the same means, and is therefore not such an invention as will sustain a patent.
Re Claims 3 and 11, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above; except, (Claim 3) wherein generating the electric machine power during the operating condition comprises generating the electric machine power during the operating condition in kilowatts, and wherein generating the low pressure turbine power during the operating condition comprises generating the low pressure turbine power during the operating condition in horsepower and (Claim 11) wherein the electric machine power is in kilowatts, and wherein the low pressure turbine power is in horsepower. Webster’s Ninth New Collegiate Dictionary, published in 1990 defined horsepower as “2: a unit of power equal in the U.S. to 746 watts and nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second”, defined kilowatt as “1000 watts”, and defined watt as “the absolute meter-kilogram second unit of power equal to the work done at the rate of one absolute joule per second or to the rate of work represented by a current of one ampere under a pressure of one volt and taken as the standard in the U.S.”. It was a scientific fact that the SI unit for work was kJ/kg (kilojoule / kilogram) and the SI unit for mass flow rate was kg/s (kilogram / second) resulting in the SI unit for power being kJ/s which converts to horsepower (Hp) by multiplying the numerical value of the power in kJ/s by 1.341 to convert the numerical value of the power into horsepower (Hp) units. [Note: The following well-known in the art statement is taken to be admitted prior art because Applicant failed to traverse Examiner’s assertion of Official Notice in the Office Action mailed on 07/17/2025 in Applicant’s reply filed on 09/29/2025. MPEP 2144.03(C)] Examiner takes Official Notice that, at the time of the invention, horsepower was one of the conventional units of power used to quantify the output power of a low pressure turbine and kilowatts was one of the conventional units of power used to quantify the output power of electric machine/generator.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, and Apke, to quantify the output power of the low pressure turbine in horsepower (Hp) and to quantify the output power of the electric machine/generator in kilowatts (kW) because horsepower (Hp) and kilowatts (kW) were conventional units of power used to quantify the output power of turbines and electric machine/generator, respectively.
Re Claim 15, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above, including wherein the electric machine is positioned aft of the mid-fan and aft of the low pressure turbine along an axial direction, and wherein the electric machine is positioned inward of a core duct along a radial direction.
As shown in Newton Fig. 1, the electric machine (36) was positioned aft of the mid-fan (13) and aft of the low pressure turbine (19) along an axial direction (central longitudinal axis), and wherein the electric machine (36) was positioned inward of a core duct (14-15-16-17-18-19) along a radial direction (direction perpendicular to the central longitudinal axis).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that in the combination of Sargisson, i.v., Miller, Newton, and Apke, the electric machine would have been positioned aft of the mid-fan and aft of the low pressure turbine along an axial direction, and wherein the electric machine would have been positioned inward of a core duct along a radial direction similar to the arrangement taught by Newton.
Sargisson, i.v., Miller, Newton, and Apke, as discussed above, is silent on wherein the electric machine power is in kilowatts, and wherein the low pressure turbine power is in horsepower. Webster’s Ninth New Collegiate Dictionary, published in 1990 defined horsepower as “2: a unit of power equal in the U.S. to 746 watts and nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second”, defined kilowatt as “1000 watts”, and defined watt as “the absolute meter-kilogram second unit of power equal to the work done at the rate of one absolute joule per second or to the rate of work represented by a current of one ampere under a pressure of one volt and taken as the standard in the U.S.”. It was a scientific fact that the SI unit for work was kJ/kg (kilojoule / kilogram) and the SI unit for mass flow rate was kg/s (kilogram / second) resulting in the SI unit for power being kJ/s which converts to horsepower (Hp) by multiplying the numerical value of the power in kJ/s by 1.341 to convert the numerical value of the power into horsepower (Hp) units. [Note: The following well-known in the art statement is taken to be admitted prior art because Applicant failed to traverse Examiner’s assertion of Official Notice in the Office Action mailed on 07/17/2025 in Applicant’s reply filed on 09/29/2025. MPEP 2144.03(C)] Examiner takes Official Notice that, at the time of the invention, horsepower was one of the conventional units of power used to quantify the output power of a low pressure turbine and kilowatts was one of the conventional units of power used to quantify the output power of electric machine/generator.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, and Apke, to quantify the output power of the low pressure turbine in horsepower (Hp) and to quantify the output power of the electric machine/generator in kilowatts (kW) because horsepower (Hp) and kilowatts (kW) were conventional units of power used to quantify the output power of turbines and electric machine/generator, respectively.
Re Claims 4, 5, 12, 13, 16, and 17, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above; except, (Claim 4) wherein rotating the rotor of the electric machine relative to the stator of the electric machine further comprises generating an electrical power output by the electric machine from 100 kilowatts to 3,000 kilowatts and a voltage in volts of direct current from 270 volts of direct current to 3,000 volts of direct current during the operating condition and (Claims 12 and 16) wherein in generating the electric machine power, the electric machine is configured to provide an electrical power output from 100 kilowatts to 3,000 kilowatts and a voltage in volts of direct current from 270 volts of direct current to 3,000 volts of direct current during the operating condition (Claim 16) of the three-stream gas turbine engine and (Claims 5, 13, and 17) wherein a power to voltage ratio of the electric machine is equal to or greater than 0.3 and less than or equal to 2.0 during the operating condition.
[Note: The following well-known in the art statement is taken to be admitted prior art because Applicant failed to traverse Examiner’s assertion of Official Notice in the Office Action mailed on 07/17/2025 in Applicant’s reply filed on 09/29/2025. MPEP 2144.03(C)] Examiner takes Official Notice that it was well known in the art that the equation for electrical power (P) was P = I x V, where P = power in watts, I = current in amps, and V = volts. Accordingly, the power to voltage ratio of the electric machine would have been the kiloamps generated: P [kW] / V [volt] = I [kiloAmps].
Therefore, the power to voltage ratio was recognized as a result-effective variable, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that the power to voltage ratio produces the current (measured in kiloAmps) generated by the electric machine that was available to power one or more loads: P [kW] / V [volt] = I [kiloAmps]. When P = 100 kW and V = 270 Volts, the calculated output current was 0.37 kAmps. When P = 1 MW = 1,000 kW and V = 3,000 Volts, the calculated output current was 0.33 kAmps. Therefore, since the general conditions of the claim, i.e., that power to voltage ratio was just the current in kiloAmps generated by the electric machine, were disclosed in the prior art by the equation to calculate electric power, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art at the time of the invention to modify the electric machine taught by Sargisson, i.v., Miller, Newton, and Apke, to have (Claim 4) wherein rotating the rotor of the electric machine relative to the stator of the electric machine further comprises generating an electrical power output by the electric machine from 100 kilowatts to 3,000 kilowatts and a voltage in volts of direct current from 270 volts of direct current to 3,000 volts of direct current during the operating condition and (Claims 12 and 16) wherein in generating the electric machine power, the electric machine is configured to provide an electrical power output from 100 kilowatts to 3,000 kilowatts and a voltage in volts of direct current from 270 volts of direct current to 3,000 volts of direct current during the operating condition (Claim 16) of the three-stream gas turbine engine and (Claims 5, 13, and 17) wherein a power to voltage ratio of the electric machine is equal to or greater than 0.3 and less than or equal to 2.0 during the operating condition. As discussed above, the claimed electrical power output divided by the claimed voltages yields a power to voltage ratio of 0.33 kiloAmps to 0.37 kiloAmps which is within the claimed range.
Note 1: It has been held that “[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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980); MPEP 2144.05(II)(B). In Smith v. Nichols, 88 U.S. 112, 118-19 (1874) the Supreme Court held that “a change in form, proportions, or degree "will not sustain a patent". It was held that "It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions.", In re Williams, 36 F.2d 436, 438 (CCPA 1929); MPEP 2144.05(II)(A).
Re Claim 8, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above, and Sargisson further teaches, in Fig. 1, wherein the three-stream gas turbine engine (Fig. 1) further comprises: an engine core (18-20-22-24); a core cowl (56) surrounding the engine core (18-20-22-24); a core duct (54) being defined between the engine core (18-20-22-24) and the core cowl (56); a fan cowl (50) surrounding the core cowl (56); a fan duct (52) being defined between the core cowl (56) and the fan cowl (50); and an inlet duct (annular inlet defined between 42 and 50) in flow communication with the core duct (54) and the fan duct (52), the inlet duct being defined between the engine core (18-20-22-24) and the fan cowl (50), the mid-fan (12) being positioned within the inlet duct (shown in Fig. 1), wherein the gas turbine engine is an unducted turbofan engine (refer to Claim 1 rejection above).
Claims 2 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Sargisson et al. (4,446,696) in view of Miller et al. (11,391,298) in view of Newton et al. (5,867,979) in view of Apke, “Boeing 787: All Electric Engines”, ASEN 5063, December 15, 2009, hereinafter “Apke” as evidenced by Sheyman et al. (6,390,785) in further view of Airplane Flying Handbook, FAA-H-8083-3A, U.S. Department of Transportation, Federal Aviation Administration (FAA), 2004, hereinafter “FAA-H-8083-3A”.
Re Claims 2 and 20, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above; except, wherein the operating condition is a flight idle operating condition.
FAA-H-8083-3A, on Pg. G-6, defined flight idle operating condition as “Engine speed, usually in the 70-80 percent range, for minimum flight thrust”. Therefore, every aircraft engine that was designed and operated to produce propulsive thrust could be operated in the conventional “flight idle operating condition”.
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, and Apke, with the flight idle operating condition, taught by FAA-H-8083-3A, because all the claimed elements, i.e., the three-stream gas turbine engine comprising: a primary fan, a mid-fan, and a low pressure turbine all coupled to the same shaft and an electric machine/generator having a stator and a rotor coupled to the shaft and the flight idle operating condition, were known in the art, and one skilled in the art could have substituted the flight idle operating condition, taught by FAA-H-8083-3A, for the operating condition of Sargisson, i.v., Miller, Newton, and Apke, with no change in their respective functions, to yield predictable results, i.e., when set to the flight idle operating condition the three-stream gas turbine engine would have generated the minimum propulsive thrust to maintain flight, i.e., aircraft speed is greater than the stall speed so the wings generate sufficient lift, and would have been used during descent and approach for landing on a runway of an airport. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
Claims 7 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Sargisson et al. (4,446,696) in view of Miller et al. (11,391,298) in view of Newton et al. (5,867,979) in view of Apke, “Boeing 787: All Electric Engines”, ASEN 5063, December 15, 2009, hereinafter “Apke” as evidenced by Sheyman et al. (6,390,785) in further view of “PM generator dual DC output Model 5613” [https://meggitt.com/wp-content/uploads/2019/09/5613.pdf posted September 2019], hereinafter “Model-5613” in view of W.N. Dalton III, “Ultra High Bypass Ratio Low Noise Engine Study”, NASA/CR-2003-212523, National Aeronautics and Space Administration, November 2003, hereinafter “Dalton”.
Re Claim 7, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above; except, (Claims 7 and 18) wherein the three-stream gas turbine engine further defines an electric machine tip radius to low pressure turbine last stage hub radius ratio as being equal to or greater than 0.1 and less than or equal to 1.0, (Claim 7) the electric machine tip radius to low pressure turbine last stage hub radius ratio being defined by a radius spanning between a longitudinal axis defined by the three-stream gas turbine engine and an outermost point of the rotor of the electric machine to a radius spanning between the longitudinal axis and an outermost point of a hub of a last stage turbine blade of the low pressure turbine.
PNG
media_image2.png
796
936
media_image2.png
Greyscale
Model-5613 teaches, in enlarged portion of Section A-A figure (marked-up below), an electric generator for an air vehicle (in this case a long range missile, i.e., cruise missile) having a rotor assembly and a stator/housing assembly where the length of the electric machine spanning between a leading edge and a trailing edge of the rotor of the electric machine along the axial direction was about 1.8 inches and the radius spanning between a longitudinal axis (rotational axis) and an outermost point of the rotor of the electric machine was about 0.9 inches.
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, and Apke, with the dimensions of the electric machine, taught by Model-5613, because all the claimed elements, i.e., the three-stream gas turbine engine having a low pressure turbine operatively coupled with a shaft, a gas turbine engine having a low pressure turbine operatively coupled with a shaft that was connected to an electric machine located within a tailcone downstream of the trailing edge of the hub of a last stage turbine blade of the low pressure turbine, and an electric machine having a length of spanning between a leading edge and a trailing edge of the rotor of the electric machine along the axial direction was about 1.8 inches and the radius spanning between a longitudinal axis (rotational axis) and an outermost point of the rotor of the electric machine was about 0.9 inches, were known in the art, and one skilled in the art could have substituted the electric machine rotor length and radius, taught by Model-5613, for the unknown electric machine length and radius of Sargisson, i.v., Miller, Newton, and Apke, with no change in their respective functions, to yield predictable results, i.e., in ‘generator mode’ the low pressure turbine would have rotated the rotor of the electric machine via the shaft to generate electricity and the electric machine tip radius (about 0.9 inches) would have been defined by a radius spanning between a longitudinal axis defined by the three-stream gas turbine engine and an outermost point of the rotor of the electric machine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
Dalton teaches, in Fig. 1 on Pg. 41, a similar gas turbine engine having a maximum diameter of 82.37 inches, fan diameter of 70.79 inches and maximum length of 141.77 inches from leading edge of fan nacelle to trailing edge of core nacelle. As shown below in the enlarged portion of Dalton - Fig. 1, the low pressure turbine (labeled) had three stages with a length of about 6 inches spanning between a leading edge of a hub of a first stage turbine blade (labeled) of the low pressure turbine to a trailing edge of a hub of a last stage turbine blade (labeled) of the low pressure turbine and a radius of about 9 inches spanning between the longitudinal axis and an outermost point of a hub of a last stage turbine blade of the low pressure turbine. Dalton - Fig. 1 further teaches a hollow tailcone (labeled) having a length of about 17 inches. As shown in Newton – Fig. 1, the electric machine (36 - motor/generator) was located inside the hollow tailcone.
PNG
media_image3.png
638
964
media_image3.png
Greyscale
It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, Apke, and Model-5613, with the dimensions of the low pressure turbine, taught by Dalton, because all the claimed elements, i.e., the three-stream gas turbine engine having a low pressure turbine operatively coupled with a shaft and a three-stage low pressure turbine having a length of about 6 inches spanning between a leading edge of a hub of a first stage turbine blade to a trailing edge of a hub of a last stage turbine blade of the low pressure turbine and a radius of about 9 inches spanning between the longitudinal axis and an outermost point of a hub of a last stage turbine blade of the low pressure turbine, were known in the art, and one skilled in the art could have substituted the low pressure turbine length and radius, taught by Dalton, for the unknown low pressure turbine length and radius of Sargisson, i.v., Miller, Newton, Apke, and Model-5613, with no change in their respective functions, to yield predictable results, i.e., the low pressure turbine would have converted a portion of the thermal and kinetic energy of the combustion gases into mechanical rotational power by expanding the high pressure and high temperature combustion gases upstream of the leading edge of a hub of a first stage turbine blade to a lower pressure and lower temperature downstream of the trailing edge of a hub of a last stage turbine blade of the low pressure turbine the low pressure turbine last stage hub radius (about 9 inches) spanning between the longitudinal axis and an outermost point of a hub of a last stage turbine blade of the low pressure turbine. KSR, 550 U.S. 398 (2007), 82 USPQ2d at 1395; MPEP 2143(B).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that the combination of Sargisson, i.v., Miller, Newton, Apke, Model-5613, and Dalton, taught the claimed electric machine tip radius to low pressure turbine last stage hub radius ratio because about 0.1 (0.9 / 9 = 0.1) was within the claimed range of equal to or greater than 0.1 and less than or equal to 1.0.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Sargisson et al. (4,446,696) in view of Miller et al. (11,391,298) in view of Newton et al. (5,867,979) in view of Apke, “Boeing 787: All Electric Engines”, ASEN 5063, December 15, 2009, hereinafter “Apke” as evidenced by Sheyman et al. (6,390,785) as applied to Claim 1 above, and further in view of “PM generator dual DC output Model 5613” [https://meggitt.com/wp-content/uploads/2019/09/5613.pdf posted September 2019], hereinafter “Model-5613”.
Re Claim 9, Sargisson, i.v., Miller, Newton, and Apke, teaches the invention as claimed and as discussed above, and Sargisson further teaches, in Fig. 1, wherein the three-stream gas turbine engine (Fig. 1) defines a radial direction (direction perpendicular to the rotational longitudinal axis of the three-stream gas turbine engine), the three-stream engine further comprising: an engine core (18-20-22-24); a core cowl (56) surrounding the engine core (18-20-22-24); a core duct (54) being defined between the engine core (18-20-22-24) and the core cowl (56); a fan cowl (50) surrounding the core cowl (56); a fan duct (52) being defined between the core cowl (56) and the fan cowl (50); and an inlet duct (annular inlet defined between 42 and 50) in flow communication with the core duct (54) and the fan duct (52), the inlet duct being defined between the engine core (18-20-22-24) and the fan cowl (50), wherein the gas turbine engine is an unducted turbofan engine (refer to the Claim 1 rejection above).
Sargisson, i.v., Miller, Newton, and Apke, as discussed above, is silent on the electric machine being directly mechanically coupled with the shaft. Model-5613 teaches, in Section A-A figure on Pg. 2, splines on the electric machine/generator rotor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Sargisson, i.v., Miller, Newton, and Apke, with the splines on the electric machine/generator rotor, taught by Model-5613, because it was conventional in the art to directly mechanically couple the electric machine to a rotating shaft by mating male splines on the rotor shaft with female splines on the rotating shaft, or vice versa.
Sargisson, i.v., Miller, Newton, Apke, and Model-5613, as discussed above, is silent on the electric machine being positioned inward of the core duct along the radial direction. However, as shown in Newton Fig. 1, the electric machine/generator (36) was concentric with the longitudinal rotational axis of the gas turbine engine and therefore the electric machine/generator (36) was positioned inward of the core duct (14-15-16-17-18-19) along the radial direction (direction perpendicular to the rotational longitudinal axis of the gas turbine engine).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, that the combination of Sargisson, i.v., Miller, Newton, Apke, and Model-5613, would have had the electric machine being positioned inward of the core duct along the radial direction to facilitate locating the electric machine/generator within the empty space inside the tailcone and downstream of the last stage of the low pressure turbine so that the exhaust gases would have flowed over and around the outer surface of the tailcone.
Response to Arguments
Applicant's arguments filed 02/20/2026 have been fully considered and to the extent possible have been addressed in the rejections above, at the appropriate locations.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LORNE E MEADE whose telephone number is (571)270-7570. The examiner can normally be reached Monday - Friday 8-5 EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Phutthiwat Wongwian can be reached at 571-270-5426. 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.
/LORNE E MEADE/Primary Examiner, Art Unit 3741